baxi 124 Combi User guide

Installation and Service Manual

Condensing Combination Boiler

124 - 128

Combi

United Kingdom

These instructions include the Benchmark Commissioning Checklist and should be left with the

user for safe keeping. They must be read in conjunction with the Flue Installation Guide.

Model Range

Baxi 124 Combi

G.C.No 47-077-25

Baxi 128 Combi

G.C.No 47-077-26

© Baxi Heating UK Ltd 2017 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 Limited, Brooks House, Coventry Road, Warwick. CV34 4LL

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.

The Benchmark Scheme

Benchmark places responsibilities on both manufacturers and installers. The purpose is to ensure that customers are provided with the correct equipment for their needs, that it is installed, commissioned and serviced in accordance with the manufacturer’s instructions by competent persons and that it meets the requirements of the appropriate Building Regulations. The Benchmark Checklist can be used to demonstrate compliance with Building Regulations and should be provided to the customer for future reference.

Installers are required to carry out installation, commissioning and servicing work in accordance with the Benchmark Code of Practice which is available from the Heating and Hotwater Industry Council who manage and promote the Scheme. Visit www.centralheating.co.uk for more information.

0086

ISO 9001

FM 00866

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. This can be achieved via a Competent Persons Self Certification Scheme as an option to notifying the Local Authority directly.

The Health & Safety Executive operates the ‘Gas Safe Register’, 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.

This boiler can be used by children aged 8 years and above and by persons with reduced physical, sensory or mental capabilities or lack of experience and knowledge when they have been given supervision or instruction concerning the safe use of the device and understand the resulting risks. Children must not be allowed to play with the appliance. Cleaning and user maintenance must not be carried out by children without supervision.

Warning !

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 the ‘Gas Safe

the Building Regulations

certificate on members’ 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 ‘Gas Safe Register’ on:

0800 408 5577

or log onto:

www.gassaferegister.co.uk

within 10 days

You must ensure that the

certificate number issued by

the ‘Gas Safe Register’ is written

onto the Benchmark Checklist

‘Gas Safe Register’ will issue a

Building Regulations Compliance

Certificate to the property owner

and inform the relevant LABC

Complete the

Benchmark Checklist

LABC will record the data

and will issue a

certificate of compliance

Legislation

Codes of Practice - refer to the most recent version

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 Gas Safe 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.

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 Gas Safe 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).

All Gas Safe registered engineers carry an ID card with their licence number and a photograph. You can check your engineer is registered by telephoning 0800 408 5500 or online at www.gassaferegister.co.uk

In GB the following Codes of Practice apply: Standard Scope

BS 6891 Gas Installation. BS 5482 Part 1 Butane & Propane Gas Installation BS 5546 Installation of hot water supplies for domestic

purposes. BS EN 12828 Heating systems in buildings. BS EN 12831 Heating systems in buildings - Calculation of load. BS EN 14336 Installation & commissioning of water based

heating 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 standards give valuable additional information; BS 5546 Installation of hot water supplies for domestic

purposes. BS EN 12828 Heating systems in buildings. BS EN 12831 Heating systems in buildings - Calculation of load. BS EN 14336 Installation & commissioning of water based

heating systems. BS 7074 Expansion vessels and ancillary equipment for

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

central heating systems.

Homologations

CE Marking

EC - Declaration of Conformity

Baxi Heating UK Limited being the manufacturer / distributor within the European Economic Area of the following

Baxi Combi 124 - 128

declare that the above is in conformity with the provisions of the Council Directive

2009/142/EC, 92/42/EEC, 2009/125/EC, 2010/30/EC, 2014/35/EU, 2014/30/EU

and has been subject to the following conformity procedures laid down in

Annex 2 - Article 3 of 2009/142/EC

under the supervision of the British Standards Institution, a Notified Body authorized by the United Kingdom Competent Authority, and carrying the Notified Body Number 0086.

Type test for purpose of Regulation 5 certified by: Notified Body 0085.

Product/Production certified by: Notified Body 0086.

