Protherm 40, 50 CI, 40 CI Instructions For Use Installation And Servicing

9275

One Contact Local Service

Customer Services:
Tel: [phone]
Fax: [phone]

221973A.10.01

All replacement parts
All labour charges
All call-out charges

Thank you for installing a new PROTHERM appliance in your home.

The appliance is manufactured to the very highest standard so we are pleased to offer our customers' a

Comprehensive First Year Guarantee.

In the centre pages are to be found your Guarantee Registration Card, which we recommend you complete and

return as soon as possible.

If this card is missing you can obtain a copy or record your registration by telephoning the Heatcall Customer

Service number 01773 828100.

Our Guarantee gives you peace of mind plus valuable protection against breakdown by covering the cost of:

Guarantee Registration

Fanned Flue Boiler

Reference in these instructions to British Standards and Statutory

Regulations/Requirements apply only to the United Kingdom.

For Ireland the rules in force must be used.

The instructions consist of three parts, User, Installation and Servicing Instructions, which includes the Guarantee Registration

Card. The instructions are an integral part of the appliance and must, to comply with the current issue of the Gas Safety

(Installation and Use) Regulations, be handed to the user on completion of the installation.

To be left with the user

❏

✔

❏

✔

❏

✔

Instructions for Use

Installation and Servicing

G.C. No. 41-047-53

REGISTER YOUR APPLIANCE

FOR 1ST YEAR GUARANTEE PROTECTION

CALL 0208 247 9857

40 - 50 CI

Cat I

2H

PROTHERM

2

221973A

Testing and Certification

This boiler is tested and certificated for safety and performance. It is therefore important that no alteration is made to the boiler, without
permission, in writing, from Hepworth Heating Ltd.

Any alteration not approved by Hepworth Heating Ltd., could invalidate the certification, boiler warranty and may also infringe the current issue of
the Statutory Requirements, see Section 1.4.

CE Mark

This boiler meets the requirements of Statutory Instrument No. 3083 The boiler (Efficiency) Regulations, and therefore is deemed to meet the
requirements of Directive 92/42/EEC on the efficiency requirements for new hot water boilers fired with liquid or gaseous fuels.

Type test for purposes of Regulatioon 5 certified by: Notified body 0086.
Product/productioncertifiedby: Notified body 0086.

The CE mark on this appliance shows compliance with:

1. Directive 90/396/EEC on the approximation of the laws of the Member States relating to appliances burning gaseous fuels.

2. Directive 73/23/EEC on the harmonization of the Laws of the Member States relating to the electrical equipment designed for use within
certain voltage limits.

3. Directive 89/336/EEC on the approximation of the Laws of the Member States relating to electromagnetic compatibility.

INFORMATION FOR THE INSTALLER AND SERVICE ENGINEER.

Under Section 6 of The Health and Safety at Work Act 1974, we are required to provide information on substances hazardous to health.

CERAMIC FIBRE/INSULATION PADS.

These can cause irritation to skin, eyes and the respiratory tract. If you have a history of skin complaint you may be susceptible to irritation. High dust
levels are usual only if the material is broken. Normal handling should not cause discomfort, but follow normal good hygiene and wash your hands
before eating, drinking or going to the lavatory. If you do suffer irritation of the eyes or severe irritation to the skin seek medical attention.

THERMOSTATS

These contain very small amounts of xylene in the sealed phial and capillary. If broken, under normal circumstances the fluid does not cause a
problem, but in case of skin contact, wash with cold water. If swallowed drink plenty of water and seek medical attention.

CUT-OFF DEVICES

These contain activated charcoal and a very small amount of chlorodifluormethane in the sealed phial and capillary. If broken, under normal
circumstances the fluid does not cause a problem. If there is irritation to the eyes or skin then seek medical attention.

SPARE PARTS

REMEMBER, When replacing a part on this appliance, use only spare parts that you can be assured conform to the safety and
performance specification that we require. Do not use reconditioned or copy parts that have not been clearly authorised by Hepworth
Heating Ltd.

Important Information

Introduction 3
Lighting the Boiler 4

General Data 1 5
Flue & Ventilation 2 8
Water Systems 3 9
Flue and Appliance Preparation 4 12
Boiler Installation 5 18
Commissioning 6 21
Instructions to User 7 24

Servicing 8 24
Fault Finding 9 26
Replacement Parts 10 32
Spare Parts 11 36

CONTENTS DESCRIPTION SECTION PAGE No.

INSTRUCTIONS

FOR USE

INSTALLATION

INSTRUCTIONS

SERVICING

INSTRUCTIONS

3

221973A

9270

Diagram 1

9364

CONTROLS COVER

DATA &
SERIAL
NUMBER
LABEL

RESET
BUTTON

VIEWING WINDOW

SETTING POINT

CONTROL
THERMOSTAT
KNOB

GAS SERVICE
COCK (Shown
Off)

Boiler Clearances

If fixtures are positioned close to the boiler space must be left
as shown in diagram 2. At least a minimum clearance of 500mm
must be left in front of the boiler to allow for servicing.

Boilers Installed in a Compartment or
Cupboard

If the boiler is installed in a compartment or cupboard do not
obstruct any ventilation openings.

Do not use the compartment or cupboard for storage.

Cleaning

WARNING. This appliance contains metal parts (components)
and care should be taken when handling and cleaning, with
particular regard to edges.

Clean the casing occasionally by wiping it over with a damp
cloth or dry polishing duster.

Do not use an abrasive cleaner.

Instructions for Use

Introduction

WARNING. It is important that the case (not the controls cover)
is not disturbed or removed other than for servicing by a
competent person.

Please read these instructions and follow them carefully for the
safe and economical use of your boiler.

The Protherm CI series are fanned flue boilers designed to
provide central heating and indirect domestic hot water.

The boiler is fully automatic in operation having only one user
control, the control thermostat

The Gas Safety (Installation and Use)
Regulations

In your interest and that of gas safety it is the law that ALL gas
appliances are installed by a competent person in accordance
with the above regulations.

Gas Leak or Fault

If a gas leak or fault exists or is suspected, the boiler must be
turned off, including the electrical supply and must not be used
until the fault has been put right.

Advice/help should be obtained from your installation/servicing
company or the local gas undertaking.

Electrical Supply Failure

Failure of the electrical supply will cause the burner to go out.
Should this occur, operation of the appliance will normally
resume after the electrical supply is restored.

If the boiler does not relight after an electrical supply failure the
overheat safety cutoff device may need resetting, remove the
controls cover and press the reset button, refer to diagram 1.

Overheat Safety Cutoff

If the overheat safety cutoff device operates on any other
occasion than an electrical supply failure, press the reset button
as in “Electrical Supply Failure”. If the overheat operates again,
turn the appliance off and contact your installation/servicing
company.

Maintenance

To ensure the continued efficient and safe operation of the
boiler it is recommended that it is checked and serviced as
necessary at regular intervals. The frequency of servicing will
depend upon the particular installation conditions and usage,
but in general once a year should be enough.

If this appliance is installed in a rented property there is a duty
or care imposed on the owner of the property by the current
issue of The Gas Safety (Installation and Use) Regulations,
Section 35.

It is the law that any servicing is carried out by a competent
person.

To obtain service, please call your installer or Heatcall using the
telephone number given on the controls tray.

Please be advised that the ‘Benchmark’ logbook should be
completed by the installation engineer on completion of
commissioning and servicing.

All CORGI Registered Installers carry a CORGI ID card, and
have a registration number. Both should be recorded in your
boiler Logbook. You can check your installer is CORGI registered
by calling CORGI direct on :- 01256 372300.

4

221973A

500mm
FROM A PERMANENT FIXTURE

6mm

6mm

FRONT
VIEW

6mm

6mm

6mm

160mm

65mm

Diagram 2

Boiler Electrical Supply

WARNING. This boiler must be earthed.
The boiler must only be connected to a 230V~50Hz supply

protected by a 3A fuse.
All wiring must be in accordance with the current issue of

BS7671.
Wiring to the boiler must be PVC insulated type to the current

issue of BS6500 Table 16, not less than 0.75mm

2

(24/0.20mm).
The colours of three core flexible cable are:
Brown - live, Blue - neutral,
Green/yellow - earth.
As the markings on your plug may not correspond with these

colours continue as follows:
The cable coloured blue must be connected to the terminal

marked “N” or black.
The cable coloured brown must be connected to the terminal

marked “L” or red.
The cable coloured green/yellow must be connected to the

terminal marked “E”, or green or the earth symbol

.

To Light the Boiler

WARNING. Sealed Systems
A sealed water system must be filled and pressurised by a

competent person.
Only light the boiler when you are sure that the system has been

filled and pressurised.

The pressure gauge should show at least 0.7bar, anything less
than this figure could indicate a leak and you MUST contact your
installation/servicing company.

If there is any doubt about the boiler being full of water consult
your installation/servicing company.

ALL SYSTEMS.
Turn the electrical supply on to the boiler and check that all

remote controls are calling for heat.

To Turn the Boiler On

Remove the controls cover by withdrawing it forward and off,
see diagram 1.

Turn the control thermostat knob clockwise to any position
between MIN and MAX. The maximum temperature setting is
about 82

o

C (180oF), see diagram 1.
The boiler lighting operation is now automatic as follows.
The fan operates, followed by an ignition spark until the pilot is

lit. When the pilot is alight the ignition system switches off and
the main burner lights. The flames can be seen through the
viewing window, see diagram 1.

The main burner will remain alight until switched off by the
control thermostat or any remote control.

If the boiler is switched OFF, by hand, wait at least 30 seconds
before switching on again.

When the boiler switches off, both the pilot and main burner go
out.

The automatic lighting sequence will operate again when heat
is required.

Refit the controls cover.
It should be noted that this is a fan flue appliance and fan

operation may be heard.

To Turn the Boiler Off

For short periods, turn the control thermostat knob anti-clockwise
to “O” Off. To relight, turn the control thermostat knob to any
position between “MIN” and “MAX”.

For longer periods, turn the control thermostat knob fully anti­clockwise to “O” Off and switch off the electrical supply to the
boiler.

To relight follow the lighting sequence given above.

Protection Against Freezing.

If the boiler is to be out of use for any long period of time during
severe weather conditions we recommend that the whole of the
system, including the boiler, be drained off to avoid the risk of
freezing up. Make sure that, if fitted, the immersion heater in the
cylinder is switched off.

For the position of the serial number, see diagram 1.

