Installation & Servicing Instructions

Baxi Duo - tec Combi HE Range

Gas Fired Wall Mounted Condensing Combination Boiler

These instructions include the Benchmark Commissioning Checklist and should be left with the user for safe keeping.

© BAXI Heating UK 2006

Page 1

Natural Gas

Baxi Duo-tec Combi 24 HE

G.C.No 47 075 23

Baxi Duo-tec Combi 28 HE

G.C.No 47 075 25

Baxi Duo-tec Combi 33 HE

G.C.No 47 075 24

© BAXI Heating UK 2006 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, 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.

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With the introduction of Self Certification Schemes, the Benchmark Logbook is being withdrawn.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.

"Baxi" supports

The code of practice for the installation, commissioning & servicing of central heating systems.

BAXI Heating UK is a BS-EN ISO 9001 Accredited Company

Page 2

Installer Notification Guidelines

Page 3

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

The boiler meets the requirements of Statutory Instrument " The Boiler (Efficiency) Regulations 1993 No 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 0085.

Product/Production certified by: Notified Body 0086.

For GB/IE only.

Legislation

Baxi 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 6.2).

Codes of Practice - refer to the most recent version

Page 4

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 !!

Page 5

CONTENTS

Section

1.0 Introduction
2.0 General Layout
3.0 Appliance Operation
4.0 Technical Data
5.0 Dimensions and Fixings
6.0 System Details
7.0 Site Requirements
8.0 Installation
9.0 Commissioning
10.0 Completion
11.0 Servicing
12.0 Changing Components
13.0 Combustion Check
14.0 Electrical
15.0 Short Parts List
16.0 Fault Finding
Benchmark Checklist

Page 6

1.0 Introduction

1.1 Description

1. The Baxi Duo-tec Combi HE is a fully automatic gas fired wall mounted condensing combination boiler. It is room sealed and fan assisted, and will serve central heating and mains fed domestic hot water.

2. The boiler is set to give a maximum output of :-

24 models - 24 kW DHW

25.9 kW CH (Condensing)

28 models - 28 kW DHW

25.9 kW CH (Condensing)

33 models - 33 kW DHW

30.3 kW CH (Condensing)

3. It is designed for use on Natural Gas (G20).

4. The boiler is suitable for use only on fully pumped sealed heating systems. Priority is given to domestic hot water.

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

Fig. 1

6. The boiler model name and serial number are also shown on the information label on the underside of the facia. This is for user reference.

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

8. The boiler must be installed with one of the purpose designed flues such as the standard horizontal telescopic flue kit, part no. 5118069.

9. All systems must be thoroughly flushed and treated with inhibitor (see section 6.2).

1.2 Optional Extras

Plume displacement kits and various flue extensions, bends, vertical flue kits, integral timer, RF room thermostat etc. are available as optional extras. These are detailed in a separate publication.

Page 7

2.0 General Layout

2.1 Layout

1. Expansion Vessel
2. Automatic Air Vent
3. DHW Plate Heat Exchanger
4. Circulation Pump
5. Drain Off Point
6. Pressure Relief Valve
7. Selector Switch
8. Central Heating System Pressure Gauge
9. PCB
10. Control Box
11. 3-Way Valve Assembly
12. Condensate Trap
13. Flame Sensing Electrode
14. Spark Electrode
15. Primary Heat Exchanger
16. Fan Assembly
17. On/Off/Reset Selector Switch
18. Central Heating Temperature Control
19. Hot Water Temperature Control
20. Venturi
21. Air/Gas Collector
22. Combustion Box Cover & Burner
23. Igniter
24. Burner On Light
25. Central Heating Mode Light
26. Domestic Hot Water Mode Light
27. Display
28. Position of Optional Integral Timer

