Glow-worm 120CF User Manual

Instructions for Use

Installation and Servicing

T o be left with the user

Hideaway 120

G.C. No. 41 313 29

Open Flue Boiler

221758A.10.00

1369

BS 6332
BS 5258

This is a Cat I2H Appliance

Reference in these instructions to British Standards and Statutory

Regulations/Requirements apply only to the United Kingdom.

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

For Ireland the rules in force must be used.

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.

Guarantee Registration

Thank you for installing a new Glow-worm appliance in your home.

Glow-worm appliances' are manufactured to the very highest standard so we are pleased

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

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

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

✔

All replacement parts

❏

✔

All labour charges

❏

All call-out charges

✔

❏

to offer our customers' a Comprehensive First Year Guarantee.

return as soon as possible.

Service number 01773 828100.

REGISTER YOUR GLOW-WORM APPLIANCE

FOR 1ST YEAR GUARANTEE PROTECTION

CALL 0208 247 9857

One Contact Local Service

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

Hepworth Heating Ltd.,

Nottingham Road, Belper, Derbyshire. DE56 1JT

General/Sales enquiries:

Tel: [phone] Fax: [phone]

Important Information

Notes and General Information

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

The boiler is automatic in operation, once the pilot is lit and the
controls have been set.

Glow-worm Hideaways’ are central heating boilers, to provide
heating and if required an indirect domestic hot water supply.

Gas Safety (Installation and Use) Regulations

In your own interests and that of safety, it is the Law that ALL gas
appliances are installed by a competent person in accordance
with the current issue of the above regulations.

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 Regulation 5 certified by:

Notified body 0086.

Product/production certified:

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 electrical equipment designed for
use within certain voltage limits.

3. Directive 89/336/EEC on the approximation of the Laws of
the Members States relating to electromagnetic
compatibility.Information for the Installer and Service Engineer.

Control of Substances Hazardous to Health

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

The adhesives and sealants used in this appliance are cured
and give no known hazard in this state.

Insulation Pads/Ceramic Fibre, Glassyarn

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 to the eyes or severe irritation to the skin
seek medical attention.

Boiler Thermostat

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 cases of skin contact, wash
with cold water.

If swallowed drink plenty of water and seek medical attention.

CONTENTS DESCRIPTION SECTION PAGE No.

INSTRUCTIONS

FOR USE

Introduction 3
Lighting the Boiler 4

INSTALLATION

INSTRUCTIONS

General Data 1 5
Water Systems 2 7
Flue and Ventilation 3 8
Installation 4 9
Casing Location 5 11
Electrical Wiring 6 12
Commissioning 7 13

SERVICING

INSTRUCTIONS

Servicing 8 15
Replacement Parts 9 17
Fault Finding 10 20
Spare Parts 11 24

221758A

2

Instructions for Use

Warning

Make sure that nothing obstructs the rear side grilles or
clearances. See diagram 1.2 and 1.3 for minimum clearances.

Boilers Installed in a Compartment

If the boiler is fitted in a compartment, cupboard etc., do not
obstruct the purpose built compartment vents or grille on the
boiler.

Do not use the compartment for storage purposes.

Maintenance

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 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
of 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 servicing is carried out by a competent person.
To obtain service please call your installer or Heatcall (Glow-

worm’s own service organisation) using the telephone number
given on the inside of the front panel.

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.

FLUE BLOCKAGE
SAFETY DEVICE
RESET BUTTON

SETTING
POINTS

7991

THERMOSTAT
CONTROL
KNOB 'B'

PIEZO
IGNITION
BUTTON
'C'

GAS
CONTROL
KNOB 'A'

SETTING
POINT

E

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, maximum.
All wiring must be in accordance with the current issue of

BS7671.

2

Heat resistant cable having a conductor size of 0.75mm

0.22mm), to BS6500 Table 16 must be used.

, (24/

To Connect an Electrical Plug

The colours of three core flexible cable are, Brown - live, Blue

- neutral, Green and yellow - earth.
As the markings on your plug may not correspond with these

colours continue as follows:
The wire coloured brown must be connected to the terminal

marked “L” or Red.
The wire coloured blue must be connected to the terminal

marked “N” or Black.
The wire coloured green and yellow must be connected to the

terminal marked “E”, Green or the earth symbol

.

GAS CONTROL KNOB
= OFF

= PILOT/IGNITION
= MAIN BURNER

Diagram 1

3 221758A

Instructions for Use

Safety Device

This appliance is fitted with a flue blockage safety device which
will shut down the appliance in the event of abnormal flue
conditions. This device is NOT a substitute for an independently
mounted Carbon Monoxide detector.

The safety device is reset, after three minutes, by pushing in the
button shown in diagram 1.

Shut down can occur during certain climate conditions, but if it
recurs the chimney flue and air inlet into the room must be
checked and any problems found corrected by a competent
person, before the boiler is used again.

To Light the Boiler

WARNING. If the pilot light goes out for any reason, do not
attempt to relight until three minutes have gone by.

Remove the door by pulling forwards with the fascia at the top.
Lift up to free from bottom side lugs.

Refer to diagram 1 to identify the controls.
Check that the mains electrical supply to the boiler is switched

OFF.
Check that the Flue Blockage Safety Device has not operated,

that is, the button is in. Refer to Safety Device instructions.
Push in slightly and turn gas control knob “A” clockwise until

'is against its setting point.

'
Turn thermostat control knob “B” anticlockwise until “O” is

against its setting point.
Push in slightly and turn gas control knob “A” anticlockwise until

' is against its setting point, then push fully and hold in.

'
Push and release piezo ignition button “C” until the pilot burner

lights.
Air may be present in the supply pipe so the lighting of the pilot

may need to be repeated until all the air has been expelled.
When the pilot is alight, view through window “E”, keep gas

control knob “A” fully pushed in for about 15 seconds, then
release.

If the burner fails to stay alight, wait three minutes, then repeat
the lighting procedure only now keep control knob “A” depressed
for a little longer before releasing. The Flue Blockage Safety
Device may also need resetting, refer to instructions above.

If the gas control knob “A” is turned to '
prevents it being turned on again for a short period. No attempt
should be made to relight the pilot for at least three minutes.

Make sure that the pilot is alight and stable, then switch on the
electrical supply.

Press in and turn gas control knob “A” anticlockwise until '
is against its setting point.

Set any remote controls to call for heat.
Turn the boiler thermostat knob “B” clockwise until “MAX” is

against its setting point and the main burner will light. Adjust
thermostat to required setting between “MIN” and “MAX”.
“MAX” is about 82

Refit the door by fitting the hooked runner at the bottom into the
slot in the side panels and pushing onto the studs.

o

C (180oF).

', a safety lock

To Turn the Boiler Off

For short periods. Turn the boiler thermostat control knob “B”
anticlockwise to “O”. The pilot will remain alight. To relight the
main burner turn the thermostat control knob “B” clockwise to
the desired setting between “MIN” and “MAX”.

