Glowworm Ultimate 70FF, Ultimate 80FF Installation & Servicing Instructions Manual

Hepworth Heating Ltd.,

Nottingham Road, Belper, Derbyshire. DE56 1JT

General/Sales enquiries:

Tel: [phone] Fax: [phone]

One Contact Total Service

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



Installation & Servicing Instructions

220683B.11.96

To be left with the user

70FF 80FF

GC 41 319 86 GC 41 319 60

4098

Fanned Flue Boiler

Reference in these instructions to British Standards Regulations/Requirements apply only to the United Kingdom.

For Ireland the rules in force must be used.

This is a Cat I2H Appliance

BS 6332
BS 5258

2

220683B

SIDE ELEVATION FRONT ELEVATION

B

AP

C

D

E

J

L

M

C

L

D

N

F

G

H

PUMPED

RETURN

PUMPED

FLOW

K

0075(a)M

WATER CONNECTIONS
22mm COPPER PIPE

GAS CONNECTIONS
RC

1

/2 (1/2 in. BSPT)

MODEL A B C D E F G H J K L M N P

80FF 70 300 63 146 78 360 146 94 700 574 14 63 130 38

Diagram 1.1

1 G e n e r a l

The instructions consist of two parts, Installation and
Servicing Instructions and Instructions for Use, 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.

Important Notice

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

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

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

components used shall comply with requirements of
applicable British Standards.

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

Sheet Metal Parts

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

1.1 Statutory Requirements

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

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

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

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

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

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

All dimensions are given in millimetres (except as noted)

3

220683B

1.2 Data

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

noted).

1.3 Range Rating

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

Table 2 gives the ratings and settings.

1 G e n e r a l

DATA TABLE 1.
MODEL
TOTAL DRY

WEIGHT
(Including
Terminal)

LIFT
WEIGHT

WATER
CONTENT

GAS
CONNECTION

ELECTRICITY
RATING

WATER
CONNECTION

ELECTRICITY
SUPPLY

DATA LABEL

70FF/80FF

51 kg (112 lb)

45.3 kg (100lb)

3.35 litre (0.74 gallon)

Rc 1/2 in.

71W

Internal fuse F1A

2x22mm copper pipes from

top of case

240V~50Hz, fused 3A

Bottom right hand side of case

TABLE 2. 80FF
RANGE RATING
NOMINAL kW

HEAT
INPUT Btu/h

NOMINAL kW
HEAT
OUTPUT Btu/h

BURNER m bar
SETTING
PRESSURE in. w.g.

APPROX. m3/h
GAS
RATE ft3/h

Min. Medium Max.

25.97 27.65 29.31

88,600 94,300 100,000

20.52 21.98 23.45

70,000 75,000 80,000

12.8 14.5 16.3

5.1 5.8 6.5

2.4 2.6 2.7
86 92 97

BURNER INJECTOR MARKING: 205710
BURNER INJECTOR SIZE: 4.0 mm
PILOT INJECTOR MARKING: 7218

TABLE 2. 70FF
RANGE RATING
NOMINAL kW

HEAT
INPUT Btu/h

NOMINAL kW
HEAT
OUTPUT Btu/h

BURNER m bar
SETTING
PRESSURE in. w.g.

APPROX. m3/h
GAS
RATE ft3/h

Min. Medium Max.

22.39 24.03 25.64

76,400 82,000 87,500

17.58 19.05 20.52

60,000 65,000 70,000

13.3 15.3 17.2

5.3 6.1 6.9

2.0 2.2 2.4
74 80 85

BURNER INJECTOR MARKING: 205701
BURNER INJECTOR SIZE: 3.8 mm
PILOT INJECTOR MARKING: 7218

4

220683B

1.4 B.S.I. Certification

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

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

CE Mark

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 Member States relating to electromagnetic
compatibility.

1.5 Gas Supply

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

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

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

1.6 Electrical Supply

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

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

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

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

Wiring to the boiler must be to the current issue of
BS6500 Table 16, not less than 0.75mm2 (24/0.20mm).

1 General

1.7 Contents of Packaging

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

1.8 Water System

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

1.9 Drain

System

A draining tap must be provided at the lowest points of
the system which will allow the entire system, boiler and
hot water cylinder be drained.

Draining taps should be to the current issue of BS2879.

Boiler

A draining point is fitted at the bottom right hand side of
the heat exchanger.

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

improve access.

1.10 Safety Valve

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

1.11 Location

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

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

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

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

5

220683B

1.12 Boiler Clearances

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

minimum operational and servicing clearances are
provided.

Additional clearances may be required for installation.
If fixtures are positioned next to the boiler they should

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

front of the boiler for servicing, see diagram 1.2.

