Post on 04-Apr-2018
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CL SERIES
ROOFTOP CONDENSING UNITS
INSTALLATION, SERVICE
&
OWNERS INFORMATION MANUAL
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TABLE OF CONTENTSSECTION Page
GENERAL DESCRIPTIONUnpacking..
0404
OWNERS INFORMATION......................................
Wiring Diagrams................................................
General Maintenance..
04
04
05INSTALLATION.....
Lifting and Handling..
Condenser Placement.
Compressor Compartment Exhaust Fan.
Mounting Isolation.Access Doors.
Low Ambient Operation.
LAC Valve..OROA Valve...
ORI/ORD Valves
Condenser Flooding
Electrical.Refrigerant Piping Connection
Evaporative-Cooled Condenser Field Piping Connections.
05
05
05
05
0505
05
0607
07
08
0909
09
STARTUPPre Startup..Startup
Axial Flow Fans.
111111
11
SERVICING & MAINTENANCE.......General ...
Compressors...
Refrigerant Filter Driers..
Evaporator/Heat Exchanger....Charging Refrigerant ..
Checking Liquid Sub-Cooling
Checking Evaporator Superheat.
Adjusting Sub-cooling and Superheat Temperatures.
Special Charging Instructions.Lubrication......
Service Information.
1313
13
13
1314
14
14
15
1515
15
EVAPORATIVE-COOLED CONDENSER SECTION...General Information
Pre Start-Up
Maintenance Recommendations.
Water Quality..AIR-COOLED CONDENSER SECTION...
REFRIGERANT PIPING FOR CL SERIES............
Equivalent Line Length..
Liquid Line Sizing......Suction Line Sizing.....
Hot Gas Bypass Line Sizing.......Predetermined Line Sizes...TABLE RP-1 Predetermined Line sizes for Dual Circuit CL units with R-410A..
TABLE RP-2 Predetermined Line sizes for Dual Circuit CL units with R-22...
TABLE RP-3 Predetermined Line sizes for Single Circuit CL units with R-410A...TABLE RP-4 Predetermined Line sizes for Single Circuit CL units with R-22 ...FIGURE RP-1 Riser height versus total equivalent line length Dual Circuit CL Units with R-410A ..
FIGURE RP-2 Riser height versus total equivalent line length Dual Circuit CL Units with R-22.. .
FIGURE RP-3 Riser height versus total equivalent line length Single Circuit CL Units with R-410A
FIGURE RP-4 Riser height versus total equivalent line length Single Circuit CL Units with R-22 Hot Gas Bypass Line Routing Diagrams
1616
17
20
2121
21
22
2223
232426
27
28
28
2929
30
30
31
CL SERIES STARTUP FORM 41
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It is the intent of AAON, Inc. to provide accurate and current specification information. However, in theinterest of product improvement, AAON, Inc. reserves the right to change pricing, specifications, and/or
design of its products without notice, obligation or liability
2007 AAON, Inc., all rights reserved throughout the world.
AAON & AAONAIRE are registered trademarks of AAON, Inc., Tulsa, OK.
R10110 Rev. B 4-07
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GENERAL DESCRIPTION
All AAON 'CL Series' condensers are factory
assembled, wired, and charged with 15 lbs. ofrefrigerant per system. Models are available for
air-cooled and evaporative-cooled applications.
Unpacking:When received, the unit should be checked for
damage that might have occurred in transit. If
damage is found it should be noted on thecarriers Freight Bill. A request for inspection by
carriers agent should be made in writing at once.
Also, check the unit nameplate to ensure thecorrect model size and voltage have been
received to match the job requirements.
OWNER'S INFORMATION
Warning:
Failure to observe the following instructions
will result in premature failure of your system,and possible voiding of the warranty. Never cut off the main power supply to the unit,
except for complete shutdown. When power is
cut off from the unit, any compressors usingcrankcase heaters cannot prevent refrigerant
migration. This means the compressor will cool
down, and liquid refrigerant may accumulate inthe compressor. Since the compressor is designed
to pump refrigerant gas, damage may occur whenpower is restored.
Before unit operation, the main power switch
must be turned on for at least twenty four hours
for units with compressor crankcase heaters. Thiswill give the crankcase heater time to clear any
liquid accumulation out of the compressor before
it is required to run. Always control the system from the thermostat,
or control panel, never at the main power supply
(except for emergency or for complete shutdownof the system).
Improper installation, adjustment, alteration,
service, or maintenance can cause property
damage, personal injury or loss of life.Installation and service must be performed by a
qualified installer, service agency or if gas fired
units, the gas supplier. Refer to installationinstructions provided with the unit and this
manual.
The compressors must be on a minimum of 4minutes and offfor a minimum of 5 minutes. The
cycle rate must be no more than 8 starts per hour.
The compressor life will be seriously
shortened by reduced lubrication, and the
pumping of excessive amounts of liquid oil
and refrigerant.
Wiring Diagrams:
A complete set of unit specific wiring diagrams
in both ladder and point-to-point form arelaminated in plastic and located inside the control
compartment door.
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OWNER'S INFORMATION cont.
General Maintenance:
When the initial startup is made and on aperiodic schedule during operation, it is
necessary to perform routine service checks on
the performance of the condenser. This includes
reading and recording suction pressures andchecking for normal sub-cooling and superheat.
See the evaporative-cooled condenser and air-
cooled condenser sections in this manual forspecific details.
INSTALLATION
Lifting and Handling:
If cables or chains are used to hoist the unitthey must be the same length and care should be
taken to prevent damage to the cabinet. Before lifting unit, be sure that all shippingmaterial has been removed from unit. Secure
hooks and cables at all lifting points/lugs
provided on the unit. Do not push, pull or lift the unit from anything
other than its base.
UNIT MUST BE RIGGED AT ALL
MARKED LIFTING POINTS (Typical)
Condenser Placement:
The AAON condenser is designed for outdoorapplications and mounting at ground level or on
a rooftop. It must be placed on a level and solid
foundation that has been prepared to support its
weight. When installed at ground level, a one-piece concrete slab should be used with footings
that extend below the frost line.
With ground level installation, care must betaken to protect the coil fins from damage due to
vandalism or other causes.
The placement relative to the building airintakes and other structures must be carefully
selected. Be sure to observe the dimensions that
are on the rating plate of the condenser foroperational and service clearances, which will
appear as follows:
Service Clearances
LocationUnit Size
045-135 134-230
Front - Vestibule Door Side 100" 142"
Back - Opposite of Front 100" 142"
Left Side - Condenser End 100" 100"
Right Side - Opposite of Left 100" 100"
Top UNOBSTRUCTED
Condenser coils and fans must be free of any
obstructions in order to start and operate properlywith a correct amount of airflow.
For proper unit operation, the immediate areaaround condenser must remain free of debris that
may be drawn in and obstruct airflow in the
condensing section. Consideration must be given to obstruction
caused by snow accumulation when placing the
unit.
Compressor Compartment Exhaust Fan:
Prior to unit operation the compressor
compartment exhaust fan shipping supportMUST BE removed from the exterior of the unit.
The exhaust fan also requires the installation of
the exterior rain hood provided with the unit.
Mounting Isolation: For roof mounted applications or anytimevibration transmission is a factor, vibration
isolators may be used.
Access Doors:
A lockable access door is provided to the
compressor and electrical compartment.
A light switch is on the wall of the compressorcontrol compartment.
Low Ambient Operation:
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
system below 25F outside air temperature. Asthe ambient temperature drops, the condenser
becomes more effective therefore lowering the
head pressure. When the head pressure gets too
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INSTALLATION cont.
low, there will be insufficient pressure to operate
the expansion valve properly. During lowambient temperatures, it is difficult to start a
system because the refrigerant will migrate to the
cold part of the system (condenser) and make it
difficult for refrigerant to flow. The AAON low ambient system maintains
normal head pressure during periods of low
ambient by restricting liquid flow from thecondenser to the receiver, and at the same time
bypassing hot gas around the condenser to the
inlet of the receiver. This backs liquidrefrigerant up into the condenser reducing its
capacity that in turn increases the condensing
pressure. At the same time the bypassed hot gas
raises liquid pressure in the receiver, allowingthe system to operate properly.
There are different types of low ambient control
used. The following describe the different
systems. Inspect the unit to determine the systemused.
LAC Valve:The LAC valve is a non-adjustable three way
valve that modulates to maintain receiver
pressure. As the receiver pressure drops belowthe valve setting (180 psig for R-22 and 295 psig
for R-410A), the valve modulates to bypass
discharge gas around the condenser. The
discharge gas warms the liquid in the receiverand raises the pressure to the valve setting. The
following schematic shows an example system
using the LAC valve.
Piping Schematic of Example system using the LAC valve.
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INSTALLATION cont.
OROA Valve:
This system uses a nonadjustable head pressure
control valve that performs the function of
limiting the flow of liquid refrigerant from the
condenser and at the same time regulates theflow of the hot gas around the condenser to the
receiver. The valve setpoint is 180 psig. This
valve is called an OROA valve (Open on Rise of
Outlet pressure). The following schematicshows an example system using the OROA
valve.