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 12

6.0 System Details 13

7.0 Site Requirements 16

8.0 Flue Options 21

9.0 Installation 23

10.0 Commissioning 28

11.0 Completion & System Draining 31

12.0 Servicing 32

13.0 Changing Components 34

14.0 Combustion & Calibration 43

15.0 Electrical 44

16.0 Short Parts List 45

17.0 Fault Finding 46

18.0 External Low Voltage Controls 52

19.0 ‘Service Due’ Message 56

Benchmark Checklist 58

Section Page

1.0 Introduction

1.1 Description

1. The Baxi Combi 100 Range are fully automatic gas fired wall mounted condensing combination boilers. They are 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

21.2 kW CH Pnc (Condensing)

28 models - 28 kW DHW

25.3 kW CH Pnc (Condensing)

3. The boiler is factory set for use on Natural Gas (G20). It can be adapted to operate on Propane (G31) - see Section 10.1 ‘Gas Type Check’.

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 control box. It is visible when the case front panel is removed (Fig. 2).

6. The boiler model, serial number and Gas Council number are also shown on the information label behind the boiler control flap (Fig. 1). This is for user reference.

7. The boiler is intended to be installed in residential/domestic environments on a governed meter supply only.

8. The boiler must be installed with one of the purpose designed flues such as one of the standard horizontal telescopic flue kits detailed in the Flue Installation Guide .

9. All systems must be thoroughly cleansed, flushed and

treated with inhibitor (see section 6.2).

1.2 Optional Extras

Various timers, external controls, etc. are available as optional extras. Full details are contained in the relevant sales literature.

1.3 Contents of Pack

The pack contains:-

• Boiler

• Valve & Copper Tail Set

• Template

• Fittings & Literature Pack

NOTE: These Installation & Servicing Instructions MUST be read in conjunction with the Flue Installation Guide supplied in the Literature Pack.

Fig. 1

Control Flap

Fig. 2

Information Label

Data Badge

Gas Type Label

2.0 General Layout

2.1 Layout

1. Expansion Vessel

2. Boiler Adaptor

3. Primary Heat Exchanger

4. DHW Plate Heat Exchanger

5. Pump with Automatic Air Vent

6. Central Heating System Pressure Gauge

7. Fan Assembly

8. Exp. Vessel Locating Stud

9. Flame Sensing Electrode

10. Air/Gas Collector

11. Spark Ignition Electrode

12. Combustion Box Cover & Burner

13. Control Box Display

14. Condensate Trap

15. Safety Pressure Relief Valve

16. Gas Valve

17. Diverter Valve Motor

18. Boiler Control

19. Optional Timer

20. Boiler Drain Tap

21. Heating Flow Sensor

22. Safety Thermostat

3.0 Appliance Operation

3.1 Central Heating Mode

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

2. Once the 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

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 Domestic Hot Water Sensor (‘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 Boiler Frost Protection Mode

1. The frost protection mode is integral to the appliance and functions as long as there is power to the boiler, as indicated by the standby signal .

2. With CH & DHW or CH only selected, when the boiler temperature falls below 5°C the boiler will fire until a temperature of 30°C is reached.

3. If DHW only is selected, when the boiler CH temperature falls below 5°C the boiler will fire until a temperature of 30°C is reached. When the boiler DHW temperature falls below 5°C the boiler will fire until a temperature of 7°C is reached.

4. Further protection can be incorporated by using a system frost thermostat.

3.4 Pump Protection

1. If the boiler has been inactive for a period of 24 hours the pump will automatically operate for 1 minute to prevent sticking.

