Baxi Potterton Combi 24 HE, Main Combi 24 HE Installation & Service Instructions Manual

Installation & Service Instructions;

This is a Wall Mounted Powered Flue Condensing Combination Boiler Gas Fired Central Heating Unit.

The boiler meetsthe 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 Body 0051.

For use in GB/IE only.

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

MAIN

Combi 24 HE

Natural Gas

Main Combi 24 HE G.C.N' 47 474 02

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With the introduction of Self Certification Schemes, the Benchmark Logbook is being withdrawn.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

Baxi PoUerton 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.

W.RII,

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CONTENTS

Section

Page

Legislation

1.0 Introduction 5

2.0

General Layout

3.0

Appliance Operation

4.0 Technical Data 8

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 the Boiler

12.0 Changing Components

13.0 Electrical 39

14.0 Short Parts List 40

15.0

Fault Finding

Benchmark Checklist 46

INSTALLER NOTIFICATION GUIDELINES

Install and Commission this

appliance to manufacturer's

instructions

Complete the

Benchmark Checklist

Competent Person's

Self Certification Scheme

Building Control

If you notify via CORGI Scheme,

CORGI will th~n notify the

relevant Local Authority

Building Control Scheme

on member's behalf

Contact your relevant Local

Authority Building Control

(LABC) who will arrange

an inspection or contact a government approved

inspector

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 writen onto the

Benchmark Checklist

"'"

CORGI will record the data and

will send a certificate of

compliance to the property

LABC will record the data

and will issue a

certificate of compliance

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".

Lifting -This product should be lifted and handled by two people. Stooping

should be avoided and protective equipment worn where necessary. Carrying & lifting equipment should be used as required, e.g. when installing in a loft space.

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

08704012300 or writing to:-

1 Elmwood,

Chineham Business Park,

Crockford Lane,

Basingstoke. RG24 8WG

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

LEGISLATION

Baxi Potterton declare that no substances harmful to health are contained in the appliance or used

during appliance manufacture.

"'(heappliance is suitable only for installation in GB

and IEand 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, most recent version should be used

In GB the following Codes of Practice apply: Standard Scope

BS 6891 Gas Installation. BS 5546 Installation of hot water suppliesfor

domestic purposes. Forced circulation hot water systems. Installation of gas fired hotwater boilers.

Flues. Ventilation. Expansion vessels and ancillary equipment for sealed watersystems.

Treatment of water in domestic hot water central heating systems.

BS 5449 BS 6798 BS 5440 Part 1 BS 5440 Part 2 BS 7074

BS 7593

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. Forced circulation hot water systems. Expansion vessels and ancillary equipment for sealed water systems. Treatment of water in domestic hot water

central heating systems.

BS 5449 BS 7074

BS 7593

1.0

INTRODUCTION

1.1

Description

1. The Main Combi 24 HE is a fully automatic gas fired wall mounted condensing combination boiler. It is room sealed and fan assisted, and will provide central heating and mains fed domestic hot water.

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

25.2 kW (condensing).

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

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. 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. 5111073.

8. All systems must be thoroughly flushed and treated

with inhibitor (see section 6.2).

1.2

Optional Extras

1. Various flue extensions, bends, vertical flue kits,

control accessories etc. are available as optional extras. These are detailed in a separate publication.

Case Front Panel

Control Box .....................

Fig. 1

Data Badge

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

installingor usingtheappliance. '

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".

Lifting -This product should be lifted and handled by two people. Stooping

should be avoided and protective equipment worn where necessary. Carrying & lifting equipment should be used as required, e.g. when installing in a loft space.

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

08704012300 or writing to:-

1 Elmwood,

Chineham Business Park,

Crockford Lane,

Basingstoke. RG24 8WG

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

LEGISLATION

Baxi Potterton declare that no substances harmful

to health are contained in the appliance or used during appliance manufacture.

"(heappliance is suitable only for installation in GB and IEand 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, most recent version should

be used

In GB the following Codes of Practice apply: Standard Scope

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

domestic purposes. Forced circulation hot water systems. Installation of gas fired hot water boilers.

Flues. Ventilation.

Expansion vessels and ancillary equipment for sealed water systems.

Treatment of water in domestic hot water central heating systems.

BS 5449

BS 6798

BS 5440 Part 1

BS 5440 Part 2

BS 7074

BS 7593

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.

Forced circulation hot water systems. Expansion vessels and ancillary equipment

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

central heating systems.

BS 5449

BS 7074

BS 7593

:..~ h c=:>."""On

i ~ c=:> ,F,;I""

i Q c=:> Pow"ion

, j i

21 22

Fig.2

Fig.3

10 9

2.0

GENERAL LAYOUT

2.1

Layout

Air Pressure Switch

Expansion Vessel

3. Burner Manifold

Automatic Air Vent

DHW Plate Heat Exchanger

Circulation Pump

Drain Off Point

8. Pressure Relief Valve

Optional Integral Timer Position

10.

Central Heating System Pressure Gauge

11.

Control PCB

12. Control Box

13.

3-Way Valve Assembly

14.

Condensate Trap

15.

Flame Sensing Electrode

16.

Spark Electrode

) j

""""".....4

17. Burner

18.

Primary Heat Exchanger

19.

Fan Assembly

20.

Secondary Heat Exchanger

21.

On / Off / Reset Selector Switch

22.

Burner & Fault Indicator Neon

23. Power Neon

24.

Flame Failure & Fault Indicator Neon

25.

Central Heating Temperature Control

26.

Hot Water Ternperature Control

3.0

APPLIANCEOPERATION

NOTE: All delay timers mentioned in 3.1 and 3.2

are overridden by domestic hot water demand.

3.1

Central Heating Mode (Fig. 4)

1. With a demand for heating, the pump circulates

water through the primary circuit. At a pre-determined flow rate the central heating flow 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.

':I I

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.

3.2

Domestic Hot Water Mode (Fig. 5)

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 DHW flow switch which causes 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.

IMPORTANT: When the selector switch is in the '0' (Off) position the electrical supply to the boiler

is isolated. The boiler will not operate and the integral timer (if fitted) will require resetting once

the selector switch is turned to either the DHW

or CH position.