Instructions for Use

9278

5

221973A

1 General Data

Diagram 1.1

Important Notice

This boiler is for use only on G20 gas.
This boiler can be used on open vented or sealed water

systems.
When used on an open vented system domestic hot water can

only be provided by a pumped primary circulation.
Wherever possible, all material, appliances and components

used shall comply with requirements of applicable British
Standards.

Where no British Standards exist, materials and equipment
should be fit for their purpose and of suitable quality and
workmanship.

Sheet Metal Parts

WARNING. When installing or servicing this boiler care should
be taken when handling sheet metal parts, to avoid any possibility
of personal injury.

1.1 Statutory Requirements

The installation of the boiler must be carried out by a competent
person in accordance with the relevant requirements of the
current issue of:-

9110

The manufacturer’s instructions, supplied.
The Gas Safety (Installation and Use) Regulations, The Building

Regulations, Local Water Company Byelaws, The Health and
Safety at Work Act, Control of Substances Hazardous to
Health, The Electricity at Work Regulations and any local
regulations which may apply.

Detailed recommendations are contained in the current issue of
the following British Standards and Codes of Practice:-

BS4814, BS6798, BS5440 Part 1 and 2, BS5546 Part 1,
BS5449, BS6891, BS6700, BS7074 Part 1 and 2, BS7593,
BS7671.

Manufacturer’s instructions must not be taken as overriding
statutory requirements

1.2 Data

See Table 1 and diagram 1.1.
All dimensions are given in millimetres (except as noted).

C

L

FLOW GRAVITY

RETURN PUMPED

GRAVITY RETURN

PUMPED FLOW

C

L

WATER CONNECTIONS
22mm COPPER PIPE

GAS CONNECTIONS
RC

1

/2 (1/2 in. BSPT)

SIDE ELEVATION FRONT ELEVATION

A

80B300C100D75E700F124G130H400J60K210L157M112N60P145Q90

R

40

B

A

D

N

M

L

K

Q

J

G

F

E

P

C

R

H

6

221973A

1 General Data

1.3 Range Rating

This boiler is range rated and may be adjusted to suit individual
system requirements.

See table 2 and diagram 1.3 for ratings and settings.
The Seasonal Efficiency Domestic Boilers UK (SEDBUK) is

79.2%.
The value is used in the UK Government’s Standard Assessment

Procedure (SAP) for energy rating of dwellings. The test data
from which it has been calculated have been certified by B.S.I.

1.4 B.S.I. Certification

This boiler is certificated to the current issue of British Standard
6332 Part 1, invoking the current issue of BS5258 Part 1 for
performance and safety. It is, therefore, important that no
alteration is made to this boiler without permission, in writing,
from Hepworth Heating Ltd.

Any alteration that is not approved by Hepworth Heating Ltd.,
could invalidate the B.S.I. Certification of the boiler, warranty
and could infringe the current issue of the Statutory
Requirements.

1.5 Gas Supply

The gas installation shall be in accordance with the current
issue of BS6891.

The supply from the governed meter must be of adequate size
to provide a steady inlet working pressure of 20mbar (8in wg) at
the boiler.

On completion test the gas installation for soundness using the
pressure drop method and suitable leak detection fluid, purge
in accordance with the above standard.

1.6 Electrical Supply

WARNING. This boiler must be earthed.
All system components shall be of an approved type and shall

be connected in accordance with the current issue of BS7671
and any applicable local regulations.

Connection of the boiler and system controls to the mains
supply must be through a common isolator and must be fused
3A, maximum. This method of connection must be by a fused
double pole isolating switch, with a minimum contact separation
of 3mm on both poles. The switch should be readily accessible
and preferably adjacent to the appliance. It should supply the
appliance only and be easily identifiable as so doing.

Alternatively, an unswitched shuttered socket outlet and 3A
fused 3 pin plug, both to the current issue of BS1363 may be
used provided that they are not used in a room containing a bath
or shower.

Wiring to the boiler must be to the current issue of BS6500 Table
16, not less than 0.75mm

2

(24/0.20mm).

1.7 Contents of Packaging

The boiler is delivered in one pack, refer to Section 4.1 for
contents.

1.8 Water System

This boiler may be fitted to an open vented or a sealed water
system.

1.9 Drain

System
A drain tap must be provided at the lowest points of the system

which will allow the entire system, boiler and hot water cylinder
be drained.

Draining taps should be to the current issue of BS2879.
Boiler
A draining point is fitted at the bottom right hand side of the heat

exchanger.
Cover controls to avoid water damage.
If required remove the combustion chamber front cover to

improve access.

TABLE 3. COMPARTMENT AIR VENTS

VENTILATION HIGH LEVEL LOW LEVEL
REQUIREMENTS VENT AREA VENT AREA

VENTILATION FROM
ROOM OR SPACE
VENTILATION FROM
OUTSIDE

cm

2

in

2

cm

2

in

2

165 25 165 25

83 12.5 83 12.5

TABLE 2
RANGE RATING
APPROX. m3/h

GAS
RATE ft3/h

Min. Medium Max.

1.4 1.6 1.8
51 57 62

DATA TABLE 1.
TOTAL DRY WEIGHT

(Including Terminal)
LIFT WEIGHT
WATER CONTENT

GAS CONNECTION
ELECTRICITY

RATING
WATER

CONNECTION
ELECTRICITY

SUPPLY
DATA LABEL

46kg (101lb)

BURNER INJECTOR MARKING: 203096
BURNER INJECTOR SIZE: 3.5 mm
PILOT INJECTOR MARKING: 7218

39kg (86lb)

2.35 litre (0.5 ga llon )
Rc 1/2 in.

56W

Internal fuse Type F1A

4x22mm copper pipes from

top of case

230V~50Hz, fused 3A

Bottom right hand side of case

7

221973A

500mm
FROM A PERMANENT FIXTURE

6mm

6mm

FRONT
VIEW

6mm

6mm

6mm

160mm

65mm

Diagram 1.2

1 General Data

1.10 Safety Valve

A safety valve need not be fitted to an open vented system.

1.11 Location

This boiler is not suitable for outdoor installation.
This boiler may be installed in any room, although particular

attention is drawn to the requirements of the current issue of
BS7671 with respect to the installation of a boiler in a room
containing a bath or shower. The electrical provisions of the
Building Standards (Scotland) apply to such installations in
Scotland.

The boiler must be mounted on a flat wall which is sufficiently
robust to take its total weight.

The boiler may be fitted to a wall made of combustible material.

1.12 Boiler Clearances

Refer to diagram 1.2.
This boiler must be positioned so that at least the minimum

operational and servicing clearances are provided.
Additional clearances may be required for installation.
If fixtures are positioned next to the boiler they should be made

removable for access to pipework.
At least a minimum of 500mm clearance must be left in front of

the boiler for servicing, see diagram 1.2.

1.13 Room Ventilation

The boiler is room sealed and does not require the room or
space containing it to have permanent air vents.

1.14 Boilers in a Compartment

Where the installation of the boiler will be in an unusual position,
special requirements are needed, the current issue of BS6798
gives detailed guidance on these requirements.

A compartment used to enclose the boiler must be designed
and constructed specifically for this purpose. An existing
cupboard or compartment modified for the purpose may be
used. Details of essential requirements for cupboard or
compartment design are given in the current issue of BS6798.

The doorway opening should be of sufficient size to allow for
easy removal of the boiler.

Where the boiler is fitted in a cupboard or compartment,
permanent high and low level ventilation must be provided. The
minimum ventilation areas required are given in Table 3.

1.15 Timber Frame Building

If the boiler is to be installed in a timber frame building it should
be fitted in accordance with the Institute of Gas Engineers
document IGE/UP/7/1998. If in doubt seek advice from the local
gas undertaking or Hepworth Heating Ltd.

1.16 Heating System Controls

The heating system should have installed: a programmer and
room thermostat controlling the boiler.

Thermostatic radiator valves may be installed, however they
must not be fitted in a room where the room thermostat is
located.

Note: For further information, see The Building Regulations
1991 - Conservation of fuel and power, 1995 edition - Appendix
G, table 4b.

MINIMUM CLEARANCES FROM WALLS
CEILING, FLOOR, CUPBOARD, WORKTOPS,
AND INFLAMMABLE MATERIALS

9278

Diagram 1.3

9801

8

221973A

2 Flue and Ventilation

A

A

F

G

E

A
G

G

G

B,C

B,C

F

F

K

K

K

C

G

L

L

Diagram 2.1

MINIMUM SITING DIMENSIONS
FOR FANNED FLUE
TERMINALS POSITION

A DIRECTLY BELOW, ABOVE OR

HORIZONTALLY TO AN OPENING,

AIR BRICK, OPENING WINDOWS,
AIR VENT OR ANY OTHER

VENTILATION OPENING. 300

B BELOW GUTTER, DRAIN/SOIL PIPE 75
C BELOW EAVES 200
D BELOW A BALCONY OR CAR PORT 200
E FROM VERTICAL DRAIN PIPES AND

SOIL PIPES 75
F FROM EXTERNAL CORNERS 300
G ABOVE ADJACENT GROUND OR

BALCONY LEVEL 300
H FROM A SURFACE FACING THE

TERMINAL 600

I FACING TERMINALS 1200

J FROM OPENING (DOOR/WINDOW) IN

CAR PORT INTO DWELLING 1200
K VERTICAL FROM A TERMINAL 1500
L HORIZONTALLY FROM A TERMINAL 300
M FROM INTERNAL CORNERS 25

MINIMUM
SPACING

in mm

0103M

Under Car Port etc.

H,I

J

D

F

K

M

Note. Detailed recommendations for flue are given in the
current issue of BS5440 Part 1.

2.1 Terminal Position

The minimum acceptable siting dimensions for the terminal
from obstructions, other terminals and ventilation openings are
shown in diagram 2.1.

The terminal must be exposed to the external air, the position
allowing free passage of air across it at all times.

Car ports or similar extensions of a roof only, or a roof and one
wall, require special consideration with respect to any openings,
doors, vents or windows under the roof. Care is required to
protect the roof if it is made of plastic sheeting. If the car port
consists of a roof and two or more walls, seek advice from the
local gas company before installing the boiler.

If the terminal is fitted within 600mm below plastic guttering or
painted soffit an aluminium shield 1500mm long should be fitted
immediately beneath the guttering or eaves. If the terminal is
fitted within 450mm below painted eaves or a painted gutter, an
aluminium shield 750mm long should be fitted immediately
beneath the guttering or eaves.