For longer periods. Push in slightly and turn gas control knob
“A” fully clockwise until “
thermostat control knob “B” anticlockwise to “O”. Isolate the
boiler from the electrical supply. Follow the full lighting procedure
to relight.

Refer also to “Protection Against Freezing”.

” is against its setting point. Turn

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 the local gas undertaking or your installation/servicing
company.

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. If an immersion heater is fitted in the domestic hot
water cylinder make sure it is switched off.

Sheet Metal Parts

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

Cleaning

Keep the casing clean by wiping it over occasionally with a
damp soapy cloth and dry with a polishing cloth.

Do not use abrasive cleaners.

Replacement Parts/Boiler Identification

If replacement parts are required apply to your local supplier or
gas undertaking. Please quote the name of the boiler and its
serial number which can be found on the data label positioned
on the boiler top, to the rear of the inclined flueway cleaning
door.

Clearance

Minimum clearances must be left around the boiler as shown in

'

diagram 1.2 and 1.3.

221758A

4

1 General

C

L

A

✽

N

C

L

✝ F(MIN.)

FLUE

C

M

L

B

D

J(MIN.)

C

E

GENERAL DIMENSIONS - given in millimetres (Approx. inches)

ABCDE FGHJK LMN

FLUE

L

L(MIN.)
G(MIN.)

H

K

(MIN)

✝ A SPECIAL TOP CASING

TO SUIT 600mm (23

5

/

in.)

8

WORKTOPS IS AVAILABLE

GAS CONNECTION

1

Rc

1

/

(

/

2

2

in. B.S.P.T.)

WATER CONNECTIONS
Rc1 (1in. B.S.P.T.)

WATER CONNECTIONS Rc1
reduced with DISTRIBUTOR

3

TUBE to Rc

3

/

(

/

4

in. B.S.P.T.)

4

(pumped return)

✽ INSIDE DIAMETER OF

SOCKET FOR 152mm (6in.)
NOMINAL DIAMETER FLUE
TO BS567

Diagram 1.1

1307

mm 474 214 598 294 400 533 3 300 445 121 89 900 172
in. 1811/1681/2231/2111/2153/421

1

/8113/4171/243/431/2351/263/

Sheet Metal Parts

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

Important Notice

This boiler is for use only on G20 gas.
Wherever possible, all materials, appliances and components

to be used shall comply with the requirements of British
Standards.

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

1.1 Data

Approx.weight of boiler: 140kg (310 lb)
Water content: 11.7litre (2.57 gal)
Gas connection: Rc1/2(1/2 BSP)
Water connection: Rc1 (1inch BSP)
Electrical supply: 230V - 50Hz fused at 3A
Burner: Aeromatic

The Seasonal Efficiency Domestic Boilers UK (SEDBUK) is
73%.

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.

1.2 Range Rating

This boiler is range rated and may be adjusted to suit individual
systems. The table gives settings and outputs.

The boiler input is supplied preset to maximum and should be
adjusted to suit system requirements.

RANGE RATING

NOMINAL
HEAT INPUT
(GROSS)

NOMINAL
HEAT
OUTPUT

BURNER
SETTING
PRESSURE
(HOT)

INJECTOR

1.3 Statutory Requirements

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

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

Regulations, Local Water Company Byelaws, The Building
Standards (Scotland) Regulations, applicable in Scotland, The
Health and Safety at Work Act, The Control of Substances
Hazardous to Health, The Electricity at Work Regulations and
any applicable local regulations.

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

BS6798, BS5440 Part 1 and 2, BS5449, BS6700, BS6891,
BS5546, BS7478, BS7593, BS7671.

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

HIDEAWAY 120

kW

37.10 40.5 43.96

126,600 138,200 150,000

Btu/h

kW

29.31 32.24 35.17

Btu/h

100,000 110,000 120,000

mbar

in.w.g

4

min medium max

9.4 11.1 12.9

3.8 4.4 5.2

205746

5 221758A

1 General

1.4 B.S.I. Certification

This boiler is certificated by B.S.I. for safety and performance.
It is, therefore, important that no alteration is made to the boiler
unless approved, in writing, by Hepworth Heating Ltd.

Any alteration not approved by Hepworth Heating Ltd., could
invalidate the B.S.I. certification, boiler warranty and could also
infringe 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 using the pressure drop
method and suitable leak detection fluid, purge in accordance
with the current issue of BS6891.

1.6 Electrical

Warning. This boiler must be earthed.
The electrical installation must be carried out by a competent

person. All external components must be of the approved type
and must be connected in accordance with the current issue of
BS7671 and any local regulations which may apply.

Connection of the boiler and any system controls to the mains
supply should be through a 3A fused double pole isolating
switch, having a minimum double pole contact separation of
3mm, serving only the boiler and system controls.

2

Heat resistant flexible cable of at least 0.75mm
issue of BS6500 Table 16 must be used for all connections
within the boiler casing.

, to the current

1.7 Boiler Location

The boiler must not be installed in a room used or intended to
be used as sleeping accommodation or a room containing a
bath or shower.

This boiler is not suitable for installation out of doors.
The boiler must stand on a level floor, conforming with local

authority requirements and building regulations. The base
temperature is within the requirements of the current issue of
BS5258. The boiler may be stood on a wooden floor but a metal
plate is required to protect plastic tiles and similar floor coverings.

Suitable clearance needs to be available at the sides of the
boiler to ease connection of pipework. The actual clearances
will vary according to site conditions.

When the boiler is to be installed level with work surfaces,
minimum clearances to fixtures, walls and the like should be
provided, see diagram 1.2.

To ease minimum clearances it may be necessary to modify
units or fixtures.

A front access clearance should be provided as shown in
diagram 1.3.

The minimum gap behind the top casing is dimension “G” in
diagram1.1. The boiler can be sited further away from the wall
if required to align with kitchen units.

Combustible wall material must be 25mm (1in) away from flue
components.

A special top casing, part number 425562 can be bought, to
enable boiler casings to be arranged flush with 600mm (23
deep worktops.

Where the installation of the boiler will be in an unusual location,
special procedures may be necessary, the current issue of
BS6798 gives detailed guidance on this aspect.

5

/8in)

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 features of cupboard and compartment
design are given in the current issue of BS6798.

Make sure that nothing will obstruct the side clearances or side
grilles. If installing the boiler in a compartment make sure that
openings and vents are not obstructed.

1.8 Heating System Controls

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

Thermostatic radiator valves may be installed in addition to the
room thermostat.

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

WORKTOP

254

W

(10 in.)

BOILER

Y

BOILER

Diagram 1.2

Diagram 1.3

Z

0911

X

W

X

BOILER

W (MIN) X (MIN) Y (MIN) Z (MIN)
mm in mm in mm in mm in

NOT PERMITTED 624 245/8 75 3

TOP & SIDE CLEARANCES

WALL OR
FIXTURE

530 (21in.)

FRONT CLEARANCE

1308

221758A

6

2 Water Systems

2.1 Water Pressure Head

This boiler must not be connected to a sealed water system.
This boiler shall only be connected to an open vented cistern

water supply, with a minimum head of 1metre (39in) and a
maximum of 27metre (90ft).

