main HE System 18, HE System 24, HE System 28 User guide

Download

Installation & Service Instructions

System HE

Range

These instructions include the Benchmark Commissioning Checklist

and should be left with the user for safe keeping.

Natural Gas

Main System 18 HE

G.C.No41 467 01

Main System 24 HE

G.C.No41 467 02

Main System 28 HE

G.C.No41 467 03

Building Regulations and the Benchmark Commissioning Checklist

Building Regulations (England & Wales) require notification of the installation of a heating appliance to the relevant Local Authority Building Control Department. From 1 April 2005 this can be achieved via a Competent Persons Self Certification Scheme as an option to notifying the Local Authority directly. Similar arrangements will follow for Scotland and will apply in Northern Ireland from 1 January 2006.

CORGI operate a Self Certification Scheme for gas heating appliances.

These arrangements represent a change from the situation whereby compliance with Building Regulations was accepted as being demonstrated by completion of the Benchmark Logbook (which was then left on site with the customer).

With the introduction of Self Certification Schemes, the Benchmark Logbook is being withdrawn. However, a similar document in the form of a commissioning checklist and service interval record is incorporated at the back of these instructions.

This company is a member of the Benchmark initiative and fully supports the aims of the programme. Its aim is to improve the standards of installation and commissioning of central heating systems in the UK and to encourage the regular servicing of all central heating systems to ensure safety and efficiency.

Building Regulations require that installations should comply with manufacturer's instructions. It is therefore important that the commissioning checklist is completed by the installer. The relevant section of Building Regulations only relates to dwellings. Therefore the checklist only applies if the appliance is being installed in a dwelling or some related structure.

The flowchart opposite gives guidance for installers on the process necessary to ensure compliance with Building Regulations.

The code of practice for the installation,

commissioning & servicing of central

heating systems.

“Main” supports

Baxi Heating UK Ltd is a

BS-EN ISO 9001 Accredited Company

© Baxi Heating UK Ltd 2007 All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, or stored in any retrieval system of any nature (including in any database), in each case whether electronic, mechanical, recording or otherwise, without the prior written permission of the copyright owner, except for permitted fair dealing under Copyrights, Designs and Patents Act 1988.

Applications for the copyright owner’s permission to reproduce or make other use of any part of this publication should be made, giving details of the proposed use, to the following address:

The Company Secretary, Baxi Heating UK Ltd, Pentagon House, Sir Frank Whittle Road, Derby, DE21 4XA.

Full acknowledgement of author and source must be given.

WARNING: Any person who does any unauthorised act in relation to a copyright work may be liable to criminal prosecution and civil claims for damages.

Installer Notification Guidelines

Choose Building

Regulations Notification

Route

Competent Person's

Self Certification Scheme

Install and Commission this appliance to manufacturer's

instructions

Complete the

Benchmark Checklist

If you notify via CORGI Scheme,

CORGI will then notify the

relevant Local Authority

Building Control Scheme

on member's behalf

Building Control

Contact your relevant Local

Authority Building Control

(LABC) who will arrange

an inspection or contact a government approved

inspector

Install and Commission this appliance to manufacturer's

instructions

Scheme Members only

Call CORGI on: 0870 88 88 777

or log onto:

www.corgi-notify.com

within 10 days

You must ensure that the

notification number issued by

CORGI is written onto the

Benchmark Checklist

CORGI will record the data and

will send a certificate of

compliance to the property

Complete the

Benchmark Checklist

LABC will record the data

and will issue a

certificate of compliance

Legislation

Codes of Practice, most recent version should be used

IMPORTANT - Installation, Commissioning, Service & Repair

This appliance must be installed in accordance with the manufacturer’s instructions and the regulations in force. Read the instructions fully before installing or using the appliance.

In GB, this must be carried out by a competent person as stated in the Gas Safety (Installation & Use) Regulations.

Definition of competence: A person who works for a CORGI registered company and holding current certificates in the relevant ACS modules, is deemed competent.

In IE, this must be carried out by a competent person as stated in I.S. 813 “Domestic Gas Installations”.

The addition of anything that may interfere with the normal operation of the appliance without express written permission from the manufacturer or his agent could invalidate the appliance warranty. In GB this could also infringe the Gas Safety (Installation and Use) Regulations.

Warning - Check the information on the data plate is compatible with local supply conditions.

All CORGI registered installers carry a CORGI identification card and have a registration number. You can check your installer is registered by telephoning 0870 4012300 or writing to:-

1 Elmwood,

Chineham Business Park,

Crockford Lane,

Basingstoke. RG24 8WG

or check online at www.corgi-gas-safety.com

This company declare that no substances harmful to health are contained in the appliance or used during appliance manufacture.

The appliance is suitable only for installation in GB and IE and should be installed in accordance with the rules in force, and only used in a suitably ventilated location.

In GB, the installation must be carried out by a CORGI Registered Installer. It must be carried out in accordance with the relevant requirements of the:

• Gas Safety (Installation & Use) Regulations.

• The appropriate Building Regulations either The Building Regulations, The Building Regulations (Scotland), Building Regulations (Northern Ireland).

• The Water Fittings Regulations or Water Byelaws in Scotland.

• The Current I.E.E. Wiring Regulations.

Where no specific instructions are given, reference should be made to the relevant British Standard Code of Practice.

In IE, the installation must be carried out by a competent Person and installed in accordance with the current edition of I.S. 813 ‘Domestic Gas Installations’, the current Building Regulations and reference should be made to the current ETCI rules for electrical installation.

All systems must be thoroughly flushed and treated with inhibitor (see section 6.1).

In GB the following Codes of Practice apply: Standard Scope

BS 6891 Gas Installation. BS 5546 Installation of hot water supplies for

domestic purposes. BS 5449 Forced circulation hot water systems. BS 6798 Installation of gas fired hot water boilers. BS 5440 Part 1 Flues. BS 5440 Part 2 Ventilation. BS 7074 Expansion vessels and ancillary equipment

for sealed water systems. BS 7593 Treatment of water in domestic hot water

central heating systems.

In IE the following Codes of Practice apply: Standard Scope

I.S. 813 Domestic Gas Installations. The following BS standards give valuable additional information; BS 5546 Installation of hot water supplies for

domestic purposes. BS 5449 Forced circulation hot water systems. BS 7074 Expansion vessels and ancillary equipment

for sealed water systems. BS 7593 Treatment of water in domestic hot water

central heating systems.

The boiler meets the requirements of Statutory Instrument “ The Boiler (Efficiency) Regulations 1993 N

3083” and is deemed to meet the requirements of Directive 92/42/EEC on the energy efficiency requirements for new hot water boilers fired with liquid or gaseous fuels:-

Type test for purpose of Regulation 5 certified by: Notified Body 0051.

Product/Production certified by: Notified Bodies 0051.

For GB/IE only.

Safe Manual Handling

General

The following advice should be adhered to, from when first handling the boiler to the final stages of installation, and also during maintenance.

Most injuries as a result of inappropriate handling and lifting are to the back, but all other parts of the body are vulnerable, particularly shoulders, arms and hands. Health & Safety is the responsibility of EVERYONE.

There is no ‘safe’ limit for one man - each person has different capabilities. The boiler should be handled and lifted by TWO PEOPLE.

Do not handle or lift unless you feel physically able.

Wear appropriate Personal Protection Equipment e.g. protective gloves, safety footwear etc.

Preparation

Co-ordinate movements - know where, and when, you are both going.

Minimise the number of times needed to move the boiler - plan ahead.

Always ensure when handling or lifting the route is clear and unobstructed. If possible avoid steps, wet or slippery surfaces, unlit areas etc. and take special care on ladders/into lofts.

Technique

When handling or lifting always use safe techniques - keep your back straight, bend your knees. Don’t twist - move your feet, avoid bending forwards and sideways and keep the load as close to your body as possible.

Where possible transport the boiler using a sack truck or other suitable trolley.

Always grip the boiler firmly, and before lifting feel where the weight is concentrated to establish the centre of gravity, repositioning yourself as necessary. See the ‘Installation’ section of these instructions for recommended lift points.

Remember

The circumstances of each installation are different. Always asses the risks associated with handling and lifting according to the individual conditions.

If at any time when installing the boiler you feel that you may have injured yourself STOP !! DO NOT ‘work through’ the pain - you may cause further injury.

IF IN ANY DOUBT DO NOT HANDLE OR LIFT THE BOILER - OBTAIN ADVICE OR ASSISTANCE BEFORE PROCEEDING !!

CONTENTS

1.0 Introduction 7

2.0 General Layout 8

3.0 Appliance Operation 9

4.0 Technical Data 10

5.0 Dimensions and Fixings 13

6.0 System Details 14

7.0 Site Requirements 16

8.0 Flue Options 20

9.0 Plume Displacement 25

10.0 Installation 29

11.0 Commissioning 34

12.0 Completion 36

13.0 Servicing 37

14.0 Changing Components 39

15.0 Electrical 48

16.0 Short Parts List 49

17.0 Fault Finding 50

Benchmark Checklist 54

Section Page

1.0 Introduction

1.1 Description

1. The Main System HE range are fully automatic gas fired wall mounted system boilers. They are room sealed and fan assisted.

2. The boilers are set to give a maximum output of

18.9kW, 25.2kW or 29.3kW when in condensing mode.

3. They are designed for use on Natural Gas (G20) and can be converted to use Propane.

4. The boiler incorporates a circulating pump and expansion vessel. It is suitable for use only on fully pumped sealed systems.

5. The boiler data badge gives details of the model, serial number and Gas Council number and is situated on the control box. It is visible when the case front panel is removed (Fig. 1).

6. The boiler is intended to be installed in residential / commercial / light industrial E.M.C. environments on a governed meter supply only.

7. The boiler must be installed with one of the purpose designed flues such as the standard horizontal flue kit, part no. 5118489.

8. All systems must be thoroughly flushed and treated with

inhibitor (see section 6.1).

NOTE: There are several detail differences between

each model. Generally these do not affect the installation or maintenance of the boiler, unless otherwise stated.

1.2 Contents of Pack

The pack contains:-

Boiler Wall Plate (including taps) Set of Pipe Connections Template Literature Pack

Data Badge

Fig. 1

Control Box

Case Front Panel

2.0 General Layout

2.1 Layout

1. Air Pressure Switch

2. Expansion Vessel

3. Burner Manifold

4. Automatic Air Vent

5. Circulation Pump

6. Drain Off Point

7. Pressure Relief Valve

8. System Pressure Gauge

9. PCB

10. Control Box

11. Condensate Trap

12. Flame Sensing Electrode

13. Spark Electrode

14. Burner

15. Primary Heat Exchanger

16. Fan Assembly

17. Secondary Heat Exchanger

18. On/Off/Reset Selector Switch

19. Temperature Control

20. Flame Failure or Blocked Condensate Drain

21. Safety Thermostat Activated (Boiler or Flue)

22. Fault on Fan or Flue

23. Fault on Pump or Low System Pressure

24. Fault on Temperature Sensor

25. Fault on Temperature Sensor

26. Power On

27. Boiler On

28. Burner On

When neons 20 to 25 are constantly illuminated, they indicate the temperature of the central heating water.

bar

30° 40° 50° 60° 70° 80°

Reset

30° 40° 50° 60° 70° 80°

20 21

27 28

3.0 Appliance Operation

3.1 Operating Mode (Fig. 2)

1. With a demand for heating, the pump circulates water through the primary circuit. At a pre-determined flow rate the hydraulic differential pressure switch operates, initiating the ignition sequence.

