Stratton Wall HungStainless Steel Condensing Boilers Natural Gas or LPGOutputs 45kW to 100kW

Hamworthy

2

Durable stainless steel heat exchanger

Accurate load matching

Fully modulating for greater efficiency

System design flexibility

Burner controllable for maximum

condensing operation

The new Stratton boiler from Hamworthy brings together the design flexibility of a compact commercial wall hung modular boiler system with the reliability assurance of a stainless steel heat exchanger for long life and consistent high efficiency performance.

Four models are available from 45kW to 100kW output (in condensing operation). Higher outputs can be achieved by combining multiple Stratton boiler modules together under the control of a Merley sequence controller (maximum 16 boilers).

Hamworthy offer a range of standard horizontal mounting header and flue assembly kits, with kits for 1, 2, 3 or 4 boilers in series, to aid the designer and installer.

All models feature an advanced pre-mix combustion system with fully modulating burner and intelligent microprocessor control to maximise efficiency and to keep CO2 and NOX emissions to a minimum with all models achieving European Class 5 NOX rating. Consequently, the Stratton provides a safe, ultra clean, efficient and quiet commercial heating solution, or potable hot water solution if used with a Powerstock or equivalent calorifier.

Designed for sealed system use and with installation to include a low loss header, each model is supplied optimised for natural gas and can be converted for LPG usage on-site. With flexibility of installation in mind, the Stratton can be installed with either a room sealed flue or a conventional open flue system in line with B23, C13, C33 or C53.

Maximum output temperature is 80°C with no minimum return temperature and maximum working pressure of 4 barg.

The high efficiency condensing Stratton

range of commercial modular boilers

features a robust heat exchanger

designed in stainless steel for corrosion

resistance and long life.

BE

NE

FIT

S

Stratton boiler modules with pipe kit and flue header kit

StrattonWall Hung, Pre-mix Gas Fired Modular Boilers

Options Single and multiple boiler controls

Natural gas or propane Pipe kits and low loss header

Flue header kits Range of flue components

3

Stainless Steel Counter-flow Heat Exchanger

The Stratton boiler features a stainless steel, counter-flow, radial heat exchanger with a co-axially mounted burner. The heat exchanger comprises a primary (combustion) coil connected, via a manifold, to a secondary (condensing) coil running directly above and parallel to the primary coil.

Each coil is a spiral waterway made from 316L grade stainless steel for high resistance to corrosion and long life.

Oval cross-section waterways improve heat transfer and save space, making the Stratton a powerful and responsive, yet highly compact boiler.

The primary coil is directly heated by the cylindrical burner, which is mounted inside, and concentric with, the primary coil. The burner emits flames radially, giving an even heat distribution along the entire length of the coil, even at low modulation.

The secondary coil is also heated by the combustion gases from the burner as they rise up to the flue exhaust. However, when condensing conditions prevail i.e. the flue gas temperature falls below 57°C, the secondary coil also recovers latent heat from the combustion gases as they condense around the coil, adding to the overall efficiency of the boiler and reducing heat losses through the flue. Any condensate formed in the process drains away via a condensate drain which includes a syphon trap to prevent any risk of escape of any combustion gases via the condensate drain.

Primary Circulation

An integral boiler pump circulates water for the heating circuit through the heat exchanger. Water circulates from secondary coil to primary coil, via a manifold which changes the direction of rotation of the flow, and then is output to the heating circuit, via a low loss header. Turbulent flow is maintained throughout the passage through the coils, maximising heat transfer.

The controller ensures a short pump overrun is included after the burner is turned off to continue circulation and protect the heat exchanger from overheating.

Summary

Stratton boilers feature an advanced pre-mix fan-drawn combustion system, with cylindrical burner and twin-coil counter-flow heat exchanger, managed by an integral intelligent microprocessor-based controller with energy saving features such as reduced start/stop cycling and modulation control. Combustion power can modulate from 100% down to 25% to closely align boiler operation with the prevailing demand.

The correct gas/air ratio is held throughout the modulation range to ensure clean and efficient combustion is maintained, with burner power governed by the speed of the fan drawing the gas and air mixture to the burner. With a net efficiency of 109.3% and low emissions (NOX below 45mg/kWh, CO2 maximum volume 8.6%), the compact and durable Stratton boilers, together with their range of pipe kits and flue accessories, make a very attractive proposition for specifiers, installers and users alike.

All models are suitable for operation with room sealed flue systems or open flue systems allowing the designer greater flexibility in siting the boilers, which can be installed in almost any wall location within the building thanks to long permissible flue runs: up to 9m for concentric flues or longer with twin duct room-sealed flue systems and open flue systems.

SpecificationStratton Wall Hung BoilerTypical Layout

Stainless steel condensing heat exchanger

Flue gas test point

Flue gasexhaust

Fan-drawn combustion air inlet

Automatic air vent

Coiled stainless steel combustion heat exchanger

Water pressureswitch

Air pressureswitch

Pump

Fan

Condensate drain

Return from heatingcircuit

Condensate syphon

Control panel with integrated burner controller

Hot water flowto heating circuit

Cylindrical modulating premix burner

4

SpecificationStratton Wall Hung Boilers

Circulation Pump

Wilo Star pumps are used across the Stratton boiler range for the integral circulation pump with flow rates from 0.48l/s to 1.11l/s. In all models, the pump is sufficient for primary circulation through a calorifier.