2.2 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 in the system contact should be made
with a manufacturer so that they can recommend their most
suitable product.

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

2.3 Gravity Domestic Hot Water and Pumped
Central Heating

It is recommended that a cylinder thermostat is used to prevent
the stored water temperature becoming too high when the
heating pump is off.

The domestic hot water primary flow and return must be 28mm
od. The installation must comply with the current issue of
BS5546 and BS6700, see diagram 2.1.

If the above conditions cannot be met, it is suggested that a fully
pumped system is used.

2.4 Pumped Central Heating and Domestic Hot
Water

Where a single flow and return is taken from the boiler, a
minimum static head of 1metre (39in) must be provided between
the water level in the cold water cistern and the centre of the
waterway, see diagram 2.2.

2.5 Circulation Pump

Normally the pump should be set to give a temperature difference

oC

(20oF), across the boiler. At the appropriate flow rate the

of 11
resistance through the boiler can be found by reference to the
pressure loss graph, diagram 2.3.

Use a pump with integral valves or fit valves as close to the
pump as possible.

REFER TO BS 5546

22mm VENT

15mm COLD FEED

INDIRECT
CYLINDER

(Shown with
27metres
Max.

DRAIN OFF
COCK

recommended

thermostat and valve).

28mm

PUMP

BOILER
C

Distributor tube in
pumped return
connection

L

PUMPED HEATING AND GRAVITY
DOMESTIC (DIAGRAMMATIC)

22mm VENT

15mm
COLD FEED

1 metre
MIN.
27metres
MAX.

DRAIN OFF
COCK

TO INDIRECT
CYLINDER

PUMP

BOILER
C

L

Distributor tube in

pumped return

connection

FULLY PUMPED SYSTEM
(DIAGRAMMATIC)

0869

To Heating
Circuit

Diagram 2.1

0870

To Heating
Circuit

Diagram 2.2

2.6 Domestic Hot Water Cylinder

For all systems supplying domestic hot water the cylinder must
be indirect.

2.7 Safety Valve

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

2.8 Draining Tap

A drain tap must be fitted at the lowest points of the system
which will allow the draining of the entire system, including the
boiler and domestic hot water cylinder.

Draining taps should be to the current issue of BS2879

FLOW RATE (GALLON/MINUTE)
012345678 109

1.2

1.0

0.8

40

30

0.6
20

0.4

0.2

WATER PRESSURE LOSS

(metre HEAD OF WATER)

0

10

0

20 30

40 50

10

WATER PRESSURE LOSS

(INCHES HEAD OF WATER)

0

FLOW RATE (LITRES/MINUTE)

PRESSURE LOSS OF BOILER

Diagram 2.3

7 221758A

1370

3 Flue and Ventilation

Important Note

The boiler is fitted with a Flue Blockage Safety Device, which
will shut down the boiler if there is an unacceptable spillage of
products at the draught diverter.

This safety device MUST NOT under any circumstances be
interferred with or put out of action. The safety device must only
be replaced with the Glow-worm parts.

3.1 Flue

The integral draught diverter on the Hideaway range of boilers
makes the combustion performance independent of conditions
in the secondary flue, but in common with other fuels an efficient
flue is necessary to make sure of a trouble free installation.

The flue must be at least equivalent to 1m vertical.
The boiler flue socket is designed to take flue pipes to the

current issue of BS567. If a flue pipe to BS715 is to be used, an
adapter must be fitted to the boiler flue socket, as diagram 1.1.

The flue must be in accordance with the current issue of
BS5440 Part 1.

3.2 Flue Guidelines

The flue should be kept as short as possible. Horizontal or very
shallow runs of the flue should be avoided as they encourage
local cooling.

Always choose a flue route which will cause the least cooling of
the flue.

There should be a vertical rise of at least 600mm (2ft) before
using a bend. 90

End with a certificated flue terminal, preferably above ridge
height, but at least above the eaves of a pitched roof.

An existing chimney must be thoroughly swept and all debris
cleared away before lining.

o

elbows should not be used.

3.3 Timber Frame Buildings

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.

3.5 Ventilation for Boilers Installed in a
Cupboard or Compartment

When the boiler is fitted in a cupboard or compartment, high and
low level purpose designed, permanent openings must be
provided to supply air for combustion and compartment
ventilation.

The air vents must have minimum areas in accordance with
“Compartment Air Vent B”. The figures quoted refer to the
minimum acceptable effective area.

Both the high and low level openings must communicate with
the same room, or must both be on the same wall to outside air.

If air vent grilles are fitted to a cavity wall, the opening through
the wall must be ducted.

Where ventilation air to a compartment is taken from a room or
space, then the room or space must be fitted with a ventilation
opening as specified in “Air Vent Table A”.

For information regarding compartment requirements refer to
the appropriate section of the current issue of BS6798.

AIR VENT TABLE 'A' FOR

ROOM/SPACE INSTALLATIONS

2

EFFECTIVE
AREA OF VENT

COMPARTMENT AIR VENT TABLE 'B'

COMPARTMENT
VENTILATION
REQUIREMENTS

VENTILATION
FROM ROOM
OR SPACE

FROM
OUTSIDE

cm

in

171

2

26

HIGH LEVEL LOW LEVEL

VENT AREA VENT AREA

405cm262in2810cm2123in

202cm231in2405cm262in

2

2

3.4 Ventilation for Boiler Installed in a Room
or Space

If the boiler is to be installed in a room or space a purpose
designed permanent ventilation opening, to supply air for
combustion, must be provided on an outside wall to external air,
refer to the current issue of BS5440 Part 2 for details.

The opening may be directly into the room or the space
containing the boiler, or an outside wall of an adjacent room or
space which has an internal permanent air vent, of the same
size, into the room or space containing the boiler.

Do not ventilate through a bedroom, bedsitting room, private
garage or a room containing a bath or shower.

When the boiler is installed in a room or internal space already
containing other fuel burning appliances then the air supply of
such appliances must be taken into account.

The ventilation opening areas are given in “Air Vent Table A”.
The figures quoted refer to the minimum acceptable effective
area.

221758A

3.6 Extract Fans

If an extract fan is fitted in the premises, there is a possibility that
if adequate inlet openings are not provided, spillage of the
products from the boiler could occur.

When openings are fitted in accordance with the current issue
of BS5440 Part 2 and this section, extract fans should not cause
down draught, but where such fan installations are found, a
spillage test must be carried out in accordance with the current
issue of BS5440 Part 1 and any corrective work done.

8

4 Installation

Before fitting the boiler make sure the location selected is in
accordance with the requirements of Section 1.7.

4.1 Unpacking

The boiler casing panels are packed separately within the main
case. They are designed to enable the gas and water connections
to be made before fitting the casing panels.

The main casing brackets, distributor tube and loose items, in a
plastic bag, are packed in the top fitment.

4.2 Casing Brackets

Fit the four casing brackets as shown in diagram 4.1, using eight
No.8 screws.