Piping Schematic of Example system using the OROA valve.
ORI/ORD Valves:
This system uses a two-valve arrangement. The
head pressure control valve is an inlet pressureregulating valve and responds to changes in
condensing pressure. This valve is located in the
discharge of the condenser and is called an ORIvalve (Open on Rise of Inlet pressure). As the
ambient temperature drops, the condenser
capacity increases and the condensing pressure
falls, causing the ORI to modulate toward theclosed position. The condenser bypass valve is a
pressure differential valve that responds to
changes in the pressure differential across thevalve. This valve is called an ORD valve (Open
on Rise of Differential pressure). As the ORI
starts to restrict liquid flow from the condenser, a
pressure differential is created across the ORD.
When the differential reaches the setpoint, theORD starts to open and bypass hot gas to the
liquid line. The ORI valve is adjustable from 65
to 225 psig (factory setting of 180 psig). TheORD is not adjustable. On refrigeration systems
that are too large for a single ORI and ORD
valve, there will be two ORI and two ORD
valves in parallel. The schematic on thefollowing page shows an example system using
the ORI/ORD valves.
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INSTALLATION cont.
Piping Schematic of Example system using the ORI/ORD valve.
The pressure setting of the ORI valve determines
how well the system will operate. The proper
setting is a function of the specific system in
which is installed. Generally, the setting shouldbe equivalent to a condensing temperature of
90F to 100F or a receiver pressure equivalent
to a temperature of 80F to 90F. This meansthat as the ambient temperature falls below 70F,
the head pressure control valve will begin to
throttle. To adjust the ORI valve, remove the capand turn the adjustment screw with the proper
size hex wrench (1/4 for ORI-6 and 5/16 forORI-10). A clockwise rotation increases the
valve setting while a counter-clockwise rotation
decreases the setting. To obtain the desiredsetting, a pressure gauge should be used at the
compressor discharge service valve so the effects
of any adjustment can be observed. Smalladjustments are recommended in order to allow
the system adequate time to stabilize after each
adjustment.
Condenser Flooding:
In order to maintain head pressure in the
refrigeration system, liquid refrigerant is backed
up in the condenser to reduce condenser surface.The following chart shows the percentage that a
condenser must be flooded in order to function
properly at the given ambient temperature.
PERCENTAGE OF CONDENSER TO BE FLOODED
Ambient
Temperature
(F)
Evaporating Temperature (F)
0 10 20 30 35 40 45 50
70 40 24 0 0 0 0 0 0
60 60 47 33 17 26 20 10 450 70 60 50 38 45 40 33 28
40 76 68 60 50 56 52 46 42
30 80 73 66 59 64 60 55 51
20 86 77 72 65 69 66 62 59
0 87 83 78 73 76 73 70 68
-20 91 87 82 77 80 79 76 73
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INSTALLATION cont.
During higher ambient temperatures the entire
condenser is required to condense refrigerant.During these higher ambient temperatures, a
receiver tank is used to contain the refrigerant
that was required to flood the condenser during
low ambient operation. The receiver must besized to contain all of the flooded volume
otherwise there will be high head pressures
during higher ambient conditions.
Electrical:
The single point electrical power connectionsare made in the electrical control compartment.
Check the unit data plate voltage to make sure
it agrees with the power supply. Connect powerto the unit according to the wiring diagram
provided with the unit. The power and control wiring may be broughtup through the utility entry. Protect the branch
circuit in accordance with code requirements.
Control wires and power should not be run inside
the same conduit. The unit must be electricallygrounded in accordance with the current National
Electric Code.
Power wiring is to the unit terminal block ormain disconnect. All wiring beyond this point
has been done by the manufacturer and cannot be
modified without effecting the unit'sagency/safety certification.
Note: Startup technician must check motoramperage to ensure that the amperage listed
on the motor nameplate is not exceeded.
Refrigerant Piping Connections
CL condensing unit refrigerant piping
connections are located in the upper corner of the
service vestibule side of the unit (opposite thecondenser section) as shown in the figure.
The piping connections are protected with ashipping cover that must be removed prior to
copper connection and installation.
Evaporative-cooled Condenser Field Piping
Connections:
There are two field water connections that must
be made for the evaporative-cooled condenser.There is a PVC socket city make-up water
connection and a 2 PVC socket drain
connection (as shown on the next page). Thisdrain should connect to a sanitary sewer or other
code permitted drain. These connections can go
through the base or the wall of the unit.
There is a cutout in the base with a cap that is1 tall and the cap is sealed to the unit base to
prevent any leaks in the unit from penetrating
into the building. Any piping through the baseshould go through a field cutout in this cap. The
pipes must be sealed to the cap once the piping is
complete to prevent any leaks in the unit from
penetrating into the building. A field cutout must be made in the wall if the
evaporative-cooled condenser piping is to go
through the unit wall. This cutout must besealed once the piping is installed to prevent
water from leaking into the unit.
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Diagram of Evaporative-cooled condenser Section including field water connections and base cutouttap
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STARTUP
Pre-Startup:
After the installation and immediately before thestartup of the condenser be sure that these items
have been checked.
1. Verify that electrical power is available to theunit.
2. Verify that any remote stop/start device is
requesting the condenser to start.
While performing the Startup, use the
Condensing Startup Form at the back of thisbooklet to record motor amps and any other
comments.
Startup:
Use the General Check List at the top of theStartup Form to make a last check that all thecomponents are in place and the power supply is
energized.
Note: Condensing fan operation should start
with the first compressor.
Cycle through all the compressors to confirmthat all are operating within tolerance.
When unit is running, observe the system for a
complete operation cycle to verify that allsystems are functioning properly.
While performing the check, use the Condenser
Startup Form to record observations of amps andrefrigerant pressures.
When all is running properly, place the
controller in the Run mode and observe the
system until it reaches a steady state of operation.
Axial Flow Fans:
Multi-Wing Z Series Aluminum Fan Blade
Pitch Angle Setting Instructions:
Before You Begin, to maintain balance of fan: Mark the hub castings across a joint, so the fan
hub can be reassembled in the same orientation.
Mark the location of any balancing weight.Balancing weight will be on the outer bolt circle,
in the form of washers, and/or longer bolts, or an
additional balancing nut.
Number the blades and blade sockets, so thatthey are replaced into their original position.
If possible, note the location of the pitch setting
pin in the blade socket, and whether pin islocated in the Hub or Retainer half of the fan.
Step 1. Determine Boss Location Code: A orB The boss is the center section of the hub
through which the fan is mounted to the shaft,
and typically contains either setscrews or a
center-tapered hole where the bushing inserts.Select boss location A or B:
A is the boss on air inlet, including AS
configurations.B is the boss on air discharge, including BS.
For flange mounted fans, use boss location A for
R rotation fans, and boss location B for Lrotation fans.
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STARTUP cont.
Step 2. Find Blade Pitch Angle:
( 20, 25, 27.5, 30, 32.5, 35, 37.5, 40, 45 or 50 ) Carefully disassemble fan on flat surface and
note in which groove the pin is located. Refer to
groove number code diagram.
Using diagrams in step 5, determine if the pinwas in the hub (HUB) or retainer side (RET) of
fan.
Using table in step 4, find the possible bladepitch.
Using table in step 3, select your blade angle
based on whether your pin was in the HUB orRET.
Step 3. Determine Hub/Retainer Code: HUBor RET
Step 4. - Determine Groove Number: 1 or 2 or 3
or 4
Step 5. Final AssemblyDefinition of HUB and RET for purposes of
instructions. For 2-piece hubset:
Using the HUB or RET code found in Step 3:
If code is HUB, place the hub down on work
surface first (one or two pieces, depending onabove).
If code is RET, place one retainer ring only
down on the work surface first. (A weighted
coffee can could be used to elevate the fan fromthe work surface).
Using the groove number, place the locking pin
in the groove number that was found in Step 4.
Insert Blades:
Place the blade over the pin in the hub/retainer
blade socket, so that the pin also fits into theappropriate pitch angle groove in the blade.
Repeat for all blades. Assemble hub set together, aligning the match
marks that were made.
Replace any balancing weight to its original
position. To finish, tighten the bolts in a cross pattern to
5 to 6 ft-lbs of torque.
Multi-Wing W Series Black Glass Reinforced
Polypropylene Fan Blade Pitch Angle SettingInstructions:
Step 1.Note original position of retaining plates,
center boss and all hardware including additional
hardware used for balancing.
Step 2. Remove all the bolts and nuts.
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STARTUP cont.
Step 3. Determine blade rotation on the
concave side of the blade is a blade markingshowing 6WR, 6WL, 7WL, 7WR, or 9WR. The
L and R denote the rotation of the blade.
Step 4. Replace the pitch insert in the blade rootwith an insert of the desired pitch.
Step 5. Replace blades to their original location.
Step 6. Replace all nuts, bolts, and washers on
the fan hub.
Step 7. Replace retaining plates and center boss
to original location.