2.2 Terminal Guard

A terminal guard is required if persons could come into contact
with the terminal or the terminal could be subject to damage.

If a terminal guard is required, it must be positioned to provide
a minimum of 50mm clearance from any part of the terminal and
be central over the terminal.

A suitable guard, reference Type “K3”, can be obtained from:

Tower Flue Components Ltd
Morley Road
Tonbridge
Kent
TN9 1RA

2.3 Flue Options

Standard Top Outlet Flue Pack - Pt. No. 230483, supplied with
boiler.

1 Metre Extension Kit - Pt. No. 230484.
A flue system up to 3 metres in length can be made by
connecting 1 metre extension kits together.

Optional Wall Liner Kit - Pt. No. 900862.
45° Flue Bend Pack - Pt. No. 230485.
90° Flue Bend Pack - Pt. No. 230486.
Vertical Flue Kit - Pt. No. 458115.

2.4 Vertical Balanced Flue System

IMPORTANT NOTE : See Section 4.8 Easi-Vent Vertical Flue
Terminal, for Installation requirements and fitting instructions.

0161M

9

221973A

Diagram 3.1

3 Water Systems

The installation of the boiler must comply with the requirements
of the current issue of BS6798.

3.1 Frost Protection

If the position of the boiler is such that it may be vulnerable to
freezing it should be protected as specified in the current issue
of BS5422. It is recommended that a frost protection thermostat
be fitted.

3.2 Pump

The pump, with integral valves, should be fitted in the heating
flow pipework from the boiler, it should be set to produce a
temperature difference of 11

o

C (20oF) between the flow and
return, with the boiler thermostat set at “MAX”, which is about
82

o

C (180oF).
The pressure loss of the boiler can be found from diagram 3.1.
High resistance microbore systems may require a higher duty

pump.

3.3 Bypass - Fully Pumped and Sealed Water
System

A bypass is usually unnecessary on systems using a 3 port
diverter valve since one port will remain in the open position at
all times. This allows satisfactory operation of the pump
overrun.

However if thermostatic radiator valves are fitted to all radiators
or two port valves are used a bypass is required.

The bypass connection must be at least 2 metres away from the
boiler.

The flow through the boiler must not be allowed to fall such that
there is a temperature difference greater than 20

o

C between the

flow and return.

3.4 Water System

For an open vented system the boiler must be supplied from an
unrestricted water supply taken from a feed and expansion
cistern fitted at a maximum height of 27metres above the boiler.

The cold feed must be 15mm minimum size.
It is important that the relative positions of the pump, cold feed

and open vent are as shown in diagram 3.2.
The unrestricted open vent from the boiler must rise continuously

to discharge over the feed and expansion cistern.

3.5 Domestic Hot Water System

General. The domestic hot water service must be in accordance
with the current issue of BS5546, refer also to the current issue
of BS6700.

3.6 Cylinder

For all systems supplying domestic hot water the cylinder must
be indirect. It is recommended that the cylinder be fitted with
some form of temperature control.

3.7 Gravity Domestic Hot Water with Pumped
Heating

Important: If domestic hot water is to be provided by a gravity
circulation to the cylinder the blanked off connections must be
opened and used, using 22x28mm connections , see diagram

3.3.

3.8 Fully Pumped Heating and Domestic Hot
Water

The connection for this type of system MUST be as shown in
diagram 3.2 and 3.4.

3.9 Inhibitor

Attention is drawn to the current issue of BS5449 and BS7593
on the use of inhibitors in central heating systems.

If an inhibitor is to be used, contact a manufacturer or Hepworth
Heating Ltd., for their recommendations as to the best product
to use.

When installing in an existing system take special care to drain
the entire system, including radiators, then thoroughly cleaning
out before installing the boiler whether or not adding an inhibitor.

3.10 Sealed Water Systems

The installation should comply with the appropriate requirements
of the current issue of BS4841, BS5449, BS6759, BS6798 and
BS7074 Part 1 and 2, see diagram 3.5 for suggested layout.

3.11 Safety Valve

A safety valve must be fitted to a sealed water system.
It shall be preset, nonadjustable with a lift pressure of 3bar,

incorporating seating of a resilient material, a test device and a
connection for drain.

The drain from the safety valve must be routed clear of any
electrical fittings and positioned so that any discharge can be
seen.

3.12 Expansion Vessel

A diaphragm type expansion vessel, conforming to the current
issue of BS4814 (see also BS7404 Part 1 and 2) must be
connected at a point close to the inlet side of the circulating
pump, see diagram 3.5 unless laid down differently by the
manufacturer.

The expansion vessel volume depends upon the total water
system volume and the initial system design pressure. For any
system an accurate calculation of the vessel size is given in the
current issue of BS7074 Part 1.

Example. For an initial system design pressure of 0.7bar the
minimum total vessel volume required is 0.063xTotal System
volume.

Note. A higher initial design pressure requires a larger volume
expansion vessel.

Guidance on vessel sizing is also given in the current issue of
BS5449 and BS7074 Part 1.

The charge pressure must not be less than the static head of the
system, that is, the height of the highest point of the system
above the expansion vessel.

The water content of the boiler is given in Data Table 1.

1000

750

500

250

19.1

0

051015 20 25 30

Flow rate (litres/minute)

Water pressure loss

(mm head of water)

0088

The insertion point indicates the flow rate required to achieve
11°C temperature difference

10

221973A

1metre Min.

27 metres

Max.

22mm FOR COMBINED FEED & VENT
TO BE FITTED IN ACCORDANCE
WITH BS 5449

INDIRECT
CYLINDER

ALTERNATIVE
SYSTEM
CONTROL
VALVES

HEATING
SYSTEM

PUMP

FULLY PUMPED CIRCULATION
BYPASS (DIAGRAMMATIC)

6456

IF REQUIRED
BYPASS 15mm
MIN WITH
LOCKSHIELD
VALVE

3 Water Systems

Diagram 3.2

Diagram 3.4

22mm
PIPES

GRAVITY

RETURN

FLOW

9281

Diagram 3.3

1m MIN.
27m Max.

PUMP

HEATING
SYSTEM

INDIRECT
CYLINDER
(Shown with
recommended
thermostat and valve).

22mm VENT

15mm COLD FEED

REFER TO BS 5546

28mm

VIEWED
FROM
FRONT

9280

PUMPED

RETURN

GRAVITY

FLOW

PUMPED

FLOW

28mm
PIPES

22mm
PIPES

22mm
PIPES

COMPRESSION

JOINT

NOTE: When cutting leave sufficient length for
fittings.

*

*

RETURN

22mm
PIPES

1metre Min.

27 metres

Max.

22mm VENT & 15mm COLD FEED
TO BE FITTED IN ACCORDANCE
WITH BS 5449

INDIRECT
CYLINDER

ALTERNATIVE
SYSTEM
CONTROL
VALVES

HEATING
SYSTEM

PUMP

FULLY PUMPED CIRCULATION
SYSTEM (DIAGRAMMATIC)

6461

IF REQUIRED
BYPASS 15mm
MIN WITH
LOCKSHIELD
VALVE

6455

FEED AND
EXPANSION
CISTERN

22mm VENT
(MIN.)

15mm (MINIMUM)
COLD FEED

OPEN VENTED FULLY PUMPED WATER SYSTEM
RECOMMENDED RELATIONSHIP BETWEEN
PUMP COLD FEED AND VENT

450mm

MIN.

HEIGHT

1150mm
MIN.

RETURN

FLOW

CYLINDER

PUMP

HEATING

150mm
MAX.

BOILER

IF REQUIRED
15mm (MINIMUM)
BY-PASS WITH
LOCKSHIELD VALVE

FLOW

RET.

There must always
be a cold water path
to the return
connection
of the boiler.

11

221973A

Diagram 3.5

3 LITRES (0.66 gals)
MAKE-UP BOTTLE
(if required)

NON-RETURN
VALVE

AUTO
AIR
VENT

FLOW

DRAIN
COCK

BOILER

SAFETY
VALVE

(Make-up
alternatives)

EXPANSION
VESSEL

PRESSURE
GAUGE

CIRCULATING
PUMP

FILLING POINT

AIR
RELEASE
POINT

HEATING

CIRCUIT

IF REQUIRED
22mm (min)
BY-PASS WITH
LOCKSHIELD
VALVE

RETURN

9159

3 Water Systems

3.13 Pressure Gauge

A pressure gauge with a set pointer and covering at least the
range 0 to 4bar (0 to 60lb/in

2

) shall be permanently fitted to the
system in a position where it can be seen when filling the
system.

3.14 Domestic Hot Water Cylinder

SINGLE FEED INDIRECT CYLINDERS ARE NOT SUITABLE.
The domestic hot water cylinder must be of the indirect coil type.

It must be suitable for working at a gauge pressure of 0.35bar
above the safety valve setting.

3.15 Domestic Hot Water System - Unvented

Where a storage system will not have a vent to atmosphere the
installation must comply with Building Regulations and local
Water Company Bye-laws, see also the current issue of BS6700.

If fitting into an existing system the local authority must also be
advised.

3.16 Filling a Sealed Water System

Provision for filling the system at low level must be made. Three
methods are shown in diagram 3.6. There must be no permanent
connection to the mains water supply, even through a non­return valve.

3.17 Water Makeup

Provision must be made for replacing water lost from the
system. A make up vessel mounted above the highest point of
the system and connected through a non-return valve to the
system on the return side of either the hot water cylinder or
heating system, see diagram 3.5.

Alternatively provision for make up can be made by a filling loop.

METHOD 1

METHOD 2

METHOD 3

SUPPLY STOP
VALVE

SUPPLY
PIPE

HOSE
UNIONS

SERVICING
VALVE

TEMPORARY
HOSE

HEATING
SYSTEM

HEATING
SYSTEM

TEMPORARY
HOSE

HOSE
UNIONS

SERVICING
VALVE

SUPPLY
PIPE

SUPPLY STOP
VALVE

DOUBLE CHECK
VALVE ASSEMBLY

HEATING
SYSTEM

SERVICING
VALVE

SUPPLY
STOP VALVE

SUPPLY
PIPE

HOSE
UNIONS

DOUBLE CHECK
VALVE ASSEMBLY

OVERFLOW

CISTERN

COMBINED
CHECK VALVE
AND VACUUM
BREAKER

PRESSURE
REDUCING
VALVE

0051M

Diagram 3.6

12

221973A

REAR FLUE

SIDE FLUE

15mm

Note: Outer casing, mounting brackets & boiler details removed for clarity

Note: 1 metre extension kits can be joined together, but the total flue system must not exceed 3 metres.

