Cx Assist ant TM Sequences of Operation...unit that are connected by a direct expansion (DX)...

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Cx AssistantTM

Sequences of Operation

Developed by

CTG Energetics, Inc.

Under contract to

Pacific Gas and Electric Company

April 2004

Cx Assistant’s Sequence of Operation April 2004

IMPORTANT NOTICE: This sample document is provided for instructional purposes only. CCC is not rendering advice concerning any commission project or practices. This document is neither approved nor intended to serve as a standard form. The user of these documents should confer with qualified advisors with respect to its commissioning and other documentation.


About Cx Assistant

Energy Design Resources' Commissioning Assistant is a web-based tool designed to provide project-specific building commissioning information to design teams. The tool currently enables the users to accomplish the following six functions:

1. Evaluate probable commissioning cost.

2. Identify the appropriate commissioning scope for each project, and develop sample scope documents.

3. Develop a sample design intent document with specific inputs from their projects.

4. Develop a sample basis of design document with specific inputs from their projects.

5. Access sample commissioning specifications related to specific inputs for his/her construction project.

6. View sample sequence of operations for their HVAC equipment based upon the requirements in California Title 24- 2005.

Modules are planned to be added in 2005 that will generate a Commissioning Plan, a Training Plan and a Systems Manual.


About EDR

Energy Design Resources offers a valuable palette of energy design tools and resources that help make it easier to design and build energy-efficient commercial and industrial buildings in California. The goal of this effort is to educate architects, engineers, lighting designers, and developers about techniques and technologies that contribute to energy efficient nonresidential new construction. Additionally, design tools that reduce the time you spend evaluating the energy use impact of your design decisions are provided here at no cost. Plus, we've designed them to be quick and easy to learn so you can begin designing more efficiently today.

Did you know: Even though California already leads the nation in energy-efficient building construction, the state will again be tightening its energy standards for new construction in 2005?

We want to help make it as easy as possible for you to transition to these new regulations. Perhaps more importantly, we also want to help you exceed these standards to create more efficient buildings that will be less expensive to own and operate. This approach should make owners, tenants, and clients happy.

The development of Energy Design Resources is funded by California utility customers and administered by Pacific Gas and Electric Company, San Diego Gas & Electric, Southern California Edison, and Southern California Gas under the auspices of the California Public Utilities Commission.


Table of Contents

1. Split System Units with DX Cooling 2. Economy Heat Pump Packaged Units 3. Evaporative Cooler Units 4. Packaged VVT Units 5. Standard Packaged Units 6. Four Pipe Fan Coil Units 7. Constant Air Volume (CAV) Units with Central Plant 8. Variable Air Volume (VAV Units with Air-Cooled Chiller 9. Variable Air Volume (VAV Units with Water-Cooled Chiller 10. Water Source Heat Pump System


Notes: [SPLIT SYSTEM WITH DX COOLING]. The system consists of an indoor fan coil unit and an outdoor condensing unit that are connected by a direct expansion (DX) refrigerant loop. The fan coil unit has a supply fan and a cooling coil. The outdoor unit has a compressor, a heat rejection fan, and a condensing coil. This system is designed to provide cooling for machinery such as electrical transformers and computer equipment. The system does not include ventilation air. Vendor-provided packaged controls operate the equipment.

Appropriate reference in the specifications should be made for products that are integrated with these sequences including packaged units, economizers, and the like.

Disclaimer: The files produced by Cx Assistant are not suitable for bidding without prior review by the project's architect or engineer of record. The information is provided to the user as a sample document that is based upon a hypothetical system design. It may need to be modified in order to suit specific project requirements prior to inclusion in contract documents.

SEQUENCE OF OPERATION: SPLIT SYSTEM WITH DX COOLING

SEQUENCES OF OPERATION

1. Occupied Periods (Normal occupied operation): The zone is typically un-occupied, but the unit is enabled to run, as needed, 24 hours per day, 7 days per week.

2. Fan Operation: Run the indoor unit fan when the unit is in cooling mode.

Split System with DX Cooling 1


3. Temperature Control: A thermostat is used to determine when the space requires cooling. Set the thermostat for the following ranges:

a. Cooling: 60° F to 85° F. The default is 75° F. Maintain a dead band of 1°F to cycle the system on and off.

4. Fire Alarm: Interface system with the fire alarm controls. When the fire alarm control initiates a fire alarm, shut down the supply fan by a hardwired contact. Once reset, the unit will resume the current mode of operation.

5. Shutdown: The fan and compressor will stop when the system goes to unoccupied mode or when there is no call for cooling. The fan runs for 1 minute after a shutdown has been initiated.

6. Fire Alarm: For fire alarm mode operation, the unit will be shut down by hardwired contact. Once reset, the affected unit will resume the current mode of operation.

7. Cooling Mode Enable: When the thermostat generates a call for cooling, enable the unit’s compressor. The supply air setpoint in cooling mode is 55° F. Allow the unit’s controls to cycle the compressor to supply the needed air temperature. The package unit’s internal controls protect the equipment from excessive operating conditions including low oil pressure, high discharge pressure, low suction pressure, excessive cycling (more than one every 5 minutes or 6 cycles/hour), low refrigerant charge, high and low refrigerant temperatures, etc. If excessive operating conditions occur, shut down the unit to protect it.

8. Cooling Mode Shutdown: If a call for cooling has been satisfied, a system failure has occurred, or the supply air temperature has fallen below 50° F for more than one minute, cycle the compressor off. After the compressor has shut down, continue running the supply fan for 5 minutes before shutting it down.

9. Space Temperature Alarm: An independent thermostat will sound an alarm if the room temperature rises above 78° F for more than 5 minutes.

POINTS TABLE

Key: X Indicates type of point (only 1 point is needed)

CU Outdoor condensing unit with indoor fan coil (i.e. split system)

Note that these points are typically hard wired and not readily accessible

Point Name AI AO DI DO Analog Software Value

Digital Software Value

Other Software Value



CU Space Temperature Alarm Setpoint-Cooling

X

CU Cooling Alarm X

CU Cooling Enable X

CU Mode X

CU Fire Alarm X

CU Space Temperature Setpoint-Cooling

X

CU Space Temperature Setpoint-Deadband

X



Notes: The system consists of multiple packaged HVAC units each serving one or more zones in the building. The packaged units each have a supply fan, direct expansion (DX) cooling and heating (i.e. a heat pump), and an electric resistance back-up heater. The unit provides 100% outdoor air (i.e. “once-through” system). The system is controlled with vendor-provided packaged controls.



ECONOMY HEAT PUMP PACKAGED UNIT

SEQUENC

1.

ES OF OPERATION

Occupied Periods (Normal occupied operation): Operate the system on a programmed occupancy schedule from 7:00 AM to 6:00 PM, M-F. These periods are considered “occupied periods”. During occupied periods, run the system inOccupied Mode, including enabling the packaged unit fans. NOTE: Schedule occupied start time 1 hour before the building is expected to be occupied (for Title 24 required purge).

2. ant calls

3.

Unoccupied Periods: All hours not included in an occupied period are part of an “unoccupied period”. During these periods, the system is available for tenas needed but is not running unless commanded. Fan Operation (Ventilation Mode): Run the unit fans in all modes except unoccupied mode.

Economy Heat Pump Packaged Unit 4


4. Temperature Control: A thermostat is used to determine each space’s required mode. Set each thermostat for the following ranges:

a. Occupied Heating: 55° F to 73° F during occupied hours. The default is 73° F.

b. Occupied Cooling: 73° F to 85° F during occupied hours. The default is 78° F.

Maintain a deadband of at least 5° F between heating and cooling setpoints. When

5. rm ardwired contact.

6.

ntrols protect the equipment from

and h

ng

w

8.

9. on

system in the occupied mode for one hour. At the end of the hour, return the system to unoccupied mode.

the system is operating, the thermostat is either in heating, cooling, or ventilation mode. If a space’s temperature is more than 1.5° F higher than its temperature setpoint, the thermostat generates a call for cooling. Likewise, if a space’s temperature is more than 1.5° F lower than its temperature setpoint, the thermostat generates a call for heating. Otherwise, the thermostat generates a callfor ventilation mode. During unoccupied hours, set the heating setpoint default to55° F (adjustable) and the cooling setpoint default to 85° F (adjustable). Fire Alarm: Interface system with the fire alarm controls. When the fire alacontrol initiates a fire alarm, shut down the supply fan by a hOnce reset, the affected unit(s) will resume the current mode of operation. Cooling Mode Enable: When the zone thermostat generates a call for cooling, enable the unit’s compressor. The cooling mode supply air setpoint is 55° F. Allow the package unit’s controls to cycle the compressor to supply the needed air temperature. The package unit’s internal coexcessive operating conditions including low oil pressure, high discharge pressure, low suction pressure, excessive cycling (more than one every 5 minutes or 6 cycles/hour), low refrigerant charge, high and low refrigerant temperatures, etc. If excessive operating conditions occur, shut down the unit to protect it.

7. Heating Mode Enable: When the zone thermostat generates a call for heating outdoor temperature is above 42° F, switch the packaged unit heat pump to switcto heating mode. If the outdoor temperature is less than 42° F, lock out the heat pump t and enable the back-up resistance heater to supply heat to the zone. The package unit’s internal controls protect the equipment from excessive operaticonditions including low oil pressure, high discharge pressure, low suction pressure, excessive cycling (more than one every 5 minutes or 6 cycles/hour), lorefrigerant charge, high and low refrigerant temperatures, etc. If excessive operating conditions occur, shut down the unit to protect it. Compressor Shutdown: If a call for cooling or heating has ended, a system failure has occurred, or the supply air temperature has fallen below 40° F (or risen above 120° F) for more than one minute, cycle the compressor off. After the compressorhas shut down, continue running the supply fan for 5 minutes before shutting it down (even if an unoccupied period begins). Unoccupied Mode: Unoccupied mode occurs during unoccupied periods. In unoccupied mode, disable the packaged unit. When a thermostat’s override buttis depressed during an unoccupied period, operate the



10. Warm-up Mode: Identify Warm-up start time using an optimal start strategy based on average zone temperature. If the average zone temperature is less than

pied mode. Terminate the warm-up mode after the average zone temperature has risen above 70°F (adjustable) and transition the system to

pied mode. 11. Cool-down Mode: Identify cool-down start time using an optimal start strategy

ge zone temperature. If the average zone temperature is greater than 79°F (adjustable) at the projected start of the cool-down period, enable the

ter the average zone temperature has fallen below 78°F (adjustable) and transition the system to

ed mode ( h mo12. Night Setback/Setup: Enable system ur pie ds in the

warm-up or cool-down mode if the s perature falls below 55°F (adj.) or ve 85°F j Sto th when the thermostat reaches either its

upied heating setpoints.

s type of oin

nt is needed for each unit – a total of “n” points are needed

T = tsi air m ratu )

aged unit

ints are typically hard-wired and not rea y accessible

AI AO DI DO Analog Software

lue

Digital Software

alue


69°F (adjustable) at the projected start of the warm-up period, enable the package unit in occu

occupied mode (if scheduled) or to unoccu

based on avera

packaged unit in occupied mode. Terminate the cool-down mode af

occupi if sc eduled) or to unoccupied de. ing unoccu operation d

pace temd perio

rises abo (ad .). p e systemunoccupied cooling or unocc

Points Table

Key: X Indicate p t (only 1 point is needed)

n Indicates type of point (1 poifor this line item)

OA outside air (OA

PKG pack

ou de te pe re

Note that these po dil

Point Name

Va VOA DB Temp n

PKG-n Cooling Alarm n

PKG-n Fan Enable n

PKG-n Heating Alarm n

PKG-n Mode n

PKG Fire Alarm X

PKG Warm-up Mode Low Temp Setpoint

n



PKG Cool -dowMode High Temp Setpoint

n n

PKG-n Override n

PKG-n Space Temperature Setpoint-Cooling

n

PKG-n Space Temperature Setpoint-Heating

n

PKG-n Space Temperature Unoccupied Setpoint-Cooling

n

PKG-n Space Temperature Unoccupied Setpoint-Heating

n

PKG-n Space Temperature Setpoint-Deadband

n



Notes: The system consists of multiple packaged HVAC units each serving one or more zones in the building. The packaged units each have a supply fan, direct evaporative cooling and natural gas heating. The unit provides 100% outdoor air (i.e. “once-through” system). The system is controlled with vendor-provided packaged controls.



EVAPORATIVE COOLING PACKAGED UNIT


1. Occupied Periods (Normal occupied operation): Operate the system on a programmed occupancy schedule from 7:00 AM to 6:00 PM, M-F. These periods are considered “occupied periods”. During occupied periods, run the system in Occupied Mode, including enabling the packaged unit fans. NOTE: Schedule occupied start time 1 hour before the building is expected to be occupied (for Title 24 required purge).

2. Unoccupied Periods: All hours not included in an occupied period are part of an “unoccupied period”. During these periods, the system is available for tenant calls as needed but is not running unless commanded.

3. Fan Operation (Ventilation Mode): Run the unit fans in all modes except unoccupied mode.

Evaporative Cooler Units 8


4. Temperature Control: A thermostat is used to determine each space’s required mode. Set each thermostat for the following ranges:



Maintain a deadband of at least 5° F between heating and cooling setpoints. When the system is operating, the thermostat is either in heating, cooling, or ventilation mode. If a space’s temperature is more than 1.5° F higher than its temperature setpoint, the thermostat generates a call for cooling. Likewise, if a space’s temperature is more than 1.5° F lower than its temperature setpoint, the thermostat generates a call for heating. Otherwise, the thermostat generates a call for ventilation mode. During unoccupied hours, set the heating setpoint default to 55° F (adjustable) and the cooling setpoint default to 85° F (adjustable).

5. Fire Alarm: Interface system with the fire alarm controls. When the fire alarm control initiates a fire alarm, shut down the supply fan by a hardwired contact. Once reset, the affected unit(s) resume the current mode of operation.

6. Cooling Mode: When the zone thermostat generates a call for cooling, enable the evaporative cooler. Allow the packaged unit controls to operate the internal circulating pump that carries water to the cooling surface. Provide makeup water to the circulating pump basin as needed. The packaged unit’s internal controls protect the equipment from excessive operating conditions including low water level. If excessive operating conditions occur, shut off the circulating pump to protect it. When the call for cooling has ended, shut off the circulating pump.

7. Heating Mode Enable: When the zone thermostat generates a call for heating, the packaged unit will cycle on the gas heater to supply heat to the zone. The package unit’s internal controls protect the equipment from excessive operating conditions including high temperature, flame failure, excessive cycling (more than one every 5 minutes or 6 cycles/hour), low gas pressure, etc. If excessive operating conditions occur, shut down the unit to protect it.

8. Heating Mode Shutdown: If a call for heating has ended, a system failure has occurred, or the supply air temperature has risen above 120° F for more than one minute, cycle the heater off. After the heater has shut down, continue running the supply fan for 5 minutes before shutting it down (even if the unoccupied period begins)

9. Unoccupied Mode: Unoccupied mode occurs during unoccupied periods. In unoccupied mode, disable the packaged unit. When a thermostat’s override button is depressed during an unoccupied period, operate the system in the occupied mode for one hour. At the end of the hour, return the system to unoccupied mode.

10. Warm-up Mode: Identify Warm-up start time using an optimal start strategy based on average zone temperature. If the average zone temperature is less than 69°F (adjustable) at the projected start of the warm-up period, enable the packaged unit in heating mode. Terminate the warm-up mode after the average



zone temperature has risen above 70°F (adjustable) and transition the system to occupied mode (if scheduled) or to unoccupied mode.

11. Cool-down Mode: Identify cool-down start time using an optimal start strategy based on average zone temperature. If the average zone temperature is greater than 79°F (adjustable) at the projected start of the cool-down period, enable the unit in cooling mode. Terminate the cool-down mode after the average zone temperature has fallen below 78°F (adjustable) and transition the system to occupied mode (if scheduled) or to unoccupied mode.

12. Night Setback/Setup: Enable system operation during unoccupied periods in the warm-up or cool-down mode if the space temperature falls below 55°F (adj.) or rises above 85°F (adj.). Stop the system when the thermostat reaches either its unoccupied cooling or unoccupied heating setpoints.