Fig. 4

Central Heating Circuit

Key

1 PrimaryHeat Exchanger 2 Burner

3 Ignition Electrode

4 Flame Sensing Electrode 5 Gas Valve

6 Pump 7 AutomaticAir Vent

8 Plate Heat Exchanger 9 Flow Sensor with Filter 10 Pressure ReliefValve

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 Hydraulic Differential PressureSensor Microswitch

19 Automatic By-Pass 20 Hydraulic Differential Pressure Sensor 21 Diverter Valve Assembly 22 Domestic HotWater Flow PriorityAssembly 23 Domestic HotWater Flow PriorityMicroswitch 24 Temperature Sensor 25 Overheat Thermostat 26 Expansion Vessel 27 Secondary Heat Exchanger

Fig. 5

Domestic Hot Water Circuit

Heat Output CH(Non-Condensing)

Max Min

24 9.8

Heat Output CH(Condensing)

Max Min

kW 25.2 10.1

Heat Input DHW

Max

kW 24.8

Heat Output DHW

Max

Max Gas Rate (Natural Gas - G20)

(After 10 mins)

m3/h 2.62

Burner Pressure (NaturalGas - G20)

Max Rate Min Rate

mbar 10.2 :t 0.5 2 :t 0.2

Inlet Pressure (Natural Gas - G20)

mbar 20

Burner Injector (Natural Gas - G20)

15x 1.18mm Diameter

Electrical Supply 230V- 50Hz

(Appliance must be connected to an earthed supply)

Power Consumption

170W

External Fuse Rating

Internal Fuse Rating

Fuse 2A Fast Blow to BS 4265

4.0

Electrical Protection IPX4D

NOx Class

Condensate Drain

1" BSP

Flue Terminal Dimensions

Diameter

Projection

100mm 125mm

Connections

Gas Supply Central Heating Flow Central Heating Return

Cold Water Mains Inlet DHW Flow

Pressure Relief Discharge -

copper tails

22mm 22mm 22mm 15mm 15mm 15mm

Outercase Dimensions Casing Height Overall Height Inc Flue

Elbow Casing Width Casing Depth

780mm

965mm 450mm 345mm

Clearances Above Casing Below Casing

Front Front L.H. Side R.H. Side

200 mm Min 200 mm Min

450 mm Min (For Servicing) 5 mm Min (In Operation)

5 mm Min 5 mm Min (In Operation) 20 mm 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

Packaged Boiler Carton Installation Lift Weight

43.5

4.5 4

3.5 3

E2.5

~ 2

::;

1.5

0.5 0

0 200

TECHNICAL DATA

Central Heating Primary Circuit

Pressures

Pump

AvailableHead

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

Primary Water Content of Boiler (unpressurised)

125

1.0

Temperatures

C.H. Flow Temp (adjustable)

35°C to 85°C max(:t 5°C)

D.HW. Flow Temp

35°C to 65°C max(:t 5°C) dependent upon flow rate

Pump - Available Head

400 600 800 1000 1200

Flow Rate (I/h)

Appliance Type

C12

C32

Appliance Category

CAT II2H 3P

Heat Input CH

Max Min

kW 24.8 10.6

LPG Propane - G31 Burner Injector 15 x O.77mm diameter

Burner Pressure

Max Rate IMinRate

Propane

mbar 21.8 :t 0.514.4 :t 0.2

Inlet Pressures

mbar

bar

Safety Discharge

Max Operating

2.5

Min Operating

0.5

Recommend Operating

1-2

DHW Circuit bar Pressures

Max Operating

Min Operating

0.2

Min Operating Pressure at 11.1 I/min 0.9

Flow Rates I/min

DHW Flow Rate

@30°CRise 11.5

DHW Flow Rate

@35°CRise 9.8

Min Working DHW Flow Rate 2.5

5.0 DIMENSIONS AND FIXINGS

k- B j

3600 Orientation

L F0::11 :

D ,_I--n~

\ I ",

f:k]

- . ,,' .

--.'-'-

i7771r~ '

Fig.6

Heating

Flow

Dimensions

A 780mm

B 345mm

C 450mm

D 116mm0 Min.

E 185mm

F 190mm

G 131mm

, Tube 0 100mm

Gas Inlet

Condensate

Drain

u0 -.

68mm :

:11( .'

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -,- - - - - - --

: j

Heating

Return

--$--

Domestic Hot : Cold Water

Water Outlet ; Inlet

---U---u---ui u --0- un. u0r

65mm ' 65mm - : - 65mm -~

95mm

, ,

u0- u--- u$--

: - 65mm - ,

Left Hand Side

of Boiler

265mm

165.7mm

View from under the appliance

130mm

Fig. 7

6.0 SYSTEM DETAILS

6.1 Information

1. The Main Combi 24 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 - Seetext 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 upgrading existing systems that exhibit evidence

of sludging, it is advisable to clean the system prior to treatment in order to remove any sludge and reduce the likelihood of these deposits damaging new components.

.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. The recommended flushing and cleansing agents are Betz-Dearborn Sentinel X300 or X400 and Fernox

Superfloc Universal Cleanser which should be used following the flushing agent manufacturer's instructions.

.System additives -corrosion inhibitors and flushing

agents/descalers should be suitable for aluminium and comply to BS7593 requirements. The only system

additives recommended are 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. The boiler is designed for use in a heating system

that incorporates external controls, Le. a minimum of a timer device.

2. An integral electro-mechanical or electronic timer is available as an optional extra.

3. For optimum operating conditions and maximum economy the fitting of a programmable thermostat is

recommended.

6.0 SYSTEM DETAILS

6.5

SystemFilling 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 replacemenVrefiliing.

2. There are connection points on the mains cold water inlet and central heating return isolating taps to which the optional filling loop kit (Part No. 248221)

can be assembled.

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

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. 9)

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 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.

Double Stop Check Valve Valve

Stop

Valve

DHW Mains Inlet

... .-

Temporary

Hose

CH Return

Fig. 8

Pressure Relief Valve

Fig. 9

Discharge Pipe

Other Tap Outlets

Check Valve

Stop Tap

Expansion Vessel

6.0

SYSTEM DETAILS

6.8

Domestic Hot Water Circuit

Boiler

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 1.8.813 "Domestic Gas Installations" .

To Hot Taps

3. A single check valve must be fitted as shown in Fig. 10 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.

Fig. 10

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, R'1215bar).

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.

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 that frost protection is incorporated in

the control 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 lEE. 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 (Fig. 11 & 12)

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.

* NOTE: The boiler can be operated with a ctearance 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 alteration in the area of

installation.

450mm

20mm/5mm Min

see *NOTE:

200mm Min

780mm

Fig. 11

200mm Min

---L

450mm Min

01( .-

For Servicing

Purposes

5mm~ L

In Operation

Fig. 12

7.0 SITE REQUIREMENTS

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 isthe 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. 13).

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

Fig. 13

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.

Gas Service Cock

2. The mains supply is 230V -50Hz 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.

7.0 SITE REQUIREMENTS

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 2.50 (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 (3f.in)plastic overflow pipe which should generally discharge internally into the

household drainage system. Ifthis is not possible, discharge intoan outside drain is acceptable.

2. Ensure the discharge ofcondensate complies with any national or local regulations inforce. BS 6798:2000 & Part H1 of the Building Regulations give further guidance.

3. The discharge pipe should be run ina 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 minimumof 21.5mm diameter and must be supported using suitably spacedclips

prevent sagging.