Key

1. Pump with Automatic Air Vent

2. Diverter Valve Assembly

3. Diverter Valve motor

4. CH System Pressure Gauge

5. Central Heating Filter

6. Domestic Hot Water Filter

7. Domestic Hot Water Priority Sensor (‘Hall Effect Sensor’)

8. Domestic Hot Water NTC sensor

9. Non-return Valve

10. Hydraulic Pressure Sensor

11. Boiler Drain Tap

12. Pressure Relief Valve

13. Plate Heat Exchanger

14. Condensate Trap

15. Gas Valve

16. Safety Thermostat (105°C)

17. Heating Flow Sensor

18. Flue Sensor

19. Boiler Adaptor

20. Primary Heat Exchanger

21. Spark Ignition Electrode

22. Burner

23. Flame Sensing Electrode

24. Air/Gas Collector

25. Return Heating Sensor

26. Fan

27. Air/Gas Venturi

28. Expansion Vessel

Connections:A – Condensate Drain B – Heating Flow C – Domestic Hot Water Outlet D – Gas Inlet E – Cold Water Inlet On/Off Valve and filter F – Heating Return

Fig. 3

Boiler Schematic Layout

4.0 Technical Data

4.1 124 & 128 Combi

Flue Terminal Diameter 100mm Dimensions Projection 125mm

Outercase Dimensions

Casing Height - 700mm Overall Height Inc Flue Elbow - 860mm Casing Width - 390mm Casing Depth - 300mm* *This can be reduced to 290mm by removing the boiler control access flap

Weights

Packaged Boiler Carton 36.5kg Installation Lift Weight 32.5 kg

Central Heating Primary Circuit Pressures

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

DHW Circuit bar Pressures

Max Operating 8 Min Operating 0.15

Flow Rates (24) (28)

l/min l/min DHW Flow Rate @ 30o C Rise 10.9 12.9

DHW Flow Rate @ 35o C Rise 9.8 11.5

Min Working DHW Flow Rate 2 2

Pump

Available Head See graph below

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

bar

Min Pre-charge Pressure 1

Max Capacity of litre CH System 100

Primary Water Content of Boiler (unpressurised) 2.5

Connections copper tails Gas Inlet - 22mm Heating Flow - 22mm Heating Return - 22mm Cold Water Inlet - 15mm Hot Water Outlet - 15mm Pressure Relief Discharge - 15mm

Temperatures

C.H. Flow Temp (adjustable)

25°C to 80°C max (± 5°C)

D.H.W. Flow Temp (adjustable)

35°C to 60°C max (± 5°C) dependent upon flow rate

NOxClass 5

Clearances

Above Casing 175mm Min Below Casing 170mm Min* Front 450mm Min (For Servicing) Front 5mm Min (In Operation) L.H. Side 5mm Min R.H. Side 5mm Min :

*This is MINIMUM recommended dimension. Greater clearance will aid installation and maintenance.

Electrical Protection

IPX5D

Internal Fuse Rating F2L

Inlet Pressure (Natural Gas - G20)

mbar 20

Injector

24 model mm 4.4 28 model mm 4.6

Condensate Drain

To accept 21.5mm (3/4in) plastic waste pipe

External Fuse Rating 3A

Heat Input CH Qn Hs (Gross)

Max Min 24 model kW 20.22 3.89 28 model kW 26.64 4.32

Heat Output CH Pn (Non-Condensing)

Max Min 24 model kW 20 3.4 28 model kW 24 3.8

Appliance Category CAT II

2H 3P

Heat Output CH Pnc (Condensing)

Max Min 24 model kW 21.2 3.7 28 model kW 25.3 4.1

Heat Input DHW Qnw Hs (Gross)

Max 24 model kW 27.4 28 model kW 32.1

Heat Output DHW Max 24 model kW 24 28 model kW 28

Max Gas Rate (Natural Gas - G20)

(After 10 mins) 24 model m3/h 2.61 28 model m3/h 3.05

Inlet Pressure (Propane - G31)

mbar 37

Max Gas Rate (Propane - G31)

(After 10 mins) 24 model kg/h 1.96 28 model kg/h 2.29

NATURAL GAS ONLY !

PROPANE ONLY !

IMPORTANT: Where Low Flow Taps or Fittings are

intended to be used in the DHW system connected it is strongly recommended that the DHW flow rate DOES NOT fall below 2.5l/min. This will ensure reliable operation of the DHW function.

NOTE: All data in this section are nominal values and subject to normal production tolerances.

SAP 2009 Annual Efficiency for N. G.

models is 89%

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

has been certified by 0035.