Step 8. Tighten nuts and bolts to 14 ft-lbs of
torque.
SERVICING AND MAINTENANCE
General:
Qualified technicians must perform routineservice checks and maintenance. This includesreading and recording the condensing and
suction pressures and checking for normal sub-
cooling and superheat (see charging information
beginning on page 14). Air-cooled and evaporative-cooled condenser
units require different maintenance
schedules/procedures. Unit specific instructionsfor both types are included in this manual.
Compressors:
The scroll compressors are fully hermetic and
require no maintenance except keeping the shell
clean.
Refrigerant Filter Driers:
Each refrigerant circuit contains a replaceablecore filter drier. Replacement is recommended
when there is excessive pressure drop across the
assembly or moisture is indicated in a liquid linesight glass.
The filter driers are provided with pressure taps
and shutoff valves for isolation when changing
the core. For safety purposes a service manifoldmust be attached prior to filter maintenance.
Evaporator/Heat Exchangers:
Normally no maintenance or service work will be
required for a matching direct expansionevaporator with a thermal expansion valve to
regulate refrigerant.
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SERVICING AND MAINTENANCE
cont.
Charging Refrigerant:
Charging a system in the field must be based ondetermination of liquid sub-cooling and
evaporator superheat. On a system with a
thermostatic expansion valve liquid sub-coolingis more representative of the charge than
evaporator superheat but both measurementsmust be taken.
Before Charging:
Refer to the Unit Nameplate to determine the
proper refrigerant to charge the system with.
The unit being charged must be at or near full
load conditions before adjusting the charge. Units equipped with hot gas bypass must have
the hot gas bypass valve closed to get the proper
charge.
Units equipped with hot gas reheat must becharged with the hot gas valve closed while the
unit is in cooling mode. After adding or removing charge the system
must be allowed to stabilize, typically 10-15
minutes, before making any other adjustments.
The type of unit and options determine theranges for liquid sub-cooling and evaporator
superheat. Refer to Table 1 when determining
the proper sub-cooling. The vertical rise of the liquid line must be
known in order to adjust the sub-cooling rangefor proper charge. Units equipped with low ambient (0F) option
see special charging instructions at the end of the
charging instructions.
Checking Liquid Sub-cooling:1. Measure the temperature of the liquid line as
it leaves the condenser coil.
2. Read the gauge pressure reading of the liquid
line close to the point where the temperature was
taken. You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop.3. Convert the pressure obtained in Step 2 to a
saturated temperature using the appropriate
refrigerant temperature-pressure chart.4. Subtract the measured liquid line temperature
in Step 1 from the saturated temperature in Step
3 to determine the liquid sub-cooling.5. Compare calculated sub-cooling to TABLE 1.
for the appropriate unit type and options.
Checking Evaporator Superheat:
1. Measure the temperature of the suction line
close to the compressor.
2. Read gauge pressure at the suction line closeto the compressor.
3. Convert the pressure obtained in Step 2 to a
saturated temperature using the appropriaterefrigerant temperature-pressure chart.
4. Subtract the saturated temperature in Step 3
from the measured suction line temperature inStep 1 to determine the evaporator superheat.
5. Compare calculated superheat to TABLE 1 forthe appropriate unit type and options.
TABLE 1
Sub-
cooling
(F)
Superheat
(F)
Sub-cooling
W/Hot Gas
Reheat (F)
Air Cooled
Condenser12-18* 8-15** 15-22*
Evaporative
Cooled
Condenser
6-10* 8-15** 8-12*
Water
Cooled
Condenser
6-10* 8-15** 8-12*
* Sub-cooling must be increased by 3F per 20feet of vertical liquid line rise for R-22 and 2F
for R-410A
** Superheat will increase with long suction lineruns.
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SERVICING AND MAINTENANCE
cont.
Adjusting Sub-cooling and Superheat
Temperatures:
The system is overcharged if:
1. the sub-cooling temperature is too high and
2. the evaporator is fully loaded (low loads onthe evaporator result in increased sub-cooling)
and3. the evaporator superheat is within the
temperature range as shown in TABLE 1 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing the
amount of refrigerant in the system to lower the
sub-cooling.
The system is undercharged if:1. the superheat is too high and
2. the sub-cooling is too low
Correct an undercharged system by addingrefrigerant to the system to reduce superheat and
raise sub-cooling. If the sub-cooling is correct and the superheat is
too high, the TXV may need adjustment to
correct the superheat.
Special Charging Instructions:
For units equipped with low ambient refrigerant
flood back option being charged in the summerwhen the ambient temperature is warm:
Once enough charge has been added to get theevaporator superheat and sub-cooling values tothe correct setting more charge must be added.
Add approximately 80% of the receiver tank
volume to the charge to help fill the receiver
tank. The additional charge is required for thesystem when running in cold ambient conditions.
For units equipped with low ambient refrigerantflood back option being charged in the winter
when the ambient temperature is cold:
1. Once enough charge has been added to get theevaporator superheat and sub-cooling values to
the correct setting more charge may need to be
added. If the ambient temperature is 0F nomore charge is required. If the ambient
temperature is around 40F add approximately
40% of the receiver tank volume.2. The unit will have to be checked for proper
operation once the ambient temperature is above
80F.
Lubrication:
All original motors and bearings are furnished
with an original factory charge of lubrication.Certain applications require bearings be re-
lubricated periodically. The schedule will vary
depending on operating duty, temperaturechanges, or severe atmospheric conditions.
Bearings should be re-lubricated at normal
operating temperatures, but not when running.Rotate the fan shaft by hand and add only enough
grease to purge the seals. DO NOT
OVERLUBRICATE.
Service Information:
If the unit will not operate correctly and a servicecompany is required, only a company with
service technicians qualified and experienced in
both condensing units and air conditioning arepermitted to service the systems to keep
warranties in effect. If assistance is required, the
service technician must contact AAON.
Note: Service technician must provide the
model and serial number of the unit in all
correspondence with AAON.
Replacement parts for AAON equipment may be
obtained from AAON. When ordering parts,always reference the unit model number, serial
number and part number.
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AAON, Inc.www.aaon.com
Customer Service Department
2425 South Yukon Ave Tulsa, OK 74107Phone: 918-583-2266 Fax: 918-382-6364
ALWAYS USE AAON SPECIFIED PARTS
To order parts from the AAON Parts storeonline go to www.aaonparts.com.
EVAPORATIVE-COOLED
CONDENSER
Evaporative cooling equipment rejects heat byevaporating a portion of the recirculated water
spray and discharging it from the unit with the
hot, saturated air. As the spray water evaporates,it leaves behind the mineral content and
impurities of the supply water. If these residuals
are not purged from the water distribution
system, they will become concentrated and leadto scaling, corrosion, sludge build-up and
biological fouling.
A water treatment monitoring and controlsystem has been furnished with this unit. Be sure
to read the complete manual that has been
furnished. All water treatment is a combinationof bleed water and chemical treatment for proper
control of the residuals and to prevent any
biological contamination.
GENERAL INFORMATION
Severe Service:
The following recommended maintenance
procedures are basic requirements for normal
operating environments. For severe operatingconditions, the frequency of inspection and
service should be increased. Air containing
industrial and chemical fumes, salt, dust, or otherairborne contaminates and particulates will be
absorbed by the recirculating water system and
may form solutions and deposits harmful to theproducts and personnel.
Safety:
The recirculating water system contains chemicaladditives for water quality control and biological
contaminants removed from the air by the
washing action of the water. Personnel exposedto the saturated effluent, drift, or direct contact
should use proper precaution. Proper location of
the evaporative-cooled condenser requires goodjudgment to prevent the air discharge from
entering fresh air intakes or to avoid allowing
contaminated building exhaust from entering the
condenser.
Follow local and national codes in locating the
evaporative-cooled condenser but as minimumthe evaporative-cooled condenser sump must be
15 feet from the nearest intake.
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EVAPORATIVE-COOLED
CONDENSER cont.
Performance:
Improper location of the evaporative-cooled
condenser may seriously degrade the capacity ofthe equipment. Make sure the equipment is
located such that discharge air from the
condenser does not enter the condenser air inlet.
Warranties:
Please refer to the limitation of warranties ineffect at the time of purchase.
Condenser Tube Inspection:
The coil is leak tested at 450 P.S.I.G. beforeshipment. AAON will not be responsible for loss
of refrigerant. It is the responsibility of the
installer to verify that the system is sealed beforecharging with refrigerant. If the unit is operated
during low ambient temperature conditions,
freeze protection for the recirculating watersystem must be provided.
Freeze Protection:
In order to prevent water temperatures from
dropping below 50F, this unit is equipped with a
variable frequency drive (VFD) on the fan
motors when the refrigeration system isoperating.
Recirculating Water System:
Electric sump heaters are available to keep the
sump water from freezing when the refrigeration
system is not operating. An electric resistanceheater is supplied in the vestibule when sump
heaters are selected.
Note: The condenser should not be operated
with the fan on and the pump cycled on and
off to maintain head pressure control under
any conditions. The unit is equipped with a
water temperature controller which varies fan
speed to maintain sump water temperature.