6. Any pipe fitted externally must not exceed 3 metres.

7. Anycondensate discharge pipeworkexternal to the building (or inan unheated part of it e.g. garage) must be insulated to protect against frost. Itis also recommended that the pipe diameter is increased to

32mm.

8. Ifthe boiler is fitted inan 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

Boiler

Termination to an internal soil

and vent pipe

~PiPerun

25~

450mm min

Boiler

Externaltermination via internal

discharge branch

e.g sink waste - downstream

50rnrn

Perrn

etre of p'

2.50 ft~~ Ipe ru

,,/fi-' ---=

' ~--- n

Irnu

rnfal!

Pipe must terminate above water level but

below surrounding surface

Sink

Boiler

External termination to a drain or gully

Pipe must terminate above water level but

below surrounding surface

50rnrn

Perrn

etreof .

2.~erun 'Vl/ntrn

urnfal!

External termination to a purpose

made soak-away

Boiler

50~run

2.50 Minirnurn fal!

--..

500mm min

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

'iii"

Likely flue positions requiring

a flue terminal guard

Fig. 14

.Terminal Positionwith Minimum Distance (Fig. 14)/ (mm)

A* Directly below an openable window, air vent or any other

ventilation opening. B Below gutters, drain/soil pipe. C Below eaves.

D Below balcony/car port roof E From vertical drain pipes and soil pipes.

F From internal or external corners.

G Above adjacent ground or balcony level.

H From a surface or boundary facing the terminal. I Facing terminals.

J For opening (door/window) in car port into dwelling.

K Vertically from a terminal on the same wall. L Horizontallyfrom a terminal on the same wall. M* Above an opening, air brick, opening window etc. N* Horizontallyto an opening, air brick, opening window etc.

300

25 25 25 25

25 300 600

1200 1200 1500

300 300 300

.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.

7.0 SITE REQUIREMENTS

7.7

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.

H,I

--@

Fig. 15

:- Property Boundary Line

7.0 SITE REQUIREMENTS

7.8 Flue Dimensions

The standard horizontal flue kit allows for flue lengths

between 100mm and 685mm from elbow to terminal (Fig. 16).

The maximum permissible flue length is: 4 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. 17)

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.

r:..'O~~~

.#" 'U .

"'~ .

'\\)\)\,.

Fig. 16

--------

'---,

Fig. 17

Vertical

Flues (Twin Pipe)

Vertical Flues

Horizontal Flues

7.0 SITE REQUIREMENTS

7.11

Flue Options

1. The Main Combi 24 HE can be fitted with flue systems as illustrated.

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

3. Maximum permissible equivalent flue lengths are:-

4 metres 4 metres

12 metres

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

Their equivalent lengths are:-

Concentric Pipes:

45° bend 93° bend

Twin Flue Pipe

45° bend

91.5° bend

0.5 metres

1.0 metres

0.25 metres

0.50 metres

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

5. The illustrations opposite show examples of

maximum equivalent lengths.

6. Instructions for guidance and fitting are included

in each kit, where appropriate.

NOTE: Flue length is measured from point A to B as shown.

Horizontal Concentric Vertical Concentric

Vertical Twin Pipe

'!<

.I.

8.0 INSTAllATION

8.1

Initial Preparation

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

1. Afterconsidering the site requirements

(see Section 7.0) position the fixingtemplate on the

wallensuringitis levelboth horizontallyand

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. For side flue exit, mark as shown (Fig. 18).

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

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

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

6. Drill the wall as previously marked to accept the

wall plugs supplied. Secure the wall plate using two

of the fixing screws.

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

8.2

Flushing

1. Connect a tube to the central heating flow or return

pipe (Fig. 19).

2. Flush thoroughly (see System Details, Section

6.2).

8.3

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.

A 190mm ~

~I~

~ I ~,~ ~

'I~ ~',

A, I I

~~ ,~"

Fig. 18

Flushing Tube.

...........

--Q---

For Side Flue Exit

Central Heating Return ..........

Fig. 19

Wall Plate

,///~

,/ ~

>J:'i,/

Fig. 20

".11

(

Securing Screw

Fig. 21

Pressure Relief Valve

Fig. 22

Discharge Pipe

8.0 INSTAllATION

8.4

Fitting The Boiler

1. Lift the boiler using the lower edges. Engage the slots at the top rear of the boiler on the wall plate hooks (Fig. 20).

2. Ensure that the boiler is level and sits against the wall.

3. Take the two steel washers and remaining screws. Using the previously drilled and plugged holes, secure the bottom of the boiler to the wall (Fig. 21).

4. Remove the elbows, valves and sealing washers from the packaging. The 3/4 in valve with internal filter must be fitted to the central heating return. The filter is visible through the branch connection of the

valve.

5. Using the sealing washers provided connect the valves to the heating flow and return, and the cold

water inlet.

6. Connect the elbows to the gas service cock and hot water outlet pipe, and then connect the elbows to

the boiler. Connect the elbows with flared ends to the valves.

7. Ensure that the sealing washers are used on all connections. The rubber washers must be used on

the gas connections.

8. The gas and water supplies, central heating flow and return and domestic hot water flow can now be

connected.

8.5

Fitting the Pressure Relief Discharge Pipe (Fig. 22)

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. Using 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.

8.0

INSTAllATION

8.6

Condensate Drain (see section 7.6)

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. Ifthis is not possible, discharge into an outside drain is acceptable.

8.7

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. 23).

2. Locate the flue elbow on the adaptor at the top of the boiler. Set the elbow to the required orientation (Fig. 24).

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. 25).

4. To dimension 'X' add 5Omm. This dimension to be known as 'Y'.

IMPORTANT: Check all dimensions before cutting.

<..,

'X>s~~

"",'0

"'~ .

\\)\)\"

----------

Wall Thickness

~I ~

Fig. 23

Flue Elbow

Adaptor

Fig. 24

(X)

~ I Wall Thickness

Fig. 25

Inner Flue Support Bracket

Flue

Fig. 26

~m.m

"""

Flue Elbow

Fig. 27

Flue Trim

Fig. 28

8.0 INSTAllATION

8.7

Fitting the Flue (Cont)

5. Mark dimension 'V' on the flue as shown (Fig. 26). 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. 27).

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. 28).

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 7.9 & 7.10).

VERTICAL FLUE

1. Only a flue approved with the Main Combi 24 HE

can be used.

8.0 INSTAllATION

8.8

Making The Electrical Connections

To connect the mains input cable proceed as follows:-

1. Slacken the facia panel 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. 29).

-....

3. Remove the control box cover securing screws. Disengage the barbs on the control box from the

cover. Remove the cover (Fig. 30).