Points Table

Key:

X Indicates type of point (only 1 point is needed)

n Indicates type of point (1 point is needed for each zone – a total of “n” points are needed for this line item)

PKG packaged unit

Note that these points are typically hard wired and not user accessible




PKG-n Fan Enable n

PKG-n Heating Alarm n

PKG-n Mode n

PKG Fire Alarm n

PKG Warm-up Mode Low Temp Setpoint

n

PKG Cool -down Mode High Temp Setpoint

n

PKG-n Override n

PKG-n Space Temperature Setpoint-Cooling

n



PKG-n Space Temperature Setpoint-Heating

n

PKG-n Space Temperature Unoccupied Setpoint-Cooling

n

PKG-n Space Temperature Unoccupied Setpoint-Heating

n

PKG-n Space Temperature Setpoint-Deadband

n



Notes: The system consists of multiple packaged roof top HVAC units each serving variable volume / variable temperature (VVT) zone equipment. The packaged units each have a supply fan, direct expansion (DX) cooling, natural gas heating, outside air temperature cooling/heating lockout, and an integrated differential temperature economizer. The unit’s economizer uses return and exhaust dampers to regulate “free” cooling. Supply duct bypass dampers and variable volume terminal units control the supply air delivered to each zone. The system is controlled with vendor-provided packaged controls that operate in a master and slave fashion.

Appropriate reference in the specifications should be made for products that are integrated with these sequences including packaged units, VVT equipment, and the like.


PACKAGED GAS HEAT AND DX COOLING HVAC UNITS WITH ECONOMIZERS AND VARIABLE VOLUME, VARIABLE TEMPERATURE (VVT) ZONES

SEQ

System

1.

UENCES OF OPERATION

Modes

Occupied Periods (Normal occupied operation): Operate the system on a programmed occupancy schedule from 7:00 AM to 6:00 PM, M-F. These periods are considered “occupied periods”. During occupied periods, run the system in Occupied Mode, including enabling the packaged unit fans, opening the outside

Packaged VVT Units 12


air dampers to minimum position, and operating the zone dampers to maintain at least minimum ventilation rates. NOTE: Schedule occupied start time 1 hour before the building is expected to be occupied (for Title 24 required purge).

Unoccupied Periods: All hours not included in an occupied period are part of an “unoccupied period”. During these periods, the system is available for tenant calls as needed but is not running unless commanded. The following holidays are considered to be unoccupied periods: New Years Day, Memorial Day, Fourth July, Labor Day, Thanksgiving and the following day, Christmas. These shoulbe set up as re-occurring holidays for each zon

2.

of d

e. ry

ver). During

a

o

4. l

the other modes, the mode is changed. At the

5.

6. occupied periods. In

en a iod, operate the

system in the occupied mode for one hour. ode: Identify Warm-up start time using an optimal start strategy

age arm-

required, command the

3. Start-up & System “changeover”: “Changeover” occurs at the beginning of eveoccupied period and whenever the VVT master controller switches between cooling and heating modes (use a hard-wired stop to signal changeochangeover, open the bypass damper fully and allow the air contained in the supply duct to circulate directly to the return air stream. When the supply air temperature reaches an acceptable temperature (80°F if the system is beginningheating mode or 65° F if the system is beginning a cooling mode), modulate the damper closed. Stop modulating the bypass damper closed when the supply air duct static pressure transmitter, referenced to space pressure, registers the operating pressure of 1.0” WC. During operation, modulate the bypass damper tmaintain the SA static pressure at a setpoint of 1.0” WC. Occupied Modes: During occupied periods, the VVT master controller polls the slave controllers at least every 30 seconds to confirm their operating status. A calfor a particular mode (heating, cooling, or ventilation) is based upon the numberof requests for that mode from the slave controllers. Once the number of callers for a particular mode exceeds that of beginning of each new mode, the VVT master controller selects the reference zone (see Determination of Reference Zone). Do not change the mode more frequently than every 5 minutes. NOTE: To initiate a mode change, at least 2 (adjustable) slave controllers must request it. Determination of the Reference Zone: When the system mode is changed, the master controller selects the zone with the greatest difference between room temperature and room setpoint. This becomes the reference zone. Unoccupied Mode: Unoccupied mode occurs during ununoccupied mode, disable the packaged unit, close the outside air damper, and position the return/exhaust air dampers for full return air (no exhaust). Whzone sensor’s override button is depressed during unoccupied per

7. Warm-up Mbased on outdoor air temperature and average zone temperature. If the averzone temperature is less than 69°F (adjustable) at the projected start of the wup period, initiate the warm-up mode. If building warm-up is

return/exhaust air dampers to the return position (no exhaust) and enable the



pachas risen above 70°F (adjustable) and transition the system to occupied mode (if

8. gy

one

9. perature Limits: During any mode, when the supply air temperature

VVT Zo

1. re Control: A slave controller is used to determine each space’s

igher than its

nt, the

5° F (adjustable) and the cooling setpoint default to 85° F (adjustable).

2. o open

oling her than the space temperature, the controller

by air

3. ing and the supply air temperature is greater than the space temperature, enable the zone controller to open the zone damper to provide heating to the space. If the zone is calling for heating and the supply air temperature is lower than the space temperature, the

r closes the damper to minimum position (minimum position is determined by air balance).

kage unit. Terminate the warm-up mode after the average zone temperature

scheduled) or to unoccupied mode. Cool-down Mode: Identify cool-down start time using an optimal start stratebased on outdoor air temperature and average zone temperature. If the averagezone temperature is greater than 79°F (adjustable) at the projected start of the cool-down period, initiate the cool-down mode. If building cool-down is required,command the return/exhaust air damper to the return position (no exhaust) and enable the packaged unit. Terminate the cool-down mode after the average ztemperature has fallen below 78°F (adjustable) and transition the system to occupied mode (if scheduled) or to unoccupied mode. Supply Temexceeds 140° F, or falls below 50° F, disable the cooling or heating in the packaged unit and initiate an alarm in the VVT control system.

ne Control

Temperaturequired mode. Set each controller for the following ranges:

1. Occupied Heating: 55° F to 73° F during occupied hours. The default is 73° F.

2. Occupied Cooling: 73° F to 85° F during occupied hours. The default is 78° F.

Maintain a deadband of at least 5° F between heating and cooling setpoints. When the system is operating, the slave controller is either in heating, cooling, or ventilation mode. If a space’s temperature is more than 1.5° F htemperature setpoint, the zone controller generates a call for cooling. Likewise, ifa space’s temperature is more than 1.5° F lower than its temperature setpoizone controller generates a call for heating. Otherwise, the controller generates a call for ventilation mode. During unoccupied hours, set the heating setpoint default to 5Provide each zone with its own adjustable unoccupied heating and cooling setpoints. Cooling Mode: When a zone controller calls for cooling and the supply air temperature is less than the space temperature, enable the zone controller tthe zone damper to provide cooling to the space. If the zone is calling for coand the supply air temperature is higcloses the damper to minimum position (minimum position is determined balance). Heating Mode: When a zone controller calls for heat

controlle



4. Ventilation Mode: When in ventilation mode, enable the zone controller to open and close the zone damper to satisfy heating or cooling needs. Night Setback5. /Setup: Enable system operation during unoccupied periods in the

er falls below 55°F (adj.) or rises above 85°F (adj.). Stop the system when

6. : Provide zone groups to establish enough heating or cooling load back

e

7. t the end

Packag

2.

t mode

4.

e compressor to supply the needed air

es

ster

5.

warm-up or cool-down mode if the lowest space temperature from a slave controllthe reference zone reaches either its unoccupied cooling or unoccupied heating setpoints. Zone Groupingfor the package system to work against when answering off-hours calls or setcalls. When one zone calls for system operation after hours, (either in the night setback mode or by authorized tenant request), command all zones in the associated group to come out of setback into normal operating temperatursettings used for Occupied Modes. Unoccupied Operation: When a zone override button is depressed during unoccupied period, operate the system in occupied mode for one hour. Aof the hour, return the system to unoccupied mode.

ed Unit

1. Fan Operation: Run the unit fans in all modes except unoccupied mode. Any time the supply fan is running, open the outside air damper to provide minimum outdoor air. Shutdown: When shutdown is initiated, place the packaged unit in unoccupied mode.

3. Fire Alarm: For fire alarm mode operation, the supply fan will be shut down by hardwired contact. Once reset, the affected unit(s) will resume the currenof operation. Cooling Mode Enable: When the VVT master controller generates a call for cooling, enable the economizer mode in order to satisfy the cooling requirement. If the economizer mode cannot provide the required supply air temperature (55° F) for at least 2 minutes, disable economizer mode and enable the unit’s compressor. Reset the supply air temperature upward from 55°F to 65°F as the outdoor temperature falls from 90° F or greater to 65° F or lower. Allow the package unit’s controls to cycle thtemperature. The package unit’s internal controls protect the equipment fromexcessive operating conditions including low oil pressure, high discharge pressure, low suction pressure, excessive cycling (more than one every 5 minutor 6 cycles/hour), low refrigerant charge, high and low refrigerant temperatures, etc. If excessive operating conditions occur, generate an alarm on the VVT macontroller and shut down the package unit to protect it. Cooling Mode Shutdown: If a call for cooling has been satisfied, a system failure has occurred, or the supply air temperature has fallen below 50° F for more than one minute, cycle the compressor off. After the compressor has shut down,



continue running the supply fan for 5 minutes before shutting it down (even if the unoccupied mode is issued by the VVT).

e return air enthalpy is 2 BTU/lb dry air

the zone. Reset the supply air t ard from 90°F to 110°F as the outdoor temperature falls from 65° F or grunit’s internal controls protect the equipment from excessive operating conditions including high temperature, flame failure, excessive cycling (more than one every

e, etc. If excessive operating aster controller and shut down

de Shutdown: If a call for heating has ended, a system failure has occurred, or the supply air temperature has risen above 120° F for more than one

er has shut down, continue running the supply fan for 5 minutes before shutting it down (even if the unoccupied mode is

oller). 9. Heating System Outdoor Air Temperature Lockout: If the outdoor air temperature

system shall be locked out. If the outdoor air temperature falls below 65° F (adjustable), the heater will be allowed

tion as10. Mechanical Cooling System Out e L the outdoor air

temperature is below 63° F (adjustable), the cal system shall be ut. If do ai em e rises above 65° F (adjustable), the

llo unction as required to m intain load.

Points Table

f po t (only 1 point is needed)

po t ( oi is total of "n" points are needed

6. Enthalpy Economizer Mode: Enable enthalpy economizer mode when the VVTmaster controller issues a call for cooling or ventilation, and outdoor air temperature is 2° F less than return air temperature. Open outside air damper to 100%. Modulate the return air and exhaust air dampers in unison to maintain supply air temperature setpoint. When th(adjustable deadband) above the outdoor air enthalpy, the dampers are to be in the full exhaust position (exhaust damper fully open and return damper fully closed). As the return enthalpy decreases below this point, the dampers transition to a full return position (exhaust damper is closed to allow only minimum outdoor air and the return damper is fully open).

7. Heating Mode Enable: When the VVT master controller generates a call for heating, transition the return & exhaust dampers to full return position (exhaust damper is closed to allow only minimum outdoor air and the return damper is fully open), and the packaged unit will cycle on the gas heater to supply heat to

emperature upweater to 40° F or lower. The package

5 minutes or 6 cycles/hour), low gas pressurconditions occur, generate an alarm on the VVT mthe package unit to protect it.

8. Heating Mo

minute, cycle the heater off. After the heat

issued by the VVT master contr

rises above 68 ° F (adjustable), the heating

to func required to maintain load. door Air T mperature

mechaniockout: If

cooling locked o

pressors will be athe out or r t peratur

com wed to f a

Key:

X Indicates type o in

n Indicates type offor this line item)

in 1 p nt needed for each zone - a



OA outside air (OAT = outside air temperature)

i.e ac ge un

e and tem ra e t inal

ame AI AO DI DO Analog ftware

Digital ftware

Other ftware

Alarm Logic

RTU rooftop unit ( . p ka d it)

VVT variable volum

Point N

pe tur erm

SoValue

SoValue

SoValue

OA DB Temp X

OA RH X

OA Enthalpy X

Cooling Lockout Temp X

Heating Lockout Temp X

RTU- Low LimitSetpoint Temp

n

RTU- High Limit Setpoint Temp

n

RTU-n EconomiStaging Setpoint

zer

Temp

n

AHU-n RAT n

AHU-n RA RH n

AHU-n RA Enthalpy

n

RTU-n Staging p Deadband Tem

n

RTU-n Cooling Alarm

n

RTU-n Fan Enable n

RTU-n Cooling Status

n oof after 1 inute

Prm

RTU-n Heating n Proof after 1 inute Status m

RTU-n Heating Alarm

n



RTU-n VVT Mode n

RTU-n EconomizMode

er n

VVT Fire Alarm X

VVT Mode Override

X

VVT Supply t

X Pressure Setpoin

VVT Supply Pressure

X

VVT Warm-up Mode Low Temp

Setpoint

X

VVT Cool -down emp Mode High T

Setpoint

X

VVT Mode X

VVT Low Limit Setpoint Temp

X

VVT High Limit Setpoint Temp

X

VVT ReferencZone

e X

VVT Override X

VVT OperatinMode

g X

VVT Supply Air Temperature

X

VAV-n Supply Air Temp Reset X

VVT OAT X

VVT Bypass Mode X

VVT Bypass Status X

Zone-n Space Temperature

Setpoint-Cooling

n

Zone-n Space n



Temperature Setpoint-Heating

Zone-n Space Temperature Unoccupied Setpoint-Cooling

n

Zone-n Space Temperature Unoccupied Setpoint-Heating

n

Zone-n Space Temperature Setpoint-Deadband

n

Zone-n Damper Command

n

Zone-n Override n

Zone-n Operating Mode

n



Notes: The system consists of multiple packaged roof top HVAC units each serving one or more zones in the building. The packaged units each have a supply fan, direct expansion (DX) cooling, natural gas heating, outside air temperature cooling/heating lockout, and an integrated differential enthalpy economizer. The unit’s economizer uses return and exhaust dampers to regulate “free” cooling. The system is controlled with vendor-provided packaged controls.


The system(s) in your building that are most similar to the system described above include:

• Packaged VAV System

• Typical AHU Controls

• proto 1

• Packaged VaV

• classroom hvac

• Underfloor

• Roof-top packaged AC-4

• AH-1

• test ahu

• AHU-1

• Central System

• asdf

• VAV

• VAVS

Please note that this sample sequence will have to be modified to meet the exact systems defined in your building.


PACKAGED UNIT WITH ECONOMIZER, DX COOLING AND GAS HEAT

Standard Packaged Units 20


SEQ

ds

UENCES OF OPERATION

Occupied Periods (Normal occupied operation): Operate the system on a 1. programmed occupancy schedule from 7:00 AM to 6:00 PM, M-F. These perioare considered “occupied periods”. During occupied periods, run the system inOccupied Mode, including enabling the packaged unit fans and opening the outside air dampers to minimum position. NOTE: Schedule occupied start time 1 hour before the building is expected to be occupied (for Title 24 required purge).

2.

Day, Thanksgiving and the following day, Christmas. These should

3.

4. ostat is used to determine each space’s required

Unoccupied Periods: All hours not included in an occupied period are part of an “unoccupied period”. During these periods, the system is available for tenant callsas needed but is not running unless commanded. The following holidays are considered to be unoccupied periods: New Years Day, Memorial Day, Fourth of July, Laborbe set up as re-occurring holidays for each zone. Fan Operation (Ventilation Mode): Run the unit fans in all modes except unoccupied mode. Any time the supply fan is running, open the outside air damper to provide minimum outdoor air. Temperature Control: A thermmode. Set each thermostat for the following ranges:




b. Occupied Cooling: 73° F to 85° F during occupied hours. The defau78° F.

Maintain a deadband of at least 5° F between heating and cooling setpoints. When the system is operating, the thermostat is either in heating, cooling, or ventilation mode. If a space’s temperature is m

lt is

ore than 1.5° F higher than its temperature

l

5. ardwired contact.

6.