SEDBUK Declaration

Electrical Supply 230V~ 50H

(Appliance must be connected to an earthed supply)

Power Consumption

24 model W 85 28 model W 90

Appliance Type C

13 C33

N.G. 9.0% ± 0.7 L.P.G. 10.5% ± 1.0

Pump - Available Head

5.5

4.5

3.5

2.5

Metre (wg)

1.5

0.5

200 400 600 800 1000 1200

Flow Rate (l/h)

4.0 Technical Data

4.2 Technical Parameters

See

Technical parameters for boiler combination heaters

Baxi Combi

Condensing boiler

Low-temperature boiler

(1)

B1 boiler

Cogeneration space heater

Combination heater

Rated heat output

Useful heat output at rated heat output and high temperature regime

(2)

Useful heat output at 30% of rated heat output and low temperature regime

(1)

Seasonal space heating energy efficiency

Useful efficiency at rated heat output and high temperature regime

(2)

Useful efficiency at 30% of rated heat output and low temperature regime

(1)

Auxiliary electricity consumption

Full load

Part load

Standby mode

Other items

Standby heat loss

Ignition burner power consumption

Annual energy consumption

Prated

elmax

elmin

stby

ign

kWh GJ

Sound power level, indoors

Emissions of nitrogen oxides NO

mg/kWh

Domestic hot water parameters

Declared load profile

Daily electricity consumption

Annual electricity consumption

Water heating energy efficiency

Daily fuel consumption

Annual fuel consumption

(1) Low temperature means for condensing boilers 30°C, for low temperature boilers 37°C and for other

heaters 50°C return temperature (at heater inlet)

(2) High temperature regime means 60°C return temperature at heater inlet and 80°C feed temperature

at heater outlet.

elec

AEC

fuel

AFC

kWh

S The back cover for contact details.

124

128

Yes Yes

No No

Yes Yes

20 24

20.0 24.0

6.7 8.0

93 93

88.0 87.9

98.0 98.0

0.030 0.042

0.013 0.013

0.003 0.003

0.035 0.035

17222 20556

62 74

49 50

15 17

XL XL

0.162 0.232

36 51

88 86

21.78 22.47

17 17

5.0 Dimensions and Fixings

360° Orientation

Flue Ø 100mm

At least 1.5°

Dimensions

A 700mm

B 300mm*

*This can be reduced to 290mm by removing the boiler control access flap

C 390mm

D 116mm Ø Min.

E 160mm

(207mm for 80/125mm flue systems)

F 130mm

G 106mm

H 228mm

J 162mm

There must be no part of the air duct (white tube) visible outside the property.

Boiler Side

Condensate

Drain

Heating

Flow

(22mm)

Hot Water

Outlet

(15mm)

Pressure

Relief Valve

(15mm)

Gas Inlet

(22mm)

Cold Water

Inlet

(15mm)

Boile Side

Heating

Return

(22mm)

40 mm

162,5 mm

65 mm 65 mm 65 mm 65 mm 65 mm

6.0 System Details

6.1 Information

1. The Baxi 100 range of Condensing Combination Boilers are ‘Water Byelaws Scheme - Approved Products’. 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 Treatment of Water Circulating Systems

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.

• BS7593 gives extensive recommendations on system cleansing and water treatment.

• All systems must be thoroughly drained and flushed out using an appropriate proprietary flushing agent.

• A suitable inhibitor must then be added to the system.

• All system additives (flushing agents, cleansers, inhibitors etc.) must comply with the requirements of BS7593. Full instructions are supplied with the products and for further information contact the additive manufacturer directly or consult their website.

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 inhibitor manufacturer. (Test kits are available from inhibitor stockists.)

• For information or advice regarding any of the above contact Baxi Customer Support 0344 871 1545.

6.3 Bypass

1. The boiler is fitted with an automatic integral bypass. Some systems may require an additional external bypass.

6.4 System Control

1. Further external controls (e.g. room thermostat sensors) MUST be fitted to optimise the economical operation of the boiler in accordance with Part L of the Building Regulations (2010). A range of optional controls are available. Full details are contained in the relevant Sales Literature.