4. Slacken the cable clamp on the LH side of the boiler chassis (Fig. 31). 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. If an external control isto be connected it can be done at this point. Run the input cable from the

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 230V supply at

terminal 1 can be connected to the external control as shown. The switched output from the

external control must be connected to terminal 2. (Figs. 32).

"'"

NOTE: If the room thermostat being used incorporates an anticipator it MUST be wired as shown in Fig. 32.

IMPORTANT: The external control MUST be suitable for 230V switching.

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

9. If an optional integral timer is to be used it should be fitted at this point. Refer to the instructions supplied with the timer. NOTE: An external frost thermostat cannot be used with the integral timer.

8.9

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.

Fig. 30

Control Box Cover

Fig. 31

Cable Clamp

Fuse

Fused supply 3A

230V -50Hz

Live (brown) Neutral (blue)

Earth (green/yellow).

,----...-----

, 230V 1

.t 2

+-------

Terminal Block

Fig. 32

Externai

llt

Controls 230V

Selector I

Reset Switch

Fig. 33

Key to Wiring b - blue

br - brown bk - black r - red

g - green w - white

Fig. 29

Facia Panel

Fr"tTherm,,"t

br b

gfy bk

gly

Roem Thermo""

IMPORTANT: If an integral timer is fitted to the boiler an external frost thermostat wired as

shown will not operate correctly. Only external timers may be used in such installations, as in the diagram.

Functional Flow Diagram

Pump

br--0--b_N

~r~ PressureSwitch

Fan

br--0--b_N

b -Q Flue Thermostat

b --6 Safety OverheatThermostat

;::::()NTCSensor

PCB

bk bk

Gas Valve Modulator

Spark Electrode

Gas Valve

Condensate Trap

: ~ Hydraulic Differential Pressure Switch

: =1J DHW Flow Priority Mboswitch

Pressure Gauge

Selector Switch

Fig. 34

Screw

Automatic Air Vent

9.0 COMMISSIONING

9.1

Commissioning the Boiler

1. Reference should be made to BS 5449 Section 5

when commissioning the boiler.

2. Open the mains water supply to the boiler.

3. Open all hot water taps to purge the DHW system.

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

boiler.

5. Open the screw on the automatic air vent (Fig. 35).

6. The system must be flushed in accordance with BS 7593 (see Section 6.2) and the flushing agent

manufacturers instructions.

7. Pressurise the system to at least 0.5 bar then

close and disconnect the filling loop (Fig. 34).

8. Turn the gas supply on and purge the system according to in GB BS 6891 and in IE I.S. 813

"Domestic Gas Installations".

9. Test for gas soundness.

10. If at any time during commissioning it is required

to terminate a particular cycle, turn the selector to the OFF position and then back to either (tF) or (jffitF)

(Fig. 36).

0 ;--

iII<P

O,<P

',e' , ' , h 0 '"~~

"'0 ,'" 0

, h 0 -- ., 0'

" , Qo -~ '0,00 '0,0'

... //.( '......

Central Heating

Temperature Control

(;) \

Hot Water

Temperature Control

Fig. 36

9.0

COMMISSIONING

9.2

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 hot water and central heating temperature controls to maximum and the selector switch to the

OFF position (Fig. 37).

3. Slacken the pressure test point sealing screw on the gas valve and connect a pressure gauge (Fig. 38).

4. Disconnect the sensing tube from the gas valve.

5. Turn the selector switch fullyanticlockwise against the spring pressure to the reset position and hold for 2

seconds to reset the boiler.

6. Turn the selector switch to the Cental Heating and Domestic Hot Water position (OfF). The power ON light (Q) willilluminate(Fig. 37).

Turn on a hot water tap to give a flow rate ofat

least 10 I/min.

8. The pressure should be :-

Propane

10.2 mbar

21.8 mbar

Ifnot, check that the gas supply pressure is correct (Natural Gas 20mbar, and Propane 37mbar).

9. The pressure can be adjusted ifrequired.

10. To check and set minimum pressure first remove

one of the modulator wires.

Adjusting the Pressure (Fig39)

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

12. The smaller nut (5mm) adjusts minimum pressure

and the larger nut (8mm) maximum pressure.

13. Using a suitable spanner adjust the relevant nut untilthe correct pressure is achieved.

14.

Once the pressure has been set turn the boiler off

and disconnect the pressure gauge.

15. Tighten the pressure test screw and refitthe modulator to the valve. Reassemble in reverse order.

Selector Switch

1IIJ.F

([50

°. .F

",. . . h =-~ .. ..

. 0 h =-,.,." ',: ". .:

. . Q=-', '.' .

'. .

..' ""

. .

0C)

Central Heating

Temperature Control

Pressure Test Point

, SealingScrew

Gas Valve

Fig. 38

Plastic Protection

Cap

Maximum Rate

. . Adjustment Nut Inlmum Rate

Adjustment Nut

Fig. 39

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

Fig. 37

Hot Water

Temperature Control

Case Front Panel

Fig. 40

10.0 COMPLETION

10.1

Completion

1. Hinge the facia panel upwards and engage the securing screws. Refit the case front panel and tighten the screws (Fig. 40).

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 inthe 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 Guide and these Installation and Servicing Instructions, giving advice on the necessity of regular servicing.

11.0 SERVICING THE BOILER

11.1

Annual Servicing

1. For reasons of safety and economy. it is recommended thatthe boileris servicedannually.

Servicingmustbe performedbya competentperson.

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 (Fig. 41).

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. 43).

7. Note the positions of the three wires on the fan motor and remove them. Remove the sensing tube

from the fan spigot (Fig. 42).

8. Slacken the screws on the fan spigot outlet pipe clamp. Ease the clamp inwards over the pipe.

9. Remove the four screws securing the combustion box door and remove the door (Fig. 43).

Case Front Panel

Fig. 41

Fan Wires

Sensing Tube

Ease Fan SpigotOutlet Pipe Clamp Inwards

Fig. 42

Fan

[.""""'"

Fig. 43

Fan Spigot Outlet Pipe

Combustion

Box Door

Inner Door

Panel

...

Baffle

Fig. 44

Fig. 45

,...............................................

Fig. 46

, \

~ Threaded \

~ Bu~h \

Fig. 47

J-

L/~

Electrode

Leads

Gas Supply Pipe

Blanking

Cap

Cold Water

InletTap

Cartridge

Body

Filter Gauze

~ ~..'

Fig. 55

Flow.."'"

Regulator.

Fig. 48

Inlet/ Return Manifold

Venturi

11.0 SERVICING THE BOILE'R

11.1

Annual Servicing (Cont)

10. Ease the front edge of the left hand baffle upwards, disengaging the spring clip. Disengage the

tab on the baffle from the slot in the fan hood (Fig.44).

11. Undo the screws securing the fan hood assembly

to the appliance back panel, and draw the fan and

hood assembly forwards (Fig. 45).