2. The main burner ignites at low rate, then the gas valve controls the gas rate to maintain the heating temperature measured by the temperature sensor.

3. When the flow temperature exceeds the setting temperature, a 3 minute delay occurs before the burner relights automatically (anti-cycling). The pump continues to run during this period.

4. When the demand is satisfied the burner is extinguished and the pump continues to run for a period of 3 minutes (Pump Overrun).

IMPORTANT: When the selector switch is in the ‘0’ (Off) position the electrical supply to the boiler is isolated. The boiler will not operate.

3.2 Frost Protection Mode

1. The frost protection mode is integral to the appliance and functions when the selector switch (see Section 2.1) is in the ON position ( ). If the system temperature falls below 5° C then the boiler will fire on its minimum setting until a flow temperature of 30° C is reached. Further protection can be incorporated by using a system frost thermostat.

3.3 Pump Protection

1. With the selector switch (see Section 2.1) in the ON position ( ) the pump will automatically operate for 1 minute in every 24 hours to prevent sticking.

10 12 11

Key

1 Heat Exchanger 2 Burner 3 Ignition Electrode 4 Flame Sensing Electrode 5 Gas Valve 6 Pump 7 Automatic Air Vent 8 Pressure Relief Valve 9 Boiler Drain Point 10 Gas Inlet 11 Boiler Flow 12 Boiler Return 13 Pressure Gauge 14 Automatic By-Pass 15 Hydraulic Differential Pressure Sensor 16 Safety Thermostat 17 Temperature Sensor 18 Expansion Vessel 19 Temperature Sensor 20 Secondary Heat Exchanger

Boiler Primary Circuit

Fig. 2

4.0 Technical Data

4.1 System 18 HE

Flue Terminal Diameter 100mm Dimensions Projection 125mm

Outercase Dimensions

Casing Height - 780mm Overall Height Inc Flue Elbow - 965mm Casing Width - 450mm Casing Depth - 345mm

Clearances

Above Casing 200 mm Min Below Casing 200 mm Min Front 450 mm Min (For Servicing) Front 5 mm Min (In Operation) L.H. Side 5mm Min R.H. Side 5mm Min (In Operation)

20mm Min (See Note*)

*NOTE: The boiler can be operated with a clearance of 5mm at the right. This is also sufficient for routine maintenance. However a clearance of 20mm is required if it is necessary to remove the secondary heat exchanger. This should be considered when siting the appliance and in the event of any subsequent alterations in the area of installation

Weights kg

Packaged Boiler Carton 49 Installation Lift Weight 38.5

Central Heating Primary Circuit Pressures

bar Safety Discharge 3 Max Operating 2.5 Min Operating 0.5 Recommend Operating 1-2

Pump

Available Head See graph below

Expansion Vessel - (For Central Heating only. Integral with appliance)

bar

Min Pre-charge Pressure 0.5

litre Max Capacity of CH System 125

Primary Water Content of Boiler (unpressurised) 1.2

Connections copper tails Gas Supply - 22mm Central Heating Flow - 22mm Central Heating Return - 22mm Pressure Relief Discharge - 15mm

Temperatures

Flow Temp (adjustable)

35°C to 85°C max (± 5°C)

Heat Input

Max Min

kW 18.7 10.6

Electrical Supply 230V~ 50H

(Appliance must be connected to an

earthed supply)

Power Consumption 140W

External Fuse Rating 3A

Internal Fuse Rating

Fuse 2A Fast Blow to BS 4265

Appliance Category CAT II

2H 3P

Max Gas Rate (Natural Gas - G20)

(After 10 Mins)

m3/h 1.98

Inlet Pressure (Natural Gas - G20)

mbar 20

Burner Injector (Natural Gas - G20)

12 x 1.18mm Diameter

Burner Pressure (Natural Gas - G20)

Max Rate Min Rate

mbar 8.6 ± 0.5 3 ± 0.5

Appliance Type C

NOxClass 3

Electrical Protection

IPX5D

Heat Output (Non-Condensing)

Max Min

kW 18 9.9

Heat Output (Condensing)

Max Min

kW 18.9 10.2

Condensate Drain 1” BSP

200 400 600 800 1000 1200

0.5

1.5

2.5

3.5

Metre (wg)

Flow Rate (l/h)

Pump - Available Head

4.5

This value is used in the UK Government’s Standard Assessment Procedure

(SAP) for energy rating of dwellings. The test data from which it has been

calculated have been certified by 0051.

SEDBUK Declaration For System 18 HE

The seasonal efficiency (SEDBUK) is 87.4% (87.3% LPG)

Band B

LPG Propane - G31

Burner Injector 0.77mm diameter

Burner Pressure

Propane mbar

Inlet Pressure

mbar

Max Rate

20 ± 0.5

Min Rate

6.6 ± 0.2

4.0 Technical Data

4.2 System 24 HE

Flue Terminal Diameter 100mm Dimensions Projection 125mm

Outercase Dimensions

Casing Height - 780mm Overall Height Inc Flue Elbow - 965mm Casing Width - 450mm Casing Depth - 345mm

Clearances

Above Casing 200 mm Min Below Casing 200 mm Min Front 450 mm Min (For Servicing) Front 5 mm Min (In Operation) L.H. Side 5mm Min R.H. Side 5mm Min (In Operation)

20mm Min (See Note*)

Weights kg

Packaged Boiler Carton 51 Installation Lift Weight 40.5

Central Heating Primary Circuit Pressures

bar Safety Discharge 3 Max Operating 2.5 Min Operating 0.5 Recommend Operating 1-2

Pump

Available Head See graph below

Expansion Vessel - (For Central Heating only. Integral with appliance)

bar

Min Pre-charge Pressure 0.5

litre Max Capacity of CH System 125

Primary Water Content of Boiler (unpressurised) 1.2

Connections copper tails Gas Supply - 22mm Central Heating Flow - 22mm Central Heating Return - 22mm Pressure Relief Discharge - 15mm

Temperatures

Flow Temp (adjustable)

35°C to 85°C max (± 5°C)

Heat Input

Max Min

kW 24.8 10.6

Electrical Supply 230V~ 50H

(Appliance must be connected to an

earthed supply)

Power Consumption 170W

External Fuse Rating 3A

Internal Fuse Rating

Fuse 2A Fast Blow to BS 4265

Appliance Category CAT II

2H 3P

Max Gas Rate (Natural Gas - G20)

(After 10 Mins)

/h 2.62

Inlet Pressure (Natural Gas - G20)

mbar 20

Burner Injector (Natural Gas - G20)

15 x 1.18mm Diameter

Burner Pressure (Natural Gas - G20)

Max Rate Min Rate

mbar 10.2 ± 0.5 2 ± 0.5

Appliance Type C

NOxClass 3

Electrical Protection

IPX5D

Heat Output (Non-Condensing)

Max Min

kW 24 9.8

Heat Output (Condensing)

Max Min

kW 25.2 10.1

Condensate Drain 1” BSP

200 400 600 800 1000 1200

0.5

1.5

2.5

3.5

4.5

5.5

Metre wg

l/h

Pump - Available Head

This value is used in the UK Government’s Standard Assessment Procedure

(SAP) for energy rating of dwellings. The test data from which it has been

calculated have been certified by 0051.

SEDBUK Declaration For System 24 HE

The seasonal efficiency (SEDBUK) is 87.4% (87.2% LPG)

Band B

LPG Propane - G31

Burner Injector 0.77mm diameter

Burner Pressure

Propane mbar

Inlet Pressure

mbar

Max Rate

21.8 ± 0.5

Min Rate

4.4 ± 0.2

4.0 Technical Data

4.3 System 28 HE

Flue Terminal Diameter 100mm Dimensions Projection 125mm

Outercase Dimensions

Casing Height - 780mm Overall Height Inc Flue Elbow - 965mm Casing Width - 450mm Casing Depth - 345mm

Clearances

Above Casing 200 mm Min Below Casing 200 mm Min Front 450 mm Min (For Servicing) Front 5 mm Min (In Operation) L.H. Side 5mm Min R.H. Side 5mm Min (In Operation)

20mm Min (See Note*)

Weights kg

Packaged Boiler Carton 51 Installation Lift Weight 40.5

Central Heating Primary Circuit Pressures

bar Safety Discharge 3 Max Operating 2.5 Min Operating 0.5 Recommend Operating 1-2

Pump

Available Head See graph below

Expansion Vessel - (For Central Heating only. Integral with appliance)

bar

Min Pre-charge Pressure 0.5

litre Max Capacity of CH System 125

Primary Water Content of Boiler (unpressurised) 1.2

Connections copper tails Gas Supply - 22mm Central Heating Flow - 22mm Central Heating Return - 22mm Pressure Relief Discharge - 15mm

Temperatures

Flow Temp (adjustable)

35°C to 85°C max (± 5°C)

Heat Input

Max Min

kW 28.9 11.9

Electrical Supply 230V~ 50H

(Appliance must be connected to an

earthed supply)

Power Consumption 180W

External Fuse Rating 3A

Internal Fuse Rating

Fuse 2A Fast Blow to BS 4265

Appliance Category CAT II

2H 3P

Max Gas Rate (Natural Gas - G20)

(After 10 Mins)

m3/h 3.06

Inlet Pressure (Natural Gas - G20)

mbar 20

Burner Injector (Natural Gas - G20)

15 x 1.25mm Diameter

Burner Pressure (Natural Gas - G20)

Max Rate Min Rate

mbar 10.9 ± 0.5 2.1 ± 0.5

Appliance Type C

NOxClass 3

Electrical Protection

IPX5D

Heat Output (Non-Condensing)

Max Min

kW 28 11

Heat Output (Condensing)

Max Min

kW 29.3 11.3

Condensate Drain 1” BSP

200 400 600 800 1000 1200

0.5

1.5

2.5

3.5

4.5

5.5

Metre wg

l/h

Pump - Available Head

This value is used in the UK Government’s Standard Assessment Procedure

(SAP) for energy rating of dwellings. The test data from which it has been

calculated have been certified by 0051.

SEDBUK Declaration For System 28 HE

The seasonal efficiency (SEDBUK) is 87.3% (87.2% LPG)

Band B

LPG Propane - G31

Burner Injector 0.77mm diameter

Burner Pressure

Propane mbar

Inlet Pressure

mbar

Max Rate

29.4 ± 0.5

Min Rate

5.2 ± 0.2

5.0 Dimensions and Fixings

Dimensions

A 780mm

B 345mm

C 450mm

D 107mm Ø Min.

E 185mm

F 190mm

G 131mm

Heating

Return

(22mm)

Heating

Flow

(22mm)

Pressure Relief

Valve

(15mm)

Gas

Inlet

(22mm)

130 mm

65 mm

Tap Rail

360° Orientation

Tube Ø 100mm

At Least 1.5°

28mm Condensate Drain

6.0 System Details

6.1 Central Heating Circuit

1. The appliance is suitable for fully pumped SEALED SYSTEMS ONLY.

Treatment of Water Circulating Systems

• All recirculatory water systems will be subject to corrosion unless an appropriate water treatment is applied. This means that the efficiency of the system will deteriorate as corrosion sludge accumulates within the system, risking damage to pump and valves, boiler noise and circulation problems.

• When fitting new systems flux will be evident within the system, which can lead to damage of system components.

• All systems must be thoroughly drained and flushed out. Using, for example Betz-Dearborn Sentinel X300 or X400 or Fernox Superfloc Universal Cleanser. They should be used following the flushing agent manufacturer’s instructions.