Additional Heating System Pump(s)

In addition to the integral boiler circulation pump, one or more pumps will be required for heating circulation and/or Domestic Hot Water (DHW) circulation, which can be controlled (on/off) from the boiler controller; these pumps should be connected via a contactor.

Ignition

Safe and reliable automatic firing of the burner is ensured via spark-ignition and ionisation flame detection systems.

Burner

A small flame is held on the entire surface of the cylindrical burner combustion head. This ensures optimum combustion at any point in the modulation range of the boiler.

The Gas Train

Gas is supplied through a zero governor valve to precisely control the mixture of gas and air entering the burner as it modulates, to maintain the correct gas and air ratio for high combustion efficiency.

Low Emissions

All Stratton boilers achieve European Class 5 performance for NOX emissions, with emissions as low as 35mg/kWh.

Efficiency

Stratton condensing boilers achieve a full load efficiency of up to 88.5% gross (97.8% net) whilst at part load the efficiency rises to 98.9% gross (109.3% net). This equates to seasonal efficiencies of up to 96.9% gross, far exceeding the Building Regulations minimum seasonal efficiency requirements of 86% gross for new buildings and 82% gross for existing buildings, using natural gas.

Electrical Details

Supply 230V 50Hz Single Phase

Wiring external to the boiler must be installed in accordance with I.E.T. regulations and any local regulations which apply.

Pressure Relief Valve and Other Safety Equipment

Each Stratton boiler is protected by a pressure relief valve set to 4 bar. Additional safety features designed to stop the boiler, or prevent it from starting, include a minimum water pressure switch set to 1 bar, a safety limit thermostat set to maximum 100°C, and water flow and air differential pressure switches to check there is sufficient water and air flow for boiler operation.

Syphon Trap

The Stratton features a condensate syphon trap to prevent the escape of flue gases out of the condensate drain pipe.

Automatic Air Vent (AAV)

An automatic air vent is included in the Stratton to automatically purge air in the heating circulation water.

Pipe Kits with Low Loss Headers

The boiler must be used with a low loss header arrangement to provide hydraulic separation from the heating circuit pump(s), to ensure secondary circuit conditions do not adversely affect flow through the boilers. To support the designers and installers, Hamworthy provide a choice of pipe kits with low loss headers for single and multiple boiler arrangements.

The single boiler pipe kit includes a steel header which fits horizontally under the boiler, attaching to and supported by pre-formed flow and return steel pipework connections to the boiler. The header has R2” connections to the heating circuit flow and return, R1” connections for 1” diameter steel pipes to connect to the boiler, an Rc³�8” connection pressure gauge, and R½” drain connection.

For multiple boiler arrangements, ready-to-assemble, frame–mounted pipe kits are available. These comprise a steel wall-mounted frame sized to suit the number of boilers it supports, together with a steel vertical low loss header, steel horizontal flow and return pipes, steel gas supply pipe, polypropylene condense discharge pipe, isolation ball valves and pre-formed copper connections to the boilers. All header pipework for the water side are DN80 PN6 sized steel pipe and flanges, and DN50 PN10 for gas pipework. For more information on low loss header and pipe kits refer to page 8 and 9. Note that drain valves, gauges and blanking plugs are not HHL supply.

Wall Mounting

The Stratton has been designed with ease of installation in mind. For single boiler applications the boiler, together with its individual low loss header, is simply mounted on a suitable non-flammable wall using fasteners (not HHL supply) to suit wall type through predrilled mounting holes and slots at the top of the boiler.

For multiple boiler applications using pipe kits, these include a mounting frame. This is first assembled and then secured to the wall using appropriate fasteners for the wall type. Pipe headers and associated equipment are then fitted to the frame, followed by the boilers which are mounted on two studs per boiler at the top of the frame, and secured with M10 nuts.

Flue Connections

Each Stratton boiler has separate air and flue connections, although adapters are available for concentric flue connections. Polypropylene is used in flue pipe connections to resist the slightly acidic nature of the combustion gases and condensate. Flue connections at the boiler are 80mm dia. for STW45/STW60 and 100mm dia. for STW85/STW100. Air inlet connections are 80mm dia. for all Stratton models.

Flue Components and Flue Header Kits

Stratton boilers are suitable for flue systems designed in accordance with B23, C13, C33 and C53 schemes. Hamworthy offers flue components for all of these schemes, and also flue header kits to provide a shared B23 flue for two to four boilers, to complement the frame and pipe kits. For more information on flues refer to page 14 and 15.

5

Controls OverviewStratton Boilers

Stratton boilers can be installed in a variety of configurations, from single boiler applications to multiple boilers, and controlled locally, or remotely via a building management system.

Each boiler features an extremely versatile microprocessor based boiler control system that can be tailored to meet the exact needs of the heating system, and capable of integrating the boiler and other system components.

Every Stratton boiler is equipped with the following control features as standard:

■ Remote on/off control input (e.g. time clock control)

■ Remote modulation input (0-10V analog input)

■ External air temperature sensor input

■ Volt free contacts

■ Frost protection

■ Pump overrun for internal pump

LCD User Interface

Local control and monitoring is carried out from the controller LCD user interface on the front of the boiler. Logical pushbutton operation provides access to set or monitor control parameters.