12. Draw the burner out of the combustion box, pulling the electrode grommets from the slots in the combustion box lower panel (Fig. 46).

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

(Fig. 46).

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

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

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

NOTE: If necessary the secondary heat exchanger may be dismantled -see section 12.23

D.H.W.Filters (Fig.

48)

17. If the flow of domestic hot water is diminished, it

may be necessary to clean the filters.

18. Initially check the cold water inlet tap filter.

19. Turn the tap off. Undo the blanking cap and

remove the threaded bush (Fig. 47).

20. Extract the filter and rinse thoroughly in clean water. Reassemble and check the flow. If required

clean the manifold filter as described below.

21. Undo the filter cartridge from the inlet/return

manifold.

22. Dismantle the cartridge and carefully remove the flow regulator and filter gauze. Rinse them thoroughly

in clean water and reassemble in reverse order.

23. Check that the pressure vessel charge is 0.5bar,

reassemble in reverse order of dismantling.

24. Turn the selector switch fully anticlockwise against the spring pressure to position R and hold for 2

seconds to reset the boiler before recommissioning.

25. 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.

12.0

CHANGING COMPONENTS

IMPORTANT: When changing components ensure that both the gas and electrical supplies to the boiler are isolated before any work is started.

See Section 11.1 "Annual Servicing" for removal of

case panel, door etc.

12.1

Fan (Figs. 50 & 51)

1. Note the positions of the three wires on the fan motor and remove them. Remove the sensing tube

from the fan spigot.

2. Slacken the screws on the fan spigot outlet pipe clamp. Ease the clamp inwards over the pipe.

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

4. Ease the front edge of the left hand baffle upwards, disengaging the spring clip. Disengage the tab on the

baffle from the slot in the fan hood.

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

6. Remove the screws and spring washers securing the fan to the hood. Transfer the flue spigot outlet pipe

to the new fan.

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

8. Reassemble in reverse order of dismantling.

12.2

Pressure Switch (Fig. 49)

1. Remove the fan as described in section 12.1.

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

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

Pressure Switch """"""""",

Fig. 49

.)J ! Sensing

(~rrr;"T"'"

~ Ii ./I~

Pressure

Switch Wires

Fan Wires

Fan

Sensing

Tube

Ease Fan Spigot Outlet Pipe Clamp Inwards

Fig. 50

Fan Spigot Outlet Pipe

Baffle

Fan

Fan Hood

Fig. 51

Securing Screw

P;peCO7~;:;,:';~~~~~

! ". ~

! ;~

: ~ ~

Heat Exchanger

Fig. 52

Elect"de, ..,,:::::::lIn

.1l""""1:,b

.¥f

)

5;~~~~:, '/l~

Electrode

Leads

Burner

Fig. 53

12.0

CHANGING COMPONENTS

12.3

Heat Exchanger (Fig. 52)

1. Remove the fan as described in section 12.1.

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.

4. Fit the new heat exchanger, ensuring that the tabs on the side insulation carriers engage in the slots in the heat exchanger side plates.

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

12.4

Burner (Fig. 53)

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

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

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

4. 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.

5. Engage the burner location brackets over the studs on the injector manifold and reassemble in

reverse order.

12.0 CHANGING COMPONENTS

12.5

Injectors (Fig. 54)

1. Remove the burner as described in Section 12.4.

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.

12.6

Electrodes (Fig, 54)

1. Remove the four screws securing the combustion

box door and remove the door.

2. 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.

12.7

Insulation (Fig. 55)

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 12.3 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.

Fig. 54

Injector

, ,

"" I

":'\"

Injector

Manifold

Inlet Elbow

{

Electrodes ":::"'."]:"""" .

:H l.--Jft

EI d

...,., t ~

G:;~e~'l.~

Electrode

Leads

Burner

................................................

Side Insulation

Rear Insulation

\) \)

Combustion

Box Door

Side Insulation

Front Insulation

Fig. 55

Modulator

Wi~es i i/ ~

I/Y'Y-'~

Ignition ~ /,/ /'

Lead ~;>'1' /

~; >'1'/,<!)

[\ ~

[\ a

, Gas Valve

/<~/I

j)(

(

W'.

)

[']

: I

/ ~)

E"~ri'" l ", 0,.,

Plug ."" , @ i

EarthWire .."" ~

'"',' p;";;"" , fC

Gas Feed

Pipe

Fig. 56

............................

, ,

Flow Pipe.

..................

Safety

Thermostat

~ i/\~

4 I

Temperature

Sensor

. .

. .'

. .

. .'

. .

. .'

. .

. .'

. .

. .' . .'

Fig. 57

12.0

CHANGING COMPONENTS

12.8

Gas Valve (Fig. 56)

1. Undo the nut on the gas feed pipe at the tap rail

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 tap rail 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 '0' ring seals for damage, replacing as necessary.

9. Fit the inlet pipe and outlet manifold to the new valve, ensuring that the '0' ring seals are in place.

10. Reassemble in reverse order and check the burner pressure (Section 9.2).

12.9

Temperature Sensor (Fig. 57)

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.

12.10 Safety Thermostat (Fig. 57)

1.Pull the two 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.

12.0 CHANGING COMPONENTS

12.11

Pump - Head Only (Figs. 58 & 59)

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 Grundfos 15-60 replacement head can now be fitted. Connect the wiring to the new head. The pump speed must be set to 3.

4. Reassemble in reverse order.

12.12 Pump - Complete (Figs. 59 & 60)

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

'0' 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.

12.13 AutomaticAirVent (Fig.60)

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

2. Examine the '0' ring seal, replacing if necessary, and fit it to the new automatic air vent.

3. Reassemble in reverse order.

PumpWiring

Cover

Pump Body

Pump Head

Fig. 58

Pump Setting

Automatic

Air Vent

Fig. 59

Fig. 61

Pressure Gauge

Capillary

Gauge Retaining

Bracket

\ i

tV ,

.,..""

....

..'

Timer Cover

~ Pra,,",aGaoga

Fig. 62

Expansion Vessel

..........

............................... Retaining Clip

Upper Cross

Member

N~""""

Boiler~E

~"'va,,:ar Dotla!

Cha";",,,,'r~p,go!

~ .