• System additives - corrosion inhibitors and flushing agents/descalers should comply to BS7593 requirements, e.g. Betz-Dearborn Sentinel X100 and Fernox-Copal which should be used following the inhibitor manufacturer’s instructions.

Failure to flush and add inhibitor to the system will invalidate the appliance warranty.

• It is important to check the inhibitor concentration after installation, system modification and at every service in accordance with the manufacturer’s instructions. (Test kits are available from inhibitor stockists.)

• For information or advice regarding any of the above contact Technical Enquiries.

6.2 Bypass

1. The boiler is fitted with an automatic integral bypass.

6.3 System Control

1. For optimum operating conditions, the heating system into which the boiler is installed should include a control system.

2. Such a system will comprise of a timer control and separate room or cylinder thermostats as appropriate.

3. The boiler should be controlled so that it operates on demand only.

4. Operation of the system under control of the boiler thermostat & TRV’s only does not produce the best results.

6.0 System Detail

6.4 System Filling and Pressurising

1. A filling point connection on the central heating return pipework must be provided to facilitate initial filling and pressurising and also any subsequent water loss replacement/refilling.

2. The filling method adopted must be in accordance with all relevant water supply regulations and use approved equipment.

3. Your attention is drawn to: for GB: guidance G24.2 and recommendation R24.2 of the Water Regulations Guide. for IE: the current edition of I.S. 813 “Domestic Gas Installations”.

4. The sealed primary circuits may be filled or replenished by means of a temporary connection between the circuit and a supply pipe provided a ‘Listed’ double check valve or some other no less effective backflow prevention device is permanently connected at the inlet to the circuit and the temporary connection is removed after use.

6.5 Expansion Vessel

1. The appliance expansion vessel is pre-charged to 0.5 bar. The vessel is suitable for correct operation for system capacities up to 125 litres. For greater system capacities an additional expansion vessel must be fitted. for GB refer to BS 7074 Pt 1. For IE, the current edition of I.S. 813 “Domestic Gas Installations”.

6.6 Pressure Relief Valve (Fig. 4)

1. The pressure relief valve is set at 3 bar, therefore all pipework, fittings, etc. should be suitable for pressures in excess of 3 bar.

2. The pressure relief discharge pipe should be not less than 15mm dia, run continuously downward, and discharge outside the building, preferably over a drain. It should be routed in such a manner that no hazard occurs to occupants or causes damage to wiring or electrical components. The end of the pipe should terminate facing down and towards the wall.

3. The discharge must not be above a window, entrance or other public access. Consideration must be given to the possibility that boiling water/steam could discharge from the pipe.

Fig. 3

Fig. 4

Stop Valve

Double Check Valve

Mains Cold Water

CH Return

Temporary Hose

Pressure Relief Valve

Discharge Pipe

Stop Valve

7.0 Site Requirement

7.1 Location

1. The boiler may be fitted to any suitable wall with the flue passing through an outside wall or roof and discharging to atmosphere in a position permitting satisfactory removal of combustion products and providing an adequate air supply. The boiler should be fitted within the building unless otherwise protected by a suitable enclosure i.e. garage or outhouse. (The boiler may be fitted inside a cupboard-see Section 7.3).

2. If the boiler is sited in an unheated enclosure then it is recommended to leave the On/Off/Reset Selector Switch in the On Position.

3. If the boiler is fitted in a room containing a bath or shower reference must be made to the relevant requirements. In GB this is the current I.E.E. Wiring Regulations and Building Regulations. In IE reference should be made to the current edition of I.S. 813 “Domestic Gas Installations” and the current ETCI rules.

4. If the boiler is to be fitted into a building of timber frame construction then reference must be made to the current edition of Institute of Gas Engineers Publication IGE/UP/7 (Gas Installations in Timber Framed Housing).

7.2 Clearances (Figs. 5 & 6)

1. A flat vertical area is required for the installation of the boiler.

2. These dimensions include the necessary clearances around the boiler for case removal, spanner access and air movement. Additional clearances may be required for the passage of pipes around local obstructions such as joists running parallel to the front face of the boiler.

200mm Min

780mm

450mm

200mm Min

20mm/5mm Min

see *NOTE:

5mm Min

450mm Min

For Servicing

Purposes

Fig. 5

Fig. 6

In Operation

7.0 Site Requirement

7.3 Ventilation of Compartments

1. Where the appliance is installed in a cupboard or compartment, no air vents are required.

2. BS 5440: Part 2 refers to room sealed appliances installed in compartments. The appliance will run sufficiently cool without ventilation.

7.4 Gas Supply

1. The gas installation should be in accordance with the relevant standards. In GB this is BS 6891. In IE this is the current edition of I.S. 813 “Domestic Gas Installations”.

2. The connection to the appliance is a 22mm copper tail located at the rear of the gas service cock (Fig. 7).

3. Ensure that the pipework from the meter to the appliance is of adequate size. Do not use pipes of a smaller diameter than the boiler gas connection (22mm).

7.5 Electrical Supply

1. External wiring must be correctly earthed, polarised and in accordance with relevant regulations/rules. In GB this is the current I.E.E. Wiring Regulations. In IE reference should be made to the current edition of ETCI rules.

2. The mains supply must be 230V ~ 50Hzand fused at 3A maximum.

NOTE: The method of connection to the electricity supply must facilitate complete electrical isolation of the appliance.

Connection may be via a fused double-pole isolator with a contact separation of at least 3mm in all poles and servicing the boiler and system controls only.

3. When the system includes an indirect domestic hot water cylinder it is recommended that a cylinder thermostat is used in conjunction with a 3 port 2 position valve or 2 port zone valve.

7.6 Bath & Shower Rooms

1. If the boiler is fitted in a room containing a bath or shower, it can be fitted in zone 2, (Figs. A & B shows zone dimensions for a bathtub. For other examples refer to Section 601 of the Current I.E.E. Wiring Regulations) reference must be made to the relevant requirements. In GB this is the current I.E.E. Wiring Regulations and Building Regulations. In IE reference should be made to the current edition of I.S. 813 “Domestic Gas Installations” and the current ETCI rules.

Fig. 7

Gas Service Cock

Zone 2

Zone 1

Zone 0

Zone 2

Zone 3

Zone 2

Window Recess

0.6 m

2.4 m

Ceiling

Outside Zones

Zone 3

Zone 2

Zone 1

Zone 0

2.25 m

Zone 2

Window Recess

3.0 m

2.4 m

0.6 m

Fig. A

Fig. B

In GB Only

7.0 Site Requirement

7.7 Condensate Drain

FAILURE TO INSTALL THE CONDENSATE DISCHARGE PIPEWORK CORRECTLY WILL AFFECT THE RELIABLE OPERATION OF THE BOILER

The condensate discharge pipe MUST NOT RISE at any point along its length. There MUST be a fall of AT LEAST 2.5° (50mm per metre) along the entire run.

1. The condensate outlet terminates in a 1” BSP nut and seal for the connection of 21.5mm (

/4in) plastic overflow pipe which should generally discharge internally into the household drainage system. If this is not possible, discharge into an outside drain is acceptable.

2. Ensure the discharge of condensate complies with any national or local regulations in force.

BS 6798:2000 & Part H1 of the Building Regulations give further guidance.

3. The discharge pipe should be run in a proprietary drain pipe material e.g. PVC, PVC-U, ABS, PVC-C or PP.

4. Metal pipework is NOT suitable for use in condensate discharge systems.

5. The pipe should be a minimum of 21.5mm diameter and must be supported using suitably spaced clips to prevent sagging.

6. It is advisable to keep the condensate pipe internal.

7. External runs greater than 3 metres or runs in cold areas

should use 32mm waste pipe.

8. If the boiler is fitted in an unheated location the entire condensate discharge pipe should be treated as an external run.

9. In all cases discharge pipe must be installed to aid disposal of the condensate. To reduce the risk of condensate being trapped, as few bends and fittings as possible should be used.

10. When discharging condensate into a soil stack or waste pipe the effects of existing plumbing must be considered. If soil pipes or waste pipes are subjected to internal pressure fluctuations when WC's are flushed or sinks emptied then backpressure may force water out of the boiler trap and cause appliance lockout.

Examples are shown of the following methods of termination:i) to an internal soil & vent pipe ii) via an internal discharge branch (e.g. sink waste) iii) to a drain or gully iv) to a purpose made soakaway

Boiler

2.5° Minimum fall

Termination to an internal soil and

vent pipe

450mm min

Boiler

2.5° Minimum fall

External termination via internal discharge

branch

e.g sink waste - downstream

Sink

Pipe must terminate above water level but below surrounding surface

Boiler

Pipe must terminate above water level but below surrounding surface

2.5° Minimum fall

Termination to a drain or gully

Boiler

500mm min

2.5° Minimum fall

Termination to a purpose made soak-

away

Holes in the soak-away must face away from the building

50mm per metre of pipe run

7.0 Site Requirement

7.8 Flue

NOTE: Due to the nature of the boiler a plume of water

vapour will be discharged from the flue. This should be taken into account when siting the flue terminal.

1. The following guidelines indicate the general requirements for siting balanced flue terminals. For GB recommendations are given in BS 5440 Pt 1. For IE recommendations are given in the current edition of I.S. 813 “Domestic Gas Installations”.

2. If the terminal discharges onto a pathway or passageway, check that combustion products will not cause a nuisance and that the terminal will not obstruct the passageway.

3. If a terminal is less than 2 metres above a balcony, above ground or above a flat roof to which people have access, then a suitable terminal guard must be provided.

IMPORTANT:

• Only ONE 25mm clearance is allowed per installation.

• Under car ports we recommend the use of the plume displacement kit.

• The terminal position must ensure the safe and nuisance - free dispersal of combustion products.

Fig. 9

Fig. 8

300 min

Terminal Assembly

Top View Rear Flue

Property Boundar y Line

NOTE: The distance from a fanned draught appliance terminal installed parallel to a boundary may not be less than 300mm in accordance with the diagram below

Terminal Position with Minimum Distance (Fig. 9) (mm)

AaDirectly below an opening, air brick, opening

windows, etc. 300 BaAbove an opening, air brick, opening window etc. 300 CaHorizontally to an opening, air brick, opening window etc. 300 D Below gutters, soil pipes or drain pipes. 25 E Below eaves. 25 F Below balconies or car port roof. 25 G From a vertical drain pipe or soil pipe. 25 H From an internal or external corner. 25 I Above ground, roof or balcony level. 300 J From a surface or boundary line facing a terminal. 600 K From a terminal facing a terminal (Horizontal flue). 1200

From a terminal facing a terminal (Vertical flue). 600 L From an opening in carport (e.g. door, window)

into the dwelling. 1200 M Vertically from a terminal on the same wall. 1500 N Horizontally from a terminal on the same wall. 300 R From adjacent wall to flue (vertical only). 300 S From an adjacent opening window (vertical only). 1000 T Adjacent to windows or openings on pitched and flat roofs 600 U Below windows or openings on pitched roofs 2000

In addition, the terminal should be no nearer than 150 mm to an opening in the building fabric formed for the purpose of accommodating a built-in element such as a window frame. See BS 5440 Pt. 1.

Opening Window or Door

100mm MIN.

IMPORTANT: If fitting a Plume Displacement Flue Kit, the air inlet must be a minimum of 100mm from any opening windows or doors (see Section 9.0).