Temperature Control

All Stratton boilers are fitted with a manual reset limit thermostat set to 100°C. An electronic temperature control thermostat regulates the boiler flow temperature up to a maximum of 80°C.

Stratton boilers also incorporate a return temperature sensor, which, in conjunction with the flow temperature sensor, governs the modulation set point of the boiler.

Status Signalling

All Stratton boilers are fitted with a multi-function clip-in module to provide two volt free, normally open contacts for remote status monitoring as standard. One indicates boiler normal run (boiler lit and no errors) when closed, the other indicates a general fault alarm when closed.

0-10 Volt DC Analog Input

The standard multi-function clip-in module also provides a 0-10 volt DC analog signal interface to control the modulation level of the burner, or to set the flow temperature set point. The 0-10 volt signal can be used for remote connection of the boilers to a Building Management System, (BMS) to control remotely the temperature set point or boiler load setting. If this is used, then the 0-24V DC remote on/off control cannot be used.

Remote On/Off Control (Remote Timer)

24V DC signal and return connections are provided for remote on/off control, for example, by a remote timer, and require wiring to a volt-free contact switch at the remote controlling device. If not used, a link must remain across the 24V supply and return terminals. If this is used, then the 0-10V DC analog input control cannot be used.

LPB Bus Communications Module

The optional Siemens LPB bus communication clip-in kit is used to connect the boiler control unit (Siemens LMU64) to the optional sequence control module. Each boiler in a modular installation requires a clip-in LPB bus communications module to communicate with the boiler sequence controller.

External Air Temperature Sensor

Stratton boilers can be supplied with an optional external air temperature sensor to exploit the full functionality of the boiler controls, and enable direct temperature compensation on the boiler, maximising the opportunity for condensing operation.

When fitted with an external temperature sensor, the boiler’s own thermostat is overridden and the flow temperature is controlled as a function of external temperature conditions.

Using a range of adjustable compensation slopes built into the standard boiler controls, the flow temperature profile can be tailored to suit the needs of individual heating systems.

For multiple boilers, the external temperature sensor should be used be used in conjunction with the optional Merley boiler sequence controller.

Frost Protection

When fitted with an external air temperature sensor the boiler control system features a two stage frost protection system.

Stage one involves turning the integral boiler pump on should the external air temperature fall below 1.5°C. Stage two involves firing the boiler should the internal water temperature fall below 5°C. Whenever the boiler fires, the internal pump is automatically switched on.

For further details of controls for single boilers refer to page 10 and for multiple boilers, please see page 11.

Clip in modules on the LMU64 Boiler Management Unit

6

Technical DataStratton Performance and General Data Information

Module Size STW45 STW60 STW85 STW100

En

erg

y

Building Regulations seasonal efficiency gross (%) 96.87 96.94 96.31 96.14

Boiler output 80/60°C kW Btu/h x 1000

40136

56.5193

80273

92.6316

Boiler output 50/30°C kW Btu/h x 1000

44150

61.8211

87297

100341

Boiler input (gross)–maximum kW

Btu/h x 100046157

64.1219

91.7313

105.1359

Boiler input (net)–maximum kW

Btu/h x 100041.6143

58198

83283

95.1324

Boiler output–minimum kW 80/60°C Btu/h x 1000

12.944

14.951

26.390

26.390

Wate

r

Water temperature–maximum °C 80

Water content (not including headers) litre 4.6 6.1 9.4 9.4

Design flow rate @ 20°C Δt rise l/sec 0.48 0.68 0.96 1.11

Residual pump head kPa @ 20°C Δt rise m

252.5

3.90.39

4.90.49

4.90.49

Water pressure–maximum barg 4

Water pressure–minimum barg 1

Gas

Gas flow rate–maximum, natural gas (G20)

m3/h 4.4 6.1 8.8 10.1

Gas inlet pressure–nominal, natural gas (G20)

mbar 20

Gas inlet pressure–maximum, natural gas (G20)

mbar 25

Gas flow rate–nominal, LPG (G31) kg/h 3.2 4.5 6.5 7.4

Gas inlet pressure, LPG (G31) mbar 37

Flu

e

Approximate flue gas volume @ 15°C, 8.8% CO2, N.T.P @ 80/60°C, NG.

m3/h 59 82 118 136

Flue gas temperature–maximum @ 80/60°C °C 67 70 67 75

NOX Emission (DAF) European Class 5 mg/kWh 40 45 40 35

Pressure at flue outlet @ 80/60°C Pa

mbar85

0.851501.52

800.79

1101.12

Co

nn

ect

ion

Water flow/return connections inch G 1” G 1” G 1¼” G 1¼”

Gas inlet connection pipe thread inch G¾"

Flue diameter (I/D)–nominal mm 80 100

Air inlet diameter (I/D)–nominal mm 80

Condensate trap connection(s) (O/D) mm 25

Mis

c

Power consumption–maximum W 160 190 270 300

Supply voltage–nominal 230V 1Ph 50Hz

Boiler module running current Amps 0.7 0.83 1.17 1.3

Approximate shipping weight including packaging

kg 79 86 101

Boiler weight (dry) kg 66 73 88

Noise emissions @ 1m Max dB(A)

Min dB(A)62.734.6

59.836.9

Note: All measurements are with G20 natural gas unless otherwise stated

7

Dimensional DetailsStratton Boiler Dimensions and Clearances

Stratton Model Ref. STW45/STW60 STW85/STW100

Flue connection height/mm A 997 1007

Flue connection diameter/mm B 80 100

Flue Type B23 C13/C33 C53

Stratton Model STW45 STW60 STW85 STW100

STW45 STW60

STW85 STW100

STW45 STW60

STW85 STW100

Flue pipework diameter/mm 110 125 110 125 160 80/125 100/150 80/80 100/100

Min. clearance/mm Ref. C 405 475 465 450 655 475 525 310 350

222

600

min

clea

ranc

e

B

Plan View

125

80

932

872

A21

7

19

269

12423

2

Front of Boiler

View on underside

250 250

20 5

Air inlet 80 dia.