Page 8

3.0 Appliance Operation

3.1 Central Heating Mode (Fig. 2)

Key

1 Primary Heat Exchanger

2 Burner

3 Ignition Electrode

4 Flame Sensing Electrode

5 Gas Valve

6 Pump

7 Automatic Air Vent

8 Plate Heat Exchanger

9 Flow Sensor with Filter & Regulator

10 Pressure Relief Valve

11 Boiler Drain Point

12 Heating Return

13 Cold Water Inlet On/Off Valve and Filter

14 Gas Inlet

15 Domestic Hot Water Outlet

16 Heating Flow

17 Pressure Gauge

18 Water Pressure Sensor

19 Automatic By-Pass

20 Fan

21 Diverter Valve Assembly

22 Diverter Valve Motor

23 Domestic Hot Water Flow Temperature Sensor

24 Safety Thermostat

25 Central Heating Temperature Sensor

26 Expansion Vessel

Fig. 2

1. With a demand for heating, the pump circulates water through the primary circuit.

2. Once main burner ignites the fan speed 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).

3.2 Domestic Hot Water Mode (Fig. 3)

Fig. 3

1. Priority is given to the domestic hot water supply. A demand at a tap or shower will override any central heating requirement.

2. The flow of water will operate the Hall Effect Sensor which requests the 3 way valve to change position. This will allow the pump to circulate the primary water through the DHW plate heat exchanger.

3. The burner will light automatically and the temperature of the domestic hot water is controlled by the temperature sensor.

4. When the domestic hot water demand ceases the burner will extinguish and the diverter valve will remain in the domestic hot water mode, unless there is a demand for central heating.

3.3 Frost Protection Mode

1. The frost protection mode is integral to the appliance and functions only with the selector switch (see Section 2.1) in the domestic hot water and central heating 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.

3.4 Pump Protection

1. With the selector switch (see Section 2.1) in either the central heating or central heating and domestic hot water position, the pump will automatically operate for 1 minute in every 24 hours to prevent sticking.

Page 9

4.0 Technical Data

4.1 Duo-tec Combi 24, 28 & 33 HE

Page 10

5.0 Dimensions and Fixings

Page 11

6.0 System Details

6.1 Information

1. The Baxi Duo-tec Combi HE Condensing Combination Boiler is a 'Water Byelaws Scheme - Approved Product'. To comply with the Water Byelaws your attention is drawn to the following installation requirements and notes (IRN).

a) IRN 001 - See text of entry for installation requirements and notes.

b) IRN 302 - Byelaw 14.

2. Reference to the WRc publications, 'Water fittings and materials directory' and 'Water supply byelaws guide' give full details of byelaws and the IRNs.

6.2 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.

6.3 Bypass

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

6.4 System Control

1. Further external controls (e.g. room thermostat) should be fitted to optimise the economical operation of the boiler.

Page 12

6.5 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. A filling loop is provided with the boiler.

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.

Fig. 4

6.6 Expansion Vessel (Central Heating only)

1. The appliance expansion vessel is pre-charged to 0.5 bar. Therefore, the minimum cold fill pressure is 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".

6.7 Pressure Relief Valve (Fig. 6)

Fig. 6

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 and temperature in excess of 100°C.

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.

Page 13

6.8 Domestic Hot Water Circuit (Fig. 7)

Fig. 7

1. All DHW circuits, connections, fittings, etc. should be fully in accordance with relevant standards and water supply regulations.

2. Your attention is drawn to:

for GB: Guidance G17 to G24 and recommendation R17 to R24 of the Water Regulations Guide.

for IE: the current edition of I.S. 813 "Domestic Gas Installations".

3. A single check valve must be fitted as shown in Fig. 7 to prevent backflow to the supply pipe and to ensure the efficient operation of the expansion vessel which is required to accommodate the thermal expansion of the water.

4. When the domestic water system includes any device which prevents water expanding back towards the supply (check valve, loose jumpered stopcock, water meter, water treatment device) then an expansion vessel must be fitted (eg. Zilmet 160ml, R1/2 15bar).

5. If the hot water expansion is not provided for, then high pressures can develop which may result in damage to fittings and devices on the system.

6. The boiler's maximum working mains pressure is 8 bar, therefore all pipework, connections, fittings, etc. should be suitable for pressures in excess of 8 bar. A pressure reducing valve must be fitted for pressures in excess of 8 bar. The manufacturer of any outlet fittings, such as a shower valve, may require a lower maximum pressure. The pressure reduction must take account of all fittings connected to the DHW system.