This unit is not equipped with a compressor
discharge pressure controller for fan speed
modulation and therefore can not be operated
without water flow.
PRE START-UP
Do not start the evaporative-cooled condenser or
compressors without installation of proper water
treatment chemicals. Contact your local watertreatment expert for correct selection of water
treatment chemical, adjustment of chemical feedand bleed rates.
Cleanliness:
Dirt and debris may accumulate in the sumpduring shipping and storage. The sump should be
cleaned prior to start-up to prevent clogging the
water distribution system. Any surfaces thatshow contamination should be cleaned ONLY
with a commercial stainless steel cleaner to
restore the initial appearance. The inlet screensshould be inspected for foreign material.
Pump Operation:
Before initial start of the pump, check as follows:
1. Be sure that pump operates in the direction
indicated by the arrow on the pump casing.
Check rotation each time motor leads have beendisconnected.
2. Check all connections of motor and starting
device with wiring diagram. Check voltage,phase and frequency of line circuit with motor
name plate.
3. Check suction and discharge piping andpressure gauges for proper operation.
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EVAPORATIVE-COOLED
CONDENSER cont.
4. Turn rotating element by hand to assure that it
rotates freely.
Running:
Periodically inspect pump while running, butespecially after initial start-up and after repairs.
1. Check pump and piping for leaks. Repairimmediately.
2. Record pressure gauge readings for future
reference.3. Record voltage, amperage per phase, and kW.
Condenser Fan Motors:
The direct-drive condenser motors on AAONevaporative-cooled condensers are 1200-rpm
premium efficiency motors controlled by a VFD.These motors are totally enclosed air over motorswith weep holes in the bottom end bell so that
any condensation can drain out of the motor.
The motors have a small electric resistanceheater installed inside the casing to keep the
motors warm when they are deactivated. The
heaters are designed to keep the interior of themotor 10F warmer than the surrounding
ambient temperature. This prevents condensation
from forming inside the motor.
Ensure that fan is tightly mounted to the motorshaft and the motor mounting bolts are aligned
and secure.
Water Make-up Valve:
The sump water level is controlled by a set of
conductivity probes at different levels in thesump. This water level controller is located in
the vestibule behind the condenser pump. There
are four conductivity probes in this controller.
There is a reference probe (shown as ref on the
wiring diagram). This probe is one of the twolongest probes. The other long probe is the low
water level probe (shown as lo on the wiringdiagram). The medium length probe is for the
medium water level (shown as med on the
wiring diagram). The short probe is for the highwater level (shown as hi on the wiring
diagram). There is a solenoid valve in the make-
up water line that is activated by the water levelcontroller. The water level controller determines
the level of water in the sump based onconductivity between two probes. If the
controller sees conductivity between two probes,
it knows that water is at least at the level of that
probe. If the water in the sump is below the low probe,
it will not allow the condenser pump or the sump
heater to operate. It will activate the make-upwater solenoid to try to fill the sump assuming
water is flowing to the unit. Once water is above
the low probe, it will allow the condenser pumpand sump heater (if ordered and the ambient
temperature is below 40F) to operate. The
make-up water solenoid will remain activated
until water gets to the high water level. Themake-up water solenoid will deactivate until
water gets to the medium water level. In normal
operation, the water level should swing betweenthe medium and high water levels. The
maximum high water level should be 1 below
the overflow drain which occurs after the make-up water valve shuts off when the water level
reaches the high level probe.
Make-up water supply pressure should be
maintained between 15 and 60 psig for proper
operation of the valve. The make-up water valveassembly should be inspected monthly and
adjusted as required. Replace the valve seat if
leakage occurs when the valve is in the closedposition.
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EVAPORATIVE-COOLED
CONDENSER cont.
Water Treatment System:
All AAON evaporative-cooled condenserscome equipped with a water treatment system
that should be maintained by a local water
treatment professional trained in the watertreatment of evaporative condensers. This
system consists of a controller, three chemicalpumps and storage tanks, a conductivity sensor, a
motorized ball valve for water bleed, and a water
meter. One chemical pump and tank is typically used
for a descaling chemical to prevent scale from
forming in the condenser. The other two pumps
and tanks are typically used for two differentbiocides (to kill any microorganisms that could
grow in the condenser). Two biocides are usedto prevent organisms from becoming resistant toone chemical.
The mineral content of the water must be
controlled. All make-up water has minerals in it.As water is evaporated from the condenser, these
minerals remain. As the mineral content of the
water increases, the conductivity of the waterincreases. The water treatment controller
monitors this conductivity. As the water
conductivity rises above set point, the controller
will open a motorized ball valve on the dischargeside of the condenser pump and dumps water
into the condenser drain until conductivity is
lowered. While the motorized ball valve isopened, the controller will not disperse
chemicals.
The chemicals are dispersed by the watertreatment controller based on the scheduled input
by the water treatment professional. (See the
separate manual for the water treatment controls
for specific programming information.)
The water meter measures the quantity ofmake-up water used by the condenser.
Any water treatment program must becompatible with stainless steel, copper,
aluminum, ABS plastic and PVC. Batch feed
processes should never be used as concentratedchemicals can cause corrosion. Never use
hydrochloric acid (muratic acid) as it will
corrode stainless steel.
Sequence of Operation:
On a call for cooling, the condenser pump is
activated. A pressure switch in the pump
discharge is bypassed for six seconds by a time
delay relay in order for the pump to establishrecirculating water flow. If flow is not proven
within the six seconds, the pressure switch opens,
breaking the safety circuit, thereby shutting downthe entire system. This pressure switch is set to
close at 3 psi and open at 1 psi.
A Johnson Controls S350C measures the watertemperature in the pump discharge line. If the
sump water temperature exceeds 105F, the
cooling system will be shut down thereby
preventing damage to the evaporative condenser. If a fault occurs in the evaporative condenser
fan motor VFD, normally closed fault terminals
on the VFD will interrupt the safety circuit,thereby shutting down the system.
If the VFD does fault and cannot be reset, there
is a VFD bypass switch mounted near the VFD.This switch has four positionsline, off, drive,
and test. The line position will bypass the
VFD, sending power to the motor. In thisposition, the condenser fans will run at full
speed. The off position will not allow powerto pass through the switch. This functions as a
disconnect switch. The drive position runs
power through the VFD. This is the normal
operation for the switch. The test positionroutes power to the VFD but not to the motor.
This is useful for running tests on the VFD
without sending power to the motor. A Johnson Controls A350P controls the VFD
speed. This device sends a 0-10 VDC signal to
the VFD. This controller is set to maintain asump temperature of 70F. On a rise in sump
temperature, the controller increases the voltage
to the VFD, increasing the speed of thecondenser fans. Conversely, on a drop in sump
temperature, the controller will decrease the
voltage to the VFD, decreasing the speed of the
condenser fans. An outside air thermostat does not allow the
condenser to operate when the ambient
temperature is below 35F.
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EVAPORATIVE-COOLED
CONDENSER cont.
MAINTENANCE RECOMMENDATIONS
Pump Maintenance: Cleaning - Remove oil, dust, water, and
chemicals from exterior of motor and pump.Keep motor air inlet and outlet open. Blow out
interior of open motors with clean compressedair at low pressure.
Labeled Motors- It is imperative for repair of a
motor with Underwriters Laboratories label thatoriginal clearances be held; that all plugs, screws,
other hardware be fastened securely, and that
parts replacements be exact duplicates or
approved equals. Violation of any of the aboveinvalidates Underwriters Label.
Fan Motor Maintenance:
Same as pump maintenance
Access Doors:
If scale deposits or water is found around the
access doors, adjust door for tightness. Adjust as
necessary until leaking stops when door isclosed.
Bearings - Lubrication:
Every 6 months or after a prolonged shut down.Use waterproof, lithium based grease. Below
32F - Esso Exxon or Beacon 325. Above 32F
Mobil Mobilox EP2, Shell Alvania EP2 orTexaco RB2.
Recommended Monthly Inspection:
1. Clean sump section interior. Dirt and other
impurities which have accumulated in the sump
should be removed from the sump area. Shut off
make-up water ball valve and open the drain
connection for flushing of the sump.2. Clean dirt out of sump using a water hose (not
a pressure washer).3. Clean sump suction strainer.
4. Check water operating level. Adjust float as
required.5. Inspect fan motor(s) and water circulation
pump(s) and lubricate per the lubrication
nameplate or manufactures recommendations.
6. Inspect axial fans and eliminators removingany debris which may have accumulated during
operation.
7. Inspect the water distribution system to insure
that nozzles and spray orifices are functioningcorrectly. The inspection should be made with
the circulation pump on and fans off.
Mist Eliminators:
The mist eliminators must be correctly
positioned when they are replaced duringcleaning or service.
Air Inlet:
Inspect the air inlet louvers and mist eliminatorsinto the condenser section on a monthly basis to
remove any paper, leaves or other debris that
may block the airflow.