Wall Fixing Detail

Slot 35 x 12 dia.To suit M10 wall fixing screws

Hole 12 dia.

Front View Side View

500

552 CRS

52

500

Gland hole x 6

Gas - 57

Safety valve - 275

Flow - 333

Return - 385

Cold inlet - 445

30

47.5

65

100

105

450

C

294

275

222

347

125 143

R

Condensate discharge pipe

Safety relief valve

All dimensions in mm

8

Pipe and Header KitsSingle and Multiple Stratton Boilers

Single Boiler Pipe Kit with Low Loss Header

For individual Stratton boiler operation a simple kit is available with a square section low loss header connected to and supported by flow and return steel pipes which connect to the underside of the boiler. The kit includes:

■ Steel header unit with steel pipe connections to boiler

■ Brass adapters G 1½” to 1”, and G 1½” to 1¼” with EPDM seals to suit all boiler model connections

■ 2” heating circuit connections

■ Pre-fitted foam insulation

■ Dial pressure gauge (4 bar)

■ Drain valve

■ Connection for an expansion vessel on the return (angled) pipe

With this pipe kit the boiler is directly mounted to the wall, and so the mountings studs must take into account the weight of the boiler and the universal header.

Multiple Boiler Pipe Kits with Frame and Header

For multiple Stratton boiler systems Hamworthy offer a range of wall-mounted pipe kits, available for combinations of two, three or four boilers. Each kit includes:

■ Steel wall-mounting frame assembly

■ 150mm dia. vertical low loss header with pressure gauge and automatic air vent

■ 80mm dia. flow and return header pipes with DN80 PN6 flanges

■ Gas header pipe with isolation valve, and DN50 PN10 flanges

■ Condensate drain pipe with Tee

■ Isolating valves (flow) and three port valve (return)

■ Copper connections from flow and return header pipes to boiler

The flow and return header pipe lengths, valves and connection quantities etc. vary between kits to suit the number of boilers. The result is a neat and compact easy-to-install solution, with all the necessary parts supplied, requiring only hook-up to water gas and electrical supplies, and to the heating circuit.

The kits are sized to suit 45kW/60kW or 85kW/100kW boilers, sharing the same dimension headers, but with different length copper connections to the boiler, as the 85kW and 100kW boilers are deeper than the 45kW and 60kW boilers. Note that the wall-mounting frames have no floor-bearing capability.

405

1600

300 67

70

500

Flow Return

Min

imum

Hei

ght

1780

1457

872

585

Mountings,2 x 12 dia. holes, 405 between centres forM10 fixingsplus 2 x 12 dia. x 15 horizontal slots for alternativemounting points

269

A

B

18+4*L

M

401+4*

C 552 552 552 326 dia. D

395

390

140

78249.5

499

409

419

552

322

308

792

1780

FGH E

612

322

340

1600

15

1800

Holes 12 dia.Clearance 15 dia.

Hole centres

Stud centres

*4mm gasket width

Pipe kits (with frames) and B23 flue header kits for two (left) and three (right) Stratton boilers

Single Boiler and Low Loss Header Kit Dimensions/mm

Ref.Single Boiler Referenced Dimensions/mm

STW45/STW60 STW85/STW100

A 472 626

B 125 135

All dimensions in mm

9

Dimensional DetailsStratton Pipe Kits and Flue Header Kits

Dimensions of Boiler Modules with Multiple Boiler Pipe Kits and Flue Header Kits/mm

18+4*L

M

401+4*

C 552 552 552 326 dia. D

395

390

140

78249.5

499

409

419

552

322

308

792

1780

FGH E

612

322

340

1600

15

1800

Holes 12 dia.Clearance 15 dia.

Hole centres

Stud centres

*4mm gasket width

Output Power of Stratton Modules

Models Ref.Number of Boilers

2 3 4

STW45STW60

C 507

D 160

E 2235 2265 2295

F 2160 2160 2160

G 2265 2265 2265

H 2326 2356 2386

L 1100 1650 2204

M 1527** 2077** 2631**

STW85STW100

C 532

D 200

E 2393 2423 2453

F 2316 2316 2316

G 2440 2440 2440

H 2505 2535 2565

L 1100 1650 2204

M 1527** 2077** 2631**

Boiler Model

Number of boilers

Output PowerkW

@50/30°C

Output PowerBtu

@50/30°C

STW45

1 44 150

2 88 300

3 132 450

4 176 600

STW60

1 61.8 211

2 123.6 422

3 185.4 633

4 247.2 844

STW85

1 87 297

2 174 594

3 261 891

4 348 1188

STW100

1 100 341

2 200 682

3 300 1023

4 400 1364

The flue header kits are for B23 scheme open flue systems only and are separate from the pipe kits. See Flue Design section on page 15.