Lock Nut"' ~ """'"

\l Spring

Washer

Sensing Wires

~~~~tPipe

"""" Condensate

. Trap

Fig. 64

~ Bracket

,@,,@,

Condensate Drain Pipe

12.0

CHANGING COMPONENTS

12.14 Pressure Gauge (Figs. 61 & 62)

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.

12.15 Expansion Vessel (Fig.63)

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 bracket and lay it on it's 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.

12.16 Condensate Trap (Fig. 64)

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.

12.0 CHANGING COMPONENTS

12.17 Pressure Relief Valve (Fig. 65)

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 '0' ring seal and set to the previously noted orientation. Reassemble in reverse

order.

12.18 P.C.B. (Fig.67)

1. Note the settings of the temperature control knobs. Rotate the knobs fully anticlockwise and pull them off

the drive pins.

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. 66).

3. Note the position of all plugs and wires on the

P.C.B. and disconnect them. Pull the drive pins off the P.C.B.

4. Undo the securing screws and remove the P.C.B.

5. Reassemble in reverse order, ensuring that the

temperature controllers are reset to their previous

positions.

12.19 Selector Switch (Fig. 67)

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. 66).

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.

'0' ring seal """ ~

.. /~

~........

0 Grub Screw

. ~ Pressure Relief Valve

FI9.65/~ ~

Discharge Pipe

Fig. 66

Control Box Cover

P.C.B.

Selector

Switch ".

Fig. 67

Facia .........

11j(l1

Selector Switch Knob I,1

" I .

~~ :::::::::.. Temperature Control

0""" Knobs

Plate Heat \.:changer

Fig. 68

Rubber Seal

Sensing Pipes

',.

Mkoro,w"'" ""'<:::jf

Bracket I

Manifold

Fig. 69

"""

"""" DHW Pressure

Differential Valve

D;"'h~~gm

Diaphragm

Spring

Pushrod

Fig. 70

12.0

CHANGING COMPONENTS

12.20 Plate Heat Exchanger (Fig. 68)

1. Drain the primary circuit.

2. While supporting the heat exchanger undo the screws securing it to the brass manifolds.

3. Withdraw the heat exchanger upwards and to the left of the gas valve, taking care not to damage any

wires or controls.

Seals

4. There are four rubber seals between the manifolds and heat exchanger which may need replacement.

5. Ease the seals out of the manifold. Replace carefully, ensuring that when the seal is inserted into

the manifold it is parallel and pushed fully in.

6. When fitting the new heat exchanger note that the left hand location stud is offset towards the centre

more than the right hand one.

7. Reassemble in reverse order.

12.21

Diverter Valve Assembly (Fig. 69)

The diverter valve assembly comprises of a central

heating pressure differential valve and a domestic hot water pressure differential valve. These are connected to a manifold which is joined to the plate heat exchanger.

DHW Pressure Differential Valve (Fig. 70)

1. Drain the primary circuit.

2. Undo the screw securing the microswitch bracket to the valve (Fig. 69).

3. Disconnect the two sensing pipes and slacken the grub screws securing the valve to the diverter

manifold.

4. Draw the valve away from the diverter manifold. The valve may now be replaced or split to examine the diaphragm.

5. To examine the diaphragm hold the valve body securely and carefully remove the six screws. The diaphragm spring will force apart the two halves of

the valve.

6. Remove the plastic disc and pushrod assembly. Carefully examine the diaphragm and replace it if there is any damage.

7. Reassemble in reverse order.

12.0 CHANGING COMPONENTS

12.21

Diverter Valve Assembly (Cant)

CH Pressure Differential Valve (Fig. 71)

1. Remove the DHW pressure differential valve as

described above.

2. From the brass diverter manifold undo the nut on the heating flow pipe. Remove the screw securing the

diverter manifold to the appliance lower bracket.

3. Disconnect the pressure gauge capillary from the diverter manifold and remove the two wires from the

microswitch,

4, Prise off the spring clip securing the by-pass pipe to the diverter manifold and disconnect the sensing

pipe.

5. Ease the diverter manifold out of the plate heat exchanger manifold. Remove the assembly from the appliance.

6. Undo the screw securing the microswitch bracket to the valve body. The sensor may now be dismantled to examine the diaphragm.

7. To examine the diaphragm hold the assembly securely and carefully remove the four screws. The diaphragm spring will force the two halves of the valve

apart.

8. Carefully examine the diaphragm and replace it if

there is any damage.

9. Reassemble in reverse order.

CH Pressure Microswitch (Fig. 71)

1. Remove the two wires from the pressure

microswitch.

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

3. Reassemble in reverse order.

12.22 Flow Regulator (Figs. 71 & 72)

1. Undo the filter cartridge from the inlet/return

manifold,

2. Unscrew the venturi and remove the flow regulator.

3. Check the cleanliness of the filter gauze, rinsing thoroughly in clean water as necessary. Fit the new flow regulator and reassemble in reverse order.

Microswitch & Central Heating

Bracket Pressure Differential

"" Valve

se.7ng Pipe

DI,phffi~m ~I ~ By-

""" ~,' ~"""",'PIPe

10 l\fi~ -

~ / ~ Spring Clip

/ &;~~~1

DI"rte, Maol'old -~

. Pressure'Gauge

Capillary

Fig. 85 ~

Flow.."""

Regulator

Heating

Flow Pipe

Fig. 71

~?~,:,e

. .'

. "

. .'

: /

. .'

: / . " : /

Filter Gauze

Inlet / Return Manifold

Fig. 72

Venturi

, ~

\\/

" /'

~ rG>

! (\j/ ...

/ ~;bOW ~

Fan Spigot

OutletPipe

Fan Spigot Outlet Pipe Clamp

Secondary

Heat Exchanger

Pipe Connecting Clip

Outer Drum

Boiler Return Pipe

Heat Exchanger Return Pipe

Fig. 73

[//"

Ease FanSpigot Outlet Pipe Clamp Inwards

Fan Spigot Outlet Pipe

Fig. 74

Overheat Thermostat

12.0 CHANGING COMPONENTS

12.23 Secondary Heat Exchanger (Fig. 73)

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 fan spigot outlet pipe clamp. Ease the clamp to the left. Undo the

screw at the left hand end of the pipe.