Plume Displacement Kit

Air Inlet

Fig. 10

J,K

Likely flue positions requiring a flue terminal guard

8.0 Flue Options

8.1 Horizontal Flue Systems

1. The Main System HE can be fitted with either horizontal, vertical or twin flue systems as illustrated.

2. The standard flue is suitable only for horizontal applications.

3. Maximum permissible equivalent flue lengths are:-

Horizontal Concentric (18 model) 5m

(24 model) 4m (28 model) 3m

4. Any additional “in line” bends in the flue system must be taken into consideration. Their equivalent lengths are:Concentric Pipes:

135° bend 0.5 metres 93° bend 1.0 metres

Twin Flue Pipe

135° bend 0.25 metres

91.5° bend 0.50 metres

The elbow supplied with the standard horizontal flue is not included in any equivalent length calculations

6. The illustrations opposite show examples of maximum equivalent lengths.

NOTE: Flue length is measured from point X to Y as shown.

Horizontal Flues

Plume Displacement Kit 60 /100 Ø

1M Extensions, 45° & 93° bends are

also available - see Section 9.0

NOTE: Horizontal flue pipes should always be installed with at least a 1.5° fall from the terminal to allow condensate to run back to the boiler.

This bend is equivalent to 1 metre

Total equivalent length (upto 3m) =

A+B+C+2x90°Bends

This bend is equivalent to 1 metre

8.0 Flue Options

Vertical Flues (Twin Pipe)

Vertical Flues

The total equivalent length for this example is

= 6.5 metres.

1m extension

135°bend

91.5°bend

0.25m

0.5m

5.0m

0.5m

1.0m

AIR DUCT

Noof

fittings/pipes

Sub total

Equivalent

Length Value

Equivalent Length Air Duct = 6.5m

1m extension

135°bend

91.5°bend

0.25m

0.5m

5.0m

0.5m

1.0m

FLUE DUCT

Noof

fittings/pipes

Sub total

Equivalent

Length Value

Equivalent Length Flue Duct = 6.5m

Roof

Terminal

660mm

This bend is equivalent to 1 metre

Total Equivalent Length = A+B+C+1x90°Bend

All vertical and angled runs must be included, measured from the boiler adaptor (point X) to the joint with the flue terminal (point Y). One 91.5° bend or two 135° bends can be included without reduction of the flue length.

If further elbows are required the flue length must be reduced by the following amounts:-

1 metre for each 91.5° bend

0.5 metre for each 135° bend

8.2 Twin & Vertical Flue Systems

1. Maximum permissible equivalent flue lengths are:-

(18) (24) (28)

Vertical Concentric 5m 4m 3m Vertical Twin Pipe 10m 12m 12m

2. Any additional “in line” bends in the flue system must be taken into consideration. Their equivalent lengths are:Concentric Pipes:

135° bend 0.5 metres 93° bend 1.0 metres

Twin Flue Pipe

135° bend 0.25 metres

91.5° bend 0.50 metres

The elbow supplied with the standard horizontal flue is not included in any equivalent length calculations

NOTE: Flue length is measured from point X to Y as shown.

8.0 Flue Options

Key Accessory Size Baxi Code No

Concentric Flue System 100mm diameter

A1 Horizontal flue Terminal 5111073 A Horizontal flue Terminal (incl elbow) 5118489 B Flue extension 1000mm 5111074 C Flue Bend 93° 5111075 D Flue Bend (pair) 135° 5111085 U Pipe support 100mm 5111080 R Vertical flue adaptor 5111070 P Wall Liner 5111067 S Flue Terminal Deflector 5111068

Twin Flue System 80mm diameter

E Flue extension (pair) 1000mm 5111087 F Flue Bend (pair) 90° 5111072 G Flue Bend (pair) 135° 5111086 J Vertical flue boiler adaptor kit 5111079 H Vertical flue adaptor 5111084 W Pipe support (pair) 80mm 5111081

Vertical Flue Kits

K Vertical flue terminal 5111078 L Lead tile 25°/45° 246141

Lead tile 35°/55° 246142 M Roof cover plate 246143 N Flat roof flashing 246144

U,W

8.3 Flue Accessories

8.0 Flue Options

For Twin Flue Systems fit the adaptors as follows:-

8.4 Flue Duct Adaptor (Fig. 11)

1. Engage the flue duct adaptor on the boiler adaptor, making sure that it is pushed down as far as possible.

8.5 Air duct adaptor (Fig. 12)

1. Undo the screws securing the blanking plate to the boiler top panel. Discard the plate.

2. There are three restrictor plates supplied in the kit. One marked ‘23’ can be discarded The unmarked restrictor and

the one marked ‘27’ MUST be positioned as shown in the diagrams below.

3. Take one of the gaskets supplied in the kit and place on the boiler top panel.

4. Align the appropriate restrictor as shown. Position the second gasket over the restrictor.

5. Using the screws previously removed secure the inlet adaptor to the top panel.

6. Continue to fit the twin flue system.

Flue Duct Adaptor

Boiler Adaptor

Air Duct Adaptor

Gasket

Restrictor

Gasket

Position of Restrictor

Blanking Plate

24 kW models

28 kW models

18 kW models

Fig. 11

Fig. 12

8.0 Flue Options

Fig. 13

Fig. 14

100mm

685mm

Push Fit Adaptor

Air Duct

Flue Duct

Cut the same amount off the Air Duct & Flue Duct

Approx

1425mm

8.6 For Roof Terminals

1. In the case of a pitched roof 25 - 50 degrees, position the lead tile to replace/flash over existing roof tiling. Make an aperture in the roof suitable for the lower tube of the roof terminal and ensure the integrity of the roof cover is maintained. The adjustable plastic collar can either be positioned on the lead tile or the lower tube of the roof terminal prior to the final positioning of the vertical flue through the tile. Check the collar is correctly located to suit required roof pitch (either 25° to 38° or 37° to 50°). From inside the roof adjust the flue to a vertical position and secure to the roof structure with the clamp supplied.

2. For flat roof installations the aluminium flashing must be incorporated into the roof covering and the appropriate aperture made in the roof decking. The vertical flue is lowered onto the flashing making sure the collar of the flue locates securely with the flashing. (A mastic seal may be necessary). From inside the roof, adjust the flue to a vertical position and secure to the roof structure with the clamp supplied.

8.7 Flue Dimensions

The standard horizontal flue kit allows for flue lengths between 100mm and 685mm from elbow to terminal (Fig. 13).

The maximum permissible equivalent flue length is:

System 18 HE 5 metres System 24 HE 4 metres System 28 HE 3 metres

NOTE: Each additional 45° of flue bend will account for an equivalent flue length of 0.5m. eg. 45° = 0.5m, 90° = 2 x 45° = 1m etc.

8.8 Flue Trim

1. The rubber flue trim supplied may be fitted to either the outside wall or on the inner wall of installation.

8.9 Terminal Guard (Fig. 14)

1. When codes of practice dictate the use of terminal guards, they can be obtained from most Plumbers’ and Builders’ Merchants.

2. There must be a clearance of at least 50mm between any part of the terminal and the guard.

3. When ordering a terminal guard, quote the appliance name and model number.

4. The flue terminal guard should be positioned centrally over the terminal and fixed as illustrated.

8.10 Flue Deflector (Fig. 13a)

1. If required a flue deflector is available from your Potterton stockist.

2. Push the flue deflector over the teminal end and rotate to the optimum angle for deflecting plume. Secure the deflector to the terminal with screws provided.

Flue Deflector

Fig. 13a

9.0 Plume Displacement

9.1 Plume Displacement Kit (Fig. 14b)

Kit No 5118638

Content of kit

1 0.9m 60/100 Concentric Flue 1 1m 60 Dia Exhaust Flue Pipe 1 Adaptor 2 60 Dia Support Brackets 1 93° Elbow/Plume Outlet Assembly 1 Flexible Flue Trim 3 “O” Rings 1 ‘Jubilee Clip 1 Boiler Elbow

1. This kit is recommended for installations where the condensate plume emitted from the flue may cause a nuisance or affect the surroundings.

2. The terminal must be positioned outside the building with the air inlet facing downward and outlet connection upwards.

3. The plume outlet must always be at least 45° to the wall, with the ‘peak’ uppermost to prevent rain entry (Figs. 15 &

16), and be at least 2 metres above ground level. The plume outlet must also be at least 500mm from the air inlet in any direction (Fig. 16).

NOTE: The outlet must be positioned so that any condensate plume is directed away from adjacent surfaces. There must be a constant fall along the entire length of the flue system from the outlet back to the boiler.

4. It is possible to reduce or increase (with the addition of extensions) the length of either or both the 60/100 concentric and 60Ø exhaust.

5. Standard concentric flue extension kits may be added between the boiler elbow and the terminal assembly.

6. The minimum length of the concentric flue is 100mm when measured from the edge of the flue elbow.

IMPORTANT: The maximum equivalent length of concentric flue is:- 18 model 3.5 metres

24 & 28 model 2.5 metres Additional bends may be fitted in the concentric flue, but the equivalent length must be reduced by 1 metre (93° bend) or 0.5 metres (45° bend).

7. 60Ø 1 metre extensions (including support bracket), and additional 93° & 45° elbows are available. Any additional 93° & 45° elbows must be accounted for when calculating flue lengths.

NOTE: Permitted positions of the plume outlet relative to doors, windows etc. are the same as for conventional concentric flues as detailed in the main Installation & Servicing Instructions and BS5440 Pt. 1. It is NOT necessary to fit a terminal guard over the air inlet or the plume outlet.

Air Inlet at Bottom

‘Peak’ Uppermost

Fig. 15

Fig. 16

500mm Min.

45°

Outlet must be at least 45° from wall face

93° Elbow/Plume Outlet Assembly

60Ø Exhaust Flue Pipe

60Ø Support Bracket

Flexible Flue Trim

60/100Ø Concentric Flue

Adaptor

O Ring

‘Jubilee’ Clip

0.9 metres

Fig. 14b

Fig. 14a

Elbow

9.0 Plume Displacement

Concentric 60/100 Flue

60Ø Exhaust

Fig. 17

60 Ø Exhaust (metres)

24 & 28HE

18HE

Fig. 18

Flue Length - Worked Example Main System 24 HE

In Fig. 18 opposite an additional 93° bend has been included in the 60Ø exhaust. with 2 x 1metre extensions which have been cut to 0.25metres and fitted. The waste is discarded.

To calculate total length:-

2 x 0.25 metre Lengths = 0.5 metres 1 x 93° Elbow = 1 metre

Total 60Ø Exhaust = 1.5 metres

After consulting the table in Example 3 it can be determined that the concentric flue could be up to approximately 1.5 metres long.

Concentric Flue

Support Bracket

93° Elbow

Extension

Additional Accessories

A - 93° Elbow 5117381 B - 45° Elbow (Pair) 5117382 C - 1 metre 60Ø Extension 5117380

9.2 Determining Permissible Lengths

In the graph the solid line diagonal represents the relationship between the concentric flue assembly (and any extensions) and the 60Ø exhaust (and any extensions or additional bends).

Example 1 - Not Permissible

If, for instance, a concentric length of 3 metres was required and the 60Ø exhaust needed to be 1.5 metres the graph shows that this combination would NOT be permissible as the intersection point would be above the solid diagonal line.

Example 2 - Flue Lengths OK

Where both lengths have been determined they can be applied to the graph to check that the installation is permissible. For example, if it was known that 1 metre of concentric flue and 1.5 metres of 60Ø exhaust were required, the values could be applied to the graph as shown in Example 2. As the point of intersection of the dotted lines is below the solid diagonal line, the combination of lengths is shown to be acceptable.