Stainless Steel Base Pan:
The base pan under the tube bundles is stainlesssteel and may sometimes become tarnished due
to contamination. These surfaces should be
inspected yearly to ensure they remain clean ofany contamination that may result in damage.
Any surfaces that show contamination should becleaned ONLY with a commercial stainless steel
cleaner to restore the initial appearance.
Propeller Fans and Motors:
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assurance they are clear ofdirt or debris that would impede the airflow.
Recommended Annual Inspection:
In addition to the above maintenance activities, a
general inspection of the unit surface should be
completed at least once a year. Remove sprayheader and flush out.
Cleaning:
Mechanical cleaning, including pressurewashing, should never be performed as surfaces
and seals could be damaged. Chemical cleaning
that is safe for stainless steel, copper, aluminum,ABS plastic and PVC is the only acceptable
means of cleaning the evaporative condenser. A
proper water treatment program should reducecleaning needs.
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EVAPORATIVE-COOLED
CONDENSER cont.
WATER QUALITY
Recirculating Water Quality Guidelines:
Cycles of concentration (the ratio of dissolvedsolids in recirculated water to dissolved solids in
make-up), should be determined and monitored
frequently by a competent water treatmentexpert.
To limit cycles of concentration to maintain theabove guideline, it is necessary to bleed a
certain portion of the recirculated water. This is
achieved automatically with a solenoid valve
actuated by a conductivity meter set at thedesired conductivity corresponding to the desired
cycles of concentration. It should be noted that
these are guidelines and even though theseindividual values are met, under certain
conditions the water quality can be aggressive.
For example, water with very low alkalinity and
levels of chlorides and sulfates approachingmaximum recommended levels can be corrosive.
Mechanical Cleaning:
Do not attempt to mechanically clean the copper
tubing in the evaporative-cooled condenser. Do
not use wire brushes or any other mechanicaldevice on the copper tubing. Severe damage may
result. Contact your water treatment expert for
recommendations on chemical cleaningprocedures.
Parts:
Contact your local AAON Representative for
factory authorized parts. Orders must include the
Serial Number from the product nameplate OR
visit www.aaonparts.com for more information.
AIR-COOLED CONDENSER
The air-cooled condenser section rejects heat by
passing outdoor air over the fin tube coils forcooling of the hot refrigerant gas from the
compressors. The heated air will discharge from
the top of the section through the axial flow fans.
The condenser coils should be inspected yearlyto ensure unrestricted airflow. If the installation
has a large amount of airborne dust or other
material, the condenser coils should be cleanedwith a water spray in a direction opposite to
airflow. Care must be taken to prevent bending
of the aluminum fins on the copper tube.
REFRIGERANT PIPING FOR THE
CL SERIES
Note: This section is for information only andis not intended to provide all details required
by the designer or installer of the refrigerant
piping between the condensing unit and air
handling equipment. AAON Inc. is not
responsible for interconnecting refrigerant
piping. Consult ASHRAE Handbook 2006
Refrigeration and ASME Standards.
General:
Use only clean type L copper tubing (type K for
underground) that has been joined with hightemperature brazing alloy.
All AAON CL condensing units have factory
furnished liquid and suction line shutoff valves.
Determining Refrigerant Line size:
The piping between the condenser and low sidemust assure:
1. Minimum pressure drop, and
2. Continuous oil return, and
3. Prevention of liquid refrigerant slugging, orcarryover
Minimizing the refrigerant line size is favorable
from an economic perspective, reducinginstallation costs, and reducing the potential for
leakage. However, as pipe diameters narrow,
pressure-reducing frictional forces increase.
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REFRIGERANT PIPING cont.
Excessive suction line pressure drop causes loss
of compressor capacity and increased powerusage resulting in reduced system efficiency.
Excessive pressure drops in the liquid line can
cause the liquid refrigerant to flash, resulting in
faulty expansion valve operation and impropersystem performance. In order to operate
efficiently and cost effectively, while avoiding
malfunction, refrigeration systems must bedesigned to minimize both cost and pressure loss.
The pipe sizes must be selected to meet the
actual installation conditions, and not simply
based on the connection sizes at the
evaporator and/or condensing unit. Refer to
TABLES RP-1 through RP-4 for connection
size information.
Equivalent Line Length:
All line lengths discussed in this manual, unless
specifically stated otherwise, are Equivalent Line
Lengths. The frictional pressure drop throughvalves, fittings, and accessories is determined by
establishing the equivalent length of straight pipe
of the same diameter. Always use equivalentline lengths when calculating pressure drop.
Special piping provisions must be taken when
lines are run underground, up vertical risers, or inexcessively long line runs.
Liquid line sizing:
When sizing the liquid line, it is important tominimize the refrigerant charge to reduce
installation costs and improve system reliability.
This can be achieved by minimizing the liquidline diameter. However, reducing the pipe
diameter will increase the velocity of the liquid
refrigerant which increases the frictional pressuredrop in the liquid line, and causes other
undesirable effects such as noise. Maintaining
the pressure in the liquid line is critical toensuring sufficient saturation temperature,
avoiding flashing upstream of the TXV, andmaintaining system efficiency. Pressure losses
through the liquid line due to frictional contact,
installed accessories, and vertical risers are
inevitable. Maintaining adequate sub-cooling atthe condenser to overcome these losses is the
only method to ensure that liquid refrigerantreaches the TXV.
Liquid risers decrease head pressure. If the
evaporator section is below the condenser, and
the liquid line does not include risers, thegravitational force will increase the pressure of
the liquid refrigerant. This will allow the
refrigerant to withstand greater frictional losseswithout the occurrence of flashing prior to the
TXV.
A moisture indicating sight glass may befactory installed in the liquid line to indicate the
occurrence of premature flashing or moisture in
the line. The sight glass should not be used to
determine if the system is properly charged. Use
temperature and pressure measurements to
determine liquid sub-cooling, not the sight
glass.
Liquid Line Routing:
Care should be taken with vertical risers. Whenthe system is shut down, gravity will pull liquid
down the vertical column, and back to the
condenser when it is below the evaporator. Thiscould potentially result in compressor flooding.
A check valve can be installed in the liquid linewhere the liquid column rises above the
condenser to prevent this. The liquid line is
typically pitched along with the
suction line, or hot gas line, to minimize thecomplexity of the configuration.
Liquid Line Insulation:
When the liquid line is routed through regions
where temperature losses are expected, no
insulation is required, as this may provideadditional sub-cooling to the refrigerant. When
routing the liquid line through high temperature
areas, insulation of the line is appropriate toavoid loss of sub-cooling.
Liquid Line Guidelines:
In order to ensure liquid at the TXV, frictionallosses must not exceed available sub-cooling. A
commonly used guideline to consider is a system
design with pressure losses due to frictionthrough the line not to exceed a corresponding 1-
2F change in saturation temperature.
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REFRIGERANT PIPING cont.
If the velocity of refrigerant in the liquid line is
too great, it could cause excessive noise or pipingerosion. The recommended maximum velocities
for liquid lines are 100 fpm from the condenser
to a receiver tank to discourage fluid backup, and
300 fpm from receiver tank to the evaporator tominimize valve induced liquid hammer.
Liquid Line Accessories:
Liquid line accessories including sight glasses
and filter driers are available and factory
installed. The total length equivalent of pressurelosses through valves, elbows and fittings must
be considered when adding additional
components in the field. It is a good practice toutilize the fewest elbows that will allow the
mating units to be successfully joined.
Suction Line Sizing:
The suction line is more critical than the liquid
line from a design and construction standpoint.
More care must be taken to ensure that adequatevelocity is achieved to return oil to the
compressor at minimum loading conditions.
However, reducing the piping diameter toincrease the velocity at minimal load can result
in excessive pressure losses, capacity reduction,
and noise at full load.
Suction Line Routing:
Pitch the suction line in the direction of flow
(about 1 ft. per 100 ft of length) to maintain oilflow towards the compressor, and keep it from
flooding back into the evaporator. Crankcase
heaters are provided to keep any condensedrefrigerant that collects in the compressor from
causing damage or wear. Make sure to provide
support to maintain suction line positioning, andinsulate completely between the evaporator and
condensing unit.
It is important to consider part load operationwhen sizing suction lines. At minimum capacity,
refrigerant velocity may not be adequate to returnoil up the vertical riser. Decreasing the diameter
of the vertical riser will increase the velocity, but
also the frictional loss. A double suction riser
can be applied in this situation. The doublesuction riser is designed to return oil at minimum
load while not incurring excessive frictionallosses at full load. The double suction riser
consists of a small diameter riser in parallel with
a larger diameter riser, and a trap at the base of
the large riser. At minimum capacity, refrigerantvelocity is not sufficient to carry oil up both
risers, and it collects in the trap, effectively
closing off the larger diameter riser, anddiverting refrigerant up the small riser where
velocity of the refrigerant is sufficient to
maintain oil flow. At full load, the mass flowclears the trap of oil, and refrigerant is carried
through both risers. The smaller diameter pipe
should be sized to return oil at minimum load,
while the larger diameter pipe should be sized foracceptable pressure drop at full load.