Note: Outer casing, mounting brackets & boiler details removed for clarity

SCREW
& T APE

9370

FLUE LENGTH

MAX 570mm (std)

FLUE LENGTH

MAX 570mm (std)

15mm

SCREW
& T APE

STANDARD FLUE PACK

'X'

SIDE FLUE

SCREW
& T APE

STANDARD FLUE PACK & 1 METRE EXTENSION KIT

FLUE LENGTH

Total must not excede 3m MAX.

15mm

SCREW
& T APE

'X'

'Y'

31mm

STANDARD

REAR
SIDE R.H.
SIDE L.H.

MINIMUM

WALL

THICKNESS

MINIMUM

FLUE

LENGTH

MAXIMUM

FLUE

LENGTH

"Y"

BOILER MOUNTING FACE

TO EXTERNAL WALL FACE

"X"

BOILER CASING TO

EXTERNAL WALL FA CE

MAXIMUM DISTANCE FROM

128

93

273

527

-

-

­ 555
372

75
75
75

570
570
570

-

-

-

-

2988
2808

75
75

3000
3000

FLUE

PACKS

NOTE :
FLUE & AIR DUCT CUTTING

THE DUCTS WILL REQUIRE CUTTING FOR FLUE LENGTHS LESS THAN 280mm.
THE DUCTS CAN BE CUT FLUSH BUT MUST HAVE AN OVERLAP OF 50mm.

STANDARD

SIDE R.H.
SIDE L.H.

PLUS 1 METRE
EXTENSION KITS

Diagram 4.1

4 Flue and Appliance Preparation

13

221973A

4 Flue and Appliance Preparation

Diagram 4.2

9288

Diagram 4.3

9210

FLUE
CENTRE LINE

BOILER
MOUNTING
BRACKET

BOILER
CENTRE LINE

5mm

NOTE : Make sure that the ductings do not slope down towards
the boiler.

4.1 Flue Position and Length

Determine flue application, length and terminal position before
starting.

Refer to diagram 4.1.

4.2 Flue Preparation

All flue assemblies are designed for internal installation, given
that there is sufficient clearances opposite to the flue for the
installation of the flue.

If there is insufficient clearance the flue can be installed from
outside.

For a wall thickness of over 300mm the external flue hole will
need to be made good from the outside.

4.3 Top and Side Flue Application

Select the boiler location and flue application, with due regard
to the terminal position, see diagram 2.1.

Take the template from the boiler pack and temporarily position
it on the wall, making sure that the minimum clearances are
maintained, see diagram 4.2.

Mark the centre line position of the flue, as diagram 4.2.
For a side flue, extend centre line of flue to L.H. or R.H. corner.

Mark the position of the centre of the flue and boiler, as
diagram 4.2.

4.4 Flue Hole Cutting

Having marked out the flue centre cut a hole for the flue using,
preferably, a 115mm minimum core drill.

4.5 Wall Mounting Bracket

Reposition the template, making sure of dimensional alignment
with the flue hole.

Mark the boiler fixing points and mounting bracket position, see
diagram 4.3.

Drill holes and plug, to suit No. 12x2in wood screws, fit the
screws allowing sufficient clearance, about 5mm, to allow boiler
to be hung.

Secure the mounting bracket to the wall with two No.12x2in
wood screws and plugs, see diagram 4.3.

4.6 Flue Duct

Extend the telescopic flue to the required length, making sure
that the minimum overlap is no less than 25mm, and that the flue
terminal projects 15mm minmum beyond wall face, see diagram

4.1.
Carefully drill though air duct pilot hole and secure with self

tapping screw provided in fittings pack, see diagram 4.1.
Seal the joint with the tape provided.
If the boiler is not to be fitted for some time cover the hole in the

wall.

4.7 Top, Side Flue Fixing

Make sure that the ductings do not slope down towards the
boiler.

Make good the area around the flue inside and outside after
installation of the boiler.

SIDE FLUE

145mm

115mm
MINIMUM
HOLE

BOILER
CENTRE LINE

FLUE
CENTRE LINE

90mm

TOP BOILER
MOUNTING
POINT

BOTTOM BRACKET
MOUNTING POINT

14

221973A

4.8 Easi-Vent Vertical Flue Terminal
General

The kits shown in diagram 4.4, enable the Protherm to be fitted
with the flue configurations shown in diagram 4.6.

For other accessories, see diagram 4.5.
Only proprietary parts supplied by Hepworth Heating Ltd.

should be used.

4.9 Accessories
Ceiling Collar - Part No. 208590

Used if required as a ceiling trim immediately below the ceiling
to make a neat installation.

Fixings are required to hold ceiling collar in position.

4 Flue and Appliance Preparation

FITTINGS PACK

AIR DUCT

FLUE DUCT

FITTINGS
PACK

TOP FLUE
TRANSITION DUCT

TERMINAL ASSEMBLY

AIR/FLUE
DUCT ASSEMBLY

FLUE SPIGOT

EASI-VENT
ADAPTOR
RING

TAPE (FITTINGS
PACK SUPPLIED
WITH BOILER)

4 SCREWS
(FITTINGS PACK
SUPPLIED WITH
BOILER)

45o FLUE BEND KIT Pt No. 230485

VERTICAL FLUE PACK Pt No. 458115

1M EXTENSION KIT Pt No. 230484

7527

90o FLUE BEND KIT Pt No. 230486

7529

7528

FITTINGS PACK

FITTINGS PACK

(DISCARD)

Diagram 4.4

Support Assembly - Part No. 208591

Manufactured in galvanised steel and incorporates a fire stop
plate with fitted spacer lugs and support collar. This item should
be used to support the flue at the top of each floor joist and
provide a fire stop feature. Spacer lugs fitted to the underside
of the plate ensures that a clearance is maintained between the
inner liner of the flue and any combustible materials. The
support collar which is situated on the top of the plate should be
securely fixed around the flue by tightening the nut and bolt
fasteners provided. The plate should be nailed or screwed to
the ceiling joists.

Fire Stop Plate - Part No. 208592

Manufactured in galvanised steel and fitted with spacer lugs
which ensure that a clearance is maintained between the inner
liner of the flue and any combustible materials. The fire stop
plate should be fitted to the underside of the ceiling joists by
sliding over the flue and nailed or screwed to the joists. This
item can act as a dust plate and should be used when the flue
system passes through non combustible floors such as concrete.

15

221973A

4 Flue and Appliance Preparation

FIRESTOP PLATE
(Pt.No.208592)

ADJUSTABLE WALL BAND
(Pt.No.208594)

CEILING COLLAR
(Pt.No.208590)

CEILING PLATE
(Pt.No.208593)

SUPPORT ASSEMBLY
(Pt.No.208591)

7122

Diagram 4.5

Ceiling Plate - Two Piece - Part No. 208593

Manufactured in galvanised steel and should be used on the
underside of floor joists where the flue passes through the floor
or roof in a non vertical plane. This item is supplied without
spacer lugs and should be nailed or screwed to the underside
of the joists.

Adjustable Wall Band - Part No. 208594

The wall bracket is supplied in two parts - an aluminium band
which fits tightly around the outside of the flue and a galvanised
“T” bracket which is secured to a wall or batten. This item is used
where the flue is positioned up to 280mm from a wall or point.

4.10 Flue Terminal Position
Caution

If the flue is to pass through or near combustible material it
should be fitted in accordance with the current issue of BS5440
Part 1, which requires a minimum clearance of 25mm from the
flue duct.

The minimum clearance from the air duct is 5mm.
The terminal should be positioned so as to cause the least

problem with the dispersal of the products of combustion and
any “pluming” that can occur.

If the terminal is fitted less than 500mm below plastic gutters or
less than 500mm below painted eaves or any other painted
surface then an aluminium shield at least 1metre long should be
fitted immediately beneath the guttering or eaves.

Minimum distances for flue to walls and roof positions are
shown in diagram 4.6.

Failure to comply with these instructions could result in a
potentially dangerous installation and loss of boiler efficiency.

General guidance only can be found in the current issue of
BS5440 Part 1.

If in doubt consult Heatcall.

;

y

PITCHED ROOF WITH STRUCTURE

5712

Diagram 4.6

300mm

350mm

MINIMUM DIMENSIONS

FLAT ROOF INTERNAL CORNER

400mm

300mm

300mm

16

221973A

4.11 Installation
Warning

In the interests of safety and performance, it is essential that the
vertical flue system is fitted in strict accordance with these
instructions.

Installation Details

With due consideration to flue terminal position, choose the flue
application required, shown in diagram 4.7.

The use of weather and storm collars is preferred and can be
bought locally.

The suggested flashings are :­RiteVent or Selkirk along with their appropriate storm collar if

required.

Flue Installation and Terminal Assembly

Measure then cut the selected flue arrangement as required
ensuring an overlap of 25mm AIR DUCT and 50mm FLUE
DUCT.

Make sure that all flue pipes, joints and bends are properly
secured and tight, see diagram 4.9 for details.

Fit the split/spacing ring supplied in kit, inside the flue terminal.
Locate flue terminal in position on top of flue duct. Drill and
secure with 2 no. 8 x

3

/8 in. self-tapping screws, see diagram 4.10.

ROOF TERMINAL PITCHED ROOF (Slate orTile)

ROOF TERMINAL FLAT ROOF

5711

VERTICAL
FLUE
TERMINAL
KIT

VERTICAL
FLUE
TERMINAL
KIT

WEATHER
COLLAR

WEATHER
COLLAR

Diagram 4.8

STORM
COLLAR

STORM
COLLAR

4 Flue and Appliance Preparation

3m

VERTICAL FLUE KIT 458115

"X" MAX. FLUE LENGTH

X + Y + Z = THE MAXIMUM STRAIGHT "FLUE LENGTH" DOES NOT INCLUDE THE ELBOWS.

Diagram 4.7

"X"

HORIZONTAL and VERTICAL FLUE

VERTICAL FLUE KIT 458115

1M EXTENSION KIT 230484 (as reqd.)

FLUE BEND KIT 90° 230486 (2 reqd.)

"X"

C

L

FLUE

L

C

BOILER

"Z"

MAX

1m

"Y"

DIAGONAL and VERTICAL FLUE

90

X+Y+Z MAX. FLUE LENGTH

X+Y+Z MAX. FLUE LENGTH

1.5m 3.0m

VERTICAL FLUE KIT 458115

1M EXTENSION KIT 230484 (as reqd.)