**Includes 4mm per gasket and 18mm for blank flange widths

Pipe kit (with frame) and B23 flue header kit for four Stratton boilers, with dimensions

All dimensions in mm

All dimensions in mm

10

Control DetailsStratton Wall Hung–Single Boilers

The control options for single Stratton wall hung boilers are different to those for multiple boilers. Please refer to page 11 for controls on multiple boilers.

All controls functions are managed via the ‘boiler management unit’ Siemens LMU64. Using a combination of options, the level of control is expandable for up to two heating circuits and one domestic hot water cylinder.

A circulation pump overrun timer is incorporated within the boiler LMU.

Programmable Room Sensor

A Stratton single boiler system can be fitted with a single programmable room sensor, which should be located in the first heating zone. This room thermostat allows heating circuit management to be based on both the internal and external air temperature. The boiler will manage the heating circuit pump via a contactor according to the program requirements of the programmable room unit.

Features:

■ Individual 7 day program with auto summer / winter hour change for heating circuit 1, heating circuit 2 and DHW

■ 3 periods per day per time program

■ Constant or variable temperature flow

■ Compensated flow temperature based on external and room air temperatures

■ Optimised start / stop based on external and room air temperatures

■ Building frost protection based on room air temperature

■ Summer shutdown based on external air temperature

■ Holiday period with frost protection

■ Reduced temperature, night set back for non occupancy hours

■ Daily pump exercise function to prevent any risk of pump sticking after prolonged idle period

■ Programme lock to prevent tampering

■ Individual temperature settings for each zone

To achieve full functionality an external air sensor must be fitted.

Options for a Single Boiler only Programmable room sensor External air sensor 2nd heating circuit clip-in relay kit DHW cylinder sensor kit

External Air Sensor

An optional external air temperature sensor may be wired directly to the boiler to exploit the direct weather compensation functionality of the boiler controls. This sensor may be connected to the control scheme and should ideally be positioned on an external wall with northerly aspect.

2nd Heating Circuit Clip-in Relay Kit

To control a second heating circuit, an additional clip-in relay kit is required for fitting directly to the LMU. The kit comprises a relay and water temperature sensor complete with pocket. This kit provides outputs for a pump and mixing valve.

■ Mixing valve allows second heating circuit to operate at a different temperature set-point to heating circuit 1

■ Second heating circuit should operate at the same or lower temperature than circuit 1, e.g. underfloor heating

■ Programmed via the programmable room sensor

■ Compensated flow based on external air temp and using a curve separate to that of heating circuit 1 owing to mixing valve

■ Optimised start/stop based on external air temperature

■ Frost protection based on water temperature in second heating circuit

For the second heating circuit, the boiler will manage the circuit pump and/ or mixing valve via contactors, according to the program requirements of the programmable room sensor and the water temperature sensor.

Only one programmable room sensor may be connected, therefore the second heating circuit management is derived from time control and external air temperature measurement.

DHW Cylinder Sensor Kit

This kit is for a domestic hot water (DHW) circuit directly controlled from the boiler, but programmed via the programmable room sensor, and features:

■ Immersion sensor complete with pocket

■ DHW cylinder sensor and pump output directly from boiler LMU

■ Frost protection based on stored water temperature

■ Reduced storage temperature for non-occupancy hours

■ Anti-Legionella function

For the DHW cylinder circuit, the boiler will manage the primary coil pump according to the program requirements of the programmable room unit and the DHW cylinder sensor.

11

Options for Multiple Boilers only Boiler sequencing cascade controller LPB bus communications clip-in module Choice of room sensors External air sensor Hard wired or wireless controls DHW cylinder sensor kit

The Merley boiler sequence controller can be supplied within a dedicated housing for wall mounting or as a loose kit for integrating within a plant room control panel.

Wall Mounted Controller

Merley sequence controllers are available factory assembled within a robust steel enclosure suitable for wall mounting, with the digital interface display pre-mounted to the housing door. The sequence controller is mounted to a DIN rail attached to the panel back plate assembly, with electrical trunking to simplify routing for site cables to the appropriate wiring terminations.

A cable gland plate is located on the underside of the control panel with 6 loose cable glands supplied for fitting on site.

Loose Kit Controller

For installations where the sequence controller will be integrated within an existing or new plant room control panel, the Merley sequence controller can be supplied in loose kit form.

A suitable space must be allocated within the plant room control panel for mounting the sequence controller to the back plate and for mounting the digital display to the control panel door.

Boiler Sequence Control Strategies

The Merley sequence controller can be configured to sequence boilers in traditional cascade mode or in unison mode.

Cascade Control

Steps a boiler module on at its lowest rate and then modulates it to its maximum rate, before switching on the next boiler module to match the system load. Maintains the lowest number of boiler modules in operation for a given heat load.

This control strategy is particularly suited to boilers operating in constant temperature systems where there is no great efficiency advantage to be gained from operating boilers at part load.

Unison Control

Steps each boiler module on in turn at its lowest rate, and then modulates all boiler modules simultaneously to higher rates to match the system load.

This method of sequencing can offer higher operating efficiencies, taking advantage of the higher part load efficiencies available at low firing rates. This control strategy is particularly suited to condensing boilers operating in variable temperature systems where low water temperatures and part load boiler operation allows optimum boiler operating efficiency to be achieved.