) for at least 2 minutes, disable economizer mode and enable the unit’s ply

operating conditions occur, shut down the unit to

7. e

8. ventilation, and outdoor air temperature is

e

ble

and

pply heat to the zone. The package unit’s internal controls protect the equipment from excessive operating

setpoint, the thermostat generates a call for cooling. Likewise, if a space’s temperature is more than 1.5° F lower than its temperature setpoint, the thermostat generates a call for heating. Otherwise, the thermostat generates a calfor ventilation mode. During unoccupied hours, set the heating setpoint default to 55° F (adjustable) and the cooling setpoint default to 85° F (adjustable). Provide each zone with its own adjustable unoccupied heating and cooling setpoints. Fire Alarm: Interface system with the fire alarm controls. When the fire alarm control initiates a fire alarm, shut down the supply fan by a hOnce reset, the affected unit(s) will resume the current mode of operation. Cooling Mode Enable: When the zone thermostat generates a call for cooling, enable the economizer mode in order to satisfy the cooling requirement. If the economizer mode cannot provide the required supply air temperature (55° F, adjustablecompressor. Allow the package unit’s controls to cycle the compressor to supthe needed air temperature. The package unit’s internal controls protect the equipment from excessive operating conditions including low oil pressure, highdischarge pressure, low suction pressure, excessive cycling (more than one every5 minutes or 6 cycles/hour), low refrigerant charge, high and low refrigerant temperatures, etc. If excessiveprotect it. Cooling Mode Shutdown: If a call for cooling has been satisfied, a system failurhas occurred, or the supply air temperature has fallen below 50° F for more than one minute, cycle the compressor off. After the compressor has shut down, continue running the supply fan for 5 minutes before shutting it down (even if anunoccupied period begins). Enthalpy Economizer Mode: Enable enthalpy economizer mode when the zone thermostat issues a call for cooling or2° F less than return air temperature. Open outside air damper to 100%. Modulatthe return air and exhaust air dampers in unison to maintain supply air temperature setpoint. When the return air enthalpy is 2 BTU/lb dry air (adjustadeadband) above the outdoor air enthalpy, the dampers are to be in the full exhaust position (exhaust damper fully open and return damper fully closed). As the return enthalpy decreases below this point, the dampers transition to a full return position (exhaust damper is closed to allow only minimum outdoor airthe return damper is fully open).

9. Heating Mode Enable: When the zone thermostat generates a call for heating, transition the return & exhaust dampers to full return position (exhaust damper isclosed to allow only minimum outdoor air and the return damper is fully open),and the packaged unit will cycle on the gas heater to su



conditions including high temperature, flame failure, excessive cycling (more than one every 5 minutes or 6 cycles/hour), low gas pressure, etc. If excessiveoperating conditions occur, shut down the unit to protect it. Heating Mode Shutdown: If a call for hea

10. ting has ended, a system failure has

od

11. Unoccupied Mode: Unoccupied mode occurs during unoccupied periods. In unoccupied mode, disable the packaged unit, close the outside air damper, and

n the return/exhaust air dampers for full return air (no exhaust). When a thermostat’s override button is depressed during an unoccupied period, operate the system in the occupied mode for one hour. At the end of the hour, return the system to unoccupied mode.

e using an optimal start strategy e

arm-e warm-up mode. If building warm-up is required, command

e after the average zone temperature system to occupied mode (if

de. t strategy

perature is greater than 79°F (adjustable) at jected sown period, b ol-

command the return/exhaust air dampe tu (n st) and enable the packaged unit. Terminate th down fter the average zone

ure has fa low 8° adj table) and nsition the ystem to cupied mode (if scheduled r uno upied mod

p or cool-d n ode th spa emperature falls below 55°F (adj.) or a .). top e s tem en the thermostat reaches either its

erature Lockout: If the outdoor air temperature 8 ° F ju abl th hea g system shall be locked out. If the

ir temperature falls below 65° F (adjustable), the heater will be allowed s requ d ma tai ad

cal Cooling System Outdoor Air Temperature Lockout: If the outdoor air belo 6 F ( jus ble echanical cooling system shall be

o tdo r air mpllowed to function as required to maintain load.

occurred, or the supply air temperature has risen above 120° F for more than one minute, cycle the heater off. After the heater has shut down, continue running thesupply fan for 5 minutes before shutting it down (even if the unoccupied peribegins).

positio

12. Warm-up Mode: Identify Warm-up start timbased on outdoor air temperature and average zone temperature. If the averagzone temperature is less than 69°F (adjustable) at the projected start of the wup period, initiate ththe return/exhaust air dampers to the return position (no exhaust) and enable the package unit. Terminate the warm-up modhas risen above 70°F (adjustable) and transition the scheduled) or to unoccupied mo

13. Cool-down Mode: Identify cool-down start time using an optimal starbased on outdoor air temperature and average zone temperature. If the average zone temcool-d

the prouilding corn position mode a

tart of the down is required,o exhau

initiate the cool-down mode. Ifrs to the ree cool-

temperat llen be 7 F ( us tra soc ) o to cc e.

14. Night Setback/Setup: Enable system opewarm-u

ration during unoccupied periods in the ce tow m if e

rises above 85°F ( dj S th ys whunoccupied cooling or unocc

Outdoor Air Temupied heating setpoints.

15. Heating Systemrises above 6outdoor a

pe (ad st e), tin

to function a16. Mechani

ire to in n lo .

temperature islocked out. If thecompressors will be a

wu

3°o

ad te

taeratur

), the me rises above 65° F (adjustable), the



Points Table

Key:


int (1)

ou ide ir te perature)

it (i.e. pac ge uni

hard wired and not user accessible

I O O nalog ftware

igital ftware

ther Software alue

n Indicates type of po point is needed for each zone – a total of “n” points are needed for this line item

OA outside air (OAT = ts a m

RTU rooftop un ka d t)

Note that these points are typically

Point Name A A DI D ASoValue

DSoValue

OV

OA DB Temp X

OA RH X

OA Enthalpy X

Cooling Lockout Temp X

Heating Lockout Temp X

RTU-n Low Limit Setpoint Temp

n

RTU-n High Limit Setpoint Temp

n

RTU-n Economizer Staging Setpoint Temp

n

RTU-n RAT n

RTU-n RA RH n

RTU-n RA Enthalpy n

RTU-n StaginDeadband Temp

g n

RTU-n Cooling Alarm n

RTU-n Fan Enable n

RTU-n Cooling Status n

RTU-n Heating Status n



RTU-n Heating Alarm n

RTU-n Mode n

RTU-n Economizer Mode

n

RTU Fire Alarm X

RTU-n Minimum Air Damper Command

n

RTU-n Economizer/Return air damper Command

n

RTU-n Warm-up Mode Low Temp Setpoint

n

RTU-n Cool -down Mode High Temp Setpoint

n

RTU-n Override n

RTU-n Space Temperature Setpoint-Cooling

n

RTU-n Space Temperature Setpoint-Heating

n

RTU-n Space Temperature Unoccupied Setpoint-Cooling

n

RTU-n Space Temperature Unoccupied Setpoint-Heating

n

RTU-n Space Temperature Setpoint-Deadband

n



Notes:

The system consists of Primary/Secondary chilled and hot water loops that serve multiple four-pipe fan coil units (FCUs) for each zone in the building. Each FCU has a constant volume supply fan, a chilled water cooling coil, a hot water heating coil, and a ducted air intake for ventilation air (outdoor air). Barometric relief dampers maintain building pressurization and allow building air to be exhausted outside. The chilled water loop includes water-cooled chillers and variable speed secondary chilled water pumps. The hot water loop includes two-stage boilers and variable speed secondary hot water pumps. A building automation system (BAS) controls the HVAC equipment.

Appropriate reference in the specifications should be made for products that are integrated with these sequences including chillers, boilers, variable frequency drives (VFDs), and the like.

Controls: Furnish control device with an interface for monitoring and control of points specified in the points table. The points table includes the minimum acceptable list of interface points. The selected component controls shall easily integrate into the BAS and allow for the collection, control, trending, and archiving of the specified points with a minimal need for intermediary gateways or hardwired connections to link control systems together. Interoperable control systems are preferred.


FOUR PIPE FAN COIL UNITS WITH A CENTRAL PLANT, WATER COOLED CHILLERS AND COOLING TOWERS

Four Pipe Fan Coil Units 26



Fan Coil Units (FCUs)

1. Occupied Periods (Normal operation): When an isolation area is scheduled to be occupied, operate the fan coil units that serve it. These scheduled periods are considered “occupied periods”.

2. Unoccupied Periods: All hours not included in an occupied period are part of an “unoccupied period”. During these periods, the system is available for tenant calls as needed but is not running unless commanded. The following holidays are considered to be unoccupied periods: New Years Day, Memorial Day, Fourth of July, Labor Day, Thanksgiving and the following day, Christmas. These should be set up as re-occurring holidays for each zone.

3. Fan Operation: Run the unit fans in all modes except unoccupied mode. 4. Fire Alarm: Interface system with the fire alarm controls. When the fire alarm

control initiates a fire alarm, shut down the supply fan by a hardwired contact interface. Simultaneously, the fire alarm control must notify the BAS of the fire event to enable the BAS to disable the affected units. Once the fire alarm is reset, enable the affected unit(s) to resume normal operation.

5. Duct Pressure Safety: If negative static pressure over 2” WC is measured in the mixed air plenum or positive supply duct static pressure over 3” WC is measured in the supply duct, disable the fan via a hard wired interlock and initiate an equipment specific alarm (i.e. “FC-3 High Static Pressure” or “FC-2 Low Static Pressure”) at the operator workstation. An operator must reset each fan’s differential pressure switch before the fan may be re-enabled. Provide a local or BAS reset for this purpose.

6. Temperature Control: Use a solid state, electronic wall temperature sensor to switch the fan coil unit between “fan operation”, “cooling mode”, and “heating mode”. Each mode will vary the FCUs supply air temperature in order to satisfy the zone’s temperature setpoint. Set each temperature sensor for the following ranges:

1. Occupied Heating: 55° F to 73° F during occupied hours. The default is 73° F.

2. Occupied Cooling: 73° F to 85° F during occupied hours. The default is 78° F.

Maintain a deadband of at least 5° F between the heating and cooling setpoints. When the zone is in this deadband, set the fan coil unit to operate in “fan operation” mode only. During unoccupied hours, set the heating setpoint default to 55° F (adjustable) and the cooling setpoint default to 85° F (adjustable). Provide each zone its own adjustable unoccupied heating and cooling setpoints.

7. Cooling Mode: When the zone temperature rises to the cooling setpoint, begin modulating the chilled water valve with a control loop. When the cooling valve opens more than 30% (adj.), send a call for cooling to the central plant to maintain



a cooling mode supply air temperature setpoint of 55° F (adjustable). When the cooling valve closes to 5% (adj.), cancel the call for cooling .

8. Heating Mode: When the zone temperature falls to the heating setpoint, begin modulating the hot water valve. When the heating valve opens more than 10% (adj.), send a call for heating to the central plant to maintain a heating mode supply air temperature setpoint of 110° F (adjustable). When the heating valve closes to 5% (adj.), cancel the call for heating.

9. Filter Status: A differential pressure indicator is used to manually determine if the filter is dirty. The filter status indicator is not connected to the BAS.

Isolation Areas

1. Isolation Areas: There are XX isolation areas as indicated on the plans. Each area is composed of 1 or more spaces served by 1 or more fan coil units that are operated together. Configure each isolation area separately from other isolation areas. Configuration includes scheduling and operational modes. The default occupancy schedule is 7:00 AM to 6:00 PM, M-F. NOTE: Schedule occupied start time 1 hour before the building is expected to be occupied (for Title 24 required purge).

2. Occupied Mode: Prior to an occupied period, initiate a Warm-up mode or Cool-down mode if necessary. During Occupied Mode, enable operation of the system, including enabling the fan coil units that serve this area. At the end of an occupied period, initiate unoccupied mode.

3. Warm-up Mode: Use an optimal start strategy to initiate the warm-up start time. Base optimal start strategy upon outdoor air temperature and average zone temperature within the isolation area. If the average zone temperature is less than 69°F (adjustable) at the projected start of the warm-up period, initiate the warm-up mode. The optimal start period should pre-heat the building so that the average zone temperature is 70°F (adjustable) by the occupied period. If building warm-up is required, enable the fan coil units. Leave the chilled water valve closed (or in bypass), and leave the general exhaust fans off. Enable the central heating plant but leave the central cooling disabled. After the average zone temperature has risen above 70°F (adjustable), terminate the warm-up cycle, and initiate occupied mode.

4. Cool-down Mode: Use an optimal start strategy to initiate the cool-down start time. Base the optimal start strategy upon outdoor air temperature and average zone temperature within the isolation area. If the average zone temperature is greater than 79°F (adjustable) at the projected start of the cool-down period, initiate the cool-down mode. The optimal start period should pre-cool the building so that the average zone temperature is 78°F (adjustable) by the occupied period. If a cool-down cycle is required, enable the fan coil units and leave the general exhaust fans off. Enable the chilled water system but leave the central heating disabled. After the average zone temperature has dropped below 78°F (adjustable), terminate the cool-down cycle and initiate occupied mode.



5. Night Setback/Setup Mode: During an unoccupied period, start the fan coil units in the warm-up or cool-down mode if a zone temperature falls below the unoccupied heating setpoint or rises above the unoccupied cooling setpoint. End the setback/setup mode when the zones are below/above their unoccupied setpoints.

6. Unoccupied Mode: During unoccupied periods, disable the fan coil units, close their chilled water valves (or put them in bypass), and close their hot water valves (or put them in bypass). Cancel calls for central plant cooling and heating. When a thermostat override button is depressed during unoccupied period, operate the isolation area in occupied mode for one hour as follows: Operate the fan coil units in the isolation area in occupied mode except for the general exhaust fans (leave them off). Enable the central plant.

Chilled Water System

1. Cooling Mode Enable/Disable: When building comfort cannot be maintained, the fan coil units call for supplementary cooling by sending a cooling request to the central plant. When all of the FCU chilled water valve positions fall below 5% full open, cancel the call for cooling and initiate chiller shutdown.

2. Secondary Chilled Water Pump Enable: When the BAS registers a call for central plant cooling, enable both the secondary chilled water pumps by a start-stop command from the BAS. Initially, start the pumps at 10% speed. Proof the start of both of the pumps after 5 seconds. Modulate the speed of the pumps in order to maintain a differential pressure setpoint of 15 PSID (adj.) at the central plant. Inhibit starting of the primary pumps and chiller if both pumps fail to prove running status or fail while running. When the commanded speed falls below 40%, disable the lag pump. When the commanded speed rises above 60%, enable the lag pump. When they are both enabled, lead and lag pumps should run at the same speed.

3. Primary Chilled Water Pump Enable (Chiller Initiation): When the BAS registers a call for central plant cooling, determine the lead chiller as indicated below. Open the chilled water isolation valve to the lead chiller. If the valve has not proofed open after 30 seconds, close the valve and enable and start the lag chiller. Repeat valve operation with lag chiller. If both valves fail to open, initiate chiller shutdown operation and send equipment specific critical alarm (“CH-1 CHW Isolation Valve Failed to Open”) to operator workstation. If valve proofs open, enable the primary chilled water pump dedicated to the lead chiller. After 30 seconds, proof flow. If the flow is not proved by a differential pressure switch, disable the pump, close the valve and set the lag chiller as the lead chiller. If both pumps fail to provide flow, initiate the chiller shutdown operation. If either pump fails, send equipment specific critical alarms to the operator workstation.

4. Chiller Enable: Upon proof of primary chilled water and condenser water flow, enable the selected chiller. A hard-wired flow switch will act as a back up to ensure that chiller only starts with chilled water flow. Set the chilled water



temperature supply temperature to 45° F (adjustable). After 30 seconds, prove chiller operation by means of a hard-wired current switch. If the chiller fails to prove operation, initiate its shutdown sequence. Then, enable the lag chiller and it’s primary pump. If both chillers fail to proof, send an equipment specific alarm (“Chillers Failed”) to the operator workstation. During operation, use the chillers internal safeties to cause an alarm and shut down the machine. If the chiller does not develop at least a 3°F temperature difference after 15 minutes of being proved on, initiate an alarm on the operator work station. Operate the chillers and their associated primary pumps lead/lag. Swap the lead and lag chillers (as well as their primary pumps) on Sunday at 3:00 AM as long as the lead chiller has operated at least 40 hours and all equipment are disabled.

5. Chiller Staging: If the chilled water return temperature rises to 12°F (adjustable) above the chilled water setpoint, enable lag chiller operation and start the chiller. Run both chillers until the chilled return temperature falls to 5°F above the chilled water setpoint. At this point, initiate the lag chiller shutdown sequence. Continue running the lead chiller until the chilled water return temperature falls to the setpoint minus the deadband.