FLUE BEND KIT 45° 230485 (2 reqd.)

"X"

"Z"

"X" MIN. FLUE LENGTH

MINIMUM

FLUE

LENGTH

500mm

X 60mm A 500mm
Y ZERO B RH 192mm
Z 500mm / LH 15mm

FRONT VIEW

FRONT VIEW

FRONT VIEW

1M EXTENSION KIT 230484 (as reqd.)

MINIMUM

INSTALLATION

CLEARANCE

X 60mm A 500mm
YZERO B RH 58mm
Z500mm / LH N/A

VERTICAL FLUE

9551

NOTE: An Inline Adaptor Pt. No. 230488 with a flue length of 100mm can be used.

MINIMUM

INSTALLATION

CLEARANCE

MINIMUM

FLUE

LENGTH

"B"

"A"

"A"

"Y"

RH 192
LH 15

17

221973A

4 Flue and Appliance Preparation

STEP 1

STEP 2

STEP 4

STEP 3

Diagram 4.9

Push flue duct & air duct
into flue spigot and lock into
position by turning clockwise.

STEP 6

STEP 5

Slide flue duct & air duct
together, mark, drill, screw
and seal with tape
provided.

Push flue bend (45o or 90o)
onto flue duct or boiler end
standard flue, drill and screw
then seal with tape provided.

Push flue duct & air duct
onto flue bend (45o or 90o),
drill and screw then seal
with tape provided.

Push flue bend (45o or 90o)
onto flue duct & air duct, drill
and screw then seal with tape
provided.

FLUE BEND
(90˚ or 45˚)

SECURING
SCREW (2)

SECURING
SCREW (2)

Push flue duct
& air duct
onto flue bend
(45o or 90o),
drill and screw
then seal with
tape provided.

SECURING
SCREW (2)

FLUE BEND
(90˚ or 45˚)

SECURING
SCREW (4)

AIR/FLUE DUCT
ASSEMBLY

7382

FLUE DUCT SPIGOT
Secure to boiler with screws provided
in the boiler fittings pack.

No. 8 x 3/8 in.

3mm

TOP FLUE
TRANSITION DUCT
(DISCARD)

Diagram 4.10

FLUE
DUCT

No. 8 x 3/8 in.

3mm

AIR
DUCT

TERMINAL

EASI-VENT
ADAPTOR
RING

7390

4416

Pitched and Flat Roof

Fit Weather and Storm Collar onto air duct/terminal assembly,
see diagram 4.8.

Make sure the weather collar is correctly positioned and sealed
for the roof type.

Fit the flue adaptor into flue terminal and connect to air duct.
After the flue terminal is fitted, fit an appropiate wall band.
Make sure that a weather proof seal is made in accordance with

good building practice.

18

221973A

5 Boiler Installation

Diagram 5.1

CONTROLS
COVER

FRONT
COVER

SHAKEPROOF
WASHER

9206

NUT

5.1 Boiler Preparation

Open the carton, check the items supplied against the boiler
pack contents list on the carton flap.

With the boiler still in in the bottom tray slide the controls cover
upwards and remove, see diagram 5.1.

Remove the front cover by undoing the wing nut, nut and
washer, lift the front cover off, see diagram 5.1.

Place controls cover and front cover to one side until required.
Fit suitable compression fittings to the required tappings on the

boiler.
Note: For gravity domestic hot water use 22x28mm connections

on the stubs, see diagram 5.2.
Disconnect the air pressure tubes, see diagram 8.1.
Remove the blue and red electrical connections from the fan,

see diagram 8.1.
Remove the front right hand flue hood securing screw and

slacken off the front left hand one, see diagram 8.3.
Remove fan and flue hood assembly from boiler by drawing

assembly forward, place to one side until required.

5.2 Mounting the Boiler

Lift the boiler into position ensuring first that the bottom of the
boiler is hooked on to the boiler mounting bracket and then
engage the two keyhole slots, located on top of the boiler, on to
the securing screws. Tighten the two securing screws, see
diagram 5.3.

Note: Installations where the flue exits to the left of the boiler,
complete the water connections to the boiler before fitting the
flue.

From the fittings pack, place top turret gasket in position on
boiler flue opening, see diagram 5.4.

Taking care not to damage the gasket, secure the top turret with
flue assembly to the boiler with four self-tap screws, see
diagram 5.4.

From the fittings pack, fit flue duct extension assembly into the
top turret flue ducting and loosely fit jubilee clip on elbow of the
flue duct extension, see diagram 5.5.

Refit fan and flue hood assembly, ensuring that the flue hood fits
in the flue hood retaining clamps and engage the fan into the
elbow of flue duct extension, see diagram 8.3

Tighten up left hand flue hood securing screw, replace the right
hand one and tighten, see diagram 8.3.

Secure fan to elbow of flue duct extension by tightening up
jubilee clip, see diagram 5.5.

5.3 Water Circulation System

Complete the water connections to the boiler.
Fill, vent and flush the system.
Check for any water leaks and put right.

5.4 Safety Valve Discharge

Fit a suitable discharge pipe to the safety valve and route it to
outside the building so that any discharge can be seen but will
not cause injury to persons, damage to property or any electrical
installation.

WING
NUT

Diagram 5.2

9282

22x28mm GRAVITY
DOMESTIC CONNECTION

22mm HEATING
FLOW

NOTE: When cutting leave sufficient length for
fittings.

*

*

22mm HEATING
RETURN

22mm GRAVITY
DOMESTIC HOT
WATER STUB

9279

19

221973A

5 Boiler Installation

Diagram 5.3

SECURING
SCREWS (2)

5.5 Gas Connection

Make the gas connection to the Rc1/2in gas service cock, see
diagram 6.1.

Check for leaks using a suitable leak detection fluid.

5.6 Control Box Removal

Remove the electrical control box securing screws, see diagram

5.6. Slide the box forwards and release, hook it onto the lip
bracket at the front, see diagram 5.6.

5.7 Electrical Connection

WARNING. This boiler must be earthed.
Take care not to damage any internal wiring and capillaries.
Take plastic cable retaining clip, from the loose items pack, peel

off the backing paper and position it in a suitable place to secure
the incoming cable.

Using heat resistant (85

o

C) cable of at least 0.75mm2 (24/

0.2mm) to the current issue of BS6500 Table 16 and of a
suitable length, thread through cable clamps, secure into the
plastic clips and connect to appropriate terminals, see relevant
diagrams 5.7 and 5.8.

Standard colours are, brown - live (L), blue - neutral (N) and
green and yellow - earth (E).

The mains cable outer insulation must not be cut back external
to the cable clamp.

Make sure the cable is suitably secured.
When making connections, make sure that the earth conductor

is made of a greater length than the current carrying conductors,
so that if the cable is strained the earth conductor would be the
last to become disconnected.

Diagram 5.4

TOP
TURRET

9203

GASKET

SECURING

SCREWS

(4)

FLUE
DUCT
EXTENSION

5mm

MOUNTING
BRACKET

9283

5.8 Gravity Domestic Hot Water Systems

Fit the yellow link cable, supplied in the fittings pack, between
terminal K1 and K2, see diagram 5.7.

5.9 Pump Connection

FULLY PUMPED
The pump must be connected directly to the control box, as

shown in diagram 5.8 threading the cable through the cable
clamp in the side of the control box.

PUMPED HEATING AND GRAVITY DOMESTIC HOT WATER
The pump must be wired into the central heating remote

controls.
Make sure that the supply cable and all external cables are

secured and away from hot surfaces.

5.10 External Controls

Any external controls must only be wired to interrupt the red link
between terminals SL and 9.

See relevant wiring diagrams, for either a sealed water system,
or fully pumped open vented, as diagram 5.8 and 9.7.

PUMPED HEATING AND GRAVITY DOMESTIC HOT WATER
Make sure that the red link is connected between terminals SL

and 9 on the terminal block, as diagram 5.7.
Make sure that the supply cable and all external cables are

secured and away from hot surfaces.

20

221973A

5 Boiler Installation

5.11 Testing

Checks to ensure electrical safety must be carried out by a
competent person.

After installation of the system, preliminary electrical system
checks as below should be carried out.

1. Test insulation resistance to earth.

2. Test continuity and short circuit of all cables,

3. Test the polarity of the mains.
The installer is requested to advise and give guidance to the

user on the controls scheme used with the boiler.

Diagram 5.5

TOP TURRET
FLUE DUCTING

9139

FLUE DUCT
EXTENSION

JUBILEE
CLIP

Diagram 5.6

5739

SECURING
SCREWS (2)

LIP
BRACKET

GRAVITY DOMESTIC HOT WATER
AND PUMPED HEATING

Diagram 5.7

✽

RED
LINK

PUMP
CABLE

MAINS
CABLE

PUMP
CABLE

✽ RED
LINK

YELLOW
LINK

✽ Leave "RED LINK" if
fitting remote controls

CABLE
CLAMPS

FULLY PUMPED OPEN VENTED
OR SEALED WATER SYSTEM

Diagram 5.8

CABLE
CLAMPS

MAINS
CABLE

✽ Remove "RED LINK"
if fitting remote controls.

MAINS
CABLE

5740

4615

MAINS
CABLE

21

221973A

6 Commissioning

Diagram 6.2

9364

4108

Diagram 6.1

Please ensure the “Benchmark” logbook is completed and left
with the user.

6.1 All Systems

Commissioning should be carried out by a competent person in
accordance with the current issue of BS6798.

Make sure that the system has been thoroughly flushed out with
cold water without the pump in place.

Refit the pump, fill the system with water, making sure that all
air is properly vented from the system and pump.

Before operating the boiler check that all external controls are
calling for heat.

6.2 Sealed Water Systems Only

Flush the whole of the system with cold water without the pump
in place. Refit the pump and fill until the pressure gauge
registers 2.7bar (40lbf/in2). Clear any air locks and check for
water soundness.

Check the operation of the safety valve, by allowing the water
pressure to rise until the valve opens. The valve should open
within +/-0.3bar (+/-4.3lbf/in

2

) of the preset pressure. Where

this is not possible conduct a manual check and test.
Release cold water to initial system design pressure.
The set pointer on the pressure gauge should be set to coincide

with the indicating pointer.

6.3 Initial Lighting and Testing

CAUTION. This work must be carried out by a competent
person, in accordance with the current issue of BS6798.