6.9 Showers

1. If a shower control is supplied from the appliance it should be of the thermostatic or pressure balanced type. Thermostatic type shower valves provide the best comfort and guard against water at too high a temperature. Existing controls may not be suitable - refer to the shower valve manufacturer.

6.10 Hard Water Areas

1. If the area of the installation is recognised as a HARD WATER AREA then a suitable device should be fitted to treat the mains water supply to the boiler. Contact your Water Distribution Company for advice on suitable devices.

Page 14

7.0 Site Requirements

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 Selector Switch in the domestic hot water and central heating position to give frost protection.

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. 8 & 9)

Fig. 8

Fig. 9

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.

Page 15

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. 10).

Fig. 10

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 is 230V ~ 50H_z fused at 3A.

Page 16

7.6 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 will accept 21.5mm (¾in) 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 back-pressure 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

Termination to an internal soil and vent pipe

External termination via internal discharge branch e.g sink waste - downstream

Termination to a drain or gully

Termination to a purpose made soakaway

Page 17

7.7 Flue

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.

* In addition, the terminal should be no nearer than 150mm 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.

Fig. 11

Fig. 12

Page 18

7.8 Flue Dimensions

The standard horizontal telescopic flue kit allows for lengths between 315mm and 500mm from elbow to terminal (Fig. 13).

Fig. 13

The maximum permissible equivalent flue length is: 10 metres

7.9 Flue Trim

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

7.10 Terminal Guard (Fig. 14)

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.

Page 19

7.11 Flue Options

1. The Baxi Duo-tec Combi HE can be fitted with flue systems as illustrated.

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

3. Maximum permissible equivalent flue lengths are:-

4. Any additional "in line" bends in the flue system must be taken into consideration.

Their equivalent lengths are:-

Concentric Pipes:

Twin Flue Pipe

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

5. The illustrations opposite show examples of permissible flue systems.

6. Instructions for guidance and fitting are included in each kit, where appropriate.

Page 20

8.0 Installation

8.1 Unpacking & Initial Preparation

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

1. Remove the outer packaging and literature, and stand the boiler and inner packaging upright. Remove the base tray (Figs. 15a, 15b & 15c).

Fig. 15a

Fig. 15b

Fig. 15c

2. Slide the upper polystyrene cap off the boiler. Break off the side and rear of the lower polystyrene cap. The wall plate can now be removed (Fig. 15d).

Fig. 15d

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

4. 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 vertical fixing slots.

5. Mark the position of the centre of the flue hole (rear exit). For side flue exit, mark as shown (Fig. 16).

Fig. 16

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

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

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

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

10. 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.

8.2 Flushing

1. Connect a tube to the central heating flow or return pipe (Fig. 17).

Fig. 17

2. Flush thoroughly (see System Details, Section 6.2).

Page 21

8.3 Fitting The Boiler

1. Lift the boiler using the lower polystyrene cap. The boiler should be lifted by TWO PEOPLE. Engage the slots at the top rear of the boiler on the wall plate (Fig. 18) (see Safe Manual Handling page 5).

Fig. 18

Fig. 18A

2. Pull the lower polystyrene cap off the boiler. Ease the boiler forwards and remove the sealing caps from the boiler connections.

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.

8.4 Fitting the Pressure Relief Discharge Pipe (Fig. 19)

Fig. 19

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 6.7 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.

8.5 Condensate Drain (see section 7.6)

1. Connect the condensate drain to the trap outlet pipe.

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 connection will accept 21.5mm (¾in) 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.

Page 22

8.6 Fitting The Flue

HORIZONTAL TELESCOPIC FLUE

1. There are two telescopic sections, the Terminal Assembly and the Connection Assembly, a roll of sealing tape and two self tapping screws. A 93° elbow is also supplied. The outer duct of the Connection Assembly is painted white. On the Terminal Assembly the outer duct is unpainted.

2. The two sections can be adjusted to provide a length between 315mm and 500mm (Fig. 20) when measured from the flue elbow (there is 50mm engagement into the elbow).

Fig. 20

3. Locate the flue elbow on the adaptor at the top of the boiler. Set the elbow to the required orientation (Fig. 22).