6.0 System Details

Fig. 4

Fig. 6

Stop Valve

Double Check Valve

DHW Mains Inlet

CH Return

Temporary Loop

Stop Valve

Fig. 5

Control Box removed for clarity

Filling Loop Connections

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.

2. A filling loop that connects to the primary return & cold mains inlet valves is available as an accessory. Follow the instructions provided with it.

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

4. 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”.

5. 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.

6.6 Expansion Vessel (Central Heating only)

1. The appliance expansion vessel is pre-charged to 1 bar. Therefore, the minimum cold fill pressure is 1 bar. The vessel is suitable for correct operation for system capacities up to 100 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 Safety Pressure Relief Valve (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. If it is anticipated that any part of the pipe may be subject to freezing it should be suitably insulated. The end of the pipe should terminate facing down and towards the wall (Fig. 6a).

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.

4. A remote relief valve kit is available to enable the boiler to be installed in cellars or similar locations below outside ground level (kit no. 5121379).

5. A boiler discharge pump is available, part no. 720648301. This pump will dispose of both condensate & high temperature water from the relief valve. It has a maximum head of 5 metres.

Pressure Relief Valve

Discharge Pipe

Fig. 6a

The end of the pipe should

terminate facing down and towards the wall

6.0 System Details

Fig. 7

Boiler

Other Tap Outlets

Expansion Vessel*

To Hot Taps

Check Valve*

Pressure Reducer Valve*

Stop Tap

*See 6.8 for instances when these items may be required

IMPORTANT: Where Low Flow Taps or Fittings are intended to be used in the DHW system connected to a Baxi 124/128 Combi it is strongly recommended that the DHW flow rate DOES NOT fall below 2.5l/min. This will ensure reliable operation of the DHW function.

6.8 Domestic Hot Water Circuit (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. The Water Regulations recommendations for England and Wales prohibits backflow from appliances into the wholesome water supply due to thermal expansion. However this type of instantaneous combination boiler, with less than 15 litres of stored capacity, does not require any backflow prevention device as any thermal expansion is accommodated within the appliance. It is possible in certain circumstances that other cold water demands (e.g. washing machines, flushing of W.C.s) may affect the DHW function of the boiler. In these instances the fitting of a backflow prevention device and expansion vessel is recommended.

4. In instances where the mains water supply incorporates a nonreturn backflow prevention device, or any other device that includes one*, it is possible for a build-up of pressure to occur. This may result in damage to the boiler and other appliances. To prevent damage to the boiler it is strongly recommended that a suitable mini expansion vessel is fitted on the mains water inlet between the boiler and the non-return device. *(The manufacturer of the device should be consulted if there is any doubt regarding the presence of a non-return feature). Even in circumstances where a non-return device is not fitted any future modifications to the mains inlet (e.g. fitting of a water meter) should be considered and an expansion vessel fitted. Baxi cannot accept any responsibility for damage to the boiler if these recommendations are not followed.

5. 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. Only water that has NOT been artificially softened must used when filling or re-pressurising the primary system. If the mains cold water to the property is fitted with an artificial softening/treatment device the source use to fill or re-pressurise the system must be upstream of such a device.

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. Where the boiler is sited in an unheated enclosure and during periods when the heating system is to be unused it is recommended that the permanent live is left on to give BOILER frost protection. NOTE: THIS WILL NOT PROTECT THE SYSTEM !

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)

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.

*This is MINIMUM recommended dimension. Greater clearance will aid installation and maintenance.

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.

170mm* Min

700mm

390mm

175mm Min

(300mm Min if

using 80/125mm

flueing system)

5mm Min

450mm Min

For Servicing

Purposes

Fig. 8

Fig. 9

In Operation

5mm Min

At least 1.5°

300mm

(290mm with flap removed)

7.0 Site Requirement

Fig. 10

Gas Service Cock

7.4 Gas Supply

1. The gas installation should be in accordance with the relevant standards. In GB this is BS 6891 (NG) or BS 5482 Pt. 1 (LPG). 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).