Example 3 - Flue Lengths OK

In the example shown, assume that the concentric part of the flue needs to be 1.5 metres long. Find the position of ‘1.5’ on the horizontal axis of the graph and then project upwards to the solid diagonal line. This is represented by the vertical thick dotted line. Where this dotted line intersects with the solid diagonal line on the graph, project across to the vertical axis. As can be seen this corresponds with 1.5 metres. Therefore, the total equivalent length of the 60Ø exhaust can be up to 1 metres. Any bend equivalencies must be accounted for i.e. 93° bends are equal to 1 metre, each 45° bend to 0.5 metres.

Example 1

Flue Lengths - Not Permissible

Example 2

Flue Lengths - OK

Example 3

Flue Lengths - OK

18HE

60 Ø Exhaust (metres)

24 & 28HE

Concentric 60/100 Flue (metres)

18HE

24 & 28HE

60 Ø Exhaust (metres)

Concentric 60/100 Flue (metres)

9.0 Plume Displacement

Min. 2 metres

Fig. 19

Flue Trim

Position of ‘Jubilee’ Clip screw

Fig. 24

30mm

Fig. 21

Fig. 23

Fig. 20

Fig. 22

Adaptor

Spigot

9.3 General Fitting Notes

1. Cut a hole in the external wall which the concentric flue assembly will pass through. The hole should allow the flue to fall back to the boiler at an angle of at least 1.5°.

2. When completed the terminal must be at least 2 metres above ground level (Fig. 19).

3. Measure and cut to size the concentric assembly and any extensions that are being used.

4. Insert the concentric assembly through the hole from outside the building.

5. If required, the flexible flue trim should be fitted prior to this as it cannot be fitted after. Use the large ‘Jubilee’ clip to secure the trim to the flue (See Fig. 20, trim shown dotted), with the screw part of the clip at the bottom.

6. Connect any extensions or elbows that are being used to the concentric assembly. Engage the extension, elbow or concentric assembly in the boiler flue elbow. Fit the boiler flue elbow to the boiler adaptor.

7. Ensure that the concentric assembly and any extensions fall back to the boiler at an angle of at least 1.5° and that the external air inlet is to the bottom.

8. Use suitable brackets to support the concentric assembly and any extensions, and make good inside and outside.

9. The 60Ø exhaust can now be fitted. Slide the adaptor over the plain end of the 60Ø exhaust (Fig. 22) and engage the exhaust in the terminal. Slide the adaptor down over the spigot. Mark and drill the adaptor, using a 2mm bit, as shown in Fig. 21. Secure the adaptor to the spigot using one of the screws supplied.

10. If it is necessary to shorten the 60Ø exhaust or any of the extensions, the excess material must be cut from the plain end of the pipe.

11. Determine the position of the 60Ø exhaust and mark on the wall a suitable position for the support bracket. If extensions are being used, a support bracket is supplied in each kit.

12. Drill the wall, and fit the bracket(s) using the plug and screw provided.

13. Mark and drill the 60Ø exhaust, using a 2mm bit, as shown in Fig. 23. Complete the installation of the 60Ø exhaust, securing in the brackets.

14. Fit the 93° elbow/plume outlet and secure with the two remaining screws supplied. Ensure the plume outlet is at least 45° to the wall and that the ‘peak’ is uppermost (Fig. 24).

30mm

9.0 Plume Displacement

9.3 General Fitting Notes (cont.)

15. For aesthetic purposes it is permissible to route the 60Ø exhaust in an enclosed box, but the air inlet and plume outlet MUST remain in free air.

16. It is also possible to separate the plume outlet from the 93° elbow to allow the flue to be installed as shown in Fig. 25.

17. To do this, first slacken the two screws retaining the plume outlet to the elbow, and remove the outlet (Fig. 26). The elbow can now be used to connect the vertical to horizontal 60Ø exhaust (Fig. 25). Retighten the screws in the elbow.

18. The outlet can now be fitted into the female end of an 60Ø extension piece. It must be secured using two of the screws supplied in the bag with the ‘Jubilee’ clip.

19. Mark the female end of the extension at 30mm as shown in two positions, directly opposite each other (Fig. 27).

20. Using a suitable bit (e.g. 2mm), drill through the extension and outlet. Secure using two of the screws supplied.

21. The remaining screw must be used to secure the adaptor to the concentric terminal.

22. When the plume outlet is positioned under a balcony or other projection (Fig. 28) it must protrude at least 200mm (it is not necessary to extend it further than this).

23. When under balconies or projections it is permissible to rotate the concentric flue length up to 70°, clockwise or anti-clockwise (Fig. 29), if there is insufficient space to connect vertically.

24.This will allow the connection of the exhaust to the outlet spigot.

25. All other minimum & maximum dimensions must be adhered to, and the air inlet positioned such that it will not be subjetc to rain entry.

30mm

Fig. 26

Fig. 27

Fig. 25

Fig. 28

Plume Outlet

Elbow

Fig. 29

Outlet Spigot

Concentric Flue Length (shown end-on)

500mm Min.

200mm Min.

70°

10.0 Installation

10.1 Initial Preparation

The gas supply, gas type and pressure must be checked for suitability before connection (see Section 7.4).

1. After considering the site requirements (see Section 7.0) position the fixing template on the wall ensuring it is level both horizontally and vertically.

2. Mark the position of the two most suitable fixing slots for the wall plate and boiler lower fixing holes. It is preferable to use the horizontal fixing slots.

3. Mark the position of the centre of the flue hole (rear exit). For side flue exit, mark as shown (Fig. 30).

4. Note the shaded area on the template. Pipework may be routed upwards behind the boiler, providing it does not conflict with the shaded area.

5. If required, mark the position of the gas and water pipes. Remove the template.

6. Cut the hole for the flue (minimum diameter 116mm).

7. Drill the wall as previously marked to accept the wall plugs supplied. Secure the wall plate using the fixing screws.

8. Using a spirit level ensure that the plate is level before finally tightening the screws.

9. Connect the gas and water pipes to the valves on the wall plate using the copper tails supplied. Ensure that the sealing washers are fitted between the connections.

10.2 Flushing

1. Connect a tube to the central heating flow or return pipe (Fig. 31).

2. Flush thoroughly (see System Details, Section 6.1).

10.3 Preparing The Boiler

1. Remove all packaging.

2. Stand the boiler on its base by using the rear lower edge as a pivot.

NOTE: A small amount of water may drain from the boiler in the upright position.

Fig. 30

Fig. 31

190mm

For Side Flue Exit

Central Heating Return

Flushing Tube

Wall Plate

10.0 Installation

10.4 Fitting The Boiler

1. Remove the sealing caps from the boiler connections.

2. Lift the boiler using the lower edges. The boiler should be lifted by TWO PEOPLE. Engage the slots at the top rear of the boiler on the wall plate (Fig. 32). See ‘Safe Manual Handling’ on page 5.

3. Insert the sealing washers between the valves and pipes on the wall plate and the boiler connections. The rubber

washers must be used on the gas connection.

4. Tighten all the connections.

10.5 Fitting the Pressure Relief

Discharge Pipe (Fig. 32a)

1. Remove the discharge pipe from the kit.

2. Determine the routing of the discharge pipe in the vicinity of the boiler. Make up as much of the pipework as is practical, including the discharge pipe supplied.

3. The pipework must be at least 15mm diameter and run continuously downwards to a discharge point outside the building. See section 6.6 for further details.

4. Utilising one of the sealing washers, connect the discharge pipe to the adaptor and tighten the nut.

5. Complete the discharge pipework and route it to the outside discharge point.

IMPORTANT: Make all soldered joints before connecting to the pressure relief valve.

10.6 Condensate Drain (see section 7.7)

1. Connect the condensate drain using the 1” BSP nut and seal supplied.

Ensure the discharge of condensate complies with any national or local regulations in force (see British Gas “Guidance Notes for the Installation of Domestic Gas Condensing Boilers”.

2. The condensate outlet terminates in a 1” BSP nut and seal for the connection of 21.5mm (

/4in) plastic overflow pipe which should generally discharge internally into the household drainage system. If this is not possible, discharge into an outside drain is acceptable.

Fig. 32a

Fig. 32

Pressure Relief Valve

Wall Plate

Discharge Pipe

Suggested Lifting Points

shown as shaded area

10.0 Installation

10.7 Fitting The Flue

HORIZONTAL FLUE

1. The standard flue is suitable for lengths between 100mm minimum and 685mm maximum, as measured from the edge of the flue elbow outlet to the joint between the terminal and air duct (Fig. 33).

2. Locate the flue elbow on the adaptor at the top of the boiler. Set the elbow to the required orientation (Fig. 34).

NOTE: The flue elbow is angled at 93 degrees to ensure a fall back to the boiler.

3. Measure the distance from the outside wall face to the elbow. This dimension will be known as ‘X’ (Fig. 35).

4. To dimension ‘X’ add 50mm. This dimension to be known as ‘Y’.

IMPORTANT: Check all dimensions before cutting.

Wall Thickness

(X)

Wall Thickness

(X)

Flue Elbow

Fig. 35

100mm

685mm

Adaptor

Fig. 33

Fig. 34

10.0 Installation

10.7 Fitting the Flue (Cont)

5. Mark dimension ‘Y’ on the flue as shown (Fig. 36). Carefully cut the waste material from the flue, ensuring that the ducts are square and free from burrs.

6. The inner flue duct support bracket may be in the waste portion of the flue. In this case retrieve the bracket before discarding the waste.

7. Take the inner flue support bracket ( if not already fitted) and engage it over the flue duct. This will centralise the flue and air ducts, and ease assembly (Fig. 37).

8. Insert the flue through the hole in the wall. Fit the elbow to the boiler adaptor, ensuring that it is pushed fully in.

9. Draw the flue back through the wall and engage it in the elbow. It may be necessary to use soap solution or similar to ease assembly of the elbow adaptor and flue (Fig. 38).

10. Make good between the wall and air duct outside the building.

11. Fit the flue trim if required, and if necessary fit a terminal guard (see Section 8.8 & 8.9.

VERTICAL FLUE

1. Only a flue approved with the Main System HE range can be used.

Inner Flue Support Bracket

Flue

Waste

Flue Elbow

Fig. 36

Fig. 37

Fig. 38

10.0 Installation

10.8 Making The Electrical Connections

To connect the mains input cable proceed as follows:-

1. Slacken the facia securing screws and lift the outercase panel so that its securing tabs are clear of the facia. Remove the panel.

2. Completely undo the screws securing the facia panel and hinge it down (Fig. 39).

3. Remove the control box cover securing screws. Disengage the barbs on the control box from the cover. Remove the cover (Fig. 40).

4. Slacken the cable clamp on the LH side of the boiler chassis (Fig. 41). Insert the cable through the clamp and route it to the terminal block.

5. Slacken the screws in the terminal block, connect the input cable, and tighten the screws.

6. Run the input cable from any external control through the second cable clamp on the boiler chassis. Refer to the instructions supplied with the control.

7. To connect external control(s) remove the link between terminals 1 & 2. The switched output from the external control must be connected to terminal 2 (Fig. 42).

IMPORTANT: The external control MUST be suitable for 230V switching and fused 3A maximum

8. Ensure that both mains input and any external control input cables have sufficient slack to allow the control box to drop down. Tighten the cable clamp(s) on the boiler chassis.