Suction Line Insulation:
The entire suction line should be insulated. This
prevents condensation from forming on the line,
and reduces any potential loss in capacityassociated with heat gain placing additional load
on the system.
Suction Line Guidelines:
For proper performance, suction line velocitiesless than a 4000 fpm maximum are
recommended. The minimum velocity required
to return oil is dependent on the pipe diameter,
however a general guideline of 1000 fpmminimum may be applied.
In a fashion similar to the liquid line, a common
guideline to consider is a system design withpressure losses due to friction through the line
not to exceed a corresponding 1-2F change in
saturation temperature. At points where small pipe size can be used to
provide sufficient velocity to return oil in vertical
risers at part loads, greater pressure losses areincurred at full loads. This can be compensated
for by over sizing the horizontal and vertical
drop sections. This will however require
additional refrigerant charge.
Suction Line Accessories:
If the job requirements specify suctionaccumulators, they must be separately purchased
and installed.
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REFRIGERANT PIPING cont.
Hot Gas Bypass Line:
Hot Gas Bypass is available for use with DXsystems that may experience low suction
pressure during the operating cycle. This may be
due to varying load conditions associated with
VAV applications or units supplying a largepercentage of outside air. The system is
designed to divert refrigerant from the
compressor discharge to the low pressure side ofthe system in order to keep the evaporator from
freezing and to maintain adequate refrigerant
velocity for oil return at minimum load. Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side connector
(ASC) to false load the evaporator when reducedsuction pressure is sensed. Field piping between
the condensing unit and the evaporator isrequired.
See figures RP-5 through RP-10 for hot gas
bypass piping configurations.
Hot Gas Bypass Piping Considerations for
Evaporator Above Condensing Unit:
Pitch the hot gas bypass line downward in thedirection of refrigerant flow, toward the
evaporator.
When installing hot gas bypass risers, a drainleg must be provided at the lowest point in the
system. The drain leg must be vertical, its
diameter should be the same as the diameter of
the riser, and it should be 1 foot long. Install asight glass in the drain leg for observation. Run
an oil return line, using 1/8 inch capillary tube, 5
feet in length, from the drain leg to the suctionline. Connect the oil return line below the sight
glass, 1 inch above the bottom of the drain leg.
HGBP valves are adjustable. Factory HGBPvalve settings will be sufficient for most
applications, but may require slight adjustments
for some make up air or other process coolingapplications.
Insulate the entire length of the HGBP line witha minimum 1 inch thick Armaflex insulation.
Refer to figure RP-5 for piping diagram
Hot Gas Bypass Piping Considerations for
Evaporator Below Condensing Unit:
The line must slope downward from the hot gasbypass valve toward the evaporator.
Refer to figure RP-6 for piping diagram
Hot Gas Bypass Line Guidelines:
Choose a small size line to ensure oil return,
and minimize refrigerant charge.
Maintain velocities below a maximum of 4000fpm. A general minimum velocity guideline to
use is approximately 1000 fpm.
Hot Gas Reheat:
The AAON modulating hot gas reheat system
diverts hot discharge gas from the condenser to
the air handling unit to supply the reheat coiland/or the hot gas bypass valve. Size this line as
a discharge line.
Discharge lines should be sized to ensureadequate velocity of refrigerant to ensure oil
return, avoid excessive noise associated with
velocities that are too high, and to minimizeefficiency losses associated with friction.
Pitch the hot gas line in the direction of flow for
oil return. Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflexinsulation.
Refer to figures RP-7 through RP-10 for piping
diagrams.
Hot Gas Reheat Guidelines:
Maintain velocities below a maximum of 3500
fpm. A general minimum velocity guideline is2000 fpm.
Predetermined Line Sizes:
To aid in line sizing and selection, AAON has
predetermined line sizes for comfort cooling
applications. In order to generate this information, the
following cycle assumptions are made:
Saturated suction temperature = 50F, Saturated
condensing temperature = 125F, Sub-cooling =10F, Superheat = 15F.
The liquid lines have been chosen to maintain
velocities between 100 and 350 fpm. Thesuction line diameters are selected to limit
velocities to a 4000 fpm maximum, while a
minimum velocity restriction is imposed by theability to entrain oil up vertical suction risers
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REFRIGERANT PIPING cont.
(ASHRAE Handbook 2006 - Refrigeration p.
2.19). Hot gas bypass pipe diameters areselected to maintain velocity below a maximum
4000 fpm, while a minimum criteria guarantees
oil return up vertical rise sections, as with the
suction line (ASHRAE Handbook 2006 Refrigeration p. 2.20).
Acceptable pressure loss criteria are applied to
each of the lines: The total equivalent length ofthe liquid line available is determined such that
3F of liquid sub-cooling remain at the TXV.
This includes the pressure losses in horizontaland vertical sections, accessories, elbows, etc.
Recall that the available sub-cooling for the cycle
is assumed as 10F. To maintain at least 3F sub-cooling as a factor of safety to avoid flashing at
the TXV, we consider a maximum pressure lossequivalent to a 7F change in saturationtemperature. Pressure losses in the suction line
are not to exceed 2F. When sizing the hot gas
bypass line we consider a maximum acceptable
pressure loss in the hot gas bypass line with R-22to be 20 psi, 30 psi with R-410A refrigerant.
When to use predetermined line sizing:
The line sizes presented are not the only
acceptable pipe diameters, they are however
appropriate for general comfort coolingapplications, and satisfy common job
requirements. Examine the conditions,
assumptions, and constraints used in the
generation of the predetermined pipe diametersto ensure that this method is applicable to a
particular case. Do not assume that these line
sizes are appropriate for every case. ConsultASHRAE Handbook Refrigeration 2006 for
generally accepted system practices.
How to use predetermined line sizing:
First, read the previous section entitled (When to
use predetermined line sizing) to decide if thismethod is applicable.
Second, determine the refrigerant being used,AAON offers CL products with R-410A and R-
22 refrigerants, and the line sizes are notidentical for both.
Next, determine whether the product is operating
with single, or dual circuited compressors.
Locate the appropriate table of line sizes:TABLE RP-1: Dual Circuited R-410A
condensers
TABLE RP-2: Dual Circuited R-22 condensersTABLE RP-3: Single Circuited R-410A
condensers
TABLE RP-4: Single Circuited R-22 condensersLocate the Model number in the table. For each
model, the circuits are listed, along with the pipe
diameters of the connection sizes, and the
diameters of the predetermined line size.A figure accompanies each table.
FIGURE RP-1: Dual circuited R-410A
condensersFIGURE RP-2: Dual circuited R-22 condensers
FIGURE RP-3: Single circuited R-410A
condensersFIGURE RP-4 Single circuited R-22 condensers
Examine the appropriate figure to determine the
acceptable line dimensions. The figure is shownas total available riser height versus total
equivalent line length for the liquid line. Thiscurve identifies a region of acceptable piping
configuration when the predetermined line sizes
are selected for any model in the table. A piping
configuration above the curve falls outside theassumptions used to determine the line size and
will result in a loss of sub-cooling, and additional
pressure losses in the suction and hot gas bypasslines. The total equivalent line length definition
includes the height of vertical rise, pressure drop
through elbows and accessories, and horizontalline length, so elbows, accessories and vertical
rise must be considered when determining
horizontal length available from the totalequivalent line length.
This figure is presented in terms of the liquid
line, but it assumes that the line lengths for the
suction and hot gas bypass are similar, as theselines will commonly be routed together to
minimize the space and cost required for split
system installation.
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REFRIGERANT PIPING cont.
TABLE RP-1 Predetermined Line sizes for Dual Circuit CL units with R-410A
Tons System
R-410A
Connection Size Predetermined Line Size
Suction Line Liquid Line Hot Gas Bypass Reheat Suction Line Liquid Line Hot Gas Bypass Reheat
451
1-3/8 in. 7/8 in. 7/8 in. 7/8 in. 1-5/8 in. 7/8 in. 3/4 in. 1-1/8 in.2
601
1-5/8 in. 7/8 in. 7/8 in. 1-1/8 in. 2-1/8 in. 1-1/8 in. 3/4 in. 1-1/8 in.2
701
1-5/8 in.7/8 in.
7/8 in.1-1/8 in.
2-1/8 in. 1-1/8 in.3/4 in. 1-1/8 in.
2 1-1/8 in. 1-3/8 in. 7/8 in. 1-3/8 in.
751
1-5/8 in. 1-1/8 in. 7/8 in. 1-3/8 in. 2-1/8 in. 1-1/8 in. 7/8 in. 1-3/8 in.2
951 1-5/8 in.
1-1/8 in. 7/8 in.1-3/8 in. 2-1/8 in. 1-1/8 in. 7/8 in. 1-3/8 in.
2 2-1/8 in. 1-5/8 in. 2-5/8 in. 1-3/8 in. 1-1/8 in. 1-3/8 in.
100
1
1-5/8 in.
7/8 in.
7/8 in.
1-1/8 in.
2-1/8 in. 1-1/8 in.