Push the captive nuts, supplied loose, on to the casing brackets
as shown in diagram 4.1.

4.3 Water Connections - Gravity Domestic Hot
Water and Pumped Heating

It is important that all connections are made as shown in
diagram 4.2.

Heating flow, any one of the four upper connections may be
used.

Domestic hot water gravity flow, any one of the three remaining
upper connections may be used.

Heating return, the distributor tube, packed in the top fitment,
MUST be fitted into either one of the front lower connections on
ALL installations, see diagram 4.3.

Domestic hot water gravity return, any one of the three remaining
lower connections may be used for the gravity domestic hot
water return.

Fit plugs into all unused connections.
Note, if only limited clearance is available, it is recommended

that the front connections are used.

4.4 Water Connections - Fully Pumped
Systems

It is important that all connections are made as shown in
diagram 4.4.

The water distributor, packed in the top fitment, MUST be fitted
into the return connection on ALL installations, see diagram 4.3.

Fit plugs into all unused connections.
Note, if only limited clearance is available it is recommended

that the front connections are used.

4.5 Thermostat Pocket

Fit the thermostat phial pocket into the front tapping adjacent to
the proposed heating flow connection and plug the other front
pocket connections.

The phial pocket and plug are in the loose items pack.
Carefully unwind the thermostat capillary, insert the phial fully

into the pocket and secure with the location washer behind the
retaining split pin, supplied in the loose items pack, see diagram

4.5.

4.6 Positioning/Connecting Boiler

Having selected the position of the boiler, make sure that
sufficient clearances will be left around the boiler as described
in Section1.7.

CAPTIVE
NUT

CASING
BRACKET

No.8 SCREW (8)

CAPTIVE
NUT

CASING
BRACKET

CASING BRACKETS FITTING

DOMESTIC GRAVITY
FLOW TO ANY OF THE
3 REMAINING UPPER
CONNECTIONS

DOMESTIC
GRAVITY
RETURN TO
ANY OF THE
3 REMAINING
LOWER CONNECTIONS

WATER CONNECTIONS - GRAVITY
DOMESTIC, PUMPED HEATING

UPPER MARKER
must lie between the
two outer NOTCHES

DISTRIBUTOR
TUBE
must be in
pumped return
connection

UPPER
MARKER

DISTRIBUTOR TUBE

Diagram 4.1

ALTERNATIVE
HEATING
FLOW
(Thermostat phial
and pocket must
be adjacent to
heating flow
connection)

ALTERNATIVE
HEATING
RETURN
With distributor
tube (not
shown)

Diagram 4.2

Diagram 4.3

1000

1309

1277

9 221758A

4 Installation

Fit the distributor tube, see diagram 4.2 or 4.4 for location, see
diagram 4.3 for alignment. Fit appropriate fittings and plugs into
the boiler connections.

IMPORTANT. Do not route any pipe across the front of the
boiler thermostat pocket, the controls, burner supply pipe,
combustion chamber cover or the flueway cleaning door. The
gas supply pipe should be run along the left hand side of the
boiler. Pipework must not be routed directly below the draught
diverter hood across the boiler, but it may be routed under the
edges of the draught diverter.

When suitable installation clearances are available, position
the boiler in readiness to connect pipework.

If suitable clearances are not available it will be necessary to
preplumb the gas and water connections before positioning the
boiler.

When the front connections are used it is essential that any
pipework or fittings be assembled as shown in diagram 4.6, that
is, do not stick out more than shown.

Make the water connections to the system pipework.
Make the gas connection to gas supply at the union gas service

cock. Test the complete gas installation for soundness and
purge in accordance with the current issue of BS6891.

4.7 Pump within Boiler Casing

If the pump is to be fitted inside the boiler casing connect it as
shown to either of the upper front flow connections, see diagram

4.7.
There must be sufficient clearance “X” between the pump body

and the flueway cleaning door to allow removal of the door.
Dependent upon the type of pump used, the flow pipe

arrangements and pump may require titling backwards to clear
the casing door.

THERMOSTAT
CAPILLARY

PHIAL
POCKET

SECURING THE
THERMOSTAT PHIAL

VIEW ON ARROW 'A'

BOILER

1870

LOCATION
WASHER

RETAINING
SPLIT PIN

Diagram 4.5

'A'

1524

57 MAX.
(21/4in.)

4.8 Flue Connection

The flue should be 150mm (6in) nominal diameter, refer to
Section 3 and diagram 1.1.

Fix and seal the flue to the hood in accordance with normal
practice.

ALTERNATIVE
FLOW POSITIONS
(Must be adjacent to
THERMOSTAT
PHIAL POCKET)

ALTERNATIVE
RETURN
POSITIONS
With distributor
tube (not shown)

WATER CONNECTIONS FULLY
PUMPED SYSTEMS

Diagram 4.4

1310

57 MAX.
(21/4in.)

PIPEWORK
CASING CLEARANCES

Diagram 4.6

Clearance 'X' must be left to enable cleaning
door removal and boiler servicing

175

'X'

(7)

FLUEWAY
CLEANING
DOOR

35 (13/8)

ALTERNATIVE
R.H. FLOW
CONNECTION

L.H. FLOW
CONNECTION

PUMP CLEARANCES

ISOLATING
VALVES

Diagram 4.7

0875

221758A

10

5 Casing Location / Fitting

5.1 Side Vent Grille

One vent grille is supplied with the boiler which can be fitted at
the rear of the left or right hand side casing. The grille is fitted
on the opposite side to any pipework connections.

Fit the grille, if required, to the side panel as shown in diagram

5.1 prior to fixing the side panel. The plastic pegs are a tight fit
and are best pushed home with a flat faced tool.

Do not use the grille if water connections are on both sides of the
boiler or if the boiler is screened by fixtures.

No. 8
SCREW (2)

1018

5.2 Side Casings

Fit side casing by locating their lugs into the lower slots in the
base tray, see diagram 5.2.

Secure the casing sides to the casing bracket at the front top.

5.3 Top Casing

The top casing can be fitted in two alternative positions. that is,
with either the front edge flush with the door or overhanging it,
see diagram 5.3.

For a flush fitting top casing, fit four plastic pegs in holes “A” as
shown in diagram 5.3. For overhanging top casing, fit four
plastic pegs in holes “B”. The plastic pegs are a tight fit so they
are best pushed home with a flat faced tool.

Fit the top casing by engaging the pegs into the holes in the side
casings and then makes sure they are fully engaged by pushing
the pegs down.

PLASTIC PEG

SIDE VENT GRILLE
(If required, will fit to
left or right side casing)

0885

CASING
BRACKET

No. 8
SCREW (2)

SIDE CASINGS FITTING

PLASTIC PEG (4)

CASING
BRACKET

BOILER
PLINTH

LOCATING
LUG AND
SLOT

Diagram 5.2

TOP CASING

1180

SIDE VENT GRILLE

SIDE CASING
(R.H. SHOWN)

Diagram 5.1

A

SIDE
CASING

B

A

(L.H.)