Make sure that all naked lights and cigarettes are out.
Identify the controls by reference to diagram 6.1.
Check that the boiler is isolated from the electrical supply.
Makes sure that the control thermostat is turned to “O” the “Off”

position.
Turn the gas service cock “On”, see diagram 6.1.
Test the pilot supply tube and its connections for gas soundness

as follows:
Disconnect the ignition lead from the PCB, see diagram 5.7.
Remove the combustion chamber front, see diagram 6.3.
WARNING. The fan operates on mains voltage, terminals will

become live.
Turn the electrical supply on and check that all remote controls

are calling for heat.
Check that the pump is circulating water through the system.
To complete the test it is necessary to operate the boiler without

its case, but UNDER ALL OTHER CIRCUMSTANCES the case
must be correctly fitted and sealed.

Turn the control thermostat knob fully clockwise and the fan will
work.

Note. There will be no sparks at the pilot. Take care and light
the pilot with a match.

Test the pilot supply and connections for gas soundness, using
a suitable leak detection fluid.

Very cold weather may delay the operating sequence.
The pilot rate is preset and must not be adjusted. The step

adjustment screw must not be touched.
The pilot flame length should be as shown in diagram 6.4.

OVERHEAT SAFETY
CUT-OFF

SETTING
POINT

CONTROL
THERMOSTAT
KNOB

GAS SERVICE COCK
(SHOWN OFF)

GAS PRESSURE
ADJUSTMENT
SCREW

MULTI­FUNCTIONAL
CONTROL

MAIN
BURNER
PRESSURE
TEST SCREW

NOTE:

DO NOT ADJUST ANY
OTHER SETTING SCREWS

Turn the control thermostat knob to “O” and isolate the boiler
from the electrical supply.

Fit the combustion chamber front.
Note: Make sure it fits under lip of flue hood.
Reconnect the ignition lead to the PCB.
Stick the self adhesive arrow indicator to the data label, against

the rating that the boiler is going to be set to, for future reference.
The arrow is in the loose items pack.

Loosen the main burner pressure test point screw and connect
a suitable pressure gauge, see diagram 6.2.

Make sure that any remote controls are calling for heat.
Switch on/connect the electrical supply to the boiler and heating

system, neon 1 will light.
Note: The neon indicator lights on the printed circuit board are

an aid to fault finding, for details refer to section 9.

22

221973A

6 Commissioning

Diagram 6.3

Diagram 6.4

NOTE:

PILOT SHIELD
REMOVED FOR
CLARITY

SPARK GAP
2 to 4mm

10 to 20mm FLAME LENGTH

9136

VIEWING

WINDOW

SECURING
SCREW (4)

4146

4139

6.4 Testing - Electrical

Turn the boiler thermostat knob fully clockwise to the maximum
setting, which is about 82oC (180oF), neon 2 will light.

The lighting sequence is automatic as follows:
The fan operates
The spark ignition operates
The pilot solenoid opens
The pilot burner lights
The ignition spark stops
The main solenoid opens
and after a short period of time the main burner will light, look

through viewing window, see diagram 6.3.
Very cold weather may delay the operating sequence.
The main burner will stay alight until switched off, either by the

control thermostat or a remote system control.
To make sure thet the flame supervision device is working

correctly the following should be done.

1. With the main burner alight, turn the gas service cock “Off”,
see diagram 6.1.

After a short period the main burner and pilot will go out.

2. The correct working of the flame supervision device is shown
by neon 4 going out within 10 seconds and the ignition starting
up.

Neons 1, 2 and 3 should stay alight.

3. If the above does not happen, refer to fault finding Section

9.1.

4. To carry on turn gas service cock “On” see diagram 6.1.
When the boiler switches “Off”, both the pilot and main burner

go out. The automatic lighting sequence will work again when
heat is required.

If an external control switches the boiler off, the pump will run on
for several minutes.

6.5 Testing - Gas

With the boiler on proceed as follows:­Test for gas soundness around the boiler gas components

using a suitable leak detection fluid, in accordance with the
current issue of BS6891.

Check the main burner gas pressure at least 10 minutes after
the boiler has lit, refer to Data Label, see diagram 1.3.

If necessary adjust the gas pressure to obtain the required
setting turning screw clockwise, to decrease pressure, see
diagram 6.2.

Should any doubt exist about the gas rate, check it using the gas
meter test dial and stop watch, at least 10 minutes after the
burner has lit, making sure that all gas burning appliances and
pilot lights are off.

Turn the control thermostat knob fully anticlockwise to “O”.
Remove the pressure gauge from the test point and refit screw,
making sure a gas tight seal is made.

When the control thermostat is turned to the “Off” position, by
hand, wait at least 30 seconds before turning “On” again.

There may be an initial smell given off from the boiler when new,
this is quite normal and it will disappear after a short period of
time.

Refit the electrical controls box, see diagram 5.6.

CAPILLARY
RETAINING
CLIP

neon 3 will light

neon 4 will light

23

221973A

6 Commissioning

Diagram 6.5

Diagram 6.6

CONTROLS

COVER

WING
NUT

WASHER

TOP
SEAL

SIDE
SEAL

NOTE: MAKE SURE
OF CORRECT
ENGAGEMENT

NUT

9275

9270

6.6 Testing - Open Vented System

Allow the system to reach maximum working temperature and
examine for water leaks.

There should be no undue noise in the system and no pumping
over of water or entry of air at the open vent above the feed and
expansion cistern.

All systems - The boiler should be turned off and the system
drained off as rapidly as possible, whilst still hot.

6.7 Adjustment - Fully Pumped Open Vented
and Sealed Water Systems

When commissioning the system the boiler should first be fired
with the bypass fully closed on full service, that is, central
heating and domestic hot water. Adjust the pump to the system
design setting then balance the system. Having achieved a
satisfactory condition operate the boiler with the bypass fully
closed on minimum load, normally this will be central heating
only with one radiator in the main living area operating. The
bypass valve should be gradually opened to achieve a
temperature difference no greater than 20oC between the flow
and return.

UNDER NO CIRCUMSTANCES SHOULD THIS VALVE BE
LEFT IN THE FULLY CLOSED POSITION.

6.8 Sealed Water Systems ONLY

Adjust the system to initial design pressure. The set pointer on
the pressure gauge should be set to coincide with the indicating
pointer.

6.9 Thermostatic Radiator Valves

If thermostatic radiator valves are fitted care must be taken to
ensure that an adequate flow rate through the boiler when they
close, refer to the current issue of BS7478 for guidance.

6.10 Protection Against Freezing

If the boiler is to be out of use for a period of time during severe
weather conditions we recommend that the whole of the system,
including the boiler, be drained off to avoid the risk of freezing
up.

6.11 Operational Checks and Completion

Adjust the boiler thermostat and any system controls to their
required settings.

Do not attempt to adjust the thermostat calibration screw.
Operate the boiler again on full service and check that the

balancing is satisfactory, making adjustments as necessary.
Fit the front cover by hooking it under at the top and securing

with the wing nut, washer and nut previously removed, refer to
diagram 6.5.

Fit the controls cover by hooking into sliders and pushing it back
as far as it will go, see diagram 6.6.

SLIDERS

24

221973A

7 Instructions to the User

Diagram 8.1

Diagram 8.2

BAFFLE (6 off)

FLUE
CONNECTING
ELBOW

FLUE DUCT
EXTENSION

TOP TURRET
FLUE DUCTING

9139

9802

8 Servicing

Instruct and demonstrate the safe and efficient operation of the
boiler, heating system and domestic hot water system.

Advise the user, that to ensure the continued efficient and safe
operation of the boiler it is recommended that it is checked and
serviced at regular intervals. The frequency of servicing will
depend upon the particular installation and usage, but in general
once a year should be enough.

Draw attention, if applicable, to the current issue of the Gas
Safety (Installation and Use) Regulations, Section 35, which

imposes a duty of care on all persons who let out any property
containing a gas appliance.

It is the Law that servicing is carried out by a competent person.
Advise the user of the precautions necessary to prevent damage

to the system and building in the event of the heating system
being out of use during frost and freezing conditions.

Reminder - Leave these instructions and the “Benchmark”
logbook with the user.

REMEMBER, When replacing a part on this appliance, use only
spare parts that you can be assured conform to the safety and
performance specification that we require. Do not use
reconditioned or copy parts that have not been clearly authorised
by Hepworth Heating Ltd.

Notes. To ensure the continued efficient and safe operation of
the boiler it is recommended that it is checked and serviced as
necessary at regular intervals. The frequency of servicing will
depend upon the particular installation conditions and usage,
but in general once a year should be enough.

It is the Law that any servicing is carried out by a competent
person.

Before servicing turn off the gas and isolate the electrical supply
to the boiler.

After completing a service always test for gas soundness and
carryout functional check on controls.

Unless stated otherwise all parts are replaced in the reverse
order to removal.

8.1 Access

Remove the controls cover, by withdrawing it forward and off,
see diagram 6.6.

Remove the front cover by undoing the wing nut, nut and
washer, lift the front cover off, see diagram 6.5.

Note. As an aid to Servicing the air pressure switch tube
connection can be used to obtain a products of combustion
reading.

Remove the RED tube from the connection on the air pressure
switch and insert the analyser probe into the tube.

Switch on the electrical supply to operate the fan and turn on the
gas supply.

On completion of the test switch off the electrical supply and the
gas supply and reconnect the red tube to the air pressure
switch.

8.2 Cleaning Heat Exchanger Flueways

Disconnect the air pressure tubes, see diagram 8.1
Remove the blue and red electrical connections from the fan,

then loosen jubilee clip to release flue duct extension assembly,
see diagram 8.1.

Remove the front right hand flue hood securing screw and
slacken off the front left hand one, see diagram 8.3.

Holding the flue duct extension with the right hand and the fan
with the left, draw the fan and flue hood assembly forward
allowing the flue duct extension to rotate slightly in the top turret
flue ducting to allow the fan to be withdrawn from the flue duct
extension, see diagram 8.1.

Remove the combustion chamber front.

Remove the burner as Section 8.3.
Place a sheet of paper in the base of the combustion chamber.
Remove the baffles, see diagram 8.2.
Clean the heat exchanger flueways with a suitable stiff brush.
Remove the paper together with any debris.

8.3 Main Burner

Disconnect the pilot union connector.
Remove the pilot burner securing nut and shakeproof washer

together with the pilot shield.
Remove the pilot burner assembly taking care not to damage

the electrode and lead assembly, see diagram 8.4.