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.

12.24 Flue Overheat Thermostat (Fig. 74)

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.

13.0 ELECTRICAL

13.1

Illustrated Wiring Diagram

Fuse

Optional Timers

(

g/y

3-Way Valve

Microswitch

g/y

Condensate

Trap

bk br

I I

I I I IFA2

-------

Control PCB

- --

,-----

-------

Flame

Sensing

Electrode

br bk b

- brown

- black

- blue

- red

- yellow

- green I yellow

- white

- grey

g/y

On/Off/Reset

Selector Switch

Temperature Sensor

Hydraulic Differential

Pressure Switch

Flue Thermostat

Safety Thermostat

,-'- -

bk I

L..bk

br-

bk-

bk bk

31 b

;:° :, II

27 l!:::::eo++- br

~131

154

103

169

140

135

14.0

SHORT PARTS LIST

Short Parts List

Key G.C. No. No.

Description

Manufacturers

Part No.

5112627

5112999

5112431

5112770

248210

248037

5108265

248078

5107339

5112657

248090

371

Igniter/Gas Valve Cable

5112385

Flue Overheat Thermostat 5112395

371

E66411 Spark or Sensing Electrode

247384

Pump Complete

248042

101

E66432 Hydraulic OutletAssembly

248061

102

E66434 Valve

-3-WayAssembly

248062

103

343619 Pressure Differential Assy

248063

22 Fan

23 Pressure Switch

Heat Exchanger

41 Burner

E66402 Injector

- 1.18NG

59 E66 408 Electrode Lead

131

Temperature Sensor

135

E66 697 Safety Limit Thermostat

140 Gas Valve

154 PCB

169

E66453 Pressure Gauge

15.0 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 13.1 "Illustrated Wiring Diagram" for position of numbered terminals

Central Heating - Follow operational sequence

Turn selector to .IJ!)[iF

Q neon illuminated

YES

Turn .IJ!)[thermostat

to max.

Pump runs

YES

Air pressure

switch proved

YES

Spark at ignition

electrodes for up to 10

seconds

YES

Burner on h neon

illuminated

YES

Burner extinguishes

after 10 seconds

Burner output

modulates until set

temperature is reached

NOTE: When instructed to turn the Selector to the reset position turn the Selector Switch

fully anticlockwise against the spring pressure and hold for 2 seconds to reset the

boiler.

Go to section 'A'

External controls and,

where fitted, integral timer

calling for heat

Ensure controls are set to

demand and verify the

contacts are closed

Go to section 'c'

Turn the selector switch to

the 'Reset' position and

hold for at least 2

seconds. If regular

resetting is required, or

appliance still does not

operate, investigation is

necessary

Go to sections 'J', 'L' & '0'

Go to section 'E'

YES

Turn selector to the reset

position. If the light does

not extinguish go to

sections H & K

~ illuminated

Go to section 'F'

YES

Go to section 'I'

Go to section 'G'

Operation sequence

correct

Fan stops Pump stops

15.0

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).

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 13.1 "Illustrated Wiring Diagram" for position of numbered terminals

Central Heating -Follow operational sequence

Turn selector to .If rF=

Q neon illuminated

YES

Turn .If thermostat

to max.

Pump runs

YES

Air pressure

switch proved

YES

Spark at ignition

electrodes for up to 10

seconds

YES

Burner on hneon

illuminated

YES

Burner extinguishes

after 10 seconds

Burner output

modulates until set

temperature is reached

Go to section 'A'

Go to section 'B'

YES

External controls and,

where fitted, integral timer

calling for heat

Go to section 'c'

Turn the selector switch to

the 'Reset' position and

hold for at least 2

seconds. If regular resetting is required, or appliance still does not

operate, investigation is

necessary

Go to section 'E'

Ailluminated

YES

Go to section 'F'

YES

Go to section 'I'

Go to section 'G'

Fan stops

NOTE: When instructed to turn the Selector

to the reset position turn the Selector Switch fully anticlockwise against the spring

pressure and hold for 2 seconds to reset the boiler.

Ensure controls are set to

demand and verify the

contacts are closed

Go to sections 'J', 'L' & '0'

Turn selector to the reset

position. If the light does

not extinguish go to

sections H & K

Pump stops

Operation sequence

correct

Domestic Hot Water -Follow operational sequence

Go to section 'c'

Turn the selector switch to

the 'Reset' position and

hold for at least 2

seconds. If regular resetting is required, or appliance still does not operate investigation is

necessary

YES

Air pressure switch

proved

YES

Go to section 'E'

Spark at ignition

electrodes for up to 10

seconds

YES

~ neon illuminated

Burner on hneon

illuminated

Go to section 'F'

YES

Burner extinguishes

after 10 seconds

YES

Go to section 'I'

Burner output modulates

to maintain temperature

set at thermostat

Reduce the DHW flow

rate. If burner does not

modulate clean

temperature sensor and

DHW heat exchanger. If

modulation does not occur

go to section 'G'

YES

DHW flow valve

senses no flow.

Primary water diverted to

CH system. DHW flow

switch released off

YES

Diverter valve spindle

assembly faulty

Fan stops

15.0 FAULT FINDING

YES

Replace DHW flow

microswitch

Replace PCB

Go to section 'J', 'L' & '0'

Turn the selector to the

reset position. If the light

does not extinguish go to

section H & K

Pump stops

Operation sequence

correct

Turnselectorto rF

Go to section 'A'

Q neon illuminated

YES.

Is mainswater

IYES

filter anddifferential

assemblyclean?

YES

Turn rF thermostatto I NO I

max. Open DHW tap fully. ----.-

DHWflow switchoperated

YESJ.

. NO

ContinuityacrossDHW

Primarywateris diverted

flow microswitchterminals

fromCH systemto DHW

----.-

and PCB - M1 connector

heat exchanger and flow

terminals 13 & 14

I YES

microswitch operated

(terminals 12-14 open)

Go to section 'B'

15.0 FAULT FINDING

Fault Finding Solutions Sections A to E

IIsthere 230V at: I

Check electrical supply

Q neon INO

Illuminated

IReplace PCB I..

2. I Main terminal fuse IYES

Replace fuse

Replace fan 1

Main terminals Land N

Selector terminals a & b and a & 3. PCB - M1 connector terminals 9 & 10

Check wiring

Replace selector

B IIs there 230V at: I