PEG POSITIONS IN TOP CASING
A = FRONT EDGE FLUSH
B = 10mm (3/8 in) FRONT OVERHANG

AB

AB

SIDE
CASING

DOOR

DOOR

TOP CASING FITTING

AB

SIDE
CASING

Diagram 5.3

B

AB

11 221758A

6 Electrical Wiring

6.1 Control Box Cable Connection

Remove the screw and cover from the mains inlet connector,
see diagram 6.1.

Using heat resistant flexible cable of suitable length and rating,
as Section 1.6, connect the cable to the terminals in the
connector. Secure the outer sheathing with the clamp.

Engage slots and lugs, replace connector cover and secure
with screw.

Connect mains inlet connector to the control box and use three
of the cable clips, supplied loose, pushed on to the edge of the
left hand panel in positions “CB” as shown in diagram 6.2 to
make sure that the cable does not touch any hot surfaces.

6.2 Circulation Pump Cable Connection

Heat resistant cable with a rating as stated in Section 1.6 must
be used for all wiring near the boiler, including the pump, if within
the boiler casing.

Support the pump cable away from hot surfaces if within the
boiler casing by pushing two cable clips, supplied loose, on to
the top edge of one side casing, as shown as “P” or “AP” in
diagram 6.2.

6.3 Flue Blockage Safety Device - Capillary
and Interrupter Electrical Leads

For transit the capillary is taped to the side of the boiler.
Remove tape and place capillary into cable clips provided, see

diagram 6.2.
Note: Capillary must not touch the heat exchanger side.
Secure the interrupter electrical leads so as not to strain them,

see diagram 6.2.

N

CABLE
CLAMP

MAINS INLET CONNECTOR

SAFETY DEVICE CAPILLARY
CLIP POSITION

P

AP

230

(9)

AP

230

(9)

COVER

L

E

CB

SLOTS

LUGS

Diagram 6.1

230

(9)

P

CB

0878

8064

25
(1)

6.4 System Controls

The electrical installation must be in accordance with the
current issue of BS7671.

The electrical isolator must isolate both the boiler and system
controls.

6.5 Testing

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

In the event of an electrical fault after installation of the boiler,
preliminary system checks must be carried out, that is, earth
continuity, polarity and resistance to earth as described in a
multimeter instruction book.

Fit 2 pump cable
clips at positions P

Alternative pump
cable clips (if feed
is on the left hand
side) at positions
AP

Fit 4 control
box feed cable
clips at positions

CAPILLARY
AND
INTERRUPTER
ELECTRICAL
LEADS CLIP

CB

CABLE CLIP POSITIONS

CB

CB

Diagram 6.2

221758A

12

7 Commissioning

P

M

K
(Shown
closed)

E

= OFF

L

= PILOT/IGNITION
= MAIN BURNER

C

A

F
SETTING
POINT

J

N

SETTING
POINT

H

K
(Shown
open)

A. GAS CONTROL KNOB J. PHIAL POCKET
B. THERMOSTAT CONTROL K. GAS SERVICE COCK
C. PIEZO IGNITION BUTTON L. DATA BADGE
E. VIEWING WINDOW M. GAS CONTROL VALVE
F. BURNER GAS RATE ADJUSTMENT N. PILOT ADJUSTMENT SCREW
G. BURNER PRESSURE TEST POINT P. FLUE BLOCKAGE SAFETY
H. CONTROL BOX DEVICE RESET BUTTON

G

B

8070

BOILER COMPONENTS

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

7.1 Preliminaries

The whole of the system, with the pump removed, should be
thoroughly flushed out with cold water.

Refit the pump and fill the system.
Examine for water soundness and vent all air from the system,

including the pump. Make sure that all valves are open.

7.2 Initial Lighting, Testing and Adjustment

Caution. The following should be carried out by a competent
person.

Identify the controls by reference to diagram 7.1.
Check that the gas service cock “K” is closed, indicator slot

vertical.
Make sure that the thermostat phial is fully inserted in the phial

pocket “J” and is securely located by the retaining split pin.
Check that the mains electrical supply is switched off.
Set thermostat control knob “B” to “O”.
Remove the burner pressure test point screw “G” and fit a

suitable pressure gauge.
Open gas service cock “K”, slot horizontal.
Note: Make sure the Flue Blockage Safety Device reset button

'P' is fully pushed in.
Turn gas control knob “A” to '

in. At the same time push and release button “C” until the pilot

' pilot ignition position and push

Diagram 7.1

burner lights, view through window “E”. At this stage air may be
present in the supply pipes so this operation may need to be
repeated.

When the pilot burner lights, keep knob “A” fully pushed in for
about 15 seconds. If the pilot burner fails to stay alight repeat
the operation only this time keep knob “A” pushed in for a little
longer.

Note: Should the boiler fail to operate correctly refer to the Fault
Finding - Section 10.

If gas control knob “A” is turned to ' ', a safety lock prevents
it being turned on again. No attempt should be made to push
in and turn knob “A” until three minutes have gone by.

Make sure that the pilot burner is alight and stable, see diagram

7.2, for flame dimensions, switch on the electrical supply. Set
any remote controls so that they are calling for heat. Turn
control knob “”A” to '
control knob “B” between “MIN” and “MAX”, the main burner will
light. “MAX” is about 82oC (180oF).

Test for gas soundness around the boiler gas components with
a suitable leak detection fluid.

Ten minutes after lighting, check the burner setting pressure
and adjust if necessary, as follows, remove cover “F”, see
diagram 7.1 and turn adjustment screw to obtain the required
heat input, turn anticlockwise to decrease, see diagram 7.1 data
label “L” for settings. Replace cover.

If any doubt exists the gas rate should be checked at the gas
meter, this should be in the range:

' main burner position. Set thermostat

13 221758A

7 Commissioning

Hideaway 120 - 4.4 to 5.2m3/h 125 to 148ft3/h
These figures are for guidance only.
Stick the self adhesive arrow indicator, from the loose items

pack, to the data label against the rating the boiler is set to.
Allow the water system to warm up and set the pump to give the

correct temperature difference of 11
return.

There should be no undue noise in the pipework or heat
emitters, no pumping over of water or entry of air at the open
vent above the cold water cistern.

Allow the water system to reach maximum working temperature
and examine for water soundness. Whilst hot the system should
be drained rapidly to complete the flushing process.

Refill the system, vent and check for water soundness.

o

C (20oF) between flow and

7.3 Operational Checks

Check operation of the flame failure device as follows, with the
main burner alight, turn the gas valve control knob “A” fully
clockwise to its stop ' ', this will put out the main and pilot
flames. The safety device should close within 60 seconds, a
click from the valve will indicate this.

Remove the pressure gauge and refit the pressure test point
screw “G”. Make sure that a gas tight seal is made.

Turn thermostat knob “B” to “O” and relight the pilot burner as
Section 7.2.

Do not attempt to adjust the thermostat calibration screw.
Relight the main burner.