3/4 in. 1-1/8 in.
21-1/8 in. 1-3/8 in. 7/8 in. 1-3/8 in.
3
1101
1-5/8 in. 1-1/8 in. 7/8 in. 1-3/8 in. 2-1/8 in. 1-1/8 in. 7/8 in. 1-3/8 in.2
3
125
11-5/8 in.
1-1/8 in. 7/8 in.1-3/8 in. 2-1/8 in. 1-1/8 in. 7/8 in.
1-3/8 in.2
3 2-1/8 in. 1-5/8 in. 2-5/8 in. 1-3/8 in. 1-1/8 in.
134
11-5/8 in.
1-1/8 in. 7/8 in.1-3/8 in. 2-1/8 in. 1-1/8 in. 7/8 in.
1-3/8 in.2
3 2-1/8 in. 1-5/8 in. 2-5/8 in. 1-3/8 in. 1-1/8 in.
135
1 1-5/8 in. 7/8 in.
7/8 in.
1-1/8 in. 2-1/8 in. 1-1/8 in. 3/4 in. 1-1/8 in.
22-1/8 in. 1-1/8 in. 1-5/8 in. 2-5/8 in. 1-3/8 in. 1-1/8 in. 1-3/8 in.
3
155
1 1-5/8 in.
1-1/8 in. 7/8 in.
1-3/8 in. 2-1/8 in. 1-1/8 in. 7/8 in.
1-3/8 in.22-1/8 in. 1-5/8 in. 2-5/8 in. 1-3/8 in. 1-1/8 in.
3
170
1
2-1/8 in. 1-1/8 in. 7/8 in. 1-5/8 in. 2-5/8 in. 1-3/8 in. 1-1/8 in. 1-3/8 in.2
3
190
11-5/8 in. 1-1/8 in.
7/8 in.
1-3/8 in. 2-1/8 in. 1-1/8 in. 7/8 in.
1-3/8 in.2
32-1/8 in. 1-1/8 in. 1-5/8 in. 2-5/8 in. 1-3/8 in. 1-1/8 in.
4
210
1 1-5/8 in.
1-1/8 in. 7/8 in.
1-3/8 in. 2-1/8 in. 1-1/8 in. 7/8 in.
1-3/8 in.22-1/8 in. 1-5/8 in. 2-5/8 in. 1-3/8 in. 1-1/8 in.3
4
230
1
2-1/8 in. 1-1/8 in. 7/8 in. 1-5/8 in. 2-5/8 in. 1-3/8 in. 1-1/8 in. 1-3/8 in.2
3
4
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27
REFRIGERANT PIPING cont.
TABLE RP-2 Predetermined Line sizes for Dual Circuit CL units with R-22
Tons System
R-22
Connection Size Predetermined Line Size
Suction Line Liquid Line Hot Gas Bypass Reheat Suction Line Liquid Line Hot Gas Bypass Reheat
451
1-3/8 in. 5/8 in. 7/8 in. 7/8 in. 2-1/8 in. 7/8 in. 7/8 in. 1-1/8 in.2
601
2-1/8 in. 7/8 in. 7/8 in. 1-3/8 in. 2-1/8 in. 1-1/8 in. 7/8 in. 1-3/8 in.2
701
2-1/8 in. 7/8 in. 7/8 in. 1-3/8 in.2-1/8 in.
1-1/8 in.7/8 in. 1-3/8 in.
2 2-5/8 in. 1-1/8 in. 1-5/8 in.
751
2-1/8 in. 7/8 in. 7/8 in. 1-3/8 in. 2-5/8 in. 1-1/8 in. 1-1/8 in. 1-5/8 in.2
951 2-1/8 in. 7/8 in.
7/8 in.1-3/8 in.
2-5/8 in.1-1/8 in.
1-1/8 in. 1-5/8 in.2 2-5/8 in. 1-3/8 in. 1-5/8 in. 1-3/8 in.
100
1
2-1/8 in. 7/8 in. 7/8 in. 1-3/8 in.
2-1/8 in.
1-1/8 in.
7/8 in. 1-3/8 in.
22-5/8 in. 1-1/8 in. 1-5/8 in.
3
1101
2-1/8 in. 7/8 in. 7/8 in. 1-3/8 in. 2-5/8 in. 1-1/8 in. 1-1/8 in. 1-5/8 in.2
3
125
12-1/8 in. 7/8 in.
7/8 in.1-3/8 in.
2-5/8 in.1-1/8 in.
1-1/8 in. 1-5/8 in.2
3 2-5/8 in. 1-3/8 in. 1-5/8 in. 1-3/8 in.
134
12-1/8 in. 7/8 in.
7/8 in.1-3/8 in.
2-5/8 in.1-1/8 in.
1-1/8 in. 1-5/8 in.2
3 2-5/8 in. 1-3/8 in. 1-5/8 in. 1-3/8 in.
135
1 2-1/8 in. 7/8 in.
7/8 in.
1-3/8 in. 2-1/8 in. 1-1/8 in. 7/8 in. 1-3/8 in.
22-5/8 in. 1-3/8 in. 1-5/8 in. 2-5/8 in. 1-3/8 in. 1-1/8 in. 1-5/8 in.
3
155
1 2-1/8 in. 7/8 in.
7/8 in.
1-3/8 in.
2-5/8 in.
1-1/8 in.
1-1/8 in. 1-5/8 in.22-5/8 in. 1-3/8 in. 1-5/8 in. 1-3/8 in.
3
170
1
2-5/8 in. 1-3/8 in. 7/8 in. 1-5/8 in. 2-5/8 in. 1-3/8 in. 1-1/8 in. 1-5/8 in.2
3
190
12-1/8 in. 7/8 in.
7/8 in.
1-3/8 in.
2-5/8 in.
1-1/8 in.
1-1/8 in. 1-5/8 in.2
32-5/8 in. 1-3/8 in. 1-5/8 in. 1-3/8 in.
4
210
1 2-1/8 in. 7/8 in.
7/8 in.
1-3/8 in.
2-5/8 in.
1-1/8 in.
1-1/8 in. 1-5/8 in.22-5/8 in. 1-3/8 in. 1-5/8 in. 1-3/8 in.3
4
230
1
2-5/8 in. 1-3/8 in. 7/8 in. 1-5/8 in. 2-5/8 in. 1-3/8 in. 1-1/8 in. 1-5/8 in.2
3
4
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28
REFRIGERANT PIPING cont.
TABLE RP-3 Predetermined Line sizes for Single Circuit CL units with R-410A
Tons System
R-410A
Connection Size Predetermined Line Size
Suction Line Liquid Line Hot Gas Bypass Reheat Suction Line Liquid Line Hot Gas Bypass Reheat
45
1
1-1/8 in. 5/8 in. 7/8 in. 7/8 in. 1-3/8 in. 5/8 in. 5/8 in. 3/4 in.2
3
4
60
1
1-3/8 in. 5/8 in. 7/8 in. 7/8 in. 1-3/8 in. 3/4 in. 3/4 in. 7/8 in.2
3
4
70
1 1-3/8 in.
5/8 in. 7/8 in. 7/8 in.
1-3/8 in. 3/4 in.
3/4 in.
7/8 in.
2 1-5/8 in. 1-5/8 in. 7/8 in. 1-1/8 in.
3 1-3/8 in. 1-3/8 in. 3/4 in. 7/8 in.
4 1-5/8 in. 1-5/8 in. 7/8 in. 1-1/8 in.
75
1
1-5/8 in. 5/8 in. 7/8 in. 7/8 in. 1-5/8 in. 7/8 in. 3/4 in. 1-1/8 in.23
4
95
1
1-5/8 in.
5/8 in.
7/8 in.
7/8 in. 1-5/8 in. 7/8 in. 3/4 in.
1-1/8 in.2 7/8 in. 1-1/8 in. 2-1/8 in. 1-1/8 in. 7/8 in.
3 5/8 in. 7/8 in. 1-5/8 in. 7/8 in. 3/4 in.
4 7/8 in. 1-1/8 in. 2-1/8 in. 1-1/8 in. 7/8 in.
TABLE RP-4 Predetermined Line sizes for Single Circuit CL units with R-22
Tons System
R-22
Connection Size Predetermined Line Size
Suction Line Liquid Line Hot Gas Bypass Reheat Suction Line Liquid Line Hot Gas Bypass Reheat
45
1
1-3/8 in. 5/8 in. 7/8 in. 7/8 in. 1-5/8 in. 5/8 in. 3/4 in. 7/8 in.2
3
4
60
1
1-3/8 in. 5/8 in. 7/8 in. 7/8 in. 1-5/8 in. 3/4 in. 7/8 in. 1-1/8 in.2
3
4
70
1
1-3/8 in. 5/8 in. 7/8 in. 7/8 in.
1-5/8 in.
3/4 in. 7/8 in. 1-1/8 in.2 2-1/8 in.
3 1-5/8 in.
4 2-1/8 in.
75
1
1-3/8 in. 5/8 in. 7/8 in. 7/8 in. 2-1/8 in. 3/4 in. 7/8 in. 1-1/8 in.2
3
4
95
1 1-3/8 in. 5/8 in.