6. Chiller Shutdown: Upon a call from the BAS or an internal chiller alarm, initiate chiller shutdown. Disable the chiller but continue to run the primary pump and the condenser water pump serving the chiller for 5 minutes. After 5 minutes, disable the pumps and close the chiller’s isolation valves. If no other chiller is enabled, initiate the condenser water system shutdown and shutoff the secondary water pumps. Use a timer in the BAS to keep the chiller from cycling on and off more often than every 5 minutes [this may be redundant to the chiller’s internal safeties].

7. Chiller Safeties: Initiate chiller shutdown if the BAS senses low chilled water flow, low condenser water flow, low chilled water temperature (less than 38° F), or high condenser water temperature (over 90° F). Initiate an equipment specific alarm at the operator workstation.

8. Chilled Water System Outdoor Air Temperature Lockout: If the outdoor air temperature falls below 63° F (adjustable), lock out the chilled water system such that the chillers and chilled water pumps do not run. If the outdoor air temperature rises above 65° F (adjustable) for 20 minutes (adjustable), enable the chilled water system.

Condenser Water System

1. Chemical Treatment: Provide chemical treatment for the cooling towers via an automatic chemical feed and bleed system. Run the water treatment system independently of the BAS.

2. Safeties: Disable the condenser water pump and the chiller operation if the water level in the cooling tower basin falls below the minimum. Initiate an equipment specific alarm (“Low Water Level in CT-1”) at the operator workstation.

3. Condenser Water Pump Enable: When the BAS registers a call for cooling from the central plant, enable the lead condenser water pump. Prove condenser water



flow within 30-seconds (adjustable) using a differential pressure switch. If the flow is not proved, disable the pump, and enable and start the lag pump. Send equipment specific critical alarm (“CWP-1 Failed”) to the operator workstation. The lag pump is also enabled by the start-up of the lag chiller. If both pumps fail to provide flow, initiate chiller shutdown operation and initiate a critical alarm (“Condenser Water Pumps failed”) to the operator workstation. Swap the lead and lag pumps on Sunday at 3:00 AM as long as the lead pump has operated at least 40 hours and both pumps are shut down.

4. Condenser Water Temperature Control: Prior to operation of the condenser water pump, the cooling tower bypass valve should be in the bypass position (bypassing the cooling towers) and the cooling tower fans shut off. Once condenser water flow is proved, operate the cooling tower fan and bypass valve in order to maintain a condenser water supply setpoint between 75° F and 85° F. Modulate the condenser water bypass valve so that at 80° F condenser water supply temperature, the water is not bypassing the cooling tower. Start both cooling tower fans at minimum speed when the water temperature increases to 82°F. Modulate the tower fans speed as necessary to maintain the setpoint temperature. If the temperature exceeds the high limit of 90° F, initiate the chiller shutdown sequence and send an equipment specific alarm (“Condenser Water High Limit Temperature”) to the operator workstation. As the temperature falls below 82 ° F, disable the fans and modulate the bypass valve to maintain setpoint temperature. If the condenser supply temperature falls below the low limit of 70° F after running for 5 minutes, initiate the chiller shutdown sequence and send an equipment specific alarm (“Condenser Water Low Limit Temperature”) to the operator workstation.

5. Condenser Water System Shutdown: When the lag chiller is shutdown, disable the lag chilled water pump after a 5 minute run time. Adjust the condenser water fan speed and bypass valve positions to maintain temperature as indicated elsewhere. When the lead chiller is shutdown, run the lead condenser water pump for 5 minute. Then disable the cooling tower fans, disable the lead pump, and modulate the bypass valve to full bypass.

Heating Hot Water System

1. Heating Mode Enable: Generate a call for heating from zone controllers if any of the zone valve positions is greater than 10% (adjustable) of full open until all are below 5% (adjustable).

2. Secondary Hot Water Pump Enable: When the BAS registers a call for central plant heating, enable both the secondary hot water pumps by a start-stop command from the BAS. Initially, start the pumps at 10% speed. Proof the start of both of the pumps after 15 seconds using a differential pressure switch. Modulate the speed of the pumps in order to maintain a pressure drop of 10 PSID at the hot water using a differential pressure transmitter. Inhibit starting of the primary pumps and boiler if both pumps fail to prove running status or fail while running. When the commanded speed falls below 40%, disable the lag pump. When the commanded speed rises above 60%, enable the lag pump. If either pump fails to



start, initiate an equipment specific critical alarm at the operator workstation. When they are both enabled, lead and lag pumps should run at the same speed.

3. Primary Hot Water Pump Enable (Boiler Initiation): Open the lead boiler’s isolation valves. If the valve opening fails to proof within 30-seconds, close the valve, enable the lag boiler, and send an equipment specific alarm (“B-1 Isolation Valve Failed to Open”) to the operator workstation. If valve opening is successful, enable the primary hot water pump dedicated to the lead boiler. If the flow is not proved within 30 seconds, disable the pump, close the valve and set the lag boiler as the lead boiler. If both valves fail to open, initiate boiler shutdown operation and send equipment specific alarms to the operator workstation. If both pumps fail to provide flow, initiate boiler shutdown operation and send equipment specific alarms to the operator workstation. After 40 hours of operation, on Sunday at 3:00 AM when both boilers and pumps are shut down, swap the lead and lag pumps.

4. Boiler Enable: Upon proof of primary hot water flow, enable the selected boiler. Use a hard-wired flow switch as a back up to ensure that boiler only starts with hot water flow. Send an initial hot water temperature of 180° F to the boiler controller. After 60 seconds, prove boiler operation by means of a hard-wired current switch. Operate the boilers lead/lag. After 40 hours of operation, on Sunday at 3:00 AM when both boilers and pumps are shut down, swap the lead position. Enable the lag boiler to start. If either or both boilers fail to prove or fail to proof when required to operate, initiate boiler shutdown and send equipment specific alarms to the operator workstation. During operation, use the boiler’s internal safeties to initiate an equipment alarm at the operator workstation and disable the machine. If the boiler does not develop at least a 3°F temperature difference after 15 minutes of being enabled initiate a equipment specific alarm at the operator workstation.

5. Boiler Staging: Modulate internal boilers controls between the boiler’s two stages to meet the BAS water loop setpoint. If during boiler operation, the hot water temperature differential falls to 5°F (adjustable), initiate the lag boiler operation. Continue to run both boilers until the hot water temperature differential rises to 12° F. At this point, initiate the lag boiler shutdown sequence.

6. Boiler Shutdown: When all calls for central plant heating are cancelled or an internal alarm occurs, initiate boiler shutdown. Provide the BAS with redundant sensors for hot water flow, hot water temperature Hi Limit (more than 200° F). Disable operation of the affected boiler(s) if the limits are exceeded. If both boilers trip or fail to proof, initiate an equipment specific alarm at the operator workstation. Prevent the boiler from cycling on and off more often than once every 5 minutes (this may be redundant to the boiler’s internal safeties). For each boiler, disable the boiler before shutting down its pump. After disabling the boiler, run the primary boiler pump serving the boiler for 5 minutes. After 5 minutes, shut down the primary boiler pump and close the hot water isolation valves. If no other boiler is enabled, shut off the secondary water pumps.

7. Hot Water System Outdoor Air Temperature Lockout: If the outdoor air temperature rises above 75° F (adjustable), lock out the hot water system so the



boilers and hot water pumps do not run. If the outdoor air temperature falls below 70° F (adjustable) for 20 minutes (adjustable), enable the hot water system.

Points Table

Key:



B boiler

DB dry-bulb

CH chiller or chilled (i.e. CHW = chilled water)

Cmd command

COV change of value

CT cooling tower

FCU Fan coil unit


P pump (PP = primary pump, SP = secondary pump)

R return (RAT = return air temperature)

S supply (SAT = supply air temperature)

SL secondary loop

W water (CW = condenser water, HW = hot water)

Resolution of analog inputs:

°F 0.1

psid 0.005 ” water

cfm 1



rpm 1

kW 0.1

% 0.1




Alarm Logic

Interval or COV

Show on Graphic

OA DB Temp X 15 X

CHW Lockout Temp

X COV 0.5,15 X

HHW Lockout Temp

X COV 0.5,15 X

CHWR Temp X1 15 X

CHWS Temp X1

>60 when CH flow after 1 minute, <38

15 X

CHW SL Pressure Drop Setpoint

X COV-10%,15 X

CHW SL Pressure Drop

X =Cmd after 1 minute

COV-10%,15 X

CHWSP-n Enable n1 COV X

CHWSP-n Override n COV X

CHWSP-n Status n1

Proof after 1 minute

COV X

CHWSP-n n >1000 COV 1






Alarm Logic

Interval or COV

Show on Graphic

Runtime

CHWSP-n Cycle Counter

n > 6 hour COV

CHWSP-n Cmd Speed n

CHWSP-n Run Speed n

=Cmd after 1 minute

COV-10%,15 X

CHWSP-n Alarm n

CHWSP-n Power n X

CHWSP Lead/Lag X COV X

CH-n Inlet Temp n1 15 X

CH-n Outlet Temp n1

>60 when call for cooling, <38

15 X

CH Setpoint Temp X COV

CH Staging Setpoint Temp

X COV

CH Staging Deadband Temp

X COV

CH-n CHW Isolation Valve Cmd

n1 COV

CH-n CHW Isolation Valve Feedback

n1 COV X






Alarm Logic

Interval or COV

Show on Graphic

CH-n CW Isolation Valve Cmd

n1 COV

CH-n CW Isolation Valve Feedback

n1 COV X

CH-n Alarm n COV X

CH-n Enable n1 COV X

CH-n Override n COV X

CH-n CHW flow status n1 COV X

CH-n CW flow status n1 COV X

CH-n Status n1 Proof after 1 minute

COV X

CH-n Chiller Runtime n >1000 COV 1

CH-n Re-Start Timer n

5 Minutes to re-start

CH-n Cycle Counter n > 6

hour COV

CH Lead/Lag X COV X

CHWPP-n Enable n1 COV X

CHWPP-n Override n COV X

CHWPP-n Status n1


COV X

CHWPP-n Runtime n >1000 COV 1






Alarm Logic

Interval or COV

Show on Graphic

CHWPP Lead/Lag X COV X

CWR Temp X1 15 X

CWS Temp X1

>87 , < 72 when flowing for 5 minutes

15 X

CWP-n Enable n1 COV X

CW-n Override n COV X

CWP-n Status n1


COV X

CWP-n Runtime n >1000 COV 1

CWP Lead/Lag X COV X

CW Bypass Cmd X COV-

10%,15 X

CW Bypass Feedback X

=Cmd after 1 minute

COV-10%,15 X

CW Temp Set point X COV-

0.5,15 X

CW Minimum Temp

X COV

CW Maximum Temp

X COV

CW Temp Set point deadband

X COV






Alarm Logic

Interval or COV

Show on Graphic

CW Valve Set point Temp

X COV

CT-n Alarm n COV X

CT-n Enable n1 COV X

CT-n Override n COV X

CT-n Status n1 Proof after 1 minute

COV X

CT-n Power n 15 X

CT-n Runtime n >1000 COV 1

CT-n Cycle Counter n > 6

hour COV

CT Lead/Lag X COV X

CT-n Low Water Alarm n COV X

HWS Temp X1

>180 or <110 when CH flow after 1 minute

15 X

HW SL Pressure Drop Setpoint

X COV-10%,15 X

HW SL Pressure Drop


COV-10%,15 X

HWSP-n Enable n1 COV X

HWSP-n override n COV X






Alarm Logic

Interval or COV

Show on Graphic

HWSP-n Status n1


COV X

HWSP-n Runtime n >1000 COV 1

HWSP-n Cycle Counter

n > 6 hour COV

HWSP-n Cmd Speed n1

HWSP-n Run Speed n

=Cmd after 1 minute

COV-10%,15 X

HWSP Lead/Lag X COV X

B-n Inlet Temp n 15 X

B-n Outlet Temp n1

>190 or <110 when CH flow after 1 minute

15 X

B Setpoint Temp X COV

B Staging Setpoint Temp

X COV

B Staging Deadband Temp

X COV

B-n Isolation Valves n1 COV

B-n Alarm n COV X

B-n Enable n1 COV X






Alarm Logic

Interval or COV

Show on Graphic

B-n HW Isolation Valve Cmd

n1 COV

B-n HW Isolation Valve Feedback

n1 COV X

B-n Override n COV X

B-n HW flow status n COV X

B-n Status n Proof after 1 minute

COV X

B-n Runtime n >1000 COV 1

B-n Re-Start Timer n


B-n Cycle Counter n > 6

hour COV

B Lead/Lag X COV X

HWPP-n Enable n1 COV X

HWPP-n Override n COV X

HWPP-n Status n1


COV X

HWPP-n Runtime n >1000 COV 1

HWPP Lead/Lag X COV X

FCU-n Fire Alarm n1 COV X

FCU-n Operating n COV X






Alarm Logic

Interval or COV

Show on Graphic

Mode

FCU-n Mode Override n COV X

FCU-n SAT n 15 X

FCU-n Supply Fan Enable

n1 COV X

FCU-n Supply Fan Status

n1 Proof after 1 minute

COV X

FCU-n Supply Fan Runtime

n >1000 COV 1

FCU-n CHWV Bypass Cmd

n COV-10%,15 X

FCU-n CHWV Bypass Feedback

n =Cmd after 1 minute

COV-10%,15 X

FCU-n HHWV Bypass Cmd

n COV-10%,15 X

FCU-n HHWV Bypass Feedback


COV-10%,15 X

FCU-n Warm-up Mode Low Temp Setpoint

n COV X

FCU-n Cool-Down Mode High Temp Setpoint

n COV X

FCU-n Call n COV






Alarm Logic

Interval or COV

Show on Graphic

for Heating

FCU-n Call for Cooling n COV

FCU-n Space Temperature Sensor

n COV-0.5,15 X

FCU-n Space Temperature Setpoint-Cooling

n COV X

FCU-n Space Temperature Setpoint-Heating

n COV X

FCU-n Space Temperature Unoccupied Setpoint-Cooling

n COV X

FCU-n Space Temperature Unoccupied Setpoint-Heating

n COV X

FCU-n Space Temperature Setpoint-Deadband

n COV X

1 When a gateway is used to integrate controls, these points shall be hardwired to the DDC system.



Notes:

The system consists of Primary/Secondary chilled and hot water loops, multiple air handling units (AHUs), and 1 single duct constant air volume (CAV) terminal unit for each zone in the building. The CAV units provide conditioned air to the occupied space and, at the perimeter of the building, they include a hot water coil and automatic two-way valve to re-heat the main supply air. Each AHU has a constant volume supply fan, a chilled water cooling coil, and an outdoor air damper with a 2-position actuator. Barometric relief dampers maintain building pressurization and allow building air to be exhausted outside. The chilled water loop includes air-cooled chillers and variable speed secondary chilled water pumps. The hot water loop includes two-stage boilers and variable speed secondary hot water pumps. A building automation system (BAS) controls the HVAC equipment.

Appropriate reference in the specifications should be made for products that are integrated with these sequences including chillers, boilers, and the like.



CONSTANT-AIR VOLUME (CAV) UNITS WITH A CENTRAL PLANT, AIR COOLED CHILLERS

Constant Air Volume Units with Central Plant 43



Air Handling Units (AHUs)

1. Occupied Periods (Normal operation): When an isolation area is scheduled to be occupied, operate the air handling unit that serves it. These scheduled periods are considered “occupied periods”.


3. Fan Operation: Run the unit fans in all modes except unoccupied mode. Open the minimum outside air dampers when the supply fan is running. Proof the supply fan using an external current switch (CS).

4. Fire Alarm: Interface system with the fire alarm controls. When the fire alarm control initiates a fire alarm, shut down the supply fan by a hardwired contact interface. Simultaneously, the fire alarm control must notify the BAS of the fire event to enable the BAS to disable the affected units. Once the fire alarm is reset, enable the affected unit(s) to resume normal operation.

5. Duct Pressure Safety: If negative static pressure over 2” WC is measured in the mixed air plenum or positive supply duct static pressure over 3” WC is measured in the supply duct, disable the fan via a hard wired interlock and initiate an equipment specific alarm (i.e. “AH-3 High Static Pressure” or “AH-2 Low Static Pressure”) at the operator workstation. An operator must reset each fan’s differential pressure switch before the fans may be re-enabled. Provide a local or BAS reset for this purpose.