FLAME
DIMENSION

3-4 (1/8)
SPARK
GAP

PILOT
BURNER
ASSEMBLY

PILOT FLAME AND
SPARK GAP DIMENSIONS

UPPER
HOOK

VIEW 1

13 (1/2 in.)
APPROX.

VIEWING
WINDOW

Diagram 7.2

STUD

DOOR
FASCIA

0890

1356

7.4 Spillage Test

Test the appliance spillage of the flue products at the draught
diverter as detailed in the current issue of BS5440 Part 1.

7.5 Completion and User Information

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

Hand the Instructions for Use to the user, for keeping and make
sure that they are understood.

Advise the user that 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.

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.

Advise that the boiler is fitted with a Flue Blockage Safety
Device and refer to the Instructions for Use.

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

Fit the plinth front by locating the sides over the boiler plinth then
lowering to engage the upper and lower hooks, see diagram

7.3.
Fit the door by locating the hooked runner at the bottom into the

slots in the side casings and pushing onto the studs on the side
casings.

LOWER
HOOK

VIEW 2

VIEW 1

VIEW 2

PLINTH / DOOR FITTING

PLINTH
FRONT

Diagram 7.3

221758A

14

8 Servicing

Servicing must be carried out by a competent person.
Before starting any servicing, turn off the gas and electrical

supply to the boiler.
Always test for gas soundness after completing any servicing

or replacement of gas carrying components.

8.1 Gain Access to Boiler

Pull door forwards at the top to disengage studs and lift to
release from the slots, see diagram 7.3.

Lift the plinth front up and forwards to withdraw, see diagram

7.3.
If the top casing is removed, care must be taken not to damage

or lose any plastic pegs when refitting, see Section 5.3.

8.2 Boiler Flueways

Unscrew the union nut securing the gas service cock to the gas
valve, see diagram 8.1.

Remove the mains inlet connector by pulling downwards, see
diagram 8.1.

Remove electrical connections from the interupter, see diagram

8.1.
Remove the retaining split pin from the phial pocket then

withdraw the phial and capillary, see diagram 4.5.
Remove the four screws retaining the combustion chamber

cover and burner assembly, see diagram 8.3.
Ease the gas service cock away from the gas valve and unhook

the pipe support bracket from the tie bar to enable the assembly
of cover, control box, gas valve and burner to be withdrawn
forward.

Remove graphite coated nuts to release baffle tray, remove
from combustion chamber taking care not to damage the
insulation material on th sides of the chamber.

Remove self-tapping screws which retain the flueway cleaning
door and lift door clear, see diagram 8.3.

Remove flueway baffles, see diagrams 8.6.
Place a sheet of paper in the combustion chamber to catch any

flue debris.
Access for flueway cleaning is made through the flueway

cleaning and combustion chamber openings.
Thoroughly clean boiler flueways and fins from the top and

bottom with a suitable stiff brush. Remove any debris from the
base of the combustion chamber.

Check that the flueways are clear, view with the aid of a mirror
or reflector.

GAS
SERVICE
COCK
(turn off)

MAINS INLET
CONNECTOR
(pull downwards)

(shown
closed)

ELECTRICAL
CONNECTIONS

ISOLATION OF
GAS AND ELECTRICITY

INTERUPTER
CONNECTIONS

BAFFLE
TRAY

PIPE
SUPPORT
BRACKET

COMBUSTION
CHAMBER
COVER

ACCESS FOR SERVICING

FLUEWAY
CLEANING
DOOR

Diagram 8.1

TIE BAR

GRAPHITE
COATED
NUT

SECURING SCREW (5)

Diagram 8.2

7992

8071

0908

SELF­TAPPING
SCREWS (4)

ACCESS TO FLUEWAY

15 221758A

Diagram 8.3

8 Servicing

8.3 Burners and Injectors

Follow instructions to remove the cover, burner and controls
assembly as described in Section 8.2.

Remove the screw securing the lint arrester gauze to combustion
chamber cover. Remove arrester by lifting slightly and
withdrawing forwards to clear burner supply pipe and
thermocouple etc., see diagram 8.4.

Remove the four burner securing nuts from the flange of the
burner supply pipe.

Remove the burner from the cover/supply pipe flange.
Remove the securing nut, washer and burner end cap from

burner, see diagram 8.5.
Clean the burner parts and lint arrester with a vacuum cleaner.
Check that the main burner injector is not damaged or blocked.

Clean or renew as necessary, do not clean with a wire or sharp
instrument. Refer to Section 9.2 and diagram 8.5.

When replacing the lint arrester locate the two lugs into the slots
on the combustion chamber cover and locate around the feed
pipe etc., then secure with the screw.

8.4 Service Checks

Inspect the thermocouple and pilot burner, clean or renew as
necessary.

Check the condition of the insulation panels in the combustion
chamber. Renew if necessary.

Check the condition of the seals on the flueway cleaning door
and the combustion chamber, renewing if necessary.

MAIN
BURNER (2)

INJECTOR (2)

SECURING
NUT (2+2)

REMOVAL OF BURNER

COMBUSTION
CHAMBER
COVER

LINT
ARRESTER

SECURING
SCREW

BURNER (2)

1275

BURNER
SUPPLY
PIPE

Diagram 8.4

1276

8.5 Reassembly

Make sure that the baffle tray is replaced and secured with the
graphite coated nut, previously removed.

Make sure that the thermostat phial is fully inserted into the phial
pocket. Position the location washer behind the retaining split
pin, see diagram 4.5.

8.6 Operational Check

Light the boiler and carry out the operational checks as described
in Sections 7.2 and 7.3.

BURNER
END CAP (2)

WASHER (2)

BURNER STRAP

SECURING
NUT (2)

SECURING NUT (2)
(GRAPHITE COATED)

BURNER SERVICING

BURNER
STRAP

Diagram 8.5

6116

BAFFLE

221758A

16

BAFFLES

HEAT
EXCHANGERS

Diagram 8.6

9 Replacement of Parts

Before removing or replacing any parts turn off the gas and
electrical supplies to the boiler.

Always test for gas soundness after replacing any gas carrying
components.

Replacement of parts is in the reverse order to removal unless
stated otherwise.

9.1 Gas Valve

Gain access to the boiler as Section 8.1.
Refer to the relevant parts of Section 8.2.
Disconnect the thermocouple nut, interrupter electrical

connections and pilot tube connections at the gas valve, see
diagram 9.1.

Support the valve and remove the four right hand flange screws
to disconnect the gas valve from the burner supply pipe.

Ease the gas service cock union out and remove the valve
taking care not to damage the “O” ring seal at the flange.

Inspect the condition of the “O” ring seal and renew if necessary.
Remove the union half and refit into replacement valve on the

inlet, left hand side. Use a little jointing compound, on external
thread only, to ensure gas soundness.

It will be necessary to purge air from the gas supply, relighting
should be carried out as Section 7.2.