1. IPump I---i If pump jammed, release ~I Replace pump I

2. IPCB - M1 connector terminals 8 & 15 INO . IReplace PCB

YES

1. ICH system pressure 0.5 to 1.5 bar ~ NO

"I Re-pressurisesystem I

IOpen the automatic air vent I

2. NO

Check the tap of the automatic air vent is opened

Primary flow valve diaphragm damaged

YES

Replace diaphragm

Flow valve rod obstructed

Continuity across flow microswitch and PCB M2

connector terminals 3 & 4

IReplace microswitch I

2. Primary temperature sensor faulty. IYE~

Cold resistance approx. 11K ohms IReplace sensor I

(resistance reduces with increase in temp.)

Fan connections correct at fan. PCB - M5 connector, is 230V

across terminals 28 & 29

YES ,YES

'I Fan jammed or faulty winding

INO

'I ReplacePCB I

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

PCB -M4 connector is approx 230V AC,

terminals 36 & 38

15.0 FAULT FINDING

Gas at burner

Ensure gas is on and purged

YES

Replace gas valve

Turn selector switch

to 'Reset' position

Replace gas valve

Replace PCB

Check and correct if necessary

1. Ignition electrode and lead

2. Electrode connection

3. Spark gap and position

230V at Main PCB -M4

NO I ReplacePCB I

connector across terminals

37 & 38. Check wiring YES I Replace gas

valve electrical

plug/igniter assy

Check the burner setting pressure of

the gas valve

(see Section 9.2 of Commissioning)

2. Voltage at modulating coil of gas valve is:

Max. burner press.approx 9V DC (13V DC LPG) Min. burner press.approx 1V DC

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

YES

15.0

FAULT FINDING

Boiler overheat thermostat

operated or faulty, i.e. continuity

across thermostat terminals

Allow to cool. Continuity

across thermostat terminals

more than 1.5 ohm

YES

Replace boiler

overheat thermostat

YES

Replace

PCB

I Replace ON/OFF/RESET selector I

I Replace PCB I

Check terminal 1 of ON/OFF/RESET selector is in

connection with PCB -M1 connector terminal 16

Check electrical continuity across terminals 1 & a of

ON/OFF/RESET selector when turned to 'Reset' position

YES

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. If the flue overheat thermostat has not been

activated see section 'D'

Ensure that mains input

terminal L is Live (230V) and

N is Neutral (OV)

YES

Check and correct if necessary

1. Flame sensing electrode and lead connections

2. Electrode position YES

I ReplacePCB I

Flame current should be 1 IJAapprox.

Replace flame sensing electrode I

~ '-'-~ '4~"~-

- - ~ -- ~- --- -

BENCHMARKNo. I511111518I0I9

-- ~-

a./Khl!lw:f)

GASBOILERCOMMISSIONINGCHECKLIST

BOILERSERIALNo. NOTIFICATIONNo.

-- --N-,-..~- .- ~-~- ---

CONTROLS

TocomplywiththeBuildingRegulations,eachsectionmusthaveatickinoneorotherof theboxes

- ~ - - -- ~- - -~ ..- - ~ -. - ~-'. ~."- '.'-

_.-

PROGRAMMABLEROOMSTAT0

COMBIBOILER[

NOTREQUI'3EDn

NOTREQUIREDri

TIME&TEMPERATURECONTROLTOHEATING TIME&TEMPERATURECONTROLTOHOTWATER HEATINGZONEVALVES HOTWATERZONEVALVES THERMOSTATICRADIATORVALVES AUTOMATICBYPASSTOSYSTEM

ROOMT/STAT&PROGRAMMERITIMER0

CYLINDERT/STAT&PROGRAMMERITIMERC

FITTEDn

FITTEDr-1 FITTED~

FITTED0

""-, " ~-~- -- -

FORALLBOILERSCONFIRMTHEFOLLOWING

- --

- - _.~

THESYSTEMHASBEENFLUSHEDINACCORDANCEWITHTHEBOILERMANUFACTURER'SINSTRUCTIONS? THESYSTEMCLEANERUSED THEINHIBITORUSED

----

~- " ~ - _. . ~

FORTHECENTRALHEATINGMODE,MEASURE&RECORD

- --- --- -

GASRATE BURNEROPERATINGPRESSURE(IFAPPLICABLE)

CENTRALHEATINGFLOWTEMPERATURE CENTRALHEATINGRETURNTEMPERATURE

] m3/hr

0 N/A

-- - --

FORCOMBINATIONBOlliERSONLY

,',. -.

- --

HASAWATERSCALEREDUCERBEENFITTED?

WHATTYPEOFSCALEREDUCERHASBEENFITTED?

- - ~ - ~-

-- --

FORTHEDOMESTICHO,rWATIlRMODE,MeASURE&RECORD

~ ~ -~

GASRATE MAXIMUMBURNEROPERATINGPRESSURE(IFAPPLICABLE)

COLDWATERINLETTEMPERATURE HOTWATEROUTLETTEMPERATURE

WATERFLOWRATE

] --- I m3/hr

0 N/A

---------------

---- - - - ---

FORCONDENSINGBOILERSONLYCONFIRMTHEFOLLOWING

-~ --- _.- --

THECONDENSATEDRAINHASBEENINSTALLEDINACCORDANCEWITH THEMANUFACTURER'SINSTRUCTIONS?

- -~- ~

FORALLINSTALLATIONSCONFIRMTHEFOLLOWING

- - -- - - -- @

THEHEATINGANDHOTWATERSYSTEMCOMPLIES WITHCURRENTBUILDINGREGULATIONS

.------

THEAPPLIANCEANDASSOCIATEDEQUIPMENTHASBEENINSTALLEDANDCOMMISSIONED

INACCORDANCEWITHTHEMANUFACTURER'SINSTRUCTIONS

IFREQUIREDBYTHEMANUFACTURER,HAVEYOURECORDEDACO/CO2RATIOREADING? N/A0 YES[

THEOPERATIONOFTHEAPPLIANCEANDSYSTEM

CONTROLSHAVEBEENDEMONSTRATEDTOTHECUSTOMER

THEMANUFACTURER'SLITERATUREHASBEENLEFTWITHTHECUSTOMER

COMMISSIONINGENG'SNAME PRINT

SIGN

CORGIIDNo.

DATE

46-

-- -~--

--- ---

NOTREQUIREDJ

---

-- - -

i Ift3/hr

I ] mbar

F==---'l °C

j ~

YES0 NO 0 ~

! Imbar

I I°C

!-_J ~g-

r: IIts/miD j

YES0 '

]CO/CO2RATIO

0 0

SERVICE 1 DATE

ENGINEERNAME COMPANYNAME

TELNo.

CORGIIDCARDSERIALNo. COMMENTS

~~--. ~.

SERVICE 2 DATE

ENGINEERNAME COMPANYNAME TELNo. CORGIIDCARDSERIALNo. COMMENTS

SIGNATURE SIGNATURE

w_-~~--~

~~-- -_. -~-_.

SERVICE 3 DATE

ENGINEERNAME COMPANYNAME

TELNo.

CORGIIDCARDSERIALNo. COMMENTS

f SERVICE4 DATE

ENGINEERNAME COMPANYNAME TELNo. CORGIIDCARDSERIALNo. COMMENTS

SIGNATURE

Ak --

SERVICE 5 DATE

ENGINEERNAME COMPANYNAME TELNo. CORGIIDCARDSERIALNo. COMMENTS

SERVICE 6 DATE

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Publication No. 5115809 - 188. 3 (05/2005)

General Enquiries (GB)

Tel. 08706 060 780

Technical (GB)

Tel. 08706 049 049

Service (GB)

Tel. 08701 655 644

Fax. 01926 410 006

Literature Request (GB)

Tel. 08706 060 623

Technical (IE)

Tel. 1850 560570

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 said subject to our standard Conditionsof Saie which are available on request.

MAIN

BAXI POTTERTON

A Trading Division of Saxi Heating UK LId

Brownedge Road Bamber Bridge Preston Lancashire PR5 6SN After Sales Service 08701 655644 Technical Enquiries 08706 049 049 Website www.baxipotterton.co.uk

A BAXI GR8UP company

924.151.1

Baxi Potterton Combi 24 HE, Main Combi 24 HE Installation & Service Instructions Manual

Specifications and Main Features

Frequently Asked Questions

User Manual