7/8 in.
7/8 in.
2-1/8 in.
3/4 in. 7/8 in. 1-1/8 in.
2 2-1/8 in. 7/8 in. 1-3/8 in. 1-1/8 in. 1-1/8 in. 1-3/8 in.
3 1-3/8 in. 5/8 in. 7/8 in. 3/4 in. 7/8 in. 1-1/8 in.
4 2-1/8 in. 7/8 in. 1-3/8 in. 1-1/8 in. 1-1/8 in. 1-3/8 in.
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29
REFRIGERANT PIPING cont.
FIGURE RP-1. Riser height versus total equivalent line length for R-410A split system applications with
dual circuited CL-045 through CL-230 units. The region of acceptable riser height is the lighter area.Select the corresponding predetermined line size from TABLE RP-1 on page 26.
FIGURE RP-2. Riser height versus total equivalent line length for R22 split system applications with dualcircuited CL-045 through CL-230 units. The region of acceptable riser height is the light area. Select the
corresponding predetermined line size from TABLE RP-2 on page 27.
Acceptable Region
Acceptable Region
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30
REFRIGERANT PIPING cont.
FIGURE RP-3. Riser height versus total equivalent line length for R-410A split system applications with
single circuited CL-045 through CL-230 units. The region of acceptable riser height is the lighter area.Select the corresponding predetermined line size from TABLE RP-3 on page 28.
FIGURE RP-4. Riser height versus total equivalent line length for R22 split system applications withsingle circuited CL-045 through CL-230 units. The region of acceptable riser height is the light area.
Select the corresponding predetermined line size from TABLE RP-4 on page 28.
Acceptable Region
Acceptable Region
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31
FIGURE RP-2. Hot Gas Bypass Piping Diagram with air handler above condenser.
Note: Components shown within air
handler and condensing unit are factory
installed; all other components are fieldinstalled.
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32
FIGURE RP-3. Hot Gas Bypass Piping Diagram with air handler below condenser.
Note: Components shown within airhandler and condensing unit are factory
installed; all other components are field
installed.
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33
FIGURE RP-4. Hot Gas Reheat Piping Diagram with air handler above condenser.
Note: Components shown within airhandler and condensing unit are factory
installed; all other components are field
installed.
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34
FIGURE RP-5. Hot Gas Reheat Piping Diagram with air handler below condenser.
Note: Components shown within air
handler and condensing unit are factoryinstalled; all other components are field
installed.
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35
FIGURE RP-6. Hot Gas Reheat Piping Diagram with air handler above condenser and field installed
suction line accumulator.
Note: Components shown within air
handler and condensing unit are factory
installed; all other components are fieldinstalled.
TO BE INSTALLED IN FIELD
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36
FIGURE RP-7. Hot Gas Reheat Piping Diagram with air handler above condenser and field installed
suction line accumulator.
Note: Components shown within airhandler and condensing unit are factory
installed; all other components are field
installed.TO BE INSTALLED IN FIELD
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37
FIGURE RP-8. Reheat/Hot Gas Bypass Piping Diagram with air handler above condenser.
Note: Components shown within air
handler and condensing unit are factory
installed; all other components are field
installed.
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38
FIGURE RP-9. Reheat/Hot Gas Bypass Piping Diagram with air handler below condenser.
Note: Components shown within air
handler and condensing unit are factoryinstalled; all other components are field
installed.
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39
FIGURE RP-10. Reheat/Hot Gas Bypass Piping Diagram with air handler evaporator above condenser
and field installed suction line accumulator.
Note: Components shown within airhandler and condensing unit are factory
installed; all other components are field
installed.
TO BE INSTALLED IN FIELDTO BE INSTALLED IN FIELD
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40
FIGURE RP-11. Reheat/Hot Gas Bypass Piping Diagram with air handler below condenser and field
installed suction line accumulator.
Note: Components shown within airhandler and condensing unit are factory
installed; all other components are field
installed.TO BE INSTALLED IN FIELD
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41
FIGURE RP-5. Hot Gas Bypass Piping Diagram with air handler above condenser.
Note: Components shown within air
handler and condensing unit are factory
installed; all other components are fieldinstalled.
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42
FIGURE RP-6. Hot Gas Bypass Piping Diagram with air handler below condenser.
Note: Components shown within airhandler and condensing unit are factory
installed; all other components are field
installed.
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43
FIGURE RP-7. Hot Gas Reheat Piping Diagram with air handler above condenser.
Note: Components shown within airhandler and condensing unit are factory
installed; all other components are field
installed.
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44
FIGURE RP-8. Hot Gas Reheat Piping Diagram with air handler below condenser.
Note: Components shown within air
handler and condensing unit are factoryinstalled; all other components are field
installed.
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45
FIGURE RP-9. Hot Gas Reheat Piping Diagram with air handler above condenser and field installed
suction line accumulator.
Note: Components shown within air
handler and condensing unit are factory
installed; all other components are fieldinstalled.
TO BE INSTALLED IN FIELD
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46
FIGURE RP-10. Hot Gas Reheat Piping Diagram with air handler above condenser and field installed
suction line accumulator.
Note: Components shown within airhandler and condensing unit are factory
installed; all other components are field
installed.TO BE INSTALLED IN FIELD
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47
FIGURE RP-11. Reheat/Hot Gas Bypass Piping Diagram with air handler above condenser.
Note: Components shown within air
handler and condensing unit are factory
installed; all other components are field
installed.
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48
FIGURE RP-12. Reheat/Hot Gas Bypass Piping Diagram with air handler below condenser.
Note: Components shown within air
handler and condensing unit are factoryinstalled; all other components are field
installed.
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49
FIGURE RP-13. Reheat/Hot Gas Bypass Piping Diagram with air handler evaporator above condenser
and field installed suction line accumulator.
Note: Components shown within airhandler and condensing unit are factory
installed; all other components are field
installed.
TO BE INSTALLED IN FIELD
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50
FIGURE RP-14. Reheat/Hot Gas Bypass Piping Diagram with air handler below condenser and field
installed suction line accumulator.
Note: Components shown within airhandler and condensing unit are factory
installed; all other components are field
installed.TO BE INSTALLED IN FIELD
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Condenser and Condenser Unit Startup Form
Date:______________Job Name:_____________________________________________________________________
Address:______________________________________________________________________
Model Number:_______________________________________________________________________________________________________________________________________________
Serial Number:_____________________________________________ Tag:_______________
Startup Contractor:______________________________________________________________Address:__________________________________________________ Phone:_____________
Pre Startup Checklist
Installing contractor should verify the following items.
1. Is there any visible shipping damage? Yes No
2. Is the unit level? Yes No
3. Are the unit clearances adequate for service and operation? Yes No4. Do all access doors open freely and are the handles operational? Yes No
5. Have all shipping braces been removed? Yes No
6. Have all electrical connections been tested for tightness? Yes No
7. Does the electrical service correspond to the unit nameplate? Yes No
8. On 208/230V units, has transformer tap been checked? Yes No
9. Has overcurrent protection been installed to match the unit nameplate
requirement? Yes No
10. Have all set screws on the fans been tightened? Yes No
11. Do all fans and pumps rotate freely? Yes No
12. Is all copper tubing isolated so that it does not rub? Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________F Ambient Wet Bulb Temperature ________F
Compressors / DX Cooling
Compressor
Number L1 L2 L3
HeadPressure
PSIG
SuctionPressure
PSIG
CrankcaseHeater
Amps
1
2
34
5
6
7
8
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Refrigeration System 1
PressureSaturated
Temperature
Line
TemperatureSub-cooling Superheat
Discharge N/A N/A
Suction N/A
Liquid N/ARefrigeration System 2
PressureSaturated
Temperature
Line
TemperatureSub-cooling Superheat
Discharge N/A N/A
Suction N/A
Liquid N/A
Refrigeration System 3
PressureSaturated
Temperature
Line
TemperatureSub-cooling Superheat
Discharge N/A N/ASuction N/A
Liquid N/A
Refrigeration System 4
PressureSaturated
Temperature
Line
TemperatureSub-cooling Superheat
Discharge N/A N/A
Suction N/A
Liquid N/A
Condenser Fans
Alignment Check Rotation Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
5
6
Condenser Pump
Check Rotation Nameplate Amps________
Number hp L1 L2 L3
1
2
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Maintenance Log
This log must be kept with the unit. It is the responsibility of the owner and/or
maintenance/service contractor to document any service, repair or adjustments. AAON Service
and Warranty Departments are available to advise and provide phone help for proper operationand replacement parts. The responsibility for proper start-up, maintenance and servicing of the
equipment falls to the owner and qualified licensed technician.
Entry Date Action Taken Name/Tel.
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CL SERIES CONDENSING
UNIT
INSTALLATION, SERVICE
&
OWNERS INFORMATION MANUAL
AAON, Inc.2425 South Yukon
Tulsa, Oklahoma 74107
Ph (918) 583 2266 F (918) 583 6094