1.13 Room Ventilation

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

1.14 Boilers in a Compartment

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

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

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

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

1.15 Timber Frame Building

If the boiler is to be installed a timber frame building it
should be fitted in accordance with the British Gas
publication “Guide for Gas Installation in Timber
Framed Housing”, reference DM2. If in doubt seek
advice from the local gas undertaking or Hepworth
Heating Ltd.

1 General

Diagram 1.2

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

500mm

Additional clearances may be
required for installation

65mm

6mm6mm

FRONT

VIEW

100mm

0081M

SIDE OR
REAR FLUE
5mm

5mm

TABLE 3. COMPARTMENT AIR VENTS

VENTILATION HIGH LEVEL LOW LEVEL
REQUIREMENTS VENT AREA VENT AREA

VENTILATION
FROM ROOM
OR SPACE

VENTILATION
FROM
OUTSIDE

MODEL

cm

2

in

2

cm

2

in

2

80FF 264 41 264 41
70FF 231 35 231 35

80FF 264 41 264 41
70FF 231 35 231 35

80FF 132 21 132 21
70FF 116 18 116 18

80FF 132 21 132 21
70FF 116 18 116 18

6

220683B

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

2.1 Terminal Position

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

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

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

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

2.2 Terminal Guard

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

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

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

Tower Flue Components Ltd.,
Morley Road,
Tonbridge,
Kent.
TN9 1RA

Diagram 2.1

2 F l u e a n d V e n t i l a t i o n

MINIMUM SITING DIMENSIONS
FOR FANNED FLUE
TERMINALS POSITION

A DIRECTLY BELOW AN OPENABLE

WINDOW, AIR VENT, OR ANY OTHER

VENTILATION OPENING 300
B BELOW GUTTER, DRAIN/SOIL PIPE 75
C BELOW EAVES 200
D BELOW A BALCONY OR CAR PORT 200
E FROM VERTICAL DRAIN PIPES AND

SOIL PIPES 75
F FROM INTERNAL OR EXTERNAL

CORNERS 300
G ABOVE ADJACENT GROUND OR

BALCONY LEVEL 300
H FROM A SURFACE FACING THE

TERMINAL 600

I FACING TERMINALS 1200

J FROM OPENING (DOOR/WINDOW) IN

CAR PORT INTO DWELLING 1200
K VERTICAL FROM A TERMINAL 1500
L HORIZONTALLY FROM A TERMINAL 300

MINIMUM
SPACING

in mm

0103M

A

A

F

G

E

A

G

G

G

B,C

B,C

F

F

K

K

K

C

G

L

L

Under Car Port etc.

H,I

J

D

F

K

0161M

7

220683B

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

3.1 Frost Protection

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

3.2 Pump

The pump, with integral valves, should be fitted in the
heating flow pipework from the boiler, it should be set to
produce a temperature difference of 11oC (20oF) between
the flow and return, with the boiler thermostat set at
“MAX”, which is about 82oC (180oF).

The pressure loss of the boiler can be found from
diagram 3.1.

High resistance microbore systems may require a higher
duty pump.

3.3 Bypass - Fully Pumped and Sealed
Water System

A bypass MUST be fitted to a fully pumped and sealed
water systems.

Where the water system allows the boiler and pump to
operate on bypass only, the bypass connection must be at
least 2.5metres away from the boiler.

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

3 W a t e r S y s t e m s

1000

750

500

250

0

0 5 10 15 20 25 30

Flow rate (litres/minute)

Water pressure loss

(mm head of water)

PRESSURE LOSS
OF BOILER 80FF

0088(a)M

30.6

litre/min

Design Flow Rate

The intersection point indicates the Flow Rate
required to achieve 110C temperature difference.

Diagram 3.1

PRESSURE LOSS OF BOILER

30.6

LITRE/MIN

8

220683B

3.4 Water System

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

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

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

continuously to discharge over the feed and expansion
cistern.

3.5 Domestic Hot Water System

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

3.6 Cylinder

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

3.7 Fully Pumped Domestic Hot Water

The connection for this type of system MUST be as
shown in diagram 3.2 and 3.3.

3 W a t e r S y s t e m s

Diagram 3.2

0089M



FEED AND
EXPANSION
CISTERN

22mm VENT
(MIN.)

15mm (MINIMUM)
COLD FEED

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

450mm
MIN.
HEIGHT

1150mm
MIN.

RETURN

FLOW

CYLINDER

PUMP

HEATING

150mm
MAX.

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

BOILER

22mm (MINIMUM)
BY-PASS WITH
LOCKSHIELD VALVE

FLOW

RET.

9

220683B

3.8 Inhibitor

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

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

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

3 W a t e r S y s t e m s

Diagram 3.3

FLOW

RETURN

1metre Min.