6. Supply Air Temperature Control: The chilled water valve modulates to maintain the supply air temperature when at least one zone serves by the unit is calling for cooling. The supply air temperature setpoint is 55° F (adjustable). When the valve opens more than 30% (adj.), send a call for cooling to the central plant. When the valve closes to 5% (adj.), cancel the call for cooling. If no zones are calling for cooling, close the chilled water valve.

7. Filter Status: Whenever the supply fan is running, send an equipment specific alarm (“AH-1 Dirty Filter”) to the operator workstation if the differential pressure over the filter exceeds 150% (adjustable) of the its design value.

Isolation Areas

1. Isolation Areas: There are XX isolation areas as indicated on the plans. Each area is composed of 1 or more spaces served by 1 or more CAV terminal units that are operated together. Configure each isolation area separately from other isolation areas. Configuration includes scheduling and operational modes. The default occupancy schedule is 7:00 AM to 6:00 PM, M-F.



NOTE: Schedule occupied start time 1 hour before the building is expected to be occupied (for Title 24 required purge).

2. Occupied Mode: Prior to an occupied period, initiate a Warm-up mode or Cool-down mode if necessary. During Occupied Mode, enable operation of the system, including enabling the air handling unit fans that serve this area and opening the outdoor air dampers to100% open. At the end of an occupied period, initiate unoccupied mode.

3. Warm-up Mode: Use an optimal start strategy to initiate the warm-up start time. Base optimal start strategy upon outdoor air temperature and average zone temperature within the isolation area. If the average zone temperature is less than 69°F (adjustable) at the projected start of the warm-up period, initiate the warm-up mode. The optimal start period should pre-heat the building so that the average zone temperature is 70°F (adjustable) by the occupied period. If building warm-up is required, enable the air handling units. Leave the chilled water valve closed (or in bypass), and leave the general exhaust fans off. Enable the CAV unit hot water valves to normal occupied operation. Enable the central heating plant but leave the central cooling disabled. After the average zone temperature has risen above 70°F (adjustable), terminate the warm-up cycle, and initiate occupied mode.

4. Cool-down Mode: Use an optimal start strategy to initiate the cool-down start time. Base the optimal start strategy upon outdoor air temperature and average zone temperature within the isolation area. If the average zone temperature is greater than 79°F (adjustable) at the projected start of the cool-down period, initiate the cool-down mode. The optimal start period should pre-cool the building so that the average zone temperature is 78°F (adjustable) by the occupied period. If a cool-down cycle is required, enable the air handling units and leave the general exhaust fans off. Enable the chilled water system but leave the central heating and CAV hot water valves disabled. After the average zone temperature has dropped below 78°F (adjustable), terminate the cool-down cycle and initiate occupied mode.

5. Night Setback/Setup Mode: During an unoccupied period, start the air-handling unit in the warm-up or cool-down mode if a zone temperature falls below the unoccupied heating setpoint or rises above the unoccupied cooling setpoint. End the setback/setup mode when the zones are below/above their unoccupied setpoints.

6. Unoccupied Mode: During unoccupied periods, close CAV unit hot water valves (or put them in bypass), disable the air handling units, close their chilled water valves (or put them in bypass), and close their outside air damper(s). Cancel calls for central plant cooling and heating. When a thermostat override button is depressed during unoccupied period, operate the isolation area in occupied mode for one hour as follows: Operate the air handling unit in occupied mode except for the general exhaust fans (leave them off). Enable the central plant.

CAV Zone Control



1. Temperature Control: Use a solid state, electronic wall temperature sensor to adjust the zone setpoint. Set each temperature sensor for the following ranges:



Maintain a deadband of at least 5° F between the heating and cooling setpoints. During unoccupied hours, set the heating setpoint default to 55° F (adjustable) and the cooling setpoint default to 85° F (adjustable). Provide each zone its own adjustable unoccupied heating and cooling setpoints.

2. Zone Cooling Mode: When the zone’s temperature rises to 1°F (adjustable) above its setpoint, send a call for cooling to the air handling unit.

3. Zone Heating Mode (Perimeter Zones Only): When the zone’s temperature falls to 1 ° F (adjustable) below its setpoint, the zone is in heating mode. Modulate the reheat coil control valve to satisfy the space temperature. Once the valve opens to more than 10% (adj.), send a call for heating to the central plant. When the valve closes to 5% (adj.), cancel the call for heating.


1. Cooling Mode Enable/Disable: When building comfort cannot be maintained, the air handlers call for cooling by sending a cooling request to the central plant. When all of the AHU chilled water valve positions fall below 5% full open, cancel the call for cooling and initiate chiller shutdown.


3. Primary Chilled Water Pump Enable (Chiller Initiation): When the BAS registers a call for central plant cooling, determine the lead chiller as indicated below. Open the chilled water isolation valve to the lead chiller. If the valve has not proofed open after 30 seconds, close the valve and enable and start the lag chiller. Repeat valve operation with lag chiller. If both valves fail to open, initiate chiller shutdown operation and send equipment specific critical alarm (“CH-1 CHW Isolation Valve Failed to Open”) to operator workstation. If valve proofs open, enable the primary chilled water pump dedicated to the lead chiller. After 30 seconds, proof flow. If the flow is not proved by a differential pressure switch, disable the pump, close the valve and set the lag chiller as the lead chiller. If both



pumps fail to provide flow, initiate the chiller shutdown operation. If either pump fails, send equipment specific critical alarms to the operator workstation.

4. Chiller Enable: Upon proof of primary chilled water, enable the selected chiller. A hard-wired flow switch will act as a back up to ensure that chiller only starts with chilled water flow. Set the chilled water temperature supply temperature to 45° F (adjustable). After 30 seconds, prove chiller operation by means of a hard-wired current switch. If the chiller fails to prove operation, initiate its shutdown sequence. Then, enable the lag chiller and it’s primary pump. If both chillers fail to proof, send an equipment specific alarm (“Chillers Failed”) to the operator workstation. During operation, use the chillers internal safeties to cause an alarm and shut down the machine. If the chiller does not develop at least a 3°F temperature difference after 15 minutes of being proved on, initiate an alarm on the operator work station. Operate the chillers and their associated primary pumps lead/lag. Swap the lead and lag chillers (as well as their primary pumps) on Sunday at 3:00 AM as long as the lead chiller has operated at least 40 hours and all equipment are disabled.

5. Chiller Staging: If the chilled water return temperature rises to 12°F (adjustable) above the chilled water setpoint, enable lag chiller operation and start the chiller. Run both chillers until the chilled return temperature falls to 5°F above the chilled water setpoint. At this point, initiate the lag chiller shutdown sequence. Continue running the lead chiller until the chilled water return temperature falls to the setpoint minus the deadband.

6. Chiller Shutdown: Upon a call from the BAS or an internal chiller alarm, initiate chiller shutdown. Disable the chiller but continue to run the primary pump serving the chiller for 5 minutes. After 5 minutes, disable the pump and close the chiller’s isolation valves. If no other chiller is enabled, shutoff the secondary water pumps. Use a timer in the BAS to keep the chiller from cycling on and off more often than every 5 minutes [this may be redundant to the chiller’s internal safeties].

7. Chiller Safeties: Initiate chiller shutdown if the BAS senses low chilled water flow or low chilled water temperature (less than 38° F). Initiate an equipment specific alarm at the operator workstation.




2. Secondary Hot Water Pump Enable: When the BAS registers a call for central plant heating, enable both the secondary hot water pumps by a start-stop command from the BAS. Initially, start the pumps at 10% speed.



Proof the start of both of the pumps after 15 seconds using a differential pressure switch. Modulate the speed of the pumps in order to maintain a pressure drop of 10 PSID at the hot water using a differential pressure transmitter. Inhibit starting of the primary pumps and boiler if both pumps fail to prove running status or fail while running. When the commanded speed falls below 40%, disable the lag pump. When the commanded speed rises above 60%, enable the lag pump. If either pump fails to start, initiate an equipment specific critical alarm at the operator workstation. When they are both enabled, lead and lag pumps should run at the same speed.




6. Boiler Shutdown: When all calls for central plant heating are cancelled or an internal alarm occurs, initiate boiler shutdown. Provide the BAS with redundant sensors for hot water flow, hot water temperature Hi Limit



(more than 200° F). Disable operation of the affected boiler(s) if the limits are exceeded. If both boilers trip or fail to proof, initiate an equipment specific alarm at the operator workstation. Prevent the boiler from cycling on and off more often than once every 5 minutes (this may be redundant to the boiler’s internal safeties). For each boiler, disable the boiler before shutting down its pump. After disabling the boiler, run the primary boiler pump serving the boiler for 5 minutes. After 5 minutes, shut down the primary boiler pump and close the hot water isolation valves. If no other boiler is enabled, shut off the secondary water pumps.

7. Hot Water System Outdoor Air Temperature Lockout: If the outdoor air temperature rises above 75° F (adjustable), lock out the hot water system so the boilers and hot water pumps do not run. If the outdoor air temperature falls below 70° F (adjustable) for 20 minutes (adjustable), enable the hot water system.

Points Table:

Key:



AHU air handling unit

B boiler


Cmd command

COV change of value

DB dry-bulb

CAV constant air volume terminal unit







SL secondary loop

Temp temperature

W water (CHW = chilled water, HW = hot water)


°F 0.1


cfm 1

rpm 1

kW 0.1

% 0.1

Point Name AI AO DI DOAnalog Software Value


Other Software

Alarm Logic

Interval or COV

Show on Graphic

OA DB Temp X 15 X

CHW Lockout Temp

X COV 0.5,15 X

HHW Lockout Temp

X COV 0.5,15 X

CHWR Temp X1 15 X

CHWS Temp X1


15 X


X COV-10%,15 X





COV-10%,15 X

CHWSP-n Enable n1 COV X


CHWSP-n Status n1


COV X

CHWSP-n Runtime n >1000 COV 1


n > 6 hour COV

CHWSP-n Cmd Speed n

CHWSP-n Alarm n


CH-n Inlet Temp n1 15 X

CH-n Outlet Temp

n1


15 X

CH Setpoint Temp

X COV


X COV


X COV


n1 COV




n1 COV X

CH-n Alarm n COV X

CH-n Alarm Text n COV X

CH-n Enable n1 COV X


CH-n Status n1


COV X

CH-n Chiller Runtime

n >1000 COV 1




hour COV

CH Lead/Lag X COV X

CHWPP-n Enable n1 COV X


CHWPP-n Status n1


COV X



HWS Temp X1 >180 or <110 15 X



when B flow after 1 minute


X COV-10%,15 X

HW SL Pressure Drop


COV-10%,15 X

HWSP-n Enable n1 COV X


HWSP-n Status n1


COV X



n > 6 hour COV

HWSP-n Cmd Speed n1

HWSP-n Alarm n



B-n Outlet Temp n1

>190 or <110 when B flow after 1 minute

15 X


B Staging X COV



Setpoint Temp


X COV

B-n Alarm n COV X

B-n Alarm Text n COV X

B-n Enable n1 COV X


n1 COV


n1 COV X



COV X





hour COV

B Lead/Lag X COV X

HWPP-n Enable n1 COV X


HWPP-n Status n1


COV X





AHU-n Fire Alarm n1 COV X

AHU-n Operating Mode

n COV X

AHU-n Mode Override

n COV X

AHU-n SAT n 15 X

AHU-n OAT n 15 X

AHU-n OA Damper Cmd

n COV-10%,15 X

AHU-n Supply Fan Enable

n1 COV X

AHU-n Supply Fan Status

n1 Proof after 1 minute

COV X

AHU-n CHWV Bypass Cmd

n COV-10%,15 X

AHU-n Warm-up Mode Low Temp Setpoint

n COV X

AHU-n Cool-Down Mode High Temp Setpoint

n COV X

AHU-n Filter Alarm

n COV X



AHU-n Call for Cooling

n COV

CAV-n Zone Temp n COV-

0.5,15 X

CAV-n Zone Temp Setpoint-Cooling

n COV X

CAV-n Zone Temp Setpoint-Heating

n COV X

CAV-n Zone Temp Unoccupied Setpoint-Cooling

n COV X

CAV-n Zone Temp Unoccupied Setpoint-Heating

n COV X

CAV-n Zone Temp Setpoint-Deadband

n COV X

CAV-n Override n COV X

CAV-n Operating Mode

n COV

CAV-n HW Valve Cmd

n COV-10%,15 X



Notes:

The system consists of Primary/Secondary chilled and hot water loops, multiple air handling units (AHUs), and 1 single duct variable air volume (VAV) terminal unit for each zone in the building. The VAV units (VAV boxes) adjust the air volume delivered to the occupied space and, at the perimeter of the building, VAV boxes include a hot water coil and automatic two-way valve to re-heat the main supply air. Each AHU has a variable volume supply fan, a variable volume return fan, a chilled water cooling coil, and a set of dampers that act as an airside economizer. The economizer has a 2-position outdoor air damper and the return and exhaust air dampers are modulated to regulate “free” cooling. The chilled water loop includes air-cooled chillers and variable speed secondary chilled water pumps. The hot water loop includes two-stage boilers and variable speed secondary hot water pumps. A building automation system (BAS) controls the HVAC equipment.




• Central VAV Air Handling Units

• Built-Up VAV Air Handlers

• 1

• Jail

• 123

• vav

• j

• VAV system

• System

• System 1

• AH-1

• Central

• Air Handling Unit AH-3

• VAV retrofit

• Jail

• HVAC test

• East MOB

• AHU with air-cooled chiller

• AHU 1

• AC-1

• AHU-1

• roof

• The Plant

• HVAC - Enthalpy Economizer

• HVAC - Minimum OA

Variable Air Volume Units with Air-Cooled Chiller 57




VARIABLE-AIR VOLUME (VAV) UNITS WITH A CENTRAL PLANT, AIR COOLED CHILLERS

NCES OF OPERATION

ndling Units (AHUs)

Occupied Periods (Normal operation): When an isolation area is scheduled to be occup

SEQUE

Air Ha

1. ied, operate the air handling unit that serves it. These scheduled periods are

2. lls

day, Christmas. These should

considered “occupied periods” Unoccupied Periods: All hours not included in an occupied period are part of an “unoccupied period”. During these periods, the system is available for tenant caas needed but is not running unless commanded. The following holidays are considered to be unoccupied periods: New Years Day, Memorial Day, Fourth of July, Labor Day, Thanksgiving and the followingbe set up as re-occurring holidays for each zone.



3. en the ly

4.

open.). Vary the return fan (RF) speed to

nd

5.

S to disable the affected units. Once the fire alarm is reset, enable

6. ode: Enable differential enthalpy economizer

or air enthalpy

rn enthalpy decreases below this point, the dampers transition turn position (exhaust damper is closed to allow only minimum outdoor

d ens

entral plant. When the valve

8.

s a

Fan Operation: Run the unit fans in all modes except unoccupied mode. Opminimum outside air dampers when the supply fan is running. Proof the suppfan using an external current switch (CS). Interlock each return fan to its respective supply fan. Supply and Return Fan Capacity Control: When the fans are running, vary the supply fan (SF) speed to maintain the supply duct static pressure setpoint. Reset the duct pressure setpoint from 1.5” to 0.2” (adjustable) based on the damper position of the most open VAV damper as long as that damper is at least 90% open (In other words the static setpoint will be reset to maintain the VAV box requiring the most static pressure at 90% allow the return fan to volumetrically track the supply fan by maintaining the scheduled fixed flow offset equal to XXX CFM (adjustable) between the SF aRF. Fire Alarm: Interface system with the fire alarm controls. When the fire alarm control initiates a fire alarm, shut down the supply and return fans by a hardwired contact interface at each fan’s variable frequency drive (VFD) E-stop contact. Simultaneously, the fire alarm control must notify the BAS of the fire event to enable the BAthe affected unit(s) to resume normal operation. Differential Enthalpy Economizer Mmode when there is a call for cooling or ventilation, and outdoor air temperature is 2° F less than return air temperature. Open outside air damper to 100%. Modulate the return air and exhaust air dampers in unison and modulate the chilled water valve, as required, to maintain supply air temperature setpoint. Maintain the chilled water valve in the closed position when outdois below 21 BTU/lb dry air (adjustable). When the return air enthalpy is 2 BTU/lb dry air (adjustable deadband) above the outdoor air enthalpy, the dampers are to be in the full exhaust position (exhaust damper fully open and return damper fully closed). As the retuto a full reair and the return damper is fully open).