3. Ensure that the pipework from the meter to the appliance is of adequate size, and the demands of any other gas appliances in the property are taken into consideration. Do not use pipes of a smaller diameter than the boiler gas connection (22mm) UNLESS the stated gas rate can be achieved with pipe of lesser diameter and with all other gas appliances operating at maximum rate.

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 ~ 50Hzfused at 3A.

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.

7.6 Bath & Shower Rooms

1. Boilers fitted with optional plug-in integral timer, RFQ receiver or thermostat CANNOT be fitted in any zone.

2. If the boiler is fitted in a room containing a bath or shower and NOT FITTED with any optional integral timer or thermostat, it can be fitted in zone 2, (Figs. A & B shows zone dimensions for a bathtub. For other examples refer to 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.

Zone 2

Zone 1

Zone 0

Zone 2

Window Recess

0.6 m

Ceiling

Outside Zones

Zone 2

Zone 1

Zone 0

2.25 m

Window Recess Zone 2

0.6 m

Fig. A

Fig. B

In GB Only

7.0 Site Requirements

7.7 Condensate Drain

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

CAREFUL CONSIDERATION MUST BE GIVEN TO THE POSSIBILITY OF THE PIPEWORK BEING SUBJECT TO FREEZING CONDITIONS AND APPROPRIATE MEASURES TAKEN TO PREVENT BLOCKAGE. CORRECT INSTALLATION IN ACCORDANCE WITH THIS SECTION WILL CONSIDERABLY MINIMISE THE LIKELIHOOD OF BLOCKAGE AND SUBSEQUENT BOILER LOCK-OUT.

A CONDENSATE DISCHARGE PUMP AND PIPE ‘TRACE HEATING’ ARE AVAILABLE AS ACCESSORIES - see paragraphs 7.7.12 to 7.715 for further details.

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 EXCEPT when employing a suitable condensate pump in basement and cellar or similar applications.

The boiler condensate trap incorporates a seal of 75mm, therefore it is unnecessary to install an air break and trap in the discharge pipework.

1. The condensate outlet will accept 21.5mm (

/4in) plastic overflow pipe. It is strongly recommended that this discharges internally into the household drainage system. Where this is not possible, discharge into an outside drain is permissible providing every possible precaution is taken to prevent freezing.

2. Ensure the discharge of condensate complies with any national or local regulations in force. BS 6798 & Part H1 of the

Building Regulations give further detailed 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 of the correct design to prevent sagging.

6. It is advisable that the full length of condensate pipe is run

internally and preferably be less than 3 metres.

7. Internal runs greater than 3 metres or runs in cold areas should use 32mm waste pipe.

8. External runs MUST be a MINIMUM of 32mm and fully insulated with material suitable for external use.

9. If the boiler is fitted in an unheated location the entire condensate discharge pipe should be treated as an external run and sized and insulated accordingly.

10. 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 and any burrs on cut pipe removed.

11. 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.

21.5mm

2.5° Minimum fall

i) Termination to an internal soil and vent pipe

450mm min*

Boiler

2.5° Minimum fall

ii) External termination via internal discharge branch

e.g sink waste - downstream*

Sink

Pipe must terminate above water level but below surrounding surface. Cut end at 45°

50mm per metre of pipe run

*450mm is applicable to properties up to 3 storeys. For multi-storey building installations consult BS 6798.

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) downstream of the trap iii) to a drain or gully iv) to a purpose made soakaway v) pumped into an internal discharge branch (e.g. sink waste) downstream of the trap vi) pumped into an external soil & vent pipe vii) to a drain or gully with extended external run & trace heating

It is strongly recommended to discharge internally into the household drainage system. If connecting to a rain water drain, that drain MUST discharge into a foul drain.

*It is NOT RECOMMENDED to connect upstream of the sink or other waste water receptacle !

32mm

Insulation

Boiler

2.5° Minimum fall

iii) Termination to a drain or gully

50mm per metre

of pipe run

Pipe must terminate above water level but below surrounding surface. Cut end at 45°

Boiler

500mm min

2.5° Minimum fall

iv) Termination to a purpose made soakaway

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

50mm per metre

of pipe run

Further specific requirements for soakaway design are referred to in BS 6798.

Boiler

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