27 metres

Max.

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

INDIRECT
CYLINDER

ALTERNATIVE
SYSTEM
CONTROL
VALVES

HEATING
SYSTEM

PUMP

FULLY PUMPED CIRCULATION
BYPASS (DIAGRAMMATIC)

0091(b)M

BYPASS 22mm
MIN WITH
LOCKSHIELD
VALVE

4114

22 x 28
UNION
CONNECTION

28mm
PIPE

10

220683B

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

NON-RETURN
VALVE

AUTO
AIR
VENT

FLOW

DRAIN
COCK

BOILER

SAFETY
VALVE

(Make-up
alternatives)

EXPANSION
VESSEL

PRESSURE
GAUGE

CIRCULATING
PUMP

FILLING POINT

AIR
RELEASE
POINT

HEATING

CIRCUIT

22mm (min)
BY-PASS WITH
LOCKSHIELD 
VALVE


RETURN

Diagram 3.4

3.9 Sealed Water Systems

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

3.4 for suggested layout.

3.10 Safety Valve

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

3bar, incorporating seating of a resilient material, a test
device and a connection for drain.

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

3.11 Expansion Vessel

A diaphragm type expansion vessel, conforming to the
current issue of BS4814 (see also BS7404 Part 1 and 2)
must be connected at a point close to the inlet side of the
circulating pump, see diagram 3.4 unless laid down
differently by the manufacturer.

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

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

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

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

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

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

3 W a t e r S y s t e m s

5814

11

220683B

3.12 Pressure Gauge

A pressure gauge with a set pointer and covering at least
the range 0 to 4bar (0 to 60lb/in2) shall be permanently
fitted to the system in a position where it can be seen
when filling the system.

3.13 Domestic Hot Water Cylinder

SINGLE FEED INDIRECT CYLINDERS ARE NOT
SUITABLE.

The domestic hot water cylinder must be of the indirect
coil type. It must be suitable for working at a gauge
pressure of 0.35bar above the safety valve setting.

3.14 Domestic Hot Water System ­Unvented

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

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

3.15 Filling a Sealed Water System

Provision for filling the system at low level must be
made. Three methods are shown in diagram 3.5.
There must be no permanent connection to the mains
water supply, even through a non-return valve.

3.16 Water Makeup

Provision must be made for replacing water lost from the
system. A make up vessel mounted above the highest
point of the system and connected through a non-return
valve to the system on the return side of either the hot
water cylinder or heating system, see diagram 3.4.

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

METHOD 1

METHOD 2

METHOD 3

SUPPLY STOP
VALVE

SUPPLY
PIPE

HOSE
UNIONS

SERVICING
VALVE

TEMPORARY
HOSE

HEATING
SYSTEM

HEATING
SYSTEM

TEMPORARY
HOSE

HOSE
UNIONS

SERVICING
VALVE

SUPPLY
PIPE

SUPPLY STOP
VALVE

DOUBLE CHECK
VALVE ASSEMBLY

HEATING
SYSTEM

SERVICING
VALVE

SUPPLY
STOP VALVE

SUPPLY
PIPE

HOSE
UNIONS

DOUBLE CHECK
VALVE ASSEMBLY

OVERFLOW

CISTERN

COMBINED
CHECK VALVE
AND VACUUM
BREAKER

PRESSURE
REDUCING
VALVE

0051M

Diagram 3.5

3 W a t e r S y s t e m s

12

220683B

Diagram 4.1

Diagram 4.2

Diagram 4.3

Standard Flue terminal illustrated.

Standard Flue terminal illustrated.

4 F l u e a n d A p p l i a n c e P r e p a r a t i o n

REAR FLUE LENGTHS

Distance R = Wall thickness

STD. 75mm to 685mm
1M 75mm to 1015mm
2M 75mm to 2015mm
3M 75mm to 2995mm

SIDE FLUE LENGTHS

Distance S = External wall face to boiler case

STD. 81mm to 693mm
1M 81mm to 1023mm
2M 81mm to 2023mm
3M 81mm to 3003mm

4791

4125

4126

CARTON TOP

WALL
TEMPLATE

LOOSE
ITEMS
PACK

MOUNTING
BRACKET

INSTRUCTIONS

BOILER

4.1 Unpacking

Open the carton, check the items supplied against the
boiler pack contents list on the flap, see diagram 4.1.

4.2 Flue Position and Length

Determine flue application, length and terminal position
before starting.

Refer to diagram 4.2 or 4.3.
If you are using a Flue Bend or a Vertical Flue Kit,

please follow the instructions supplied with that kit.
To make a neat finish to the flue outlet a flue collar kit,

part No. 443286, with instructions, is available.
The use of