9.2 Injectors

Gain access to the boiler as Section 8.1.
Refer to the relevant parts of Section 8.2 and 8.3.
Unscrew the injector from the manifold and renew as necessary.
When replacing the injector use a little jointing compound, on the

external thread only, to ensure gas soundness.
Replace thermostat phial.

9.3 Thermocouple

Gain access to boiler as Section 8.1.
Remove the lint arrester as Section 8.3.
Disconnect the thermocouple by unscrewing nuts at the gas

valve and pilot burner, see diagram 9.1 and 9.2. Withdraw the
thermocouple.

Replace the lint arrester as Section 8.3.

GAS
VALVE
PLUG

GAS
VALVE

INTERRUPTER
CONNECTIONS

REMOVAL OF GAS VALVE

PILOT
BURNER

SECURING SCREW (2)
AND NUT (2)

PILOT
INJECTOR

PILOT ASSEMBLY

8058

PILOT
TUBE NUT

GAS
OUTLET
FLANGE
SCREW
(4)

THERMOCOUPLE
NUT

Diagram 9.1

0989

SPARK
ELECTRODE

THERMOCOUPLE
NUT

IGNITION
LEAD
(CLEAR
END)

PILOT
TUBE
NUT

Diagram 9.2

9.4 Pilot Burner

Gain access to boiler as Section 8.1.
Remove cover and burner controls assembly, as relevant parts

of Section 8.2.
Remove lint arrester as Section 8.3.
Disconnect the ignition lead at the electrode, see diagram 9.2.

Disconnect the thermocouple nut at the pilot burner.
Disconnect the pilot tube nut, ease out the tube and injector

which is hooked on to the pilot tube.
Remove the nut retaining the spark electrode and remove.
Remove the two screws and nuts securing the pilot burner and

shield to the combustion chamber cover.
Reassemble in the reverse order, hooking pilot injector over

pilot tube olive when refitting.
Replace thermostat phial, Section 8.5.
Replace lint arrester, Section 8.3.
Check that the pilot flame length is as shown in diagram 7.2.

REAR
INSULATION PANEL

SIDE
INSULATION
PANEL

CLIP

BAFFLE
TRAY

CLIP

SCREW

GRAPHITE
COATED

INSULATION PANELS

17 221758A

NUT

Diagram 9.3

1274

IGNITION LEAD
(BLACK END)

THERMOSTAT
SECURING
SCREW (2)

CUT-OUT FOR
CAPILLARY

THERMOSTAT
AND CAPILLARY

9 Replacement of Parts

HOOK

7995

ELECTRICAL
CONTROL BOX
COVER

COVER
SECURING
SCREW

PIEZO UNIT

THERMOSTAT
CONTROL
KNOB

CONTROL BOX

SECURING SCREW (2)

9.5 Spark Electrode

Gain access to the boiler as Section 8.1.
Disconnect the thermocouple nut and withdraw thermocouple

from pilot burner, see diagram 9.2.
Disconnect the nut retaining the spark electrode and remove.
Check that the spark gap is as shown in diagram 7.2.

9.6 Insulation Panels

Gain access to the boiler as Section 8.1.
Remove the burner assembly as the relevant parts of Section

8.2.
Remove the two screws retaining each side insulation panel

within the combustion chamber and remove panel, see diagram

9.3.
Release the rear insulation panel upper clips and lift out panel.
Reassemble in reverse order.
Refit the thermostat phial as the relevant part of Section 8.5.

ELECTRICAL
CONTROL BOX

ELECTRICAL
CONNECTORS

Diagram 9.4

9.7 Boiler Thermostat

Follow the relevant instructions in Section 8.1.
Remove the mains inlet connector by pulling downwards, see

diagram 8.1.
Remove the retaining split pin from the phial pocket then

withdraw the phial and capillary, see diagram 4.5.
Pull off the thermostat control knob.
Gain access to inside of the control box by removing the

securing screw located at the top of control box and unhooking
at the bottom, see diagram 9.4.

Remove the two screws which secure the boiler thermostat to
the control box, see diagram 9.4.

Tilt the thermostat so that the electrical connections can be
removed.

Withdraw boiler thermostat from control box complete with
capillary tube and phial.

Refer to diagram 9.5 to connect electrical connectors.
Replace the thermostat phial as the relevant part of Section 8.5.
Make sure that the capillary is positioned so that it passes

through the cut out in the control box, see diagram 9.4.

221758A

18

9 Replacement of Parts

N
VIEW OF PLUG
WHEN REMOVED

L

E

THERMOSTAT

GAS VALVE

C

N/C

CONTROL BOX AND GAS VALVE WIRING

9.8 Piezo Unit

Pull door forward at the top to disengage the studs and lift to
release from slots, see diagram 7.3.

Remove mains inlet connector by pulling downwards, see
diagram 8.1.

Open the control box by removing securing screw and support
on the hook on the bottom of the control box cover, see diagram

9.4.
Disconnect the ignition lead at the piezo unit.
Note: To ease the removal of the piezo unit it is advisable to

temporarily remove the boiler thermostat from the control box.
Depress the retaining tabs and remove the Piezo unit.

GREEN/
YELLOW

230V~ 50Hz

MAINS SUPPLY

FUSED AT 3A

NL

CHASSIS

BLACK

EARTH

GREEN / YELLOW

BLUE

BROWN

Diagram 9.5

9.11 Flue Blockage Safety Device

Gain access to the boiler as Section 8.1.
Remove the electrical connections from the safety device body.
Remove the capillary from cable clips, see diagram 9.7.
To remove the phial assembly, first gain access through flue

cleaning door as Section 8.1.
Unscrew securing bolt and withdraw the phial assembly from

the flue, see diagram 9.8.
Remove the locknut securing the Flue Blockage Safety Device

to the bracket and withdraw the Flue Blockage Safety Device
and phial assembly, see diagram 9.6.

8079

9.9 Ignition Lead

Gain access to the boiler as Section 8.1.
Disconnect the ignition lead at the piezo unit, see diagram 9.4

and Section 9.8.
Remove the lint arrester gauze as the relevant parts of Section

8.3.
Disconnect the ignition lead at the spark electrode, see diagram

9.2.
When reconnecting the lead make sure that the clear end is

fitted to the spark electrode and that the black protective
sleeving is in place before fitting the lint arrester gauze.

9.10 Electrical Control Box

Gain access to the boiler as Section 8.1.
Disconnect the mains inlet connector, see diagram 8.1.
Remove the retaining split pin from the phial pocket then

withdraw phial and capillary, see diagram 4.5.
Disconnect the gas valve plug from the valve, see diagram 9.1.
Release the control box by removing the securing screw located

at the top of control box and unhooking at the bottom, see
diagram 9.4.

Pull the ignition lead off piezo unit, see diagram 9.4.
When refitting control box make sure the thermostat capillary is

positioned so that it passes through the cut out in the control
box, see diagram 9.4.

Refit thermostat phial, refer to Section 8.5.