10.9 Preliminary Electrical Checks

1. Prior to commissioning the boiler preliminary electrical system checks should be carried out.

2. These should be performed using a suitable meter, and include checks for Ground Continuity, Resistance to Ground, Short Circuit and Polarity.

Always fit fast

blow 2A fuse

230V ~ 50Hz

fused 3A maximum

Live (brown)

Neutral (blue)

Earth (green/yellow)

230V S/L from

external control

g/y

230 V

Selector /

Reset Switch

External Controls

br b

Pump

Hydraulic Differential Pressure Switch

Safety Overheat Thermostat

Flue Thermostat

Central Heating Flow

NTC Sensor

Gas Valve

Spark Electrode

Condensate Trap

Flame Sensing Electrode

br b

Fan

bk bk

b br bk

Pressure Switch

PCB

Central Heating Return

NTC Sensor

Gas Valve Modulator

Fig. 41

Fig. 40

Fig. 42

Fig. 43

Fig. 39

Terminal Block

Internal Fuse

Cable Clamp

Control Box Cover

Facia Panel

Functional Flow Diagram

Key to Wiring

b - blue br - brown bk - black r - red g - green

11.0 Commissioning

11.1 Commissioning the Boiler

1. Reference should be made to BS 5449 when commissioning the boiler.

2. Ensure that the filling loop is connected and open, then open the heating flow and return valves on the boiler.

3. Open the screw on the automatic air vent (Fig. 44).

4. The system must be flushed in accordance with BS 7593 and the flushing agent manufacturers instructions.

5. Pressurise the system to 1.0 bar (Fig. 45) then close and disconnect the filling loop.

6. Turn the gas supply on and purge the system according to in GB BS 6891 and in IE I.S. 813 “Domestic Gas Installations”.

7. Test for gas soundness.

8. If at any time during commissioning it is required to terminate a particular cycle, e.g. the pump overrun period, turn the selector to the Off position and then back to the On position ( ) (Fig. 46).

Automatic Air

Vent

Pressure Gauge

Screw

bar

Fig. 44

Selector Switch

Central Heating

Temperature Control

Fig. 45

bar

30° 40° 50° 60° 70° 80°

Reset

Pump

Fig. 46

Power On

Neon

11.0 Commissioning

OUT

MIN

Pressure Test Point Sealing Screw

Fig. 47

11.2 Checking the Burner Pressure

1. Turn on the gas and electrical supplies to the boiler and ensure that all external controls are calling for heat.

2. Set the temperature control to maximum and the selector switch to the Off position (Fig. 50).

3. Slacken the pressure test point sealing screw on the gas valve and connect a pressure gauge (Fig. 47).

4. Undo the screws securing the inner door panel. Lift the panel slightly to disengage it from the studs on top of the case.

5. Turn the selector switch fully anticlockwise against the spring pressure to the ‘Reset’ position and hold for 2 seconds to reset the boiler.

6. Turn the selector switch to the On Position ( ). The power On neon ( ) will illuminate (Fig. 50).

7. The pressure should be as quoted in Section 4.0 Technical Data. If not, check that the gas supply pressure is correct (Natural Gas 20mbar, and Propane 37mbar).

8. The pressure can be adjusted if required.

9. To check and set minimum pressure first remove one of the modulator wires.

Adjusting the Pressure (Fig 48)

10. Remove the plastic protection cap from the pressure adjustment nuts on the valve.

11. The smaller nut (5mm) adjusts minimum pressure and the larger nut (8mm) maximum pressure.

12. Using a suitable spanner adjust the relevant nut until the correct pressure is achieved.

13. Once the pressure has been set turn the boiler off and disconnect the pressure gauge.

14. Tighten the pressure test screw and refit the modulator to the valve. Reassemble in reverse order.

Selector Switch

Temperature Control

bar

30° 40° 50° 60° 70° 80°

Reset

Fig. 50

Power On Neon

Pressure Gauge

bar

Fig. 49

Gas Valve

Fig. 48

Plastic Protection Cap

Modulator Wire

Maximum Rate Adjustment Nut

Minimum Rate Adjustment Nut

NOTE: Gas Valve Electrical Plug/Igniter not shown for clarity

12.0 Completion

12.1 Completion

1. Hinge the facia panel upwards and refit the case front panel. Tighten the securing screws (Fig. 51).

2. Instruct the user in the operation of the boiler and system, explaining the operational sequence.

3. Carefully read and complete all sections of the Benchmark Commissioning Checklist at the rear of this publication that are relevant to the appliance and installation. These details will be required in the event of any warranty work. The publication must be handed to the user for safe keeping and each subsequent regular service visit recorded.

4. For IE, it is necessary to complete a “Declaration of Conformity” to indicate compliance with I.S. 813. An example of this is given in I.S. 813 “Domestic Gas Installations”. This is in addition to the Benchmark Commissioning Checklist.

5. Hand over the Users Operating, Installation and Servicing Instructions, giving advice on the necessity of regular servicing.

Fig. 51

Facia Panel

Case Front Panel

13.0 Servicing

13.1 Annual Servicing

1. For reasons of safety and economy, it is recommended that the boiler is serviced annually. Servicing must be performed by a competent person.

2. After servicing, complete the relevant Service Interval Record section of the Benchmark Commissioning Checklist at the rear of this publication.

3. Ensure that the boiler is cool.

4. Ensure that both the gas and electrical supplies to the

boiler are isolated.

5. Slacken the screws securing the facia panel. Lift the outercase panel so that its securing tabs are clear of the facia. Remove the panel, allowing the facia to hinge down (Fig. 52).

6. Remove the screws securing the inner door panel. Lift the panel slightly to disengage it from the studs on top of the case (Fig. 54).

7. Note the positions of the sensing tube(s) (28 HE has two

- one tube on 18 & 24 HE) on the fan spigot and three wires on the fan motor and remove them (Fig. 53).

8. Slacken the screws on the fan spigot outlet pipe clamps. Ease the clamps inwards over the pipe (28 HE). On 18 & 24 HE models undo the securing screw at the left hand end of the pipe and the clamp at the right.

9. Draw the outlet pipe away from the boiler.

10. Remove the four screws securing the combustion box door and remove the door (Fig. 54).

Case Front Panel

Fig. 52

Facia Panel Securing

Screws

Inner Door

Panel

Combustion

Box Door

Fan Wires

Fan

Sensing Tubes

Ease Fan Spigot Outlet Pipe Clamps Inwards

Fan Spigot Outlet Pipe

Fig. 53

Fig. 54

28 model

18 & 24 models

28 model

13.0 Servicing

13.1 Annual Servicing (Cont)

12. Ease the front edge of the left hand baffle upwards, disengaging the spring clip. Disengage the tabs on the baffle from the slots in the fan hood (Fig. 55).

13. Undo the screws securing the fan and hood to the appliance back panel. Draw the assembly forwards (Fig. 56).

14. On 28 HE models undo the screws securing the burner to the injector manifold.

15. Draw the burner out of the combustion box, pulling the electrode grommets from the slots in the combustion box lower panel (Fig. 57).

16. Disconnect the electrode leads and grommets from the electrodes. Completely remove the burner (Fig. 57).

17. Brush any deposits from the injectors. Do not use a pin or wire to clean them.

18. Brush the burner blades and venturis and clean the combustion box.

19. Ensure that the heat exchanger fins are clear of any obstruction.

NOTE: If necessary the secondary heat exchanger may be dismantled - see section 14.23.

20. Check that the pressure vessel charge is 0.5bar and reassemble in reverse order of dismantling.

21. Turn the selector switch fully anticlockwise against the spring pressure to position R and hold for 2 seconds to reset the boiler before recommissioning.

22. Complete the relevant Service Interval Record section of the Benchmark Commissioning Checklist at the rear of this publication and then hand it back to the user.

Burner

Electrode

Grommets

Fig. 57

Spring Clip

Fan and Hood Assembly

Baffle

Tab

Fig. 55

Fig. 56

14.0 Changing Components

IMPORTANT: When changing components ensure that

both the gas and electrical supplies to the boiler are isolated before any work is started. When the new component has been fitted turn the selector switch fully anticlockwise against the spring pressure to the ‘Reset’ position and hold for 2 seconds to reset the boiler before recommissioning.

See Section 13.1 “Annual Servicing” for removal of case panel, door etc.

14.1 Fan (Figs. 59 & 60)

1. Note the positions of the sensing tube(s) (28 HE has two

- one tube on 18 & 24 HE) on the fan spigot and three wires on the fan motor and remove them.

2. Slacken the screws on the fan spigot outlet pipe clamps. Ease the clamps inwards over the pipe (28 HE). On 18 & 24 HE models undo the securing screw at the left hand end of the pipe and the clamp at the right.

3. Draw the outlet pipe away from the boiler.

4. Remove the four screws securing the combustion box door and remove the door.

5. Ease the front edge of the left hand baffle upwards, disengaging the spring clip. Disengage the tabs on the baffle from the slots in the fan hood.

6. Undo the screws securing the fan hood to the appliance back panel, and draw the fan and hood assembly forwards.

7. Remove the screws and spring washers securing the fan to the hood.

8. Fit the new fan to the hood using the screws and spring washers previously removed.

9. Reassemble in reverse order of dismantling.

14.2 Pressure Switch (Fig. 58)

1. Remove the fan as described in section 14.1.

2. Note the positions of the two sensing tubes and three wires and remove them.

3. Remove the two screws holding the pressure switch to the bracket on the combustion box top panel.

4. Fit the new pressure switch and reassemble all components in reverse order of dismantling.

Pressure Switch

Sensing Tubes

Pressure

Switch Wires

Fig. 58

Fan Hood

Spring Washer

Securing Screw

Fan Wires

Fan

Sensing Tubes

Ease Fan Spigot Outlet Pipe Clamps Inwards

Fan Spigot Outlet Pipe

Spring Clip

Baffle

Tab

Fan

Fig. 59

Fig. 60

28 model

18 & 24 models

14.0 Changing Components

14.3 Heat Exchanger (Fig. 61)

1. Remove the fan as described in section 14.1.

2. Drain the primary circuit. Prise the pipe connecting clips off the joints in the flow and return pipes. Remove the heat exchanger return pipe.

3. Lift the heat exchanger to disconnect the flow pipe joint. Withdraw it from the appliance, taking care not to damage the rear insulation piece.

8. Fit the new heat exchanger.

9. Reassemble in reverse order of dismantling, and repressurise the system.

14.4 Burner (Fig. 62)

1. Remove the four screws securing the combustion box door and remove the door.

2. On 28 HE models undo the screws securing the burner to the injector manifold.

3. Draw the burner out of the combustion box, pulling the electrode grommets from the slots in the combustion box lower panel.

4. Disconnect the electrode leads and grommets from the electrodes. Completely remove the burner.

5. Undo the screws securing the electrodes to the burner. Examine the condition of the electrodes, replacing if necessary. Fit the electrodes to the new burner.

6. Engage the burner location brackets over the studs on the injector manifold and reassemble in reverse order.

Burner

Electrode

Grommets

Electrode

Leads

Electrodes

Fig. 61

Heat Exchanger

Pipe Connecting Clips

Fig. 62

14.0 Changing Components

14.5 Injectors (Fig. 63)

1. Remove the burner as described in Section 14.4.

2. Undo the screws securing the injector manifold to the inlet elbow and remove the manifold.

3. Unscrew and replace injectors as required and examine the sealing gasket, replacing as necessary. Reassemble in reverse order.