Hamworthy generally recommends the use of the unison control strategy as it offers the greatest overall fuel efficiencies.

The control options for multiple Stratton wall hung boilers are different to those for single boilers. Please refer to page 10 for controls on single boilers.

Sequence Controller LPB Bus

For use with multiple boilers, the optional Merley sequence controller can control up to 16 boilers. Communication between the boilers and sequence controller is facilitated via the LPB bus.

Merley is the latest generation boiler sequence controller for multiple boiler installations. Using the Siemens controls platform, Hamworthy boilers can be controlled to share the load between boiler modules to maximise efficiency and system performance.

Merley wall mounted sequence controller

As a standalone device with autonomous control of the boilers, the controller can be extended to sequence control the boilers and also to manage a complete heating circuit as well as a domestic hot water (DHW) cylinder.

A range of room and external air temperature sensors, including wireless options, ensures comfort levels within the building are maintained.

When integrated with a building management system (BMS), the Merley operates only as a boiler sequence controller, receiving the required operating temperature from the building management system via a 0 to 10 volt analog signal.

Each sequence control system is supplied with a smart digital interface display allowing the user to monitor the current operating status of the boilers, and also the building where the Merley is used to control a heating zone and hot water cylinder.

Full details of the Merley sequence controller are provided in publication, 500002524, available to download at www.hamworthy-heating.com or request a printed copy, Tel: 0845 450 2865

Control DetailsStratton Wall Hung—Multiple Boilers

12

Application & System DataStratton Boilers

Gas Supply Pipes

Supply pipes must be fitted in accordance with BS6891 or IGE/UP/2 as appropriate. Pipework must be of adequate diameter for the length of run, and must not be of a smaller diameter than the boiler’s gas connections. For gas pipe sizing calculations refer to Chartered Institute of Building Services Engineers (CIBSE) Guide C.

The complete installations must be purged and tested for soundness as described in BS6891 or IGE/UP/1 and IGE/UP/1A as appropriate.

Water Flow Requirements

The Stratton boiler is designed as a rapid response, low water content unit, to run continuously with maximum reliability. Care should be taken in the initial design and layout to ensure adequate water flow through the boiler(s) having due regard for the influence of the control system.

The primary circuit design should be such that secondary circuit conditions cannot have an influence over reliable operation of the boilers.

System Feed Water Quality

Modern heating systems often contain a diverse mix of metals which, when combined with supply water of varying chemical composition, can lead to corrosion. It is therefore important to treat water to ensure the long term satisfactory operation of the boilers and heating system.

Hamworthy recommend a water treatment specialist is appointed to undertake analysis of the water and to recommend suitable cleaning and dosing regimes, to ensure the quality of the system and make-up water remains within the following tolerances throughout the life of the installation:

Water Filter

A coarse filter and dirt separator must be fitted in the return pipework to remove suspended particles, and suitable air separation must be provided at high points in the circuit.

Condensate Discharge

Natural gas boilers typically produce condensate at a rate of 13 litres per hour per 100kW input energy when operating in condensing mode. Although the condensate produced is mildly acidic (typical pH~3.5), normally it can be disposed

of through the drainage system. If in any doubt about local regulations, check with the local water authority.

The Stratton boilers are equipped with a polypropylene syphon drain connection to which plastic polypropylene piping, with glued sealed joints should be connected, to dispose of the condensate. The condense discharge pipe should have a minimum fall of 3° to drain, and should discharge via tundish arrangement. To prevent any risk of freezing in winter, the condense pipe should be insulated and/or routed internal to the building where possible.

General Ventilation Requirements

An adequate supply of fresh air for combustion and ventilation must be provided in accordance with BS5440 for boiler installations less than 70kW net rated input (Stratton models STW45 and STW60), and in accordance with BS6644 for boiler installations greater than 70kW net rated input (Stratton models STW85 and STW100, or multiple Stratton boiler combinations). When Stratton boilers are installed as room sealed units the air supply is for ventilation only.

Boiler House Temperatures

Additional requirement of BS6644 for multiple boiler installations requires that the air supplied for boiler house ventilation shall be such that the maximum temperatures within the boiler house do not exceed:

At floor level, 25°C (or 100mm above floor level)

At mid-level, 32°C (1.5m above floor level)

At ceiling height, 40°C (or 100mm below ceiling height)

Ventilation Grille Openings

High and low level ventilation grilles shall be positioned as high and as low as practicably possible. Low level grills will be located within 1metre of floor level for Natural Gas. High level grilles are recommended to be positioned within 15% of the boiler room height from the ceiling. High and low ventilation grilles shall communicate with the same room or internal space where compartment ventilation is used. Where ventilation grilles communicate directly with outside air they shall be positioned on the same wall.

Air Supply

The air supply should be free from contamination such as building dust and insulation fibres from lagging.

To avoid unnecessary cleaning and servicing of the boiler modules, the boilers should not be fired whilst building work is being undertaken.

Where a boiler installation is to operate throughout the summer months, e.g. for domestic hot water production for more than 50% of the time, then additional ventilation allowances are required. Refer to BS6644 for more information.