CAPILLARY

ELECTRICAL
CONNECTIONS

ELECTRICAL CONNECTIONS

8056

FLUE BLOCKAGE
SAFETY DEVICE

SECURING
LOCKNUT

Diagram 9.6

19 221758A

9 Replacement of Parts

CAPILLARY

8066

6298

LOCATION STUD

SECURING NUT

CABLE CLIPS

FLUE
BLOCKAGE
SAFETY
DEVICE

CAPILLARY REMOVAL

Diagram 9.7

10 Fault Finding - Electrical

10.1 Electrical

Refer to functional flow diagram 10.1, electrical fault finding
chart, diagram 10.2 and wiring diagram 9.5.

IMPORTANT. The preliminary electrical system checks
contained in a multimeter instruction book are the first checks
to be carried out during and fault finding procedure. On
completion of the service fault finding task which has required
the breaking and remaking of electrical connections then checks.
earth continuity, polarity and resistance to earth must be
repeated.

10.2 Thermocouple

To test the thermocouple a meter with a range 0 to 30mV is
required together with a thermocouple interrupter test unit
similar to the British Gas Multimeter and interrupter.

Refer to thermocouple fault finding chart, diagram 10.3 and
diagnosis graph, diagram 10.4.

PHIAL ASSEMBLY REMOVAL

L

GAS VALVE
CONTROL SOLENOID

THERMOSTAT

C N/C

BLACK

BROWN

PHIAL

PHIAL ASSEMBLY

Diagram 9.8

L

N

VIEW OF
PLUG WHEN

BLUE

REMOVED

1073

N

10.3 Pilot and Ignition

Refer to pilot and ignition fault finding chart, see diagram 10.6
and 10.3.

10.4 Flue Blockage Safety Device

If the device operates it indicates there is a problem with the
chimney. Make sure that the air vents are free from obstruction.
Carry out spillage checks as BS5440 Part 1 and put right as
necessary.

221758A

FUNCTIONAL FLOW WIRING

20

Diagram 10.1

10 Fault Finding - Electrical

Carry out preliminary electrical checks to
make sure the electrical supply is available
at the boiler. Check that external controls
are calling for heat. Make sure that the
system is filled, the

device is reset, the gas supply is available
and the pilot is lit.

Isolate electrical supply to the
control box.
Remove the control box cover and
check all cables.

flue blockage safety

0899/A

Turn boiler thermostat to Max.
Is there continuity between
'C' and 'NC'.

YES

Turn boiler thermostat to 'O'.
Is there open circuit between 'C'
and 'NC'.

YES

Restore electrical supply with pilot
burner lit and boiler thermostat set
between 'MIN' and 'MAX', does the
main burner light.

YES

NO

Faulty thermostat.
Replace.

NO

NO

Turn boiler thermostat to "O'.
Does main burner extinguish.

Boiler controls in order.

ELECTRICAL FAULT FINDING

YES

Faulty gas valve.

NO

Replace.

Diagram 10.2

21 221758A

10 Fault Finding - Thermocouple

With the boiler cold, check connections of the thermocouple, boiler flue blockage safety device
and gas valve. Reset flue blockage safety device.
Disconnect flue blockage safety device connectors at points A and B at the gas valve,
see diagram Interrupter Electrical Connections.
Test continuity of the flue blockage safety device. Is there continuity?

YES

Re-connect boiler flue blockage
safety device to points A and B.
Disconnect thermocouple at
connection point D of the gas valve.
Test continuity between point C and the
body of the gas valve.
Is there continuity?

NO

YES

2327/B

NO

Faulty boiler flue blockage
safety device, renew.

Faulty flue blockage safety device
connectors into gas valve,
either at A or C.
Renew where faulty.

Test continuity of thermocouple between inner
connection point D and point E.
Is there continuity?

YES

Thermocouple and boiler flue blockage
safety device circuit satisfactory.

29

27
25
23
21

ABC

19

17

NO

1546

Faulty thermocouple, renew.

GAS VALVE

CONNECTION "A"

Diagram 10.3THERMOCOUPLE AND FLUE BLOCKAGE SAFETY DEVICE FAULT FINDING

5032

FLUE

BLOCKAGE

SAFETY

DEVICE

CONNECTION "E"

CONNECTION "B"

15

13
11

Open Circuit Voltage (millivolts)

9

0246810121416182022

Closed Circuit Voltage (millivolts)

DIAGNOSIS GRAPH FOR
THERMOCOUPLE CIRCUIT

221758A

Diagram 10.4

CONNECTION

"D"

INTERRUPTER ELECTRICAL
CONNECTIONS

22

POINT "C"

Diagram 10.5

10 Fault Finding - Pilot

START HERE

Check gas line - open all cocks,
rectify any blockages, purge out
any air. Check

safety device is reset,
check all thermocouple circuit
connections are clean and in good
condition.

flue blockage

Does pilot light?

NO YES NO YES

Apply match to pilot burner instead
of pressing piezo unit button.
Does pilot light?

NO YES

Undo tubing nut at pilot burner.
Press gas valve knob.
Does gas flow freely?

NO YES

Rectify blockage in pilot injector,
or renew pilot injector.

0905A

Does pilot stay alight when
gas valve knob is released?

PILOT SATISFACTORY

Does pilot flame
envelope thermocouple?

NO YES

Check aeration. If necessary ­Clean pilot, rectify blockage in
pilot injector, or replace.

Undo tubing nut at pilot outlet of
gas valve. Press gas valve knob.
Does gas flow freely?

NO YES

Change blocked pilot tube.

Change gas valve.

Check thermocouple circuit using
Thermocouple Fault - Finding
diagram.

On pressing piezo unit button
is there a spark across
electrode gap?

NO YES

Pull ignition lead off electrode.
Hold end of lead close to pilot
burner and operate piezo unit.
Is there a spark across gap?

NO YES

Pull ignition lead off piezo unit.
Using blade of a screwdriver,
touch unit chassis and leave
approx. 4mm gap from connection
tag on piezo unit. Operate piezo.
Is there a spark across gap?

NO YES

Change
piezo unit.

Change
ignition unit.

PILOT / IGNITION FAULT FINDING

Check electrode gap. Reposition,
or replace electrode as necessary.

Diagram 10.6

23 221758A

11 Spare Parts

11.1 Ordering

When ordering spare parts quote the part number and description, stating the model and serial number off the data label “L”, see
diagram 7.1.

If ordering from British Gas also quote the GC appliance number off the data label and the required spare part GC number.

1

8067

3

2

13

12

5

11

7

4

10

8

9

6

Diagram 11.1

Key No Part No Description GC Part No

1 203323 Gas control valve 394 348

2 205746 Injector - 120 x2

3 203414 Pilot burner 312 246
4 203508 Injector - pilot 395 674

5 900001 Thermocouple c/w nut
6 202571 Thermostat c/w screws

7 204687 Control knob assy - thermostat

8 202713 Piezo unit
9 WW4609 Ignition lead assembly 136 464

10 202605 Spark Electrode 395 720
11 800726 Flue Blockage Safety device 278 410

12 208302 Sight glass 312 419

13 212031 "O" Ring - gas valve 312 602

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

221758A

24