14.6 Electrodes (Fig. 63)

1. Remove the four screws securing the combustion box door and remove the door.

2. Undo the screws securing the burner to the injector manifold. Draw the burner out of the combustion box, pulling the electrode grommets from the slots in the combustion box lower panel.

3. Disconnect the lead and grommet from the electrode being replaced. Undo the securing screw and withdraw the electrode to the burner.

4. Reassemble in reverse order.

14.7 Insulation (Fig. 64)

1. Remove the four screws securing the combustion box door and remove the door.

2. Slide the side insulation pieces carefully out of their carriers.

3. To replace the rear insulation piece it is necessary to remove the heat exchanger as described in Section 14.3 and slide out the side pieces.

4. The combustion box door insulation piece can be replaced by carefully bending up the two retaining tabs.

5. Replace all insulation pieces and reassemble in reverse order.

13.8

Injector

Manifold

Inlet Elbow

Gasket

Injector

Burner

Electrode Grommets

Electrode

Leads

Side Insulation

Rear Insulation

Front Insulation

Combustion Box

Door

Side Insulation

Electrodes

Fig. 63

Fig. 64

28 model

14.0 Changing Components

14.8 Gas Valve (Fig. 65)

1. Undo the nut on the gas feed pipe under the boiler.

2. Completely undo the securing screws and hinge the facia panel down.

3. Disconnect the wires from the valve modulator and the ignition lead from the spark generator. Disconnect the pressure sensing pipe from the valve. Undo the screw securing the spark generator electrical plug to the valve and disconnect the plug.

4. Pull the earth wire off the spade terminal on the valve.

5. Remove the screws securing the inlet pipe flange to the boiler bottom panel and those securing the outlet manifold to the burner manifold.

6. Remove the valve from the boiler.

7. Note the orientation of the inlet pipe and outlet manifold. Undo the securing screws and remove the pipe and manifold.

8. Examine the ‘O’ ring seals for damage, replacing as necessary.

9. Fit the inlet pipe and outlet manifold to the new valve, ensuring that the ‘O’ ring seals are in place.

10. Reassemble in reverse order and check the burner pressure as described in Section 11.2.

14.9 Central Heating Temperature Sensor

(Fig. 66)

1. Ease the retaining tab on the sensor away and disconnect the electrical plug.

2. Unscrew the sensor from it’s pocket and reassemble in reverse order. The plug will only fit one way.

14.10 Safety Thermostat (Fig. 66)

1. Pull the electrical connections off the thermostat.

2. Remove the screws securing the thermostat to the mounting plate on the flow pipe.

3. Reassemble in reverse order. The thermostat is not polarised - either wire can fit either terminal on the thermostat.

14.11 Return Heating Temperature Sensor

(Fig. 67)

1. Ease the retaining tab on the sensor away and disconnect the electrical plug.

2. Prise the sensor retaining clip off the pipe and remove the sensor from the clip.

3. Reassemble in reverse order.

Gas Valve

Inlet Pipe

Gas Feed

Pipe

Electrical Plug

Central Heating

Temperature Sensor

Safety Thermostat

Return Heating Temperature Sensor

Retaining Clip

Heating Return Pipe

Flow Pipe

Fig. 65

Fig. 66

Fig. 67

Modulator

Wires

Ignition

Lead

14.0 Changing Components

14.12 Pump - Head Only (Fig. 68)

1. Drain the primary circuit and remove the socket head screws securing the pump head to the body and draw the head away.

2. Undo the screw on the pump wiring cover and remove the cover. Using a suitable flat bladed screw driver press the cable securing levers downwards to release each wire after noting their position.

3. A standard replacement Grundfos 15-60 head can now be fitted. Connect the pump wiring to the new head. The pump speed must be set to 3 (Fig. 69).

4. Reassemble in reverse order.

14.13 Pump - Complete (Fig. 70)

1. Drain the primary circuit and unscrew the automatic air vent from the pump body. Undo the two screws securing the body to the pipe and manifold and draw the pump forwards.

2. Undo the screw on the pump wiring cover and remove the cover. Using a suitable flat bladed screw driver press the cable securing levers downwards to release each wire after noting their position.

3. Connect the wiring to the new pump. Examine the ‘O’ ring seals on the return pipe and manifold, replacing if necessary.

4. Fit the air vent to the pump body and reassemble in reverse order.

14.14 Automatic Air Vent (Fig. 70)

1. Drain the primary circuit and unscrew the automatic air vent from the pump body.

2. Examine the ‘O’ ring seal, replacing if necessary, and fit it to the new automatic air vent.

3. Reassemble in reverse order.

Pump Setting

Pump Wiring

Cover

Socket Headed

Screw

Pump Head

Pump Body

Pump Wiring

Cover

Automatic Air

Vent

Fig. 68

Fig. 70

Fig. 69

14.0 Changing Components

14.15 Pressure Gauge (Figs. 71 & 72)

1. Drain the primary circuit and undo the nut on the pressure gauge capillary.

2. Remove the timer cover and ease the timer wiring aside. Undo the screws securing the gauge retaining bracket.

3. Remove the bracket and gauge assembly. Depress the barbs on the side of the gauge and remove the retaining bracket.

4. Reassemble in reverse order.

14.16 Expansion Vessel (Fig. 73)

1. To replace the expansion vessel it is necessary to remove the boiler from the wall.

NOTE: Alternatively a vessel of equivalent capacity can be fitted on the system return pipe as close as possible to the boiler.

2. Drain the system and undo all gas, water and condensate drain connections. Remove the flue elbow.

3. Lift the boiler off the wall plate and lay it on either side on a clean flat surface.

4. Undo the nut on the vessel outlet spigot, and remove the locknut and spring washer securing the spigot to the boiler chassis.

5. Undo the screws and remove the appliance upper cross member. Slide the expansion vessel out of the retaining clips.

6. Reassemble in reverse order. Fully recommission the appliance and system.

14.17 Condensate Trap (Fig. 74)

1. Disconnect the two sensing wires from the trap connections.

2. Squeeze together the wire spring clip to release and ease the inlet pipe from the trap spigot.

3. Undo the nut securing the condensate drain pipe to the trap. Disconnect the pipe and sealing washer.

4. From underneath the boiler remove the screws securing the trap bracket.

5. Remove the trap and bracket from the boiler. Undo the locknut securing the trap to the bracket.

6. Reassemble in reverse order.

Pressure Gauge

Timer Cover

Pressure Gauge

Capillary

Gauge Retaining

Bracket

Expansion Vessel

Retaining Clip

Vessel Outlet Spigot

Boiler Chassis

Lock Nut

Spring

Washer

Fig. 71

Fig. 72

Fig. 73

Upper Cross

Member

Inlet Pipe

Sensing Wires

Condensate Trap

Wire Spring Clip

Bracket

Condensate Drain Pipe

Fig. 74

14.0 Changing Components

14.18 Main PCB (Fig. 76)

1. Note the setting of the temperature control knob. Rotate the knob fully anticlockwise and carefully pull it off the drive pin.

2. Completely undo the screws securing the control box cover and release the cover retaining barbs from their slots. Disengage the rear of the cover from the control box hinge pin (Fig. 75).

3. Note the position of all plugs and wires on the PCB and disconnect them.

4. Undo the securing screws and remove the PCB. Transfer the control knob drive pin to the new PCB and turn it fully anticlockwise.

5. Reassemble in reverse order, ensuring that the temperature controller is reset to the previous position.

6. Ensure that the DHW potentiometer is fully anticlockwise once the new PCB is fitted.

14.19 Selector Switch (Fig. 76)

1. Note the setting of the selector switch knob and carefully pull it off the facia.

2. Completely undo the screws securing the control box cover and release the cover retaining barbs from their slots. Disengage the rear of the cover from the control box hinge pin (Fig. 75).

3. Note the position of the electrical connections and the orientation of the switch. Remove the electrical connections.

4. Remove the screws securing the switch to the facia panel.

5. Fit the new switch, ensuring that it is correctly positioned and reassemble in reverse order.

Control Box Cover

PCB

Selector

Switch

Facia

Selector Switch Knob

Temperature Control Knob

Fig. 75

Fig. 76

Control Knob

Drive Pin

DHW

Potentiometer

14.0 Changing Components

14.20 Central Heating Differential Valve

(Figs. 77 & 78)

1. Drain the primary circuit.

2. Undo the screw securing the microswitch to the differential valve. Allow the microswitch to rest to one side.

3. Undo the pressure gauge capillary nut and heating flow pipe nut from the valve.

4. Prise off the bypass connecting clips and disconnect the heating flow tap. Undo the screws securing the valve to the boiler bottom panel. Remove the valve.

5. Remove the screws securing the cover from the valve body. Examine the condition of the diaphragm, spring and pushrod, replacing as necessary.

6. If required the complete valve assembly can be replaced.

7. Examine the sealing washers and ‘O’ ring on the pipes and capillary, replacing as necessary.

14.21 Central Heating Differential Valve

Microswitch (Fig. 78)

1. Remove the two wires from the microswitch.

2. Undo the screw securing the microswitch to the valve body.

3. Reassemble in reverse order.

14.22 Pressure Relief Valve (Fig. 79)

1. Drain the primary circuit.

2. Disconnect the discharge pipe from the valve. Using a suitable hexagon key undo the grub screw sufficiently to release the valve.

3. Note the orientation of the valve, rotate it and withdraw it from the manifold.

4. Fit the new valve and ‘O’ ring seal and set to the previously noted orientation. Reassemble in reverse order.

Microswitch

Bracket

Diaphragm

Fig. 77

Fig. 78

Pressure Relief Valve

Grub Screw

‘O’ ring seal

Discharge Pipe

Fig. 79

14.0 Changing Components

14.23 Secondary Heat Exchanger) (Fig. 80)

1. Drain the primary circuit

2. Undo the four screws securing the right hand case panel. Remove the panel.

3. Prise the connecting clips from the heat exchanger return pipe and the boiler return pipe. Remove the pipes.

4. Slacken the screws on the left hand fan spigot outlet pipe clamp. Ease the clamp to the right.

5. Remove the nut securing the elbow to the secondary heat exchanger. Draw the elbow and outlet pipe forwards.

6. Remove the secondary heat exchanger from the outer drum by easing it forward.

7. Reassemble in reverse order of dismantling.

14.24 Flue Overheat Thermostat (Fig. 81)

NOTE: The flue overheat thermostat includes a reset

button. Check that the thermostat will not reset before replacing.

1. Remove the fan spigot outlet pipe from the fan and elbow.

2. Pull the two wires off the terminals on the flue overheat thermostat. Unscrew the thermostat from the adaptor in the outlet elbow.

3. Reassemble in reverse order of dismantling.

Ease Fan Spigot Outlet Pipe Clamps Inwards

Fan Spigot Outlet Pipe

Overheat Thermostat

Fan Spigot Outlet Pipe Clamp

Fan Spigot Outlet Pipe

Secondary Heat Exchanger

Outer Drum

Boiler Return Pipe

Pipe Connecting Clip

Elbow

Heat Exchanger Return Pipe

Fig. 80

Fig. 81

28 model

18 & 24 model

15.0 Electrical

- brown

- black

- blue

- red

br bk b r

- green

- green / yellow

- white

g g/y w

Return Heating Temperature Sensor

Reset Selector Switch

Control PCB

A1 A2

212 3341

234 12

454

556789

Central Heating NTC Sensor

Fan

Gas Valve

Overheat Stat

Hydraulic Differential Pressure Switch

Air Pressure

Switch

Flame

Mains Input

Fuse

Link

g/y

Sensing Electrode

Pump

bbbk b

bkbrbr

Flue Stat

g/y

15.1 Illustrated Wiring Diagram

16.0 Short Part List

Key G.C. Description Manufacturers No. No. Part No.