7. Supply Air Temperature Control: Operate economizer mode dampers and chilled water valve in conjunction to maintain the supply air temperature. When the outside air temperature is not sufficient to provide “free” cooling, open the chillewater valve to maintain the supply air temperature setpoint. When the valve opmore than 30% (adj.), send a call for cooling to the ccloses to 5% (adj.), cancel the call for cooling. Reset the supply air temperature upward from 55°F to 65°F as the outdoor temperature falls from above 90° F to below 65° F. Filter Status: Establish the filter pressure drop alarm with the system in operationat actual flow rate as follows: Where DP 100 is the high limit pressure drop at design cfm (determine limit fromfilter manufacturer) and DP x is the high limit at speed signal x (expressed afraction of full supply fan signal). For instance, the setpoint at 50% of speed



would be (0.5) 1.4 or 38% of the design high limit pressure drop. Send an equipment specific alarm (“AH-1 Dirty Filter”) to the operator workstation at 150% (adjustable) of the value calculated during system operation

n Areas

Isolation Areas: There are XX isolation areas as indicated on the plans. Each area is composed of 1 or more spaces served by 1 or more VAV terminal unit

.

Isolatio

1. s that are

operated together. Configure each isolation area separately from other isolationareas. Configuration includes scheduling and operational modes. The default occupancy schedule is 7:00 AM to 6:00 PM, M-F. NOTE: Schedule occupied start time 1 hour before the building is expected to be occupied (for Title 24 required purge).

2.

3. e. t strategy upon outdoor air temperature and average zone

ffset economizer mode to the return position, leave the chilled water valve

4. erature and average

e is

ng ature is 78°F (adjustable) by the occupied period.

wn cycle is required, enable the air handling units, command the acking offset to 0, and leave the general exhaust fans off. Enable the

5. e temperature falls below the

unoccupied heating setpoint or rises above the unoccupied cooling setpoint. End

Occupied Mode: Prior to an occupied period, initiate a Warm-up mode or Cool-down mode if necessary. During Occupied Mode, enable operation of the system, including enabling the air handling unit fans that serve this area and opening the outdoor air dampers to100% open. At the end of an occupied period, initiate unoccupied mode. Warm-up Mode: Use an optimal start strategy to initiate the warm-up start timBase optimal startemperature within the isolation area. If the average zone temperature is less than69°F (adjustable) at the projected start of the warm-up period, initiate the warm-up mode. The optimal start period should pre-heat the building so that the averagezone temperature is 70°F (adjustable) by the occupied period. If building warm-up is required, enable the air handling units and set the return fan tracking oto 0. Set theclosed (or in bypass), and leave the general exhaust fans off. Enable the VAV units to normal occupied operation. Enable the central heating plant but leave the central cooling disabled. After the average zone temperature has risen above 70°F(adjustable), terminate the warm-up cycle, and initiate occupied mode. Cool-down Mode: Use an optimal start strategy to initiate the cool-down start time. Base the optimal start strategy upon outdoor air tempzone temperature within the isolation area. If the average zone temperaturgreater than 79°F (adjustable) at the projected start of the cool-down period, initiate the cool-down mode. The optimal start period should pre-cool the buildiso that the average zone temperIf a cool-doreturn fan trVAV units to normal occupied operation. Enable the chilled water system butleave the central heating disabled. After the average zone temperature has dropped below 78°F (adjustable), terminate the cool-down cycle and initiate occupied mode. Night Setback/Setup Mode: During an unoccupied period, start the air-handlingunit in the warm-up or cool-down mode if a zon



the bsetpoin

6. Uno ir handling units, close their chilled water valves (or put them in bypass), close their

VAV Zo



2. Zone Cooling Mode: When the zone’s temperature rises to 1°F (adjustable) above its setpoint, the zone is in cooling mode and the VAV damper begins to modulate open. As the temperature rises 2° F hotter than its setpoint, the VAV damper is fully open and the zone’s airflow is increased to maximum. As the zone’s temperature approaches the cooling setpoint, modulate the air volume toward minimum.

3. Zone Heating Mode (Perimeter Zones Only): When the zone’s temperature falls to 1 ° F (adjustable) below its setpoint, the zone is in heating mode and the VAV damper modulates to minimum airflow. Once the valve opens to more than 10% (adj.), send a call for heating to the central plant. Modulate the reheat coil control valve to satisfy the space temperature within the reset bounds. Reset the supply air temperature upward from 90°F to 110°F as the outdoor temperature falls from 65° F or greater to 40° F or lower. When the valve closes to 5% (adj.), cancel the call for heating.

set ack/setup mode when the zones are below/above their unoccupied ts.

ccupied Mode: During unoccupied periods, disable VAV units, disable the a

outside air damper(s) and position their return/exhaust air dampers for full returnair (no exhaust). Cancel calls for central plant cooling and heating. When a thermostat override button is depressed during unoccupied period, operate the isolation area in occupied mode for one hour as follows: Operate the air handling unit in occupied mode except for the return-fan volumetric tracking offset (set it to 0) and the general exhaust fans (leave them off). Enable the central plant.

ne Control

1. Temperature Control: Use a solid state, electronic wall temperature sensor to adjust the zone velocity controller setpoint. Airflow to the zone will fluctuate between its minimum and the maximum and supply air temperature will vary in order to maintain a constant room temperature based on this setpoint. Set each temperature sensor for the following ranges:





1. Cooling Mode Enable/Disable: When building comfort cannot be maintained by economizer mode outdoor air temperature, the air handlers call for supplementary cooling by sending a cooling request to the central plant. When all of the AHU chilled water valve positions fall below 5% full open, cancel the call for cooling and initiate chiller shutdown.



4. Chiller Enable: Upon proof of primary chilled water, enable the selected chiller. A hard-wired flow switch will act as a back up to ensure that chiller only starts with chilled water flow. Set the chilled water temperature supply temperature to 45° F (adjustable). After 30 seconds, prove chiller operation by means of a hard-wired current switch. If the chiller fails to prove operation, initiate its shutdown sequence. Then, enable the lag chiller and it’s primary pump. If both chillers fail to proof, send an equipment specific alarm (“Chillers Failed”) to the operator workstation. During operation, use the chillers internal safeties to cause an alarm and shut down the machine. If the chiller does not develop at least a 3°F temperature difference after 15 minutes of being proved on, initiate an alarm on the operator work station. Operate the chillers and their associated primary pumps lead/lag. Swap the lead and lag chillers (as well as their primary pumps) on Sunday at 3:00 AM as long as the lead chiller has operated at least 40 hours and all equipment are disabled.

5. Chiller Staging: If the chilled water return temperature rises to 12°F (adjustable) above the chilled water setpoint, enable lag chiller operation and start the chiller.



Run both chillers until the chilled return temperature falls to 5°F above the chilled water setpoint. At this point, initiate the lag chiller shutdown sequence. Continue running the lead chiller until the chilled water return temperature falls to the setpoint minus the deadband.

6. Chiller Shutdown: Upon a call from the BAS or an internal chiller alarm, initiate chiller shutdown. Disable the chiller but continue to run the primary pump serving the chiller for 5 minutes. After 5 minutes, disable the pump and close the chiller’s isolation valves. If no other chiller is enabled, shutoff the secondary water pumps. Use a timer in the BAS to keep the chiller from cycling on and off more often than every 5 minutes [this may be redundant to the chiller’s internal safeties].

7. Chiller Safeties: Initiate chiller shutdown if the BAS senses low chilled water flow or low chilled water temperature (less than 38° F). Initiate an equipment specific alarm at the operator workstation.




2. Secondary Hot Water Pump Enable: When the BAS registers a call for central plant heating, enable both the secondary hot water pumps by a start-stop command from the BAS. Initially, start the pumps at 10% speed. Proof the start of both of the pumps after 15 seconds using a differential pressure switch. Modulate the speed of the pumps in order to maintain a pressure drop of 10 PSID at the hot water using a differential pressure transmitter. Inhibit starting of the primary pumps and boiler if both pumps fail to prove running status or fail while running. When the commanded speed falls below 40%, disable the lag pump. When the commanded speed rises above 60%, enable the lag pump. If either pump fails to start, initiate an equipment specific critical alarm at the operator workstation. When they are both enabled, lead and lag pumps should run at the same speed.

3. Primary Hot Water Pump Enable (Boiler Initiation): Open the lead boiler’s isolation valves. If the valve opening fails to proof within 30-seconds, close the valve, enable the lag boiler, and send an equipment specific alarm (“B-1 Isolation Valve Failed to Open”) to the operator workstation. If valve opening is successful, enable the primary hot water pump dedicated to the lead boiler. If the flow is not proved within 30 seconds, disable the pump, close the valve and set the lag boiler as the lead boiler. If both valves fail to open, initiate boiler shutdown operation and send equipment specific alarms to the operator workstation. If both pumps fail to provide flow, initiate boiler shutdown operation and send equipment specific alarms to the operator workstation. After 40 hours of operation, on



Sunday at 3:00 AM when both boilers and pumps are shut down, swap the lead and lag pumps.




7. Hot Water System Outdoor Air Temperature Lockout: If the outdoor air temperature rises above 75° F (adjustable), lock out the hot water system so the boilers and hot water pumps do not run. If the outdoor air temperature falls below 70° F (adjustable) for 20 minutes (adjustable), enable the hot water system.

Points Table

Key:






B boiler


Cmd command

COV change of value

DB dry-bulb

M “mixed” such as the air in the mixed air plenum (MAT = mixed air temperature)





SL secondary loop

Temp temperature

W water (CHW = chilled water, HW = hot water)


°F 0.1


cfm 1

rpm 1

kW 0.1

% 0.1




Alarm Logic

Interval or COV

Show on Graphic



OA DB Temp X 15 X

OA RH X 15 X

OA Enthalpy X 15 X

CHW Lockout Temp

X COV 0.5,15 X

HHW Lockout Temp

X COV 0.5,15 X

CHWR Temp

X 1 15 X

CHWS Temp X 1


15 X


X COV-10%,15 X



COV-10%,15 X

CHWSP-n Enable n 1 COV X


CHWSP-n Status n

1 Proof after 1 minute

COV X



n > 6 hour COV

CHWSP-n Cmd Speed n



CHWSP-n Run Speed n

=Cmd after 1 minute

COV-10%,15 X

CHWSP-n Alarm n

CHWSP-n Power n X


CH-n Inlet Temp n 1 15 X

CH-n Outlet Temp n 1


15 X



X COV


X COV


n 1 COV


n 1 COV X

CH-n Alarm n COV X


CH-n Enable n 1 COV X


CH-n CHW flow status n

1 COV X



CH-n Status n 1 Proof after 1 minute

COV X

CH-n Voltage 3n

10% high or low

60

CH-n Amperage 3n 60

CH-n Power n 15 X

CH-n Phase monitor alarm

n COV X

CH-n Chiller Runtime n >1000 COV 1




hour COV

CH Lead/Lag X COV X

CHWPP-n Enable n 1 COV X


CHWPP-n Status n


COV X


CHWPP-n Power n X


HWR Temp X 1 15 X

HWS Temp X 1

>180 or <110 when B

15 X



flow after 1 minute


X COV-10%,15 X

HW SL Pressure Drop


COV-10%,15 X

HWSP-n Enable n 1 COV X


HWSP-n Status n


COV X



n > 6 hour COV

HWSP-n Cmd Speed n 1

HWSP-n Run Speed n

=Cmd after 1 minute

COV-10%,15 X

HWSP-n Alarm n

HWSP-n Power n X



B-n Outlet Temp n 1

>190 or <110 when B flow after 1

15 X



minute



X COV


X COV

B-n Alarm n COV X


B-n Enable n 1 COV X


n 1 COV


n 1 COV X




COV X





hour COV

B Lead/Lag X COV X

HWPP-n Enable n 1 COV X




HWPP-n Status n


COV X


HWPP-n Power n X


AHU-n Fire Alarm n

1 COV X


n COV X

AHU-n Mode Override

n COV X

AHU-n SAT n 15 X

AHU-n OAT n 15 X

AHU-n RAT n 15 X

AHU-n RA RH n 15 X

AHU-n RA Enthalpy n 15 X

AHU-n MAT n 15 X

AHU-n Supply Flow n


15 X

AHU-n Return Flow n


15 X

AHU-n Outdoor Air Flow

n

<5000 CFM for 5 minutes

15 X

AHU-n Flow Offset n COV

AHU-n OA Damper Cmd n COV-

10%,15 X



AHU-n RA Damper Cmd n COV-

10%,15 X

AHU-n MA Damper Cmd n COV-

10%,15 X

AHU-n Economizer High Ambient Lockout Temp

n COV-0.5,15 X

AHU-n Economizer CHW Minimum Temp

n COV-0.5,15 X

AHU-n Supply Reset Temp

n COV-0.5,15 X

AHU-n Supply Pressure Setpoint

n COV-10%,15 X

AHU-n Supply Pressure

n >3” 15 X


n 1 COV X


n 1


COV X

AHU-n Supply Fan Runtime

n >1000 COV 1

AHU-n Supply Fan Cmd Speed

n 1 15 X

AHU-n-Supply Fan Run Speed


COV-10%,15 X

AHU-n n



Supply Fan Alarm

AHU-n Supply Fan Power

n X

AHU-n Return Fan Enable

n 1 COV X

AHU-n Return Fan Status

n 1


COV X

AHU-n Return Fan Runtime

n >1000 COV 1

AHU-n Return Fan Cmd Speed

n 1 15 X

AHU-n-Return Fan Run Speed


COV-10%,15 X

AHU-n Return Fan Alarm

n

AHU-n Return Fan Power

n X


n COV-10%,15 X

AHU-n CHWV Bypass Feedback


COV-10%,15 X

AHU-n Warm-up Mode Low Temp Setpoint

n COV X

AHU-n Cool-Down Mode High Temp

n COV X



Setpoint

AHU-n Filter Alarm n COV X

AHU-n Call for Cooling n COV

VAV-n Zone Temp n COV-

0.5,15 X

VAV-n Zone Temp Setpoint-Cooling

n COV X

VAV-n Zone Temp Setpoint-Heating

n COV X

VAV-n Zone Temp Unoccupied Setpoint-Cooling

n COV X

VAV-n Zone Temp Unoccupied Setpoint-Heating

n COV X

VAV-n Zone Temp Setpoint-Deadband

n COV X

VAV-n Override n COV X

VAV-n Operating Mode

n COV

VAV-n Supply Air Temperature

n COV-0.5,15 X

VAV-n Supply Air Temp Reset

n X



VAV-n HW Valve Cmd n COV-

10%,15 X

VAV-n Damper Cmd n COV X



Notes: The system consists of Primary/Secondary chilled and hot water loops, multiple air handling units (AHUs), and 1 single duct variable air volume (VAV) terminal unit for each zone in the building. The VAV units (VAV boxes) adjust the air volume delivered to the occupied space and, at the perimeter of the building, VAV boxes include a hot water coil and automatic two-way valve to re-heat the main supply air. Each AHU has a variable volume supply fan, a variable volume return fan, a chilled water cooling coil, and a set of dampers that act as an airside economizer. The economizer has a 2-position outdoor air damper and the return and exhaust air dampers are modulated to regulate “free” cooling. The chilled water loop includes water-cooled chillers and variable speed secondary chilled water pumps. The hot water loop includes two-stage boilers and variable speed secondary hot water pumps. A building automation system (BAS) controls the HVAC equipment.




• AH-1



Variable Air Volume Units with Water-Cooled Chiller 76


VARIABLE-AIR VOLUME (VAV) UNITS WITH A CENTRAL PLANT, WATER COOLED CHILLERS AND COOLING TOWERS


Air Handling Units (AHUs)

1. Occupied Periods (Normal operation): When an isolation area is scheduled to be occupied, operate the air handling unit that serves it. These scheduled periods are considered “occupied periods”.


3. Fan Operation: Run the unit fans in all modes except unoccupied mode. Open the minimum outside air dampers when the supply fan is running. Proof the supply fan using an external current switch (CS). Interlock each return fan to its respective supply fan.

4. Supply and Return Fan Capacity Control: When the fans are running, vary the supply fan (SF) speed to maintain the supply duct static pressure setpoint. Reset the duct pressure setpoint from 1.5” to 0.2” (adjustable) based on the damper



position of the most open VAV damper as long as that damper is at least 90% open (In other words the static setpoint will be reset to maintain the VAV box requiring the most static pressure at 90% open.). Vary the return fan (RF) speed to allow the return fan to volumetrically track the supply fan by maintaining the scheduled fixed flow offset equal to XXX CFM (adjustable) between the SF and RF.