Water Properties Permitted Levels

Acidity level 8.2<pH<9.5

Concentration of dissolved oxygen <0.1 mg/l

Chlorides (Cl) <50 mg/l

Calcium Carbonate (CaCO3)

<100mg/l (initial fill)<10mg/l (top up)

13

Electrical DetailsStratton Boiler Connections

The following electrical connections are provided on each boiler:

■ Supply live neutral and earth

■ Heating circuit pump output

■ DHW circuit pump output

■ Optional programmable room sensor

■ Remote on/off control input

■ Optional external air temperature sensor

■ Optional DHW cylinder temperature sensor

With alternative wiring options for either:

■ 0-10V analog controls

■ BMS input signal for remote signalling

■ Boiler general fault signal output to BMS

■ Boiler normal run signal output to BMS

Or

■ 0-10V analog controls

■ Powered supply for remote signalling

■ Powered boiler general fault signal output

■ Powered boiler normal run signal output

Electrical Supply

An independent isolator and fused electrical supply is recommended for each boiler. Supply is 230 volt, 50Hz, single phase. Wiring to the boiler must be installed in accordance with the latest IET regulations and any local regulations which apply. Wiring external to the boiler must be installed in accordance with IET 7671:2008 (2011), wiring regulations.

Wiring must be completed in heat resistant 3-core cable (size 1.0mm2 c.s.a.). External fuses should be rated 6 amps for each boiler.

To prevent drawing excessive current (>1 amp) through the boiler control panel, it is recommended that external pumps are connected via contactors.

Electrical Connections

Separate entry points are provided in the boiler for power and signal cables, with gland plates fitted in the bottom of the boiler frame to accept these cables. Two termination strips are provided for all external connections inside the font cover. Access to the gland plates and termination strips is made by lifting and then tipping forward the black panel which retains the controller.

Status Signalling

Volt free contacts are provided to indicate the following operating conditions

■ Boiler normal run

■ Boiler general fault

L

NK1

NK3

N

OT

OTRT+

RTMB9M

B3

X51-

01X52-

01X52-02X52-

03

0-10V Analog input

Ground

BMS input signal forremote signalling

Boiler fault signal outputto BMS

Boiler run signal outputto BMS

0-10V Analog input

Ground

Powered supply for

remote signalling

Boiler fault signal output

powered

Boiler run signal output

powered

X51-01

X52-01

X52-02

X52-03

OR

L

N

L

N

L

N

Supply 230V 1Ph 50Hzfused 6 amps

Heating circuit pump outputmaximum 1A or via contactor

DHW circuit pump outputmaximum 1A or via contactor

Optional programmable room sensor

Remote on/off input signal(remove link)

Optional external air temperature sensor

Optional DHW cylinder temperature sensor

Powered output contacts rated230V ~ 50Hz, maximum 1A

13

0-10 Volt DC Analog Input

A 0-10 volt DC analog signal interface is provided to control the boiler from an external Building Management System (BMS). If using this interface, remove the link on the remote on/off terminals.

The interface can be configured to control the boiler according to either power requirement or temperature requirement.

Remote On/Off

Facilitating control from an external source the remote on/off circuit is powered at 24V DC and requires a volt-free contact device, such as a relay in a remote timer to enable/disable operation. The boiler will operate using its own internal temperature regulation controls in remote on/off operation mode.

Optional Sensors and Sensor Cables

The following optional sensors are listed below together with their maximum cable length in metres.

■ DHW sensor, maximum cable length 10m

■ External sensor, maximum cable length 40m

■ Ambient thermostat, maximum cable length 40m

■ Ambient sensor, maximum cable length 50m

14

Flue DesignStratton BoilersSingle Wall Flue SystemsB23 and B23 Headers, C13, C33 and C53

Stratton boilers are suitable for flue systems designed in accordance with B23, C13, C33 or C53 schemes. Hamworthy offers flue components to suit these flue schemes for single boilers, and also B23 flue header kits for multiple boilers. All flue systems must be installed in accordance with the 3rd edition of the Clean Air Act Memorandum 1956.Piping, elbows and terminals for all Stratton boilers are a single-wall polypropylene construction (not UV stabilised, except for terminals) with EPDM joint seal, so therefore only suitable for internal use. Where flue systems must be run or be located externally, please contact our technical team for further assistance. B23 terminal only is stainless steel.Flue connections at the boiler are 80mm dia. for STW45/STW60 and 100mm dia. for STW85/STW100. Air inlet connections are 80mm dia. for all Stratton models. Pipework is available in different diameters to suit the flue scheme and design requirements. Single wall individual or concentric pipe is available in standard lengths of 1m and 0.5m. Telescopic pipe and 90° or 45° elbows are also available to reach the desired termination point. Other optional accessories are available and include support brackets and roof flashing. To simplify the flue ordering process, Hamworthy have a flue order form available for you to call off all your flue component requirements. To request a Stratton flue system order form, telephone 0845 450 2865 or email sales@hamworthy-heating.com and state which flue system you are planning to use.Maximum Flue LengthsFor B23 flue schemes, the maximum linear flue length is given in the table below where 90°and 45° elbows both count as 1.5m equivalent linear length. For C13 and C33 concentric schemes, for all pipe diameters the maximum linear flue length is 9m. For C53 twin duct room sealed systems, the maximum linear lengths of the separate flue and inlet ducts varies with boiler model in line with the following three graphs. (The intersection of flue and air duct lengths must fall in shaded area for natural gas, or fall below line for LPG.) For C13, C33 and C53 schemes, 90°and 45° elbows count as 1m and 0.5m equivalent linear length respectively.Note: ‘90°’ elbows in the Stratton flue systems are more precisely 87° (93° internal angle), with a 3° fall to allow condensate to drain. 45° elbows are a true 45°.