FAN

AIR PRESSURE
TUBES

ELECTRICAL
CONNECTIONS

RED

JUBILEE
CLIP

25

221973A

8 Servicing

Diagram 8.5

Diagram 8.6

Diagram 8.7

WING
NUT

MAIN
BURNER
INJECTOR

PILOT
BURNER

SPRING
CLIP

ELECTRODE

PILOT
INJECTOR

4141

4142

4143

Remove the wing nut from the burner support bracket, see
diagram 8.5.

Remove the main burner from the main injector at the rear.
Raise the burner up and forwards, easing the pilot pipe down,
to clear, take care not to damage the combustion chamber
insulation or the pilot burner assembly.

Use a vacuum cleaner or suitable stiff brush to clean the burner
thoroughly, making sure that all the burner ports are clear and
unobstructed.

Note. On refitting and after cleaning the heat exchanger make
sure the burner is fitted correctly, that is, located on the main
injector and horizontal.

8.4 Main Injector

With the main burner removed the main injector can be inspected
and cleaned as necessary, see diagram 8.6.

If removing for cleaning do not use a wire or sharp instrument
on the hole.

Use a little suitable sealant on the external thread when refitting
making sure a gas tight seal is made.

8.5 Pilot Burner/Electrode and Pilot Injector

Clean the pilot burner and electrode.
To remove the electrode release the spring clip, see diagram

8.7.
When removing and replacing the pilot injector from the pilot

burner take care not to damage the electrode, see diagram 8.7,
clean the injector by blowing through it.

Check that the spark gap is as shown in diagram 6.4.

8.6 Operational Checks

After completing a service and before fitting the case, check
condition of the case seal and renew if necessary.

Examine flue hood and terminal to make sure they are clean
and clear of obstructions.

Light the boiler and carryout the functional checks as described
in Section 6.

Diagram 8.4

SECURING NUT AND
SHAKEPROOF WASHER

PILOT PIPE

ELECTRODE AND
LEAD ASSEMBLY

UNION
CONNECTOR

4094

Diagram 8.3

SECURING SCREWS

JUBILEE CLIP

FLUE HOOD
RETAINING
CLAMP

FLUE HOOD
RETAINING
CLAMP

9367

26

221973A

Diagram 9.1

9 Fault Finding

NEON
INDICATORS

Neon Indicators - An Aid to Fault Finding

THE NEON INDICATORS ARE AN AID TO FAULT FINDING ONLY. FAILURE OF ANY OF THE NEON INDICATORS DOES NOT

WARRANT THE REPLACEMENT OF AN OTHERWISE SATISFACTORY PRINTED CIRCUIT BOARD (PCB).

Fault with mains supply or PCB fuse

Ignition, pilot or flame proving fault ­see detailed fault finding chart.

Air flow proving fault - that is fan or air
pressure switch - see detailed fault finding
chart.

NO

NO

NO

Overheat cut off device tripped or
thermostat, overheat cut off device faulty

- see detailed fault finding chart.

Is neon 2 lit?

Is neon 4 lit?

System satisfactory

Is neon 3 lit?

Is main burner operating?

Is neon 1 lit?

NO

NO

YES

YES

YES

YES

YES

Multi-functional control/harness problem

- see detailed fault finding chart.

4120

9.1 Electrical

Important. On completion of the Service/Fault Finding task
which has required the breaking and remaking of the electrical
connections the earth continuity, polarity, short circuit and
resistance to earth checks must be repeated using a suitable
multimeter.

Refer to neon indicators “An Aid to Fault Finding” diagram 9.1,
Boiler Fault Finding diagram 9.2, Pump Overrun Fault Finding
diagram 9.3, the Functional Flow diagram 9.4 , Gravity Domestic
Hot Water and Fully Pumped Central Heating, diagram 9.5,
Fully Pumped Open Vented or Sealed Water System, the
Pictorial Wiring diagram 9.6, Gravity Domestic Hot Water and
Fully Pumped Central Heating and diagram 9.7, Fully Pumped
Open Vented or Sealed Water System.

9.2 Electrical Supply Failure

Failure of the electrical supply will cause the burner to go out.
Operation will normally resume on restoration of the electrical

supply. If the burner does not relight after an electrical supply
failure the overheat device may need resetting.

Remove the control cover, see diagram 6.6 and push the reset
button on the front of the control box, see diagram 6.1.

If the cut off operates at any other time press the reset button
and the burner should relight.

If the fault persists refer to fault finding chart.
Note: The pump may run for several minutes when power is first

applied, regardless of call for heat.

4120

27

221973A

9 Fault Finding

Diagram 9.2

Is neon 1 lit?

Is neon 2 lit?

Correct power supply problem.

Is there 230V~
between 3 on thermostat and N ?

Replace thermostat.

Is neon 3 lit?

Is there 230V~ between
"N/C" on air pressure switch and N ?

Check yellow cable between printed circuit
board and air pressure switch.
If satisfactory replace printed circuit board.

Is there 230V~ between "C" on air
pressure switch and N ?

Replace air pressure switch.

Does fan run?

Replace fan.

Replace printed circuit board.

Does fan Hunt?

Inspect air tubes for leaks, kinks and correct
fitting. If satisfactory replace faulty air pressure
switch.

Is there 230V~between "N/O" on air
pressure switch and N ?

Isolate supply, test harness continuity.
If satisfactory replace printed circiut board.

Is there 230V~ between pilot
multi-functional control solenoid
blue and brown connections?

Check lead continuity and inspect electrode and
lead for damage.

Is there a spark at pilot burner?

Check for pilot jet blockage, incorrect electrode
adjustment. If satisfactory replace
multi-functional control.

Does pilot light?

Inspect electrode lead /connection
for poor contact. Check electrical supply
polarity and correct if necessary.
If satisfactory replace printed circuit board.

With pilot lit does spark stop?

Isolate supply, test harness and replace as required.

Is there 230V~ between main
multi-functional control solenoid black
and blue cables?

YES

Replace multi-functional control.

Is Neon 4 lit?

Does main burner light?

System satisfactory

Is there 230V~ between SL and
N and between L and N ?

Is there 230V~ between yellow connection
on overheat device and N ?

Is there 230V~ between motor connections on fan?

Isolate electrical supply test fan
harness continuity.
If satisfactory replace printed circuit board.

For gravity domestic hot water systems only,
check continuity of yellow link. For fully
pumped systems, check overheat reset.
If satisfactory replace overheat device.

Before detailed checking of electrical components ensure that remote controls are calling for heat. Check the gas supply is free of obstructions and purged of

air. Check the overheat cutoff has not operated, for fully pumped systems only. Isolate the electrical supply and physically check ALL cables, connections

and the printed circuit board fuse. Check the air tubes to the air pressure switch. Switch on the electrical supply and check for correct polarity. Turn the

boiler thermostat to its maximum setting. Also check fuses.

YES

YES

YES

YES

YES

NO

NO

NO

NO

NO

NO

NO

NO

YES

NO

YES

YES

YES

YES

YES

NO

NO

YES

NO

YES

YES

YES

YES

YES

NO

NO

NO

NO

NO

NO

YES

NO

M A I N T E R M I N A L S T R I P

C O N T R O L T H E R M O S T A T

28

221973A

9 Fault Finding

Does pump continue to run after
SL is interrupted?

YES

Does pump stop after several
minutes?

System satisfactory.

Faulty PCB. Replace

NO

YES

YES

NO

NO

Does the pump run when SL is applied ?

Pump Overrun Operation For Fully Pumped System Only

The PCB has a timed pump overrun facility.

The pump should run for several minutes after remote controls have stopped calling for heat.

Before using the fault finding chart ensure all wiring is correct and in good condition, the pump is not faulty and check the PCB fuse F2

FOR FULLY PUMPED OPEN VENTED
OR SEALED WATER SYSTEMS ONLY Diagram 9.3

29

221973A

9 Fault Finding

FUSE
TYPE F1 & F2
(F1A)

AIR PRESSURE SWITCH CONNECTIONS

SPARK
ELECTRODE

O/H CUTOFF

CONTROL STAT

FAN

AIR
PRESSURE
SWITCH

PILOT
SOLENOID

MAIN
SOLENOID

N

N

N

N

N

N

N

(N/O) (C)

(N/C)

L

K2

K1

2

3

N

N

b

w

w

br

y

y

y

rb

r

bk

b

y

br b

b

bk

b

KEY

bk BLACK
br BROWN
b BLUE
p PURLPLE

or ORANGE
w WHITE
r RED
y YELLOW

SL

MAIN TERMINAL STRIP CONNECTIONS
CONTROL THERMOSTAT CONNECTIONS
PRINTED CIRCUIT BOARD CONNECTIONS

FULLY PUMPED OPEN VENTED
OR SEALED WATER SYSTEM

PN

9

P

L

PUMP

br b

brbr

b

b

*

RED

LINK

*

Remove red link between 9 and SL when
fitting a time control etc (if no switch is fitted,
link will make the circulation pump run constantly)

F1

F2

or

or

or

p

Diagram 9.4 Diagram 9.5

FUSE
TYPE F1 &F2
(F1A)

SPARK
ELECTRODE

O/H CUTOFF

CONTROL STAT

FAN

AIR
PRESSURE
SWITCH

PILOT
SOLENOID

MAIN
SOLENOID

N

N

N

N

N

N

N

(N/O) (C)

(N/C)

L

K2

K1

23

N

N

bl
w

w

br

y

y

y

rbl

r

bk

bl

y

br bl

bl

bk

bl

KEY

bk BLACK
br BROWN
bl BLUE
p PURPLE

or ORANGE
w WHITE
r RED
y YELLOW

SL

PUMP WIRED INTO CENTRAL HEATING
SYSTEM REMOTE CONTROLS

GRAVITY DOMESTIC HOT WATER AND
FULLY PUMPED CENTRAL HEATING

*

YELLOW
LINK

AIR PRESSURE SWITCH CONNECTIONS
MAIN TERMINAL STRIP CONNECTIONS
CONTROL THERMOSTAT CONNECTIONS
PRINTED CIRCUIT BOARD CONNECTIONS

9

P

F1

F2

or

or

p

**

RED LINK

*

Yellow Link fitted to bridge out
the overheat cutoff

**

Red Link must be fitted between
SL and 9.

bl

30

221973A

9 Fault Finding

Diagram 9.6

KEY:

b-BLUE
bk - BLACK
br - BROWN
g/y - GREEN/YELLOW
or - ORANGE
p-PURPLE
r-RED
y-YELLOW
w-WHITE