5. Fire Alarm: Interface system with the fire alarm controls. When the fire alarm control initiates a fire alarm, shut down the supply and return fans by a hardwired contact interface at each fan’s variable frequency drive (VFD) E-stop contact. Simultaneously, the fire alarm control must notify the BAS of the fire event to enable the BAS to disable the affected units. Once the fire alarm is reset, enable the affected unit(s) to resume normal operation.

6. Duct Pressure Safety: If negative static pressure over 2” WC is measured in the mixed air plenum or positive supply duct static pressure over 3” WC is measured in the supply duct, disable the fan VFDs via hard wired interlocks to their E-stop contacts and initiate an equipment specific alarm (i.e. “AH-3 High Static Pressure” or “AH-2 Low Static Pressure”) at the operator workstation. An operator must reset each fan’s differential pressure switch before the VFDs may be re-enabled. Provide a local or BAS reset for this purpose.

7. Differential Dry-Bulb Economizer Mode: Enable differential economizer mode when there is a call for cooling or ventilation, and outdoor air temperature is 2° F less than return air temperature. Open outside air damper to 100%. Modulate the return air and exhaust air dampers in unison and modulate the chilled water valve, as required, to maintain supply air temperature setpoint. Maintain the chilled water valve in the closed position when outdoor air temperature is below 52° F (adjustable). When the return air temperature is 2° F (adjustable deadband) or more above the outdoor air temperature, exhaust and return dampers are to be in the full exhaust position (exhaust damper fully open and return damper fully closed). As the return air temperature decreases below this point, the dampers transition to a full return position (exhaust damper is closed to allow only minimum outdoor air and the return damper is fully open).

8. Supply Air Temperature Control: Operate economizer mode dampers and chilled water valve in conjunction to maintain the supply air temperature. When the outside air temperature is not sufficient to provide “free” cooling, open the chilled water valve to maintain the supply air temperature setpoint. When the valve opens more than 30% (adj.), send a call for cooling to the central plant. When the valve closes to 5% (adj.), cancel the call for cooling. The supply air temperature is reset upwards from 90°F to 110°F as the outdoor temperature falls from 65° F or greater to 40° F or lower.

9. Filter Status: Establish the filter pressure drop alarm with the system in operation at actual flow rate as follows: Where DP 100 is the high limit pressure drop at design cfm (determine limit from filter manufacturer) and DP x is the high limit at speed signal x (expressed as a fraction of full supply fan signal). For instance, the setpoint at 50% of speed



would be (0.5) 1.4 or 38% of the design high limit pressure drop. Send an equipment specific alarm (“AH-1 Dirty Filter”) to the operator workstation at 150% (adjustable) of the value calculated during system operation.

Isolation Areas

1. Isolation Areas: There are XX isolation areas as indicated on the plans. Each area is composed of 1 or more spaces served by 1 or more VAV terminal units that are operated together. Configure each isolation area separately from other isolation areas. Configuration includes scheduling and operational modes. The default occupancy schedule is 7:00 AM to 6:00 PM, M-F. NOTE: Schedule occupied start time 1 hour before the building is expected to be occupied (for Title 24 required purge).

2. Occupied Mode: Prior to an occupied period, initiate a Warm-up mode or Cool-down mode if necessary. During Occupied Mode, enable operation of the system, including enabling the air handling unit fans that serve this area and opening the outdoor air dampers to100% open. At the end of an occupied period, initiate unoccupied mode.

3. Warm-up Mode: Use an optimal start strategy to initiate the warm-up start time. Base optimal start strategy upon outdoor air temperature and average zone temperature within the isolation area. If the average zone temperature is less than 69°F (adjustable) at the projected start of the warm-up period, initiate the warm-up mode. The optimal start period should pre-heat the building so that the average zone temperature is 70°F (adjustable) by the occupied period. If building warm-up is required, enable the air handling units and set the return fan tracking offset to 0. Set the economizer mode to the return position, leave the chilled water valve closed (or in bypass), and leave the general exhaust fans off. Enable the VAV units to normal occupied operation. Enable the central heating plant but leave the central cooling disabled. After the average zone temperature has risen above 70°F (adjustable), terminate the warm-up cycle, and initiate occupied mode.

4. Cool-down Mode: Use an optimal start strategy to initiate the cool-down start time. Base the optimal start strategy upon outdoor air temperature and average zone temperature within the isolation area. If the average zone temperature is greater than 79°F (adjustable) at the projected start of the cool-down period, initiate the cool-down mode. The optimal start period should pre-cool the building so that the average zone temperature is 78°F (adjustable) by the occupied period. If a cool-down cycle is required, enable the air handling units, command the return fan tracking offset to 0, and leave the general exhaust fans off. Enable the VAV units to normal occupied operation. Enable the chilled water system but leave the central heating disabled. After the average zone temperature has dropped below 78°F (adjustable), terminate the cool-down cycle and initiate occupied mode.

5. Night Setback/Setup Mode: During an unoccupied period, start the air-handling unit in the warm-up or cool-down mode if a zone temperature falls below the unoccupied heating setpoint or rises above the unoccupied cooling setpoint. End



the setback/setup mode when the zones are below/above their unoccupied setpoints.

6. Unoccupied Mode: During unoccupied periods, disable VAV units, disable the air handling units, close their chilled water valves (or put them in bypass), close their outside air damper(s) and position their return/exhaust air dampers for full return air (no exhaust). Cancel calls for central plant cooling and heating. When a thermostat override button is depressed during unoccupied period, operate the isolation area in occupied mode for one hour as follows: Operate the air handling unit in occupied mode except for the return-fan volumetric tracking offset (set it to 0) and the general exhaust fans (leave them off). Enable the central plant.

VAV Zone Control

1. Temperature Control: Use a solid state, electronic wall temperature sensor to adjust the zone velocity controller setpoint. Airflow to the zone will fluctuate between its minimum and the maximum and supply air temperature will vary in order to maintain a constant room temperature based on this setpoint. Set each temperature sensor for the following ranges:




2. Zone Cooling Mode: When the zone’s temperature rises to 1°F (adjustable) above its setpoint, the zone is in cooling mode and the VAV damper begins to modulate open. As the temperature rises 2° F hotter than its setpoint, the VAV damper is fully open and the zone’s airflow is increased to maximum. As the zone’s temperature approaches the cooling setpoint, modulate the air volume toward minimum.

3. Zone Heating Mode (Perimeter Zones Only): When the zone’s temperature falls to 1 ° F (adjustable) below its setpoint, the zone is in heating mode and the VAV damper modulates to minimum airflow. Modulate the reheat coil control valve to satisfy the space temperature within the reset bounds. Reset the supply air temperature upward from 90°F to 110°F as the outdoor temperature falls from 65° F or greater to 40° F or lower. Once the valve opens to more than 10% (adj.), send a call for heating to the central plant. When the valve closes to 5% (adj.), cancel the call for heating.




1. Cooling Mode Enable/Disable: When building comfort cannot be maintained by economizer mode outdoor air temperature, the air handlers call for supplementary cooling by sending a cooling request to the central plant. When all of the AHU chilled water valve positions fall below 5% full open, cancel the call for cooling and initiate chiller shutdown.



4. Chiller Enable: Upon proof of primary chilled water and condenser water flow, enable the selected chiller. A hard-wired flow switch will act as a back up to ensure that chiller only starts with chilled water flow. Set the chilled water temperature supply temperature to 45° F (adjustable). After 30 seconds, prove chiller operation by means of a hard-wired current switch. If the chiller fails to prove operation, initiate its shutdown sequence. Then, enable the lag chiller and it’s primary pump. If both chillers fail to proof, send an equipment specific alarm (“Chillers Failed”) to the operator workstation. During operation, use the chillers internal safeties to cause an alarm and shut down the machine. If the chiller does not develop at least a 3°F temperature difference after 15 minutes of being proved on, initiate an alarm on the operator work station. Operate the chillers and their associated primary pumps lead/lag. Swap the lead and lag chillers (as well as their primary pumps) on Sunday at 3:00 AM as long as the lead chiller has operated at least 40 hours and all equipment are disabled.

5. Chiller Staging: If the chilled water return temperature rises to 12°F (adjustable) above the chilled water setpoint, enable lag chiller operation and start the chiller.



Run both chillers until the chilled return temperature falls to 5°F above the chilled water setpoint. At this point, initiate the lag chiller shutdown sequence. Continue running the lead chiller until the chilled water return temperature falls to the setpoint minus the deadband.

Condenser Water System

1. Chemical Treatment: Provide chemical treatment for the cooling towers via an automatic chemical feed and bleed system. Run the water treatment system independently of the BAS.

2. Safeties: Disable the condenser water pump and the chiller operation if the water level in the cooling tower basin falls below the minimum. Initiate an equipment specific alarm (“Low Water Level in CT-1”) at the operator workstation.

3. Condenser Water Pump Enable: When the BAS registers a call for cooling from the central plant, enable the lead condenser water pump. Prove condenser water flow within 30-seconds (adjustable) using a differential pressure switch. If the flow is not proved, disable the pump, and enable and start the lag pump. Send equipment specific critical alarm (“CWP-1 Failed”) to the operator workstation. The lag pump is also enabled by the start-up of the lag chiller. If both pumps fail to provide flow, initiate chiller shutdown operation and initiate a critical alarm (“Condenser Water Pumps failed”) to the operator workstation. Swap the lead and lag pumps on Sunday at 3:00 AM as long as the lead pump has operated at least 40 hours and both pumps are shut down.

4. Condenser Water Temperature Control: Prior to operation of the condenser water pump, the cooling tower bypass valve should be in the bypass position (bypassing the cooling towers) and the cooling tower fans shut off. Once condenser water flow is proved, operate the cooling tower fan and bypass valve in order to maintain a condenser water supply setpoint between 75° F and 85° F. Modulate the condenser water bypass valve so that at 80° F condenser water supply temperature, the water is not bypassing the cooling tower. Start both cooling tower fans at minimum speed when the water temperature increases to 82°F. Modulate the tower fans speed as necessary to maintain the setpoint temperature. If the temperature exceeds the high limit of 90° F, initiate the chiller shutdown sequence and send an equipment specific alarm (“Condenser Water High Limit Temperature”) to the operator workstation. As the temperature falls below 82 ° F, disable the fans and modulate the bypass valve to maintain setpoint temperature. If the condenser supply temperature falls below the low limit of 70° F after running for 5 minutes, initiate the chiller shutdown sequence and send an equipment specific alarm (“Condenser Water Low Limit Temperature”) to the operator workstation.

5. Condenser Water System Shutdown: When the lag chiller is shutdown, disable the lag chilled water pump after a 5 minute run time. Adjust the condenser water fan speed and bypass valve positions to maintain temperature as indicated elsewhere. When the lead chiller is shutdown, run the lead condenser water pump for 5



minute. Then disable the cooling tower fans, disable the lead pump, and modulate the bypass valve to full bypass.


1. Heating Mode Enable: Generate a call for heating from zone controllers if any of the zone valve positions is greater than 10% (adjustable) of full open until all are below 5% (adjustable)

2. Secondary Hot Water Pump Enable: When the BAS registers a call for central plant heating, enable both the secondary hot water pumps by a start-stop command from the BAS. Initially, start the pumps at 10% speed. Proof the start of both of the pumps after 15 seconds using a differential pressure switch. Modulate the speed of the pumps in order to maintain a pressure drop of 10 PSID at the hot water using a differential pressure transmitter. Inhibit starting of the primary pumps and boiler if both pumps fail to prove running status or fail while running. When the commanded speed falls below 40%, disable the lag pump. When the commanded speed rises above 60%, enable the lag pump. If either pump fails to start, initiate an equipment specific critical alarm at the operator workstation. When they are both enabled, lead and lag pumps should run at the same speed.







Points Table

Key:




B boiler


Cmd command

COV change of value

CT cooling tower

DB dry-bulb








SL secondary loop

Temp temperature

W water (CW = condenser water, HW = hot water)


°F 0.1


cfm 1

rpm 1

kW 0.1

% 0.1



Other Software

Alarm Logic

Interval or COV

Show on Graphic

OA DB Temp X 15 X

OA RH X 15 X

OA Enthalpy X 15 X

CHWR Temp

X 1 15 X

CHWS Temp X 1


15 X


X COV-10%,15 X





COV-10%,15 X

CHWSP-n Enable n 1 COV X


CHWSP-n Status n


COV X



n > 6 hour COV

CHWSP-n Cmd Speed n

CHWSP-n Run Speed n

=Cmd after 1 minute

COV-10%,15 X

CHWSP-n Alarm n

CHWSP-n Power n X


CH-n Inlet Temp n 1 15 X

CH-n Outlet Temp n 1


15 X



X COV

CH Staging X COV



Deadband Temp


n 1 COV


n 1 COV X

CH-n CW Isolation Valve Cmd

n 1 COV

CH-n CW Isolation Valve Feedback

n 1 COV X

CH-n Alarm n COV X


CH-n Enable n 1 COV X


CH-n CHW flow status n

1 COV X

CH-n CW flow status n

1 COV X

CH-n Status n 1 Proof after 1 minute

COV X

CH-n Voltage 3n

10% high or low

60

CH-n Amperage 3n 60

CH-n Power n 15 X

CH-n Phase monitor alarm

n COV X

CH-n Chiller n >1000 COV 1



Runtime




hour COV

CH Lead/Lag X COV X

CHWPP-n Enable n 1 COV X


CHWPP-n Status n


COV X


CHWPP-n Power n X


CWR Temp X 1 15 X

CWS Temp X 1


15 X

CWP-n Enable n 1 COV X

CW-n Override n COV X

CWP-n Status n


COV X

CWP-n Runtime n >1000 COV 1

CWP-n n X



Power

CWP Lead/Lag X COV X

CW Bypass Cmd X COV-

10%,15 X

CW Bypass Feedback X

=Cmd after 1 minute

COV-10%,15 X

CW Temp Set point X COV-

0.5,15 X

CW Minimum Temp

X COV

CW Maximum Temp

X COV

CW Temp Set point deadband

X COV

CW Valve Set point Temp

X COV

CT-n Alarm n COV X

CT-n Enable n 1 COV X

CT-n Override n COV X

CT-n Status n 1 Proof after 1 minute

COV X

CT-n Power n 15 X

CT-n Runtime n >1000 COV 1

CT-n Cycle Counter n > 6

hour COV

CT Lead/Lag X COV X

CT-n Low Water Alarm n COV X

HWR Temp X 15 X



1

HWS Temp X 1


15 X


X COV-10%,15 X

HW SL Pressure Drop


COV-10%,15 X

HWSP-n Enable n 1 COV X


HWSP-n Status n


COV X



n > 6 hour COV

HWSP-n Cmd Speed n 1

HWSP-n Run Speed n

=Cmd after 1 minute

COV-10%,15 X

HWSP-n Alarm n

HWSP-n Power n X





B-n Outlet Temp n 1


15 X



X COV


X COV

B-n Alarm n COV X


B-n Enable n 1 COV X


n 1 COV


n 1 COV X




COV X





hour COV

B Lead/Lag X COV X



HWPP-n Enable n 1 COV X


HWPP-n Status n


COV X


HWPP-n Power n X


AHU-n Fire Alarm n

1 COV X


n COV X

AHU-n Mode Override

n COV X

AHU-n SAT n 15 X

AHU-n OAT n 15 X

AHU-n RAT n 15 X

AHU-n RA RH n 15 X

AHU-n RA Enthalpy n 15 X

AHU-n MAT n 15 X

AHU-n Supply Flow n


15 X

AHU-n Return Flow n


15 X

AHU-n Outdoor Air Flow

n

<5000 CFM for 5 minutes

15 X



AHU-n Flow Offset n COV

AHU-n OA Damper Cmd n COV-

10%,15 X

AHU-n RA Damper Cmd n COV-

10%,15 X

AHU-n MA Damper Cmd n COV-

10%,15 X

AHU-n Economizer High Ambient Lockout Temp

n COV-0.5,15 X

AHU-n Economizer CHW Minimum Temp

n COV-0.5,15 X

AHU-n Supply Reset Temp

n COV-0.5,15 X

AHU-n Supply Pressure Setpoint

n COV-10%,15 X

AHU-n Supply Pressure

n >3” 15 X


n 1 COV X


n 1


COV X

AHU-n Supply Fan Runtime

n >1000 COV 1

AHU-n Supply Fan Cmd Speed

n 1 15 X



AHU-n-Supply Fan Run Speed


COV-10%,15 X

AHU-n Supply Fan Alarm

n

AHU-n Supply Fan Power

n X

AHU-n Return Fan Enable

n 1 COV X

AHU-n Return Fan Status

n 1


COV X

AHU-n Return Fan Runtime

n >1000 COV 1

AHU-n Return Fan Cmd Speed

n 1 15 X

AHU-n-Return Fan Run Speed


COV-10%,15 X

AHU-n Return Fan Alarm

n

AHU-n Return Fan Power

n X


n COV-10%,15 X

AHU-n CHWV Bypass Feedback


COV-10%,15 X

AHU-n Warm-up Mode Low Temp

n COV X



Setpoint

AHU-n Cool-Down Mode High Temp Setpoint

n COV X

AHU-n Filter Alarm n COV X

AHU-n Call for Cooling n COV

VAV-n Zone Temp n COV-

0.5,15 X

VAV-n Zone Temp Setpoint-Cooling

n COV X

VAV-n Zone Temp Setpoint-Heating

n COV X

VAV-n Zone Temp Unoccupied Setpoint-Cooling

n COV X

VAV-n Zone Temp Unoccupied Setpoint-Heating

n COV X

VAV-n Zone Temp Setpoint-Deadband

n COV X

VAV-n Override n COV X

VAV-n Operating Mode

n COV

VAV-n Supply Air Temperature

n COV-0.5,15 X



VAV-n Supply Air Temp Reset

n X

VAV-n HW Valve Cmd n COV-

10%,15 X

VAV-n Damper Cmd n COV X



Notes: The system consists of multiple water source heat pump units, 2 boilers with primary pumps and 2 fluid coolers with integral pumps (not shown) all connected to a condenser water loop. The water source heat pump units (WSHP) have integral variable flow supply fans, internally controlled by the unit, that provide conditioned air to the occupied spaces. Outside air is provided through ducted air intakes. Barometric relief dampers maintain building pressurization and allow building air to be exhausted outside. The fluid coolers and boilers provide temperature control for the condenser water loop (or water loop) and two variable-speed water loop pumps circulate the water to each component of the system. Together the water loop, its pumps, the fluid coolers, and the boilers are described as the “water loop central plant”. A building automation system (BAS) controls the equipment.