B23 Maximum Flue Length for Single Boilers

Stratton Model STW45 STW60 STW85 STW100

Flue AdapterDiameters/mm

80/110 80/125 80/110 80/125 100/110 100/125 100/160 100/110 100/125 100/160

Maximum Flue Length@80/60°C /metres

66 100 53 100 12 39 100 8 46 100

Maximum Flue Length@50/30°C /metres

45 100 24 100 N/A 37 100 N/A 39 100

0

2

4

6

8

10

12

14

16

18

0 2 4 6 8 10 12 14 16 18 20

Maximum length (linear) of air duct/mLe

ngth

(lin

ear)

of

flue

duct

/m

Maximum length of ductsfor G20 Natural Gas

Maximum length of ductsfor G31 LPG (Propane)

0

2

4

6

8

10

12

14

16

18

0 2 4 6 8 10 12 14 16 18 20

Maximum length (linear) of air duct/m

Length

(lin

ear)

of

flue

duct

/m

Maximum length of ductsfor G20 Natural Gas Maximum length of ducts

for G31 LPG (Propane)

-1

1

3

5

7

9

11

13

15

0 2 4 6 8 10 12 14 16 18 20

Maximum length (linear) of air duct/m

Len

gth

(lin

ear)

of

flu

e d

uct

/m

Maximum length of ductsfor G20 Natural Gas

Maximum length of ductsfor G31 LPG (Propane)

C53 Maximum Flue and Air Duct Lengths: Stratton STW45

C53 Maximum Flue and Air Duct Lengths: Stratton STW60

C53 Maximum Flue and Air Duct Lengths: Stratton STW85/100

C33 Room Sealed, Concentric, Vertical Balanced Flue (Diagram 3)—Individual Boiler with Vertical Terminal (Roof)

C33 flue components include a C33 concentric terminal and roof flashing (flat, shallow or steep). The flue is extendable to a maximum 9m (linear) with optional concentric pipework. For C33 schemes flue pipework and fittings are available in: 80/125mm dia. for STW45/STW60 only and 100/150mm dia. for STW85/STW100 only.

C53 Room Sealed, Twin Pipe Flue—Individual Boiler with Horizontal Air Inlet and Vertical Flue Terminal (Diagram 4)

C53 flue components include a C53 air inlet terminal, flue terminal, elbow and boiler connectors. The kit is extendable with optional pipework to maximum flue and air duct lengths in accordance with the graphs on page 14.

For C53 schemes flue pipework, adapters and fittings are available in: (flue/air) 80/80mm dia. for STW45/STW60 and 100/100mm dia. STW85/STW100 only.

Flue DesignStratton BoilersSingle Wall Flue SystemsB23 and B23 Headers, C13, C33 and C53

B23 Open Flue—Individual Boiler with Vertical Terminal or Existing Chimney (Diagram 1)

B23 flue terminal kits include a 130 or 180mm dia. terminal with rain protector and 1.5m pipe, pitched or flat roof flashing, and an adapter (terminal dia. to interconnecting pipe dia.). Interconnecting pipe is in 110, 125 (all boiler models) or 160mm dia. (for STW85/STW100 only), in 1m and 0.5m lengths, and 90° and 45° bends. Boiler connection kits include an adapter (80mm dia. to interconnecting pipe dia.) and an 80mm dia. air inlet filter.

The maximum length (linear equivalent) of flue pipework, for different flow/return temperatures is given in the table on page 14. Note that if the user changes the specified flow and return temperatures after installation then the flue design may need revisiting. The dimensions of the flue ducts must be determined by taking in to account a combustion gas pressure of 0Pa at the boiler outlet.

B23 Open Flue—Multiple Boiler Systems with Horizontal Terminal (<150 kW only), Vertical Terminal or Existing Chimney

B23 open flue header kits for 2, 3 or 4 boilers are available (see illustrations on page 8 and 9) and comprise all components for boiler flue outlet connection to the header including a condensate drain. Onward pipework, elbows and vertical discharge are not included in the header kits.

Header pipework diameters and dimensions are shown on page 9. Maximum length of flue pipe run (not HHL supply) after header depends on overall maximum power of the multiple boiler system and the diameter of the common flue.

C13 Room Sealed, Concentric, Horizontal Balanced Flue—Individual Boiler with Horizontal Wall Terminal (Diagram 2)

C13 flue components include a C13 horizontal concentric terminal (800mm), wall-plates, dual flow adapter and a 90° concentric elbow. Maximum total pipework length is 9m (linear). For C13 schemes concentric flue pipework and fittings are available in 80/125mm dia. only for STW45/STW60 and in 100/150mm dia. only for STW85/STW100.

Diagram 2 C13

Diagram 3 C33

Diagram 4 C53

30mm/m fall to boiler

30mm/m fall to boiler

30mm/m fall to boiler

Diagram 1 B23

15

}}}

Flue terminal kit

Interconnecting pipework

Boiler connection kit

Customer Service Centre

Hamworthy Heating Limited Fleets Corner, Poole, Dorset BH17 0HH

Telephone: 0845 450 2865 Email: sales@hamworthy-heating.com Web: www.hamworthy-heating.comHamworthy reserves the right to make changes and improvements which may necessitate alteration to the specification without prior notice.

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