22 Fan (18 HE) 5113278

Fan (24 HE) 5112627

Fan (28 HE) 5112430

23 Pressure Switch (18 HE) 5113280

Pressure Switch (24 & 28 HE) 248466

32 Heat Exchanger (18 HE) 5113284

Heat Exchanger (24 & 28 HE) 5112431

41 Burner (18 HE) 5113286

Burner (24 & 28 HE) 5112770

44 Injector 1.18 (18 & 24 HE) 247439

Injector 1.25 (28 HE) 5112376

59 E66 408 Electrode Lead 248037

63 E66 411 Spark or Sensing

Electrode 247384

72 E66 539 Pump 248042

102 Hydraulic Outlet Assy 248490

131 342 571 Temperature Sensor 247394

135 E66 439 Safety Thermostat 248079

140 Gas Valve 5107339

154 PCB 5112380

169 E66 453 Pressure Gauge 248090

528 Return Heating 248497

Temperature Sensor

371 Igniter/Gas Valve

Cable 5112385

333 Flue Overheat

Thermostat 5112395

140

102

135

154

169

131

528

333

371

17.0 Fault Finding

Carry out initial fault finding checks

1. Check that gas, water and electrical supplies are available at the boiler. Electrical supply = 230V ~ 50 Hz. CH water system pressurised to 0.5 bar when the boiler is cold. The preferred minimum gas pressure is 19.5mbar (natural gas), or 36mbar (propane).

2. Carry out electrical system checks, i.e. Ground Continuity, Resistance to Ground, Short Circuit and Polarity with a suitable meter. NOTE: These checks must be repeated after any servicing or fault finding.

3. Ensure all external controls are calling for heat and check all external and internal fuses. Before any servicing or replacement of parts ensure the gas and electrical supplies are isolated.

Refer to Section 15.0 “Illustrated Wiring Diagram” for position of numbered terminals Central Heating - Follow operational sequence

Turn selector to

neon illuminated

Primary flow switch operated

Fan runs at max speed

Burner goes out

Turn temperature control

to max.

Pump runs

Air pressure

switch proved

neon flashing

Burner on neon

illuminated

Burner output

modulates until set

temperature is reached

Spark at ignition electrodes

for up to 10 seconds

Go to section ‘A’

neon flashing

Go to section ‘B’

neon flashing

Go to section ‘C’

Go to section ‘J’

neons flashing

Go to section ‘D’

neon flashing

Go to section ‘E’

Replace PCB

Turn selector to the reset

position. If the neon does not

extinguish go to sections ‘H’

& ‘K’

Go to section ‘F’

neon flashing

Go to section ‘I’

Go to section ‘G’

Fan stops Pump stops

Operation sequence correct

neon flashing

Turn selector to reset

position. If regular resetting is

required or appliance still

does not operate

investigation is necessary

External controls calling for

heat

Ensure controls are set to

demand and verify the

contacts are closed

Burner extinguishes

after 10 seconds

YES

YES YES YES

NO NO

YES

NOTE: When instructed to turn the selector to the reset position turn the selector switch fully anticlockwise against the spring pressure to the ‘Reset’ position and hold for 2 seconds to reset the boiler.

17.0 Fault Finding

Fault Finding Solutions Sections A to E

Is there 230V at:

Main terminals L and N Check electrical supply

Main terminal fuse

Replace fuse

Replace PCB

neon

illuminated

YES

Selector terminals a & b and a & 3. PCB - A4 connector terminals 4 & 5

Check wiring Replace selector

Pump Replace pump

YES

PCB - A4 connector terminals 3 & 6

Replace PCB

Change pump supply cable

YES

CH system pressure 0.5 to 1.5 bar Re-pressurise system

Primary flow valve diaphragm damaged Replace diaphragm

Flow valve rod obstructed

YES

Check the tap of the automatic air vent is opened

Open the automatic air vent

YES

Continuity across flow microswitch and PCB - A5 connector terminals 7 & 8

Replace microswitch

1. NO

Flow or Return temperature sensor faulty. Cold resistance approx. 11K ohms (resistance reduces with increase in temp.)

Replace sensor

YES

Fan connections correct at fan. PCB - A2 connector, is 230V across terminals 5 & 7

Fan jammed or faulty winding

Replace PCB

Replace fan

YES

If pump jammed, release

Check and correct if necessary

1. Electrical and pressure tube connections

2. Blockage of pressure tubes

3. Restriction in flue

4. Venturi

Replace air pressure switch

Gas at burner

Ensure gas is on and purged

Replace PCB

Replace gas valve

neon flashing

PCB - A1 connector has 230V AC

across terminals 2 & 4

YES

Turn selector switch

to Reset position

YES

17.0 Fault Finding

Replace PCB

Check and correct if necessary

1. Ignition electrode and lead

2. Electrode connection

3. Spark gap and position

230V at PCB - A1 connector across terminals 3 & 4. Check wiring

YES

Replace gas valve,

electrical plug & igniter assembly

YES

Check the burner setting pressure of the

gas valve

(see Section 9.2 of Commissioning)

Voltage at modulating coil of gas valve is: Max. burner press.approx 9V DC (13V DC LPG) Min. burner press.approx 1V DC

Current at modulating coil of gas valve is: (Use an instrument with average function for this measure) 30 ÷ 230 mA DC (45 ÷ 310 mA DC LPG)

Replace gas valve

Replace PCB

Check and correct if necessary

1. Flame sensing electrode and lead connections

2. Electrode position

Flame current should be 1 μA approx.

Replace PCB

YES

Replace flame sensing electrode

YES

Ensure that mains input terminal L

is Live (230V) and N is Neutral

(0V)

Check terminal 1 of On/Off/Reset selector is in

connection with PCB - A4 connector terminal 2

Check electrical continuity across terminals 1 & a of

On/Off/Reset selector when turned to position

Replace On/Off/Reset selector

Replace PCB

YES

Replace overheat

thermostat

YES

Overheat thermostat operated or

faulty, i.e. continuity across

thermostat terminals

Allow to cool. Continuity

across thermostat terminals

more than 1.5 ohm

If checks in section I are completed successfully, blockage of the

condensate drain or trap may have occurred

If checks in section J are completed successfully, the flue overheat

thermostat may have operated. Press the reset button on the flue

overheat thermostat. If the boiler does not relight or repeatedly cuts out. Check the operation of the flue system or replace the

flue overheat thermostat

18.0 Notes

CONTROLS To comply with the Building Regulations, each section must have a tick in one or other of the boxes

TIME & TEMPERATURE CONTROL TO HEATING ROOM T/STAT & PROGRAMMER/TIMER PROGRAMMABLE ROOMSTAT

TIME & TEMPERATURE CONTROL TO HOT WATER CYLINDER T/STAT & PROGRAMMER/TIMER

COMBI BOILER

HEATING ZONE VALVES FITTED NOT REQUIRED

HOT WATER ZONE VALVES FITTED NOT REQUIRED

THERMOSTATIC RADIATOR VALVES FITTED

AUTOMATIC BYPASS TO SYSTEM FITTED NOT REQUIRED

FOR ALL BOILERS CONFIRM THE FOLLOWING

THE SYSTEM HAS BEEN FLUSHED IN ACCORDANCE WITH THE BOILER MANUFACTURER’S INSTRUCTIONS?

THE SYSTEM CLEANER USED

THE INHIBITOR USED

FOR THE CENTRAL HEATING MODE, MEASURE & RECORD

GAS RATE ft3/hr

BURNER OPERATING PRESSURE (IF APPLICABLE) mbar

CENTRAL HEATING FLOW TEMPERATURE °C

CENTRAL HEATING RETURN TEMPERATURE °C

FOR COMBINATION BOILERS ONLY

HAS A WATER SCALE REDUCER BEEN FITTED? YES NO

WHAT TYPE OF SCALE REDUCER HAS BEEN FITTED?

FOR THE DOMESTIC HOT WATER MODE, MEASURE & RECORD

GAS RATE ft3/hr

MAXIMUM BURNER OPERATING PRESSURE (IF APPLICABLE) mbar

COLD WATER INLET TEMPERATURE °C

HOT WATER OUTLET TEMPERATURE °C

WATER FLOW RATE

lts/min

FOR CONDENSING BOILERS ONLY CONFIRM THE FOLLOWING

THE CONDENSATE DRAIN HAS BEEN INSTALLED IN ACCORDANCE WITH THE MANUFACTURER’S INSTRUCTIONS? YES

FOR ALL INSTALLATIONS CONFIRM THE FOLLOWING

THE HEATING AND HOT WATER SYSTEM COMPLIES WITH CURRENT BUILDING REGULATIONS

THE APPLIANCE AND ASSOCIATED EQUIPMENT HAS BEEN INSTALLED AND COMMISSIONED IN ACCORDANCE WITH THE MANUFACTURER’S INSTRUCTIONS

IF REQUIRED BY THE MANUFACTURER, HAVE YOU RECORDED A CO/CO2 RATIO READING? N/A YES CO/CO2 RATIO

THE OPERATION OF THE APPLIANCE AND SYSTEM CONTROLS HAVE BEEN DEMONSTRATED TO THE CUSTOMER

THE MANUFACTURER’S LITERATURE HAS BEEN LEFT WITH THE CUSTOMER

m3/hr

/hr

COMMISSIONING ENG’S NAME PRINT CORGI ID No.

SIGN DATE

BOILER SERIAL No. NOTIFICATION No.

BENCHMARK No.

GAS BOILER COMMISSIONING CHECKLIST

COLLECTIVE MARK

N/A

5121186

SERVICE 1

DATE

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

SIGNATURE

SERVICE 2

DATE

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

SIGNATURE

SERVICE 3

DATE

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

SIGNATURE

SERVICE 4

DATE

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

SIGNATURE

SERVICE 5

DATE

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

SIGNATURE

SERVICE 6

DATE

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

SIGNATURE

SERVICE 7

DATE

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

SIGNATURE

SERVICE 8

DATE

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

SIGNATURE

SERVICE 9

DATE

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

SIGNATURE

SERVICE 10

DATE

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

SIGNATURE

SERVICE INTERVAL RECORD

It is recommended that your heating system is serviced regularly

and that you complete the appropriate Service Interval Record Below.

Service Provider. Before completing the appropriate Service Interval Record below, please ensure you have carried out the service

as described in the boiler manufacturer’s instructions. Always use the manufacturer’s specified spare part when replacing all controls

UK Comp No 5121186 - Iss. 2 - 04/07

All descriptions and illustrations provided in this leaflet have been carefully

prepared but we reserve the right to make changes and improvements in

our products which may affect the accuracy of the information contained in

this leaflet. All goods are sold subject to our standard Conditions of Sale

which are available on request.

MAIN

A Trading Division of Baxi Heating UK Ltd

Brooks House, Coventry Road, Warwick. CV34 4LL After Sales Service 08701 655 644 Technical Enquiries 08706 049 049 Website www.mainheating.co.uk e&oe

company

IT Comp No 924.899.2

main HE System 18, HE System 24, HE System 28 User guide

Specifications and Main Features

Frequently Asked Questions

User Manual