Appropriate reference(s) in the specifications should be made for products that are integrated with these sequences including fluid coolers, boilers, variable frequency drives (VFDs), and the like.





CONDENSER WATER LOOP HEAT PUMP SYSTEM

Water Source Heat Pump System 97



Water Source Heat Pump Units

1. Occupied Periods (normal operation): Operate the system on a programmed occupancy schedule from 7:00 AM to 6:00 PM, M-F. These periods are considered “occupied periods”. During occupied periods, run the system in Occupied Mode.

NOTE: Schedule occupied start time 1 hour before the building is expected to be occupied (for Title 24 required purge).


3. Fan Operation: Run the unit fans in all modes except unoccupied mode. Minimum outside air will enter the unit when the supply fan is running based on the building’s pressurization.

4. Fire Alarm: Interface system with the fire alarm controls. When the fire alarm control initiates a fire alarm, shut down the affected supply fan(s) by hardwired contact interface at the contactor. Simultaneously, fire alarm control must notify the BAS of a fire event to enable the BAS to disable the affected units. Once the fire alarm is reset, enable the affected unit(s) to resume normal operation.

5. Occupied Mode: Prior to an occupied period, use an optimal start strategy to initiate a Warm-up mode or Cool-down mode. During Occupied Mode, enable operation of heat pump units and the water loop central plant. At the end of an occupied period, initiate water loop shutdown, disable the heat pump units, and close their condenser water valves.

6. Unoccupied Mode: During unoccupied periods, the heat pump unit’s supply fans are off and the heat pump unit’s condenser water (CW) valve is closed. Each heat pump unit, supported by the central plant, can be started by the BAS to respond to after-hours calls from the zone thermostats. When a thermostat override button is depressed during unoccupied period (i.e. after-hours call), operate the system in occupied mode for one hour.

7. Warm-up Mode: Base the Warm-up start time on an optimal start strategy calculated using outdoor air temperature and average zone temperature. If the average zone temperature is less than 69°F (adjustable), initiate the warm-up mode and set the Warm-up Mode Low Temperature Setpoint to 70°F (adjustable). Enable the water loop pumps, the boilers, and the boiler pumps. Once water loop is proved, enable the heat pump unit(s), as required, to operate in heating mode. Disable fluid coolers during warm-up mode. Terminate warm-up mode when the average zone temperature rises above the Warm-up Mode Low Temperature



Setpoint and transition the system to occupied mode (if scheduled) or to unoccupied mode.

8. Cool-down Mode: Base the cool-down start time on an optimal start strategy calculated using outdoor air temperature and average zone temperature. If the average zone temperature is greater than 79°F (adjustable), initiate the cool-down mode and set the Cool-down Mode High Temperature Setpoint to 78°F (adjustable). To initiate a cool-down mode, enable the water loop pumps, and the fluid coolers. Once water loop flow is proved, enable each heat pump unit to operate in cooling mode. Disable the boilers during cool-down mode. Terminate Cool-down mode when the average zone temperature falls below the Cool-down Mode High Temperature Setpoint and transition the system to occupied mode (if scheduled) or to unoccupied mode.

9. Supply Air Temperature Control: When a call for heating or cooling is made from a zone thermostat, open the condenser water valve and prove flow with a flow switch. If flow is proved within 60 seconds of valve opening, the enable the heat pump unit. If the flow is not proved, generate an equipment specific alarm at the operator workstation. Prevent the heat pump compressor from cycling between cooling and heating more often than once every 3 minutes. Also, prevent the heat pump compressor from cycling on and off more often than once every 3 minutes.

10. Filter Status: Monitor the air filter condition with a differential pressure transducer to determine if the filter is dirty.

11. Zone Temperature Control: Use a programmable, solid state, electronic thermostat to adjust the zone velocity controller setpoint integral to each heat pump unit’s supply fan. Airflow to the zone will fluctuate between its minimum and the maximum to maintain a constant room temperature based on this setpoint. Set each thermostat for the following ranges:



Maintain a deadband of at least 5° F between heating and cooling setpoints. During unoccupied hours, set the heating setpoint default to 55° F (adjustable) and the cooling setpoint default to 85° F (adjustable). Allow each zone to have its own adjustable unoccupied heating and cooling setpoints.

12. Cooling Mode: When the thermostat indicates a call for cooling, set the heat pump to cooling mode.

13. Heating Mode: When the thermostat indicates a call for heating, set the heat pump to heating mode.

14. Night Setback/Setup: During an unoccupied period, enable the warm-up mode if any zone thermostat falls below the unoccupied heating setpoint and set the Warm-up Mode Low Temperature Setpoint equal to the unoccupied heating setpoint. Also, enable the cool-down mode if any zone thermostat rises above the unoccupied cooling setpoint and set the Cool-Down Mode High Temperature



Setpoint equal to the unoccupied cooling setpoint. Allow each unit to have its own adjustable night setback and night setup setpoints.

15. Heat Pump Compressor Shutdown: If the unit stops generating a call for heating or cooling, the condenser water system shuts down, or a refrigeration fault occurs, disable the compressor operation. After the compressor is disabled, leave the flow control valve open for two minutes and then close it.

Water Loop Central Plant

1. Chemical Treatment: Chemically treat the fluid cooler via an automatic chemical feed and bleed system. The fluid cooler water treatment system runs independently of the BAS.

2. Safeties: Disable the fluid cooler’s pump if the water level in the fluid cooler’s basin falls below its minimum allowable level. Initiate a Low Water Basin Alarm at the BAS operator workstation.

3. Water Loop Pump Enable: Start the pumps at 10% speed. If the flow is not proved within 60 seconds (adjustable) as indicated by a differential pressure switch, disable the pump(s), and initiate an equipment specific critical alarm (“CP-1 Failed”) at the operator workstation. Modulate the speed of the pumps in order to maintain a differential pressure setpoint of 15 PSID at the central plant. When the commanded speed falls below 40%, shut down the lag pump. When the commanded speed rises above 60%, start the lag pump. After 40 hours of operation, on Sunday at 3:00 AM when the system is in unoccupied mode, swap the lead and lag pumps.

4. Water Loop Cooling Temperature Control: When the water loop pumps are enabled, the fluid cooler bypass valve is in the bypass position (bypassing the fluid coolers) and the fluid cooler fans are off. As the water loop supply temperature increases to above 86° F, begin opening valve (to no bypass) and start the fluid cooler pump. As the water loop temperature increases to 87°F, start both fluid cooler fans at minimum speed. Modulate the fan speed to maintain 85°F. Below 84° F, cycle the fans off. If the water loop temperature exceeds the high limit of 90° F, generate an alarm at the operator workstation. As the water loop supply temperature falls below 83° F, begin modulating the bypass valve to full bypass and turn off the fluid cooler pump.

5. Water Loop Heating Temperature Control: When the water loop pumps are enabled, the boiler bypass valve is in the bypass position (bypassing the boilers) and the boilers are off. If the water loop supply temperature falls below 71° F for 3 minutes, begin opening the bypass valve (to no bypass) and enable the boiler pumps. As the condenser supply water temperature falls to 69° F, modulate the bypass valve to no bypass in order to maintain temperature. Enable the boilers when the bypass valve is all the way open (no bypass). If the water loop supply temperature falls below the low limit of 68° F, generate an alarm at the operator workstation. As the water loop supply temperature rises above 72° F for 3 minutes, initiate boiler shutdown and begin modulating the bypass valve to full bypass.



6. Boiler Pump Enable (Boiler Initiation): When the boiler bypass valve begins to modulate open, open the isolation valves to the lead boiler. If the valve opening fails to prove within 60 seconds, close the valve, set the lag boiler as lead and send an equipment specific alarm (“B-1 Isolation Valve Failed to Open”) to the operator workstation. Repeat valve operation with lag boiler. If both valves fail to open, initiate boiler shutdown operation and send equipment specific alarms to the operator workstation. If valve opening is successful, enable the lead primary boiler pump. If the flow is not proofed within 60 seconds, disable the pump, and set the lag pump as lead. If both pumps fail to provide flow, initiate the boiler shutdown operation. Initiate equipment specific alarms at the operator workstation for the failure of either pump. The primary pumps are operated lead/lag. After 40 hours of operation, on Sunday at 3:00 AM when both boilers and pumps are shut down, swap the lead and lag pumps.

7. Boiler Enable: Upon proof of primary hot water flow, enable the selected boiler. Provide a hard-wired flow switch to act as a back up to ensure that boiler only starts with hot water flow. Send an initial hot water temperature of 140° F to the boiler controller. Prove the boiler operation after 60 seconds in the following manner: if the boiler has not developed at least 3° F of differential temperature between its supply and return temperatures, disable the boiler and initiate its shutdown sequence. Operate the boilers lead/lag. After 40 hours of operation, on Sunday at 3:00 AM when both boilers and pumps are shut down, swap the lead position. Enable the lag boiler to start. If either or both boilers fail to prove or fail to proof when required to operate, initiate boiler shutdown and send equipment specific alarms to the operator workstation. During operation, use the boiler’s internal safeties to initiate an equipment alarm at the operator workstation and disable the machine. If the boiler does not develop at least a 3°F temperature difference after 15 minutes of being enabled initiate a equipment specific alarm at the operator workstation.

8. Boiler Staging: Modulate the internal boilers controls between the boiler’s two stages to meet the BAS water loop setpoint. If during boiler operation, the hot water temperature differential falls to 5°F (adjustable), initiate the lag boiler operation. Maintain operation of both boilers until the hot water temperature differential rises to 12° F. At this point, initiate the lag boiler shutdown sequence.

9. Boiler Shutdown: Upon a call from the BAS or an internal alarm, initiate the boiler shutdown. Provide the BAS with redundant sensors for hot water flow, hot water temperature Hi Limit (more than 200° F). Disable operation of the affected boiler(s) if the limits are exceeded. If both boilers trip or fail to proof, initiate an equipment specific alarm at the operator workstation. Prevent the boiler from cycling on and off more often than once every 5 minutes (this may be redundant to the boiler’s internal safeties). For each boiler, disable the boiler first before shutting down its pump. After disabling the boiler, run the primary boiler pump serving the boiler for 5 minutes. After 5 minutes, shut down the primary boiler pump and close the hot water isolation valves.



10. Water Loop Shutdown: When water loop shutdown is initiated, run the pumps for 5 minutes and then shut them off. When the water loop is shut down due to being disabled or due to a fault, lockout operation of the heat pump compressors.

Points Table

Key:



B boiler

FLC fluid cooler

Cmd command

COV change of value

DB dry-bulb

WSHP water-source heat pump unit

HW Hot water



P pump (FLCP = fluid cooler pump, PP = primary pump)

R return (FLCR = fluid cooler return water temperature)


SL secondary loop

CW condenser water (i.e. water loop)


°F 0.1




cfm 1

rpm 1

kW 0.1

% 0.1

Point Name AI AO DI DOAnalog Software Value



Alarm Logic

OA DB Temp X

CWS Temperature X

CWR Temperature X

CW Temp Set point X

CW Minimum Temp X Water loop

min. temp

CW Maximum Temp X Water loop

max. temp

CW Pressure Drop Setpoint X

CW Pressure Drop X =Cmd after 1 minute

CWP-n Enable n 1

CWP-n override n

CWP-n Status n 1 Proof after 1 minute

CWP-n Runtime n >1000

CWP-n Cycle Counter n > 6 hour

CWP-n Cmd Speed n 1

CWP-n Run Speed n =Cmd after 1

minute

CWP Lead/Lag X



FLC Temp Set point deadband X

FLC Bypass Valve Set point Temp

X

FLC Bypass Valve Cmd Position

X

FLC Bypass Valve Feedback X =Cmd after 1

minute

FLC-n Inlet Temp X 1

FLC-n Outlet Temp X 1


FLC-n Enable n 1

FLC-n Override n

FLC-n Status n 1 Proof after 1 minute

FLC-n Runtime n >1000

FLC-n Cycle Counter n > 6 hour

FLC Lead/Lag X

FLC-n Low Water Alarm n

FLCP-n Enable n 1

FLCP-n Override n

FLCP-n Status n 1 Proof after 1 minute

HW Temp Set point deadband X

HW Bypass Valve Set point Temp X

HW Bypass Valve Cmd Position X

HW Bypass Valve Feedback X =Cmd after 1

minute

HWR Temp X 1



HWS Temp X 1

>180 or <110 when HW flow after 1 minute

B-n Inlet Temp n

B-n Outlet Temp n 1

>190 or <110 when HW flow after 1 minute

B Setpoint Temp X

B Staging Setpoint Temp X

B Staging Deadband Temp X

B-n Alarm n

B-n Enable n 1

B-n HW Isolation Valve Cmd n 1

B-n HW Isolation Valve Feedback n 1

B-n Override n

B-n HW flow status n


B-n Runtime n >1000

B-n Re-Start Timer n 5 Minutes to

re-start

B-n Cycle Counter n > 6 per hour

B Lead/Lag X

HWPP-n Enable n 1

HWPP-n Override n

HWPP-n Status n 1 Proof after 1 minute

HWPP-n Runtime n >1000

HWPP Lead/Lag X



WSHP-n Fire Alarm n 1

WSHP-n Enable Cooling n 1

WSHP-n Enable Heating n 1

WSHP-n Supply Fan Enable n 1

WSHP-n CWV Bypass Cmd n

WSHP- Flow Status n =Cmd after 1

minute

WSHP-n Warm-up Mode Low Temp Setpoint

n

WSHP-n Cool-Down Mode High Temp Setpoint

n

WSHP-n Zone Temperature Sensor

n

WSHP-n Zone Temperature Setpoint-Cooling

n

WSHP-n Zone Temperature Setpoint-Heating

n

WSHP-n Zone Temperature Unoccupied Setpoint-Cooling

n

WSHP-n Zone Temperature Unoccupied Setpoint-Heating

n

WSHP-n Zone Temperature Setpoint-Deadband

n

WSHP-n Override n


Cx Assist ant TM Sequences of Operation...unit that are connected by a direct expansion (DX)...

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