FAN

r

r

y

C

NO

NC

CHASSIS EARTH

SL

N

L

9

L

230~50Hz
MAINS
SUPPLY
FUSED
AT 3-AMP

Pump must be wired into central
heating system remote controls
and not to control box

Yellow link fitted to bridge out the
overheat cutoff

b

g/y

E

N

K1

K2

ELECTRODE

PN

9365

GRAVITY DOMESTIC
HOT WATER AND
PUMPED CENTRAL
HEATING

b

bk

AIR
PRESSURE
SWITCH

g/y

g/y

CHASSIS
EARTH

g/y

w

p

or

y

br

b

y

w

y

OVERHEAT
CUTOFF

MULTI-FUNCTIONAL
CONTROL

br

2

Ensure RED LINK connected
between 9 and SL.

r

3-PLUGS

FUSES
F1 & F2
(F1A)

SEQUENCE
BOARD

P

3

w

p

y

CONTROL
THERMOSTAT

b

31

221973A

9 Fault Finding

Diagram 9.7

SWITCH CONTROL,
TIME SWITCH,
PROGRAMMER ETC.
(if fitted)

C

NO

L

9

w

y

w

g/y

K1

K2

FAN

r

r

bk

y

AIR
PRESSURE
SWITCH

CHASSIS EARTH

g/y

w

g/y

CHASSIS
EARTH

or

p

3-PLUGS

OVERHEAT
CUTOFF

b

L

230~50Hz
PERMANENT
MAINS
SUPPLY
FUSED
AT 3-AMP

N
E

N

g/y

br

CIRCULATON
PUMP

L

r

✽ See Note

SL

P

PN

FULLY PUMPED
OPEN VENTED
OR SEALED
WATER SYSTEM

5860

b

N

b

br

b

MULTI-FUNCTIONAL
CONTROL

br

b

✽ Remove red link between

9 and SL when fitting a time
control etc (If no switch is fitted,
link will make the circulation
pump run constantly).

ELECTRODE

NC

KEY:

b-BLUE
bk - BLACK
br - BROWN
g/y - GREEN/YELLOW
or - ORANGE
p-PURPLE
r-RED
y-YELLOW
w-WHITE

3

2

y

p

b

br

g/y

br

y

SEQUENCE
BOARD

FUSES
F1 & F2
(F1A)

CONTROL
THERMOSTAT

E

32

221973A

10 Replacement of Parts

Note. Replacement of parts must only be carried out by a
competent person.

Before replacing any parts isolate the boiler from the electrical
supply and turn the gas supply off at the gas service cock,
indicator slot should be vertical.

Unless state otherwise, all parts are replaced in the reverse
order to removal.

After replacing any parts always test for gas soundness and if
necessary carryout functional check of controls.

10.1 Access

Gain access as Section 8.1.

10.2 Control Thermostat diagram 10.1, 10.2 &

6.3.

Remove and support the electrical control box, refer to Section

5.6.
Remove the control knob. Remove the electrical connections

from the thermostat body.
Release the thermostat body by unscrewing the two screws and

shakeproof washers in the front of the control box.
Remove the split pin and withdraw the thermostat phial from its

pocket. Release the capillary from the base and plastic retaining
clip then remove it from the split grommet.

Release the capillary from its clips.
Remove the thermostat complete from the boiler.
Re-assembly note. When fitting the thermostat, make sure that

the thermostat phial is covered with heat sink compound then
fully inserted into the phial pocket and that the capillary is within
the gland seal, see diagram 10.2. Remake the electrical
connections.

There must be no kinks or sharp bends in the capillary.

10.3 Over Heat Cutoff Device - diagram 10.1,

10.2, 10.2A & 6.3.

Release the control box as Section 5.6.
Remove the overheat cutoff electrical connections.
Disconnect the air pressure switch plug from the PCB.
Remove the locking nut from the overheat cutoff.
Release the capillary from the retaining clips then remove it

from the split grommet.
Loosen the retaining bracket and remove the phial.
When refitting use the heat sink compound provided and make

sure that the phial is correctly fitted into the groove on the pipe.

CONTROL
THERMOSTAT

CONTROL
KNOB

ELECTRICAL
CONNECTIONS
YELLOW 2 & 3

SPLIT
GROMMET

RETAINING
CLIP

LOCKNUT

ELECTRICAL
CONNECTIONS

SHAKEPROOF
WASHERS AND
SCREWS

5754

Diagram 10.1

33

221973A

10 Replacement of Parts

10.4 Control Board (PCB) - diagram 102A

Release the control box, refer to Section 5.6.
Disconnect the three electrical plugs and ignition lead.
Release the cables from the plastic retaining clip, then disconnect

the cables from the PCB to the main terminal strip, control
thermostat and earth connection.

Release the main terminal strip and plastic label.
Carefully pull the board away from its supports.
When refitting refer to wiring diagrams 9.6 or 9.7 as appropriate.

10.5 Pilot Burner and Pilot Injector

Proceed as Section 8.3 and 8.5.

10.6 Electrode

Proceed as Section 8.3 and 8.5.
Gain access as Section 5.6 to remove lead from control box.

Diagram 10.2

OVERHEAT
CUTOFF
DEVICE
PHIAL

9137

PHIAL RETAINING
BRACKET SECURING
SCREW

SPLIT
PIN

CONTROL
THERMOSTAT
PHIAL POCKET

JUBILEE
CLIP

SECURING
SCREW (4)

FLUE HOOD
RETAINING
CLAMP (2)

10.7 Multifunctional Control - diagram 10.3

Disconnect the pilot supply by unscrewing the tubing nut at the
multifunctional control, take care as there is a restrictor on the
pilot pipe.

Disconnect the electrical plug.
Support the multifunctional control, remove the four extended

screws from the flanged connections at the left and right hand
side.

Remove and discard the original “O” rings from the flanged
connections and fit the new “O” ring supplied, into recess,
before fitting the replacement multifunctional control.

After assembly test for gas soundness and purge in accordance
with the current issue of BS6891.

10.8 Solenoid - diagram 10.3

Remove the electrical plug from the multifunctional control.
Remove the securing screw and then the solenoid Assembly.

Diagram 10.2A

ELECTRICAL PLUGS

PLASTIC
RETAINING
CLIP

ELECTRICAL
PLUGS

ELECTRICAL
CONNECTION
BROWN CABLE "SL"

SUPPORT
POST (4)

SECURING
SCREW (2)

IGNITION
LEAD

EARTH
CONNECTION

MAIN
TERMINAL
STRIP

ELECTRICAL
CONNECTION
BLUE CABLE "N"

5756

4090

CHASSIS
EARTH
CONNECTION

BOILER
THERMOSTAT
ELECTRICAL
CONNECTION
NO.3 "YELLOW"
CABLE

34

221973A

FRONT INSULATION

RETAINING
SCREW

9135

10 Replacement of Parts

10.9 Main Burner

Remove the main burner as Section 8.3.

10.10 Main Injector

Remove the main burner as Section 8.3.
Remove the main injector as Section 8.4.

10.11 Insulation - 10.4 & 10.5.
Combustion Chamber Front

Remove the retaining screw then the insulation.

Sides

Slide the insulation out.

Rear

With the side insulation removed the rear insulation can be
removed and replaced.

10.12 Viewing Window - diagram 10.6

Remove the old self adhesive aluminium foil gasket and the old
mica window. Replace with a new mica window. Peel off the
backing paper and secure with new self adhesive aluminium foil
gasket, see diagram 10.6. Ensure no air bubbles are trapped
underneath the foil.

Important

Make sure that the mica window fully covers the opening and
that the hole in the aluminium foil gasket is centred over
opening.

10.13 Air Pressure Switch - diagram 10.7

Release the control box as Section 5.6.
Remove the air pressure tubes and electrical connections from

the PCB, release the screws and remove the switch.
When fitting the replacement make sure that the plastic tubes

are fitted as shown in diagram 10.7 and electrical connections
are made as shown in diagram 9.6 and 9.7.

10.14 Fan - diagram 8.1

Disconnect the air pressure tubes, see diagram 8.1
Remove the blue and red electrical connections from the fan,

then loosen jubilee clip to release flue duct extension assembly,
see diagram 8.1.

Remove the front right hand flue hood securing screw and
slacken off the front left hand one, see diagram 8.3.

Holding the flue duct extension with the right hand and the fan
with the left, draw the fan and flue hood assembly forward
allowing the flue duct extension to rotate slightly in the top turret
flue ducting to allow the fan to be withdrawn from the flue duct
extension, see diagram 8.1.

Remove the fan from the flue hood by unscrewing the three
retaining screws.

Make sure that the earth connection is remade onto the new fan
assembly.

The polarity of the other connections is not important.

Diagram 10.3

SOLENOIDS

SECURING
SCREW

PILOT PIPE
TUBING NUT

RESTRICTOR

ELECTRICAL
PLUG

EXTENDED
SCREW (8)

4123

Diagram 10.4

35

221973A

Diagram 10.5

Diagram 10.7

RED

CLEAR

AIR PRESSURE
SWITCH TUBES

SECURING
SCREWS

AIR

PRESSURE

SWITCH

ELECTRICAL
CONNECTIONS

CONTROL
BOX

SIDE INSULATION

REAR INSULATION

4100

4122

10 Replacement of Parts

Diagram 10.6

SELF ADHESIVE
ALUMINIUM FOIL
GASKET

MICA WINDOW

PEEL OFF
BACKING
PAPER

OPENING
(INSIDE FACE
OF THE BOILER
FRONT COVER)

7907

36

221973A

Diagram 11.1

4

6

2

1

10

5

7

8

11

3

13

15

9629

14

9

11 Spare Parts

Key No. Part No. Description GC Part No.

1 203374 Multifunctional control
2 208040 “O” ring 334 592
3 203096 Injector 313 305
4 203431 Pilot burner 379 204
5 801236 Mica window and gasket
6 800432 Fan assembly 278 000
7 202626 Spark electrode and lead 313 998
8 K3580 Clip 390 983
9 800849 Thermostat
10 202201 Air pressure switch 313 992
11 800400 Control knob 313 917
13 202015 Fuse 334 750
14 900847 Control board PCB

15 800272 Overheat cutoff device 313 606

11.1 Part Identification

The key number on the diagram and the list will help to identify the part.

11.2 Ordering

When ordering any spare parts please quote the number and description from the list together with the model name and serial number.
If ordering from Britsh Gas also quote the GC number of the appliance and part.

Because of our constant endeavour for improvement, details may vary slightly from those shown in these instructions.