Glowworm Hideaway 40B Operating manual

Hepworth Heating Ltd.,
Nottingham Road, Belper, Derbyshire. DE56 1JT
General/Sales enquiries:
Tel: [phone] Fax: [phone]
One Contact Local Service
Customer Services:
Tel: [phone]
Fax: [phone]
221691B.12.00
All replacement parts
All labour charges
All call-out charges
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
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
Balanced Flue Boiler
This is a Cat I2H Appliance
BS 6332
BS 5258
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.
Tobeleftwiththeuser
❏
✔
❏
✔
❏
✔
Instructions for Use
Installation and Servicing
G.C. No. 41 313 16
REGISTER YOUR GLOW-WORM APPLIANCE
FOR 1ST YEAR GUARANTEE PROTECTION
CALL 0208 247 9857
40B
Hideaway
0863

2
221691B
Testing and Certification
Thisboileristestedandcertificatedforsafetyandperformance. Itisthereforeimportantthatnoalterationismadetotheboiler,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 1.3.
CE Mark
This boiler meets the requirements of Statutory Instrument No. 3083 The boiler (Efficiency) Regulations, and therefore is deemed
tomeettherequirementsofDirective92/42/EEContheefficiencyrequirementsfornewhotwaterboilersfiredwithliquidorgaseous
fuels.
Type test for purposes of Regulation 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, 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 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
notcauseaproblem,but in caseofskincontact,washwithcoldwater. If swalloweddrinkplentyofwaterand seekmedical attention.
Important Information
Introduction 3
Lighting the Boiler 4
General Data 1 5
Water Systems 2 7
Flue and Ventilation 3 8
Installation 4 10
Casing Location / Fitting 5 12
Electrical Wiring 6 14
Commissioning 7 15
Servicing 8 17
Replacement Parts 9 19
Fault Finding 10 21
Spare Parts 11 24
CONTENTS DESCRIPTION SECTION PAGE No.
INSTRUCTIONS
FOR USE
INSTALLATION
INSTRUCTIONS
SERVICING
INSTRUCTIONS

3221691B
Instructions for Use
Notes and General Information
Pleasereadtheseinstructionsandfollowthemcarefullyforthe
safe and economical use of your boiler.
The boiler is automatic in operation, once the pilot has been lit
and the controls 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
Inyourowninterestsandthatofsafety,itisthelawthatALLgas
appliances are installed by a competent person in accordance
with the current issue of the above regulations.
Warning
Make sure that nothing obstructs the rear side grille or
clearances. See page 6 for minimum clearances.
Boilers Installed in a Compartment
If the boiler is fitted in a compartment, cupboard etc., do not
obstructthepurposebuiltcompartmentventsorthegrilleonthe
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 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 servicing must be carried out by a competent
person.
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.
To obtain service please call your installer or Heatcall (Glow-
worm’sownserviceorganisation) 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.
Boiler Electrical Supply
WARNING. This boiler must be earthed.
The boiler must only be connected to a 240V~50Hz supply
protected by a 3A fuse, maximum.
All wiring must be in accordance with the current issue of
BS7671.
Heatresistantflexiblecablehavingaconductorsizeof0.75mm2,
to the current issue of BS6500 Table 16 must be used.
Diagram 1
40 BALANCED FLUE
GAS CONTROL KNOB
OFF
PILOT / IGNITION
MAIN BURNER
SETTING
POINTS
PIEZO
IGNITION
BUTTON 'C' GAS CONTROL
KNOB 'A'
THERMOSTAT
CONTROL
KNOB 'B'
E
5993

4
221691B
To Connect an Electrical Plug
The standard 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 Blue cable must be connected to the terminal marked “N”
or “Black”.
TheBrowncablemust beconnectedtotheterminal marked“L”
or “Red”.
TheGreen and yellow cablemust be connected tothe terminal
marked “E” or “Green” or the earth symbol .
To Light the Boiler
WARNING. If the pilot light goes out for any reason, do not
attempt to relight until 3 minutes have elapsed.
Remove the door by pulling forwards with the fascia at the top.
Lift up to disengage from the bottom side lugs.
Refer to diagram 1 to identify controls.
Check that the mains electrical supply to the boiler is switched
OFF.
Pushinslightlyandturngascontrolknob“A”clockwiseuntil
is against its setting point.
Turn thermostat control knob “B” anticlockwise until “O” is
against its setting point.
Pushinslightlyandturngascontrolknob“A”anticlockwiseuntil
is against its setting point, then depress fully and hold in.
Push in 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 3 minutes, then repeat the
lightingprocedureonlynowkeepcontrolknob“A”pushed infor
a little longer before releasing.
Press in and turn gas control knob “A” anticlockwise until is
against its setting point.
Ifthegascontrolknob“A”isturnedto asafetylockprevents
it being turned on again for a short period. No attempt should
be made to relight the pilot until 3 minutes have elapsed.
Make sure that the pilot is alight and stable then switch on the
electrical supply.
Set any system controls to “ON” or “HIGH”.
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 82oC (180oF).
Refit the door by locating the hooked runner at the bottom into
the slot in the side panels and pushing onto the studs.
To Turn the Boiler Off
For short periods, turn the boiler thermostat control knob “B”
anticlockwise to “O”. The pilot will stay alight. To relight the
main burner turn thermostat control knob “B” clockwise to the
desired setting between “MIN” and “MAX”.
For longer periods, depress slightly and turn gas control knob
“A” fully clockwise until is against its setting point. Turn
thermostat control knob “B” anticlockwise to “O”. Isolate the
boiler from the electrical supply. Follow full lighting procedure
to relight. Refer also to “Protection Against Freezing”.
Gas Leak or Fault
Ifagasleakfaultexistsorissuspectedtheboilermustbeturned
off,includingtheelectricalsupplyandmustnotbeuseduntilthe
fault has been put right. Advice/help should be obtained from
thelocalgasundertakingoryourinstallation/servicingcompany.
Protection Against Freezing
Iftheboileristobeoutofuseforanyperiodoftimeduringsevere
weatherconditionswerecommend the wholesystemincluding
the boiler, be drained off to avoid the risk of freezing up. If an
immersion heater is fitted to the hot water cylinder make sure it
is switched off.
Sheet Metal Parts
WARNING. Thisboilercontainsmetalparts(components)and
careshouldbetakenwhenhandlingandcleaning,withparticular
regard to edges.
Cleaning
Keep the casing clean by wiping it 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.
Pleasequotethenameoftheboileranditsserialnumberwhich
can be found on the data label, positioned on the boiler top, to
the rear of the inclined flueway cleaning door.
Clearances
Minimumclearancesmustbe leftaroundtheboileras shownin
diagrams 1.3, 1.4 & 1.5.
Instructions for Use

5221691B
General Data
Sheet Metal Parts
WARNING. Wheninstallingorservicingthisboiler,careshould
betakentoavoidanypossibilityofpersonalinjurywhenhandling
the edges of sheet metal parts.
Important Notice
This boiler is for use only on G20 gas.
Whereverpossible,allmaterials,appliancesandcomponentsto
beusedshallcomplywiththerequirementsofapplicableBritish
Standards.
Where no British Standard exists, materials and equipment
should be fit for their purpose and of suitable quality and
workmanship.
1.1 Data
Approximate weight of complete boiler : 79kg (174lb)
Water content : 5.76 litre (1.27gallons)
Gas connection : Rc1/2(1/2in BSPT)
Water connection : Rc1 (1in BSPT)
Injector 40B : 3.40mm
Electrical supply : 240V~50Hz, fused 3A
Burner : Aeromatic
All dimensions are given in millimetres (except as noted) .
The Seasonal Efficiency Domestic Boilers UK (SEDBUK)
is 71.5%.
ThevalueisusedintheUKGovernment’sStandardAssessment
Procedure (SAP) for energy rating of dwellings. The test data
from which it has been calculated have been certified by B.S.I.
ABCDE✝FG H J K L MN P
mm 300 118 558 294 225 533 3 300 445 121 132 664 292 398
in. 113/445/822 111/287/821 1/8113/4171/243/451/4261/8111/2155/8
GENERAL DIMENSIONS - given in millimetres (Approx. inches) Diagram 1.1
0684
K
✽ Refer to BOILER CASING
HEIGHT diagram
P
M
LN
H
J
D
C
B
E
✽
G(MIN.)
✝ F(MIN.)
C
L
C
L
L
C
✝ A SPECIAL TOP CASING
TO SUIT 600mm (235/8 in.)
WORKTOPS IS AVAILABLE
A
WATER CONNECTIONS
Rc1 (1in. B.S.P.T.)
WATER CONNECTIONS Rc1 reduced
with DISTRIBUTOR TUBE to
Rc 3/4(3/4in. B.S.P.T.) (pumped return)
GAS CONNECTION
Rc 1/2(1/2in. B.S.P.T.)
1.2 Range Rating
Thisboilerisrangeratedandmaybeadjustedtosuitindividual
system requirements. The table gives settings and outputs.
Theboilerinputassuppliedispresettothemaximumheatinput
and should be adjusted to suit system requirements.
Theindicatorarrowshouldbestuckonthedatalabeltoindicate
the adjusted setting. The arrow is supplied in the loose items
pack.
RANGE RATING
NOMINAL kW
HEAT INPUT
(GROSS) Btu/h
11.23 13.01 14.79
38,300 44,400 50,450
min medium max
BURNER mbar
SETTING
PRESSURE in.w.g
(HOT)
6.6 8.9 11.6
2.6 3.6 4.6
NOMINAL kW
HEAT
OUTPUT Btu/h
8.79 10.26 11.72
30,000 35,000 40,000
K7218
INJECTOR

6
221691B
1.3 Statutory Requirements
The installation of this must be carried out by a competent
personandmustbeinaccordancewiththerelevantrequirements
of the current issue of:
Manufacturer’s instructions supplied.
The Gas Safety (Installation and Use) Regulations, Building
Regulations, Local Water Company Bye-laws, The Building
Standards (Scotland) Regulations, (applicable in Scotland),
HealthandSafetyatWorkAct,ControlofSubstancesHazardous
to Health, Electricity at Work Regulations and any applicable
local regulations.
Detailedrecommendationsarecontainedinthecurrentissueof
the following British Standards and Codes of Practice,
BS6891, BS5440 Part 1 and 2, BS6798, BS5449, BS5546,
BS6700, BS7478, BS7593, BS7671.
Manufacturer’s instructions must not be taken as overriding
statutory requirements.
1.4 B.S.I Certification
This boiler is certificated by B.S.I., for safety and performance.
Itis, therefore, important that no alteration ismade to theboiler
unless agreed, 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
infringe the current issue of the Statutory Requirements.
1.5 Gas Supply
The gas installation should be fitted in accordance with the
current issue of BS6891.
The supply from the governed meter must be of adequate size
toprovideasteadyinletworkingpressureof20mbar(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 shall be of the approved type
and shall be connected in accordance with the current issue of
BS7671 and any local regulations which apply.
Connection of the boiler and any system controls to the mains
supply through an unswitched shuttered socket outlet and 3A
fused 3 pin plug, both to the current issue of BS1363.
Alternatively, a 3A fused double pole isolating switch may be
used, having a minimum double pole contact separation of
3mm, serving only the boiler and system controls.
Heat resistant cable of at least 75mm2(24/0.20mm), to the
current issue of BS6500 Table 16, must be used for all
connections within the boiler casing, to the control box, pump
etc.
1.7 Boiler Location
Thecasingcanbefittedtotheboileratvariousheights. Thetop
casing can be discarded if preferred, when fitting the boiler
under a low worktop or fixture. Refer to diagram 1.2.
The boiler must stand on a level floor, conforming with local
authority requirements and building regulations.
BOILER CASING HEIGHT(S) Diagram 1.2
MAX.900 (351/2in.)
MID. 890 (35in.)
MIN. 860 (34in.)
MAX.867 (341/8in.)
MID. 857 (333/4in.)
MIN. 827 (321/2in.)
BOILER
WITH TOP
CASING
BOILER
WITHOUT
TOP CASING
BOILER CASING ALTERNATIVE
HEIGHT POSITIONS
MIN.
MAX.
MIN.
MAX.
MID. MID.
To
floor
level
FLOOR
LEVEL
0982
General Data
Diagram 1.3
Diagram 1.4
MINIMUM CLEARANCES
LEVEL WITH WORKTOP
MINIMUM CLEARANCES
UNDER WORKTOP, FIXTURES
0866
320 MIN.
(125/8in.)
320 MIN.
(125/8in.)
CUPBOARDS
WORKTOP
0865
10
(3/8in.) 10
(3/8in.)
10
(3/8in.) 10
(3/8in.)
3 (1/8in.)
BOILER
WITH
TOP
CASING
BOILER
WITHOUT
TOP
CASING
CUPBOARD
CUPBOARD
CUPBOARD 10 (3/8in.)
WORKTOP OR FIXTURE
BOILER BOILER
5
(3/16 in.)
10
(3/8in.)

7221691B
FRONT CLEARANCE Diagram 1.5
0906
700 (271/2 in.) BOILER
WALL OR
FIXTURE
1 General Data
The base temperature is within the requirements of the current
issue of BS5258. The boiler may stand on a wooden floor but
ametal base plate is required to protect plastic tiles andsimilar
floor coverings.
When the boiler is to be installed level with work surfaces and
the like, minimum clearances should be provided as shown in
diagram 1.3. Work tops which overhang the cupboard sides,
almost in contact with the casing top, require a larger minimum
air gap. Flush sided fixtures require the same overall minimum
space but can have a reduced air gap on one side.
Boilerstobeinstalledunderworktopsorfixtures,withorwithout
the casing top fitted should be positioned to provide minimum
clearances as shown in diagram 1.4. To facilitate minimum
clearances it may be necessary to modify kitchen units and
fixtures.
A front access clearance should be provided as shown in
diagram 1.5.
The boiler may be installed in any room, although particular
attention is drawn to the requirements of BS7671 with respect
to the installation of a boiler in a room containing a bath or
shower. Any electrical switch should be so positioned that it
cannot be touched by a person using the bath or shower. The
electrical provisions of the Building Standards (Scotland)
Regulations apply to such installations in Scotland.
Wheretheinstallationoftheboilerwillbeinanunusuallocation,
special procedures are necessary the current issue of BS6798
gives detailed guidance on this aspect.
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. Detailsofessentialfeaturesofcupboardorcompartment
design are given in the current issue of BS6798.
2Water Systems
2.1 Water Pressure Head
Theboilershallonlybeconnectedtoacisternwatersupplywith
a minimum head of 1metre (3ft3in) and a maximum head of
27metres (90ft) which has an open vent in the system.
Theworkingpressuremustbewithintherange0.1barto2.7bar
(1.3 to 39lbftin2).
TheboilerMUSTNOTbe connected to a sealed water system.
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 the inhibitor manufacturers so that they can
recommend their most suitable product.
Whenusingin an existing system take specialcareto drain the
entire system, including the radiators, then thoroughly cleaned
out before fitting the boiler whether or not adding an inhibitor.
Diagram 2.1
0869
27metre
Max.
PUMP
To Heating
Circuit
INDIRECT
CYLINDER
22mm VENT
15mm COLD FEED
REFER TO BS 5546
28mm
Distributor tube in
pumped return
connection
BOILER
C
L
DRAIN OFF
COCK
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-Conservationoffuelandpower,1995edition-Appendix
G, table 4b.

8
221691B
Diagram 2.2
FULLY PUMPED SYSTEM
(DIAGRAMMATIC)
2 Water Systems
0870
1 metre
MIN.
27metres
MAX.
PUMP
To Heating
Circuit
TO INDIRECT
CYLINDER
22mm VENT
15mm
COLD FEED
Distributor tube in
pumped return
connection
BOILER
C
L
DRAIN OFF
COCK
PRESSURE LOSS OF BOILER Diagram 2.3
0872
600
500
400
300
200
100
0
12
8
4
0
0481216 20 24 28
FLOW RATE (LITRES/MINUTE)
WATER PRESSURE LOSS (mm HEAD OF WATER)
WATER PRESSURE LOSS (INCHES HEAD OF WATER)
24
16
800 32
28
20
700
0123456
FLOW RATE (GALLON/MINUTE)
2.3 Gravity Domestic and Pumped Heating
Itisrecommendedthatacylinderthermostatis used to prevent
the stored water temperature becoming unnecessarily high
when the central heating pump is off.
The domestic primary flow and return must be 28mm o.d. The
installation must comply with the current issue of BS5546 and
BS6700, see diagram 2.1.
Iftheaboveconditionscannotbemet,itissuggestedthatafully
pumped system be used.
2.4 Pumped Heating and Hot Water
Where a single flow and return is taken from the boiler, a
minimum static head of 1metre (3ft3in) must be provided
between the water line of the feed tank and the centre of the
waterway, see diagram 2.2.
2.5 Circulation Pump
Normallythepumpshouldbesettogiveatemperaturedifference
of11oC(20oF)acrosstheboiler. Attheappropriatepumpedflow
rate the pressure loss through the boiler can be found from the
graph, diagram 2.3.
Use a pump with integral valves or fit isolating valves as close
to the pump as possible.
Note: If the pump is to be fitted inside the boiler casing a heat
shield kit is required. Kit No. 425837.
2.6. Cylinder
Forall systems supplying domestic hotwater 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 draining tap must be provided at the lowest points of the
system which will allow the draining of the entire system,
including the boiler and hot water cylinder.
Draining taps should be to the current issue of BS2879.
3 Flue and Ventilation
3.1 Flue
Detailed recommendations for flues are given in the current
issue of BS5440 Part 1.
Theboilermustbeinstalledsothattheflueterminalisexposed
totheexternalair. Itisimportantthatthepositionallowsthefree
flow of air across it at all times.
3.2 Terminal Positioning
The minimum acceptable spacings for the terminal to
obstructions,otherterminalsandventilationopeningsaregiven
in diagram 3.1.
Carportorsimilarextensionsofaroofonly,orroofandonewall,
require special consideration with respect to openings, doors
and windows under the roof. Care is required in protecting the
roofifmadefromplasticsheeting. Seekfurtheradviceifthecar
port consists of a roof and two or more walls from the local gas
undertaking.
Wheretheterminaliswithin850mm(34in)belowplasticguttering,
an aluminium shield 1.5metres (5ft) long should be fitted to the
underside and immediately beneath the guttering.
The air inlet and products outlet duct and the terminal of the
boiler must not be closer than 25mm (1in) to combustible
material.
3.3 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
documentIGE/UP/7/1998. Ifindoubtseekadvicefromthelocal
gas undertaking or Hepworth Heating Ltd.

9221691B
Under Car Port etc.
H,I
JD
F
K
A
A
FGEA
GG
B,C B,C
FF
K
K
K
C
LL
G
G
3 Flue and Ventilation
1112
ADIRECTLY BELOW AN OPENABLE mm
WINDOW, AIR VENT, OR ANY
OTHER VENTILATION OPENING 300
BBELOW GUTTER,DRAIN/SOIL PIPE 300
CBELOW EAVES 300
DBELOW A BALCONY OR CAR PORT 600
E FROM VERTICAL DRAIN PIPES
AND SOIL PIPES 75
FFROM INTERNAL OR EXTERNAL
CORNERS 600
GABOVE ADJACENT GROUND OR
BALCONY LEVEL 300
HFROM A SURFACE FACING
THE TERMINAL 600
IFACING TERMINALS 600
JFROM OPENING (DOOR/WINDOW)
IN CARPORT INTO DWELLING 1200
KVERTICAL FROM A TERMINAL 1500
LHORIZONTALLY FROM A TERMINAL 300
MINIMUM SITING DIMENSIONS FOR
BALANCED FLUE TERMINALS
POSITION MINIMUM
SPACING
Diagram 3.1
3.4 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
aminimumof50mmclearancefromanypartoftheterminaland
be central over the terminal.
Guards are available from:
Tower Flue Components Ltd.,
Morley Road,
Tunbridge,
Kent.
TN9 1RA
quoting reference type “F”
3.5 Wall Thickness
Check the wall thickness where the boiler is to be fitted.
Flues available are:
Standard Pack,
part No.424671,280 to 410mm (11 to 16in).
Short Pack,
part No. 424672,150 to 280mm (6 to 11in).
Extension Kit,
part No. 424680 + standard pack, 410to610mm(16to24in).
3.6 Room Ventilation
The boiler is room sealed and does not require the room or
space containing it to have permanent air vents.
3.7 Cupboard and Compartment Ventilation
Wheretheboilerisfittedinacupboardorcompartment,thehigh
and low level permanent air vents must have effective areas in
accordance with “Compartment Air Vent Table.
Boththehighandlowlevelairventsmustcommunicatewiththe
same room or must both be on the same wall to outside air.
FROM
OUTSIDE
COMPARTMENT AIR VENT TABLE
COMPARTMENT
VENTILATION
REQUIREMENTS
68cm211in268cm211in2
VENTILATION
FROM ROOM
OR SPACE 136cm222in2136cm222in2
HIGH LEVEL LOW LEVEL
VENT AREA VENT AREA

10
221691B
CASING BRACKETS FITTING Diagram 4.1
4 Installation
0888
FRONT
CASING
BRACKET
No.8 SCREW (8)
CAPTIVE
NUT
UPPER CASING
BRACKET
CAPTIVE
NUT
Before fixing the boiler make sure that the location selected is
in accordance with the requirements of Section 1.7.
4.1 Unpacking
Theboilercasingpanelsarepackedseparatelywithinthemain
carton and are designed to enable gas and water connections
to be made before fitting the casing panels.
The casing brackets, distributor tube and loose items, in a
plastic bag, are packed in the top fitment.
4.2 Casing Brackets
Fit the two upper and two front casing brackets shown in
diagram 4.1, using eight of the No.8 screws.
Pushthecaptivenuts,suppliedloose,ontothecasingbrackets
as shown in diagram 4.1.
4.3 Water Connections - Gravity Domestic and
Pumped Heating
Fit suitable fittings into the boiler tappings, see diagram 4.2.
Make sure that all pipes are taken backwards and will clear the
casings, see diagram 1.1.
Heating flow: Any one of the four upper connections may be
used.
Domesticflow: Anyoneofthethreeremainingupperconnections
may be used.
Heating return: The water distributor tube must be fitted into
either of the front lower connections on all installations, see
diagram 4.3. This tube is packed in the top fitment.
Domestic return: Any one of the three remaining lower
connections may be used for the gravity domestic hot water
return.
Fit plugs into any unused boiler tappings.
4.4 Water Connections - Fully Pumped
Systems
Fit suitable fittings into the boiler tappings as required, see
diagram4.4. Makesurethatallpipesaretakenbackwardsand
will clear the casings.
It is important that all connections are made as shown in
diagram 4.4.
Fit the water distributor tube into the return connection, see
diagram 4.3. This tube is packed in the top fitment.
Fit plugs into any unused boiler tappings.
4.5 Pump in Boiler Casing
If the pump is to be fitted inside the boiler casing, see diagram
6.2, ensure that a heat shield kit is obtained and fitted
(Kit No. 425837).
The kit contains a flueway cleaning door with heat shield
(attached).
DISTRIBUTOR TUBE Diagram 4.3
Diagram 4.2
WATER CONNECTIONS - GRAVITY
DOMESTIC, PUMPED HEATING
0871
MARKERS
DISTRIBUTOR TUBE
MUST BE IN PUMPED
RETURN CONNECTION
Notch on DISTRIBUTOR
must lie within the shaded
area, BETWEEN TWO
MARKERS
ALTERNATIVE
HEATING
RETURN
With distributor
tube (not shown)
ALTERNATIVE
HEATING OR
DOMESTIC
HOT WATER
FLOW
GRAVITY
DOMESTIC
RETURN TO
ANY OF THE
3 REMAINING
LOWER CONNECTIONS
0873

11 221691B
Diagram 4.4
WATER CONNECTIONS FULLY
PUMPED SYSTEMS
4 Installation
0874
ALTERNATIVE
FLOW
POSITIONS
ALTERNATIVE
RETURN
POSITIONS
With distributor
tube (not shown)
4.6 Pipework
When the front tappings are used, it is essential that any
pipework of fittings do not project more than shown in diagram
4.5.
WhenusingareartappingwithRc(1inBSP)fittingfor28mmod
pipework,itisrecommendedthatashortnippleandanRthread
(BSP) to copper elbow is used. If the pipework is required to
runbacktothewall,makesurethatitwillcleartheboilerairduct
and,ifworkingtominimumclearance,doesnotstickouttoofar
from the boiler, see diagram 4.6.
Donotroute any pipework, water orgas, across the front ofthe
thermostat pocket, controls or combustion chamber cover.
Thegaspipeworkmustbealongtherighthandsideoftheboiler.
4.7 Balanced Flue Terminal
(Standard and short flue)
Mark out and cut a hole through the wall where the boiler is to
be installed, to the dimensions shown in diagram 4.7, after
checking that sufficient clearances will be left around the boiler
as described in Section 1.7.
Place the boiler in position. The balanced flue ducting will
project into the prepared hole in the wall.
Make a good seal around the boiler air duct on the inside wall.
Takethebalancedflueassemblyfromitscartonandremovethe
four screws to release the outer baffle, see diagram 4.8.
Remove the four outer wire guards then pull off the inner baffle
and flue duct assembly.
Place the air duct assembly into the hole in the wall from the
outside,engagingitaroundtheairducton theboilerandsliding
it until the wall plate contacts the outer wall surface.
Sealthejointintheairductswiththeyellowtapeprovided. Tape
four pieces into the four inside corners, followed by four along
the joints, overlapping the corner pieces, to make a good seal.
Allow a minimum of 20mm (3/4in) overlap of ductings.
Cementaround the wall plate tomake good and weatherproof.
Refit the inner baffle and flue duct assembly, sealing the joint
with the heat resistant semi-transparent tape provided.
Refit wire guards, outer baffle and secure with screws. Diagram 4.5
Diagram 4.6
PIPEWORK CASING
CLEARANCES
REAR CONNECTION
PIPEWORK (28mm)
BOILER 57 MAX.
(2 1/4in.)
'A'
VIEW ON ARROW 'A'
57 MAX.
(2 1/4in.)
1524
1525
57 MAX.
(2 1/4in.)
VIEW ON
ARROW 'B'
'B'
BOILER
57 MAX.
(2 1/4in.)
FOR
MINIMUM
CLEARANCE

12
221691B
;;
;;; ;;;
;;; ;;; ;;; ;;
Diagram 4.7
PREPARED HOLE IN
THE WALL DIMENSIONS
4 Installation
240
(91/2in.)
BALANCED
FLUE DUCT
FROM BOILER 360
(141/4in.)
485
(19 in.)
PREPARED
HOLE IN
THE WALL
3 (1/8 in.)
MIN.
0876
Diagram 4.8
TERMINAL AND AIR DUCT -
STANDARD OR SHORT
0891
BOILER AIR DUCT WALL
PLATE INNER BAFFLE/
FLUE DUCT
ASSEMBLY
SCREW (4)
OUTER BAFFLE
WIRE GUARDS
AIR DUCT
ASSEMBLY
4.8 Boiler Connection
Connect the boiler to the system pipework.
Make the gas connection to the service cock, at the lower right
hand side of the boiler.
5.1 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 where no water pipes
are connected, as shown in diagram 5.1 before fixing the side
panel. Theplasticpegsareatightfitandarebestpushedhome
with a flat faced tool.
Discard the grille if the water connections are made on both
sides of the boiler or if the boiler is screened by fixtures.
5.2 Side Casings
Fit the side casings by locating their lugs into the appropriate
slot in the boiler plinth, see diagram 5,2, depending on the
required height, see Section 1.7.
Secure the casing sides to the front upper brackets.
5 Casing Location / Fitting

13 221691B
SIDE VENT GRILLE Diagram 5.1
SIDE VENT GRILLE
(If required, will fit to
left or right side casing)
PLASTIC PEG
SIDE CASING
(R.H. SHOWN)
0885
5 Casing Location / Fitting
5.3 Top Casing
Fitfourplastic pegsintotheappropriateholesinthetopcasing,
if being fitted, see diagram 5.3. The plastic pegs are a tight fit
andarebestpushedhomewithaflatfacedtool. Thetopcasing
can be arranged to fit flush with or overhang the door. The top
casing is reversible to match, when level with, square or rolled
edge work surfaces.
Push the top casing on to all four side casing locations. From
inside the casing check that all rivets have located correctly.
For boilers fitted under work tops, not using the top casing, the
strap should be fitted using two No.8 screws, see diagram 5.4.
TOP CASING FITTING Diagram 5.3
STRAP FITTING (No top casing) Diagram 5.4
0909
PEG POSITIONS IN TOP CASING
A = FRONT EDGE FLUSH
B = 10mm (3/8in) FRONT OVERHANG
AB AB
SIDE CASING
DOOR BOILER SHOWN WITH
ROLLED EDGE FLUSH
SIDE CASING
DOOR BOILER SHOWN WITH
SQUARE EDGE FLUSH
AB AB
No.8 SECURING
SCREW
SIDE CASING
(R.H.)
CAPTIVE
NUT
STRAP fitted when no
top casing
B
A
B
A
SIDE
CASING
(L.H.)
TOP CASING
PLASTIC PEG (4)
0914
SIDE CASINGS FITTING Diagram 5.2
MAX.
MIN.
MID.
MAX.
SIDE
CASING
(L.H.)
MAX.
MID.
MIN.
MIN.
BOILER PLINTH
FRONT
CASING
BRACKET
MID.
No. 8 SCREW
(4)
UPPER
CASING
BRACKET
LOCATING
LUG AND SLOTS
0886

14
221691B
6 ElectricalWiring
MAINS INLET
CONNECTOR Diagram 6.1
CABLE CLIP POSITIONS Diagram 6.2
0878
P
CB
25
(1 in.)
AP
AP
CB P
0904
Fit 2 pump cable
clips at positions P
230
(9 in.)
Alternative pump cable
clips (if feed is on the
right hand side) at
positions AP
Fit 3 control
box feed cable
clips at positions
CB
CB
NL
CABLE
CLAMP
COVER
SLOTS
LUGS
230 (9 in.)
60
(2 3/8 in.)
E
6.1 Control Box Cable Connection
Warning. This boiler must be earthed.
Remove the screw and cover from the mains inlet connector,
supplied loose, see diagram 6.1.
Using heat resistant flexible cable of suitable length and rating
as in Section 1.6, connect the three cables to the required
terminalsintheconnector. Securetheoutersheathingwiththe
cable clamp.
Engage slots and lugs, replace cover and secure with screw.
Connect the mains inlet connector to the control box and use
three of the cable clips, supplied loose, pushed on to the edge
ofthelefthandpanelinpositions “CB”as shown indiagram6.2
to make sure the cable does not make contact with any hot
surfaces.
6.2 Pump Cable Connection
Heat resistant cable with a rating as stated in Section 1.6 must
beusedforallwiringneartheboiler,includingthepumpifwithin
the boiler casing.
Support pump cable away from hot surfaces if within the boiler
casingby pushing two cable clips, supplied loose,on to the top
edge of one side panel, shown as “P”or “AP”in diagram 6.2.
6.3 System Controls
The electrical installation must be made according to the
current issue of BS7671.
The electrical isolator must isolate both the boiler and any
system controls.
6.4 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 the
British Gas Multimeter Instruction Book or similar publication.

15 221691B
7 Commissioning
Please ensure the “Benchmark”logbook is completed and left
with the user.
7.1 Commissioning and Testing the Boiler
The whole of the system should be thoroughly flushed out with
cold water with the pump removed. Make sure that all valves
areopen. Refitthepumpandfillthesystem. Examineforwater
soundnessandventallairfromthesystem,includingthepump.
CAUTION: The following work should be carried out by a
competent person.
Identify the boiler controls by reference to diagram 7.1.
Check that the gas service tap “K”is closed, indicator line
horizontal.
Open all windows and put out any naked lights, pipes or
cigarettes.
Purge air from the gas supply in accordance with the current
issue of BS6891.
Make sure that the thermostat phial is positioned at the bottom
of the phial pocket “J”located by the washer being behind the
split pin.
See that the mains electrical supply is switched off.
Set thermostat control knob “B”to “O”.
Remove gas pressure test nipple screw “G”and fit a suitable
pressure gauge.
Open gas service cock “K”.
Turn gas control knob “A”to ignition and pilot position and
push in. At the same time push and release piezo unit button
“C”untilthe pilot burner lights. At this stage air maybe present
inthegaspipesandthelighting operation may needrepeating.
Diagram 7.1
BOILER COMPONENTS
0940
A GAS CONTROL KNOB J PHIAL POCKET
B TERMOSTAT CONTROL K GAS SERVICE COCK
C PIEZO IGNITION BUTTON L DATA LABEL
E VIEWING WINDOW
F BURNER GAS RATE GAS CONTROL KNOB 'A'
ADJUSTMENT POSITIONS:-
G BURNER PRESSURE
TEST POINT
H CONTROL BOX
= OFF
= PILOT/IGNITION
= MAIN BURNER
C
H
K
(Shown
closed)
SETTING
POINTS
BGA
F
H
L
J
E
When the pilot is alight, keep control button “A”fully pushed in
for about 15 seconds. If the pilot burner fails to stay alight,
repeat the lighting procedure but now keep the control button
pushed in for a little longer.
Ifthegascontrolknob“A”isturnedto ,asafetylockprevents
it being turned on again. No attempt should be made to push
in knob “A”until 3 minutes have gone by.
Make sure that the pilot burner is alight and stable, see
diagram 7.2 for flame dimensions, then switch the electrical
supplyon. Set any remotecontrols for duty. Turncontrol knob
“A”to main burner position. Set thermostat control knob “B”
between “MIN”and “MAX”opposite the setting point on the
controlbox,the mainburnerwillthenlight, “MAX”isabout82oC
(180oF).
Test for gas soundness around the boiler with a suitable leak
detection fluid.
Set the burner gas rate required ten minutes from lighting, see
page 2forsettings. Adjustscrew“F”, diagram 7.1 to obtain the
requiredheatinput.Turnanti-clockwisetoincrease.Theadjusting
screw should then be sealed.
Should there be any doubt about the gas rate it should be
checked at the meter.
This should be in the range of:
Hideaway 40B : 1.1 to 1.4m3/h 38 to 50ft3/h
These rates are for guide purposes, depending on the heat
setting.
Stick the self adhesive arrow indicator onto the data label
against the output the boiler is to be set to, the arrow is in the
fittings pack.

16
221691B
PILOT FLAME DIMENSION Diagram 7.2
PLINTH / DOOR FITTING Diagram 7.3
7 Commissioning
FLAME
DIMENSION
SPARK GAP
DIMENSION
0937
Pilot shield
omitted
for clarity
13 (1/2in.)
APPROX.
3-4mm.
(1/8in.)
PILOT
BURNER
ASSEMBLY
VIEWING
WINDOW
0887
STUD
UPPER
HOOK
LOWER
HOOK
VIEW 1
VIEW 2
VIEW 1
VIEW 2
PLINTH
FRONT
DOOR
FASCIA
Checktheoperation oftheflamefailuredevice asfollows: with
the main burner alight, turn gas control knob “A”fully anti-
clockwiseto its stop , themain and pilot burnerswill go out.
Relightingtheboiler willnotnowbepossible asasafetydevice
has been activated. After 60 seconds the flame failure device
shouldhaveclosed,indicatedbyaclickfromthegasvalve. Do
not attempt to relight until 3 minutes have elapsed.
Remove the pressure gauge and refit test nipple screw “G”.
Turn thermostat “B”to “O”then relight the pilot burner as the
relevant part of this Section.
Check that the boiler thermostat and all automatic controls are
working correctly.
Do not attempt to adjust the thermostat calibration screw.
Relight the main burner and check for gas soundness with a
suitable leak detection fluid.
7.2 Commissioning the System
Allow the system to heat up and set the pump adjuster to a
design position which gives a temperature difference of 11oC
(20oF) across the boiler.
Thereshouldbenounduenoiseinthesystemandnopumping
over of water or entry air at the open vent.
Allowthesystemtoreachmaximumtemperatureandexamine
for water soundness. The boiler should then be turned off and
the system drained as rapidly as possible to complete the
flushing process.
The system should then be filled again, vented and examined
for water soundness.
7.3 Completion
Instructanddemonstratetheefficientandsafeoperationofthe
boiler and system.
Hand the Instructions for Use to the user for their retention,
making sure that they are understood.
Advise the user that to ensure continued efficient and safe
operationoftheboileritisrecommendedthatitischeckedand
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.
It is the law that any servicing must be carried out by a
competent person.
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.
Reminder - Leave these instructions and the “Benchmark”
logbook with the user.
Fittheplinthfrontbylocatingthesidesovertheboilerplinththen
lowering to engage the upper and lower hooks, see diagram
7.3.
Fitthedoorbylocatingthehookedrunneratthebottomintothe
slots in side casings and push on to the studs on the side
casings, see diagram 7.3.

17 221691B
ACCESS FOR SERVICING Diagram 8.3
ACCESS TO FLUEWAY Diagram 8.4
0908
BAFFLE
TRAY
0930
COMBUSTION
CHAMBER
COVER
SECURING
SCREW (4)
NUT
FLUEWAY
CLEANING
DOOR
Diagram 8.1
Diagram 8.2
SECURING THE
THERMOSTAT PHIAL
ISOLATION OF
GAS AND ELECTRICITY
8 Servicing
0907
1870
GAS
SERVICE
COCK
UNION TURN
OFF
MAINS INLET
CONNECTOR
PULL UPWARD
THERMOSTAT
CAPILLARY LOCATION
WASHER
PHIAL
POCKET
RETAINING
SPLIT PIN
Servicing must be carried out by a competent person.
Before starting a service, turn off the gas supply at the service
cock, see diagram 8.1 and isolate the boiler from the electrical
supply.
Always test for gas soundness after completing a service or
replacement of parts.
8.1 Boiler Flueways
Pull door forwards at the top to disengage studs and lift to
release from slots, see diagram 7.3.
Lift the plinth front up and forwards to withdraw, see diagram
7.3.
Disconnecttheuniononthegasservicecock,seediagram8.1.
Remove the mains inlet connector by pulling upwards, see
diagram 8.1.
Remove the retaining split pin on the thermostat phial pocket
then withdraw the phial and capillary, see diagram 8.2.
Remove the four screws retaining the combustion chamber
coverandburnerassembly,seediagram8.3. Withdrawforwards
the complete assembly of cover, control box and burner.
Removethesecuringnuttoreleasebaffletrayandremovefrom
combustion chamber, taking care not to damage the insulation
material on the sides.
Removetheself-tapping screwswhichretainthecleaning door
and lift clear, see diagram 8.4.
Remove flueway baffles, see diagrams 8.5 and 8.6.
Placeasheetofpaperinthecombustionchambertocatchany
flue debris.
Thoroughly clean boiler flueways and fins with a suitable stiff
brush.
Replace in reverse order, after completing the relevant
instructions in Sections 8.2 and 8.3.
Makesurethatthethermostatphialisatthebottomofitspocket
and located by the location washer being behind the retaining
split pin, see diagram 8.2. Make sure that there is clearance
between the thermostat capillary and the boiler.
SELF-
TAPPING
SCREW (4)

18
221691B
8 Servicing
BURNER SERVICING Diagram 8.8
Diagram 8.7
REMOVAL OF BURNER FROM
COMBUSTION CHAMBER /
SUPPLY FEED PIPE
SUPPLY
FEED PIPE MAIN
BURNER
GRAPHITE
COATED
NUT(2)
INJECTOR
0939
GRAPHITE
COATED
NUT (2)
SUPPLY
FEED
PIPE
MAIN
BURNER
COMBUSTION
CHAMBER
COVER
0931
BURNER
SUPPORT
BRACKET
SCREW (2)
Diagram 8.6
FLUEWAY
BAFFLE
HEAT
EXCHANGERS
6139
8.2 Burner and Injector
Follow instructions to remove the cover, burner and controls
assembly as in Section 8.1.
Remove the two screws and nuts securing the burner support
bracket to the combustion chamber cover, see diagram 8.7.
Removethegraphitecoatednutsonthesupply feedpipeatthe
rearoftheburnertoreleasetheburner,takecarenottodamage
the pilot burner and shield when removing.
Clean burner thoroughly.
Check the main burner injector for blockage or damage and
replace if necessary, see Section 9.2 and diagram 8.8.
8.3 Service Checks
Inspect the pilot burner, thermocouple and clean or replace as
necessary. Ifnecessaryremovethepilotshieldbyremovingthe
securing screw and nut.
Checktheconditionofthesideandrearinsulationpanelsin the
combustion chamber.
Check the condition of the seals on the cleaning door and the
combustion chamber cover.
Replaceallitemsinthereverseorder,relightandtest theboiler.
HEAT
EXCHANGERS
FLUE
BAFFLE
FLUEWAY
BAFFLE
Diagram 8.5
6141

19 221691B
Diagram 9.1
CONTROL BOX
9 Replacement of Parts
6285
MAINS INLET
CONNECTOR
IGNITION LEAD
(BLACK END)
ELECTRICAL
CONNECTORS
THERMOCOUPLE
CONTROL BOX
COVER
GAS VALVE
SECURING
SCREW
HALF UNION
PIPE
THERMOSTAT
SECURING
SCREW (2)
THERMOSTAT
CONTROL
KNOB
SLOT
PIEZO
UNIT
BURNER
SUPPLY
PIPE
PILOT
TUBE
ELECTRICAL
CONNECTORS
GAS VALVE
SECURING
SCREW
GAS
VALVE
COVER
SECURING
SCREW
Before removing or replacing any parts, turn off the gas supply
at the gas service cock, see diagram 8.1 and isolate the
electrical supply to the appliance.
Alwaystest for gas soundness afterreplacing any gas carrying
component.
9.1 Gas Valve
Follow relevant instructions in Section 8.1.
Removecontrolboxcoverbyremovingscrewandunhookingat
the side, see diagram 9.1.
Disconnect electrical connectors, thermocouple nut and pilot
tube at the gas valve.
Removethe two screws whichsecure gas valve tocontrol box.
Tilt control box to enable it to be lifted off the gas valve.
Unscrew the half union from gas valve.
Unscrew gas valve from burner supply pipe.
When screwing the pipe into the new valve use a little jointing
compoundontheexternalthreadonly,tomakeagastightseal.
Replace thermostat phial as Section 8.1.
Reassemble in reverse order.
Itwillbenecessarytopurgethesystemofairafterchangingthe
gas valve.
Relighting should be carried out as in Section 7.1.
9.2 Injector
When the burner has been removed from the injector manifold
as in Section 8.2 the injector can be unscrewed from the
manifold and renewed, as necessary.
When replacing use a little jointing compound on the external
thread only, to ensure a gas tight seal.
Replace in reverse order.
Replace thermostat phial as in Section 8.1.
9.3 Thermocouple
Remove the door and plinth as in Section 8.1
Disconnectthermocoupleby unscrewing nuts at gas valve and
pilotburner,seediagrams9.1and9.3. Releasethecableclips
and the thermocouple can be withdrawn.
Reassemble in reverse order.
9.4 Pilot Burner
Follow instructions in Section 8.1 to remove cover and burner
controls assembly.
Disconnectthethermocouplenutatthepilotburner,seediagram
9.3.
Disconnect the nut retaining the pilot tube and injector in the
pilot burner.
Disconnect nut retaining electrode.
Remove the two screws and nuts securing the pilot burner and
shield to the front cover, see diagram 9.3.
Reassemble in the reverse order, checking that the spark gap
and pilot flame length are as shown in diagram 7.2.
Replace thermostat phial as in Section 8.1.
9.5 Boiler Thermostat
Follow relevant instructions in Sections 8.1 and 9.1.
Pull off the thermostat control knob.
Remove the two screws which secure the boiler thermostat to
the control box, see diagram 9.1.
Tilt the thermostat so that the electrical connectors can be
removed.
Withdraw boiler thermostat from control box complete with
capillary tube and phial attached.
Refer to diagram 9.2 when re-connecting.
Reassemble in the reverse order.
Replace thermostat phial as in Section 8.1.

20
221691B
PILOT ASSEMBLY Diagram 9.3
Diagram 9.2
CONTROL BOX WIRING
9 Replacement of Parts
240V~ 50Hz MAINS SUPPLY FUSED AT 3A
GRN/YEL
BLUE
RED ORANGE
C N/C
THERMOSTAT
GAS
VALVE
CHASSIS
EARTH
NL
0935 6124
PILOT
INJECTOR
PILOT
TUBE
PILOT
BURNER
ASSEMBLY
PILOT
SHIELD
SPARK
ELECTRODE
SECURING SCREW (2)
AND NUT (2)
THERMOCOUPLE
IGNITION LEAD
(CLEAR END)
INSULATION PANELS Diagram 9.4
BAFFLE
TRAY
GRAPHITE
COATED
NUT
SIDE
INSULATION
PANEL
REAR
INSULATION
PANEL
CLIP
SCREW
0897
9.6 Piezo Unit and Ignition Lead
Follow the relevant instructions in Section 8.1.
Pull off ignition lead at piezo unit, see diagram 9.1.
To replace lead also, pull off the lead at the spark electrode
terminal, see diagram 9.3.
Removethecontrolboxcoverbyremovingsecuringscrewand
unhooking at the side, see diagram 9.1.
Removethepiezo unit, secured by a nut insidethecontrol box.
Replace in reverse order.
9.7 Spark Electrode
Follow the relevant instructions in Section 8.1.
Disconnectthethermocouplenutandwithdrawthethermocouple
from the pilot burner, see diagram 9.3.
Remove the spark electrode, secured by a nut.
Replace in reverse order, checking that the spark gap is as
shown in diagram 7.2.
9.8 Insulation Panels
Follow the relevant instructions in Section 8.1.
Remove the two screws retaining each side insulation panel
withinthecombustionchamberandremovepanel,seediagram
9.4.
Release the rear insulation panel clips and lift out panel.
Replace in reverse order.
Replace thermostat phial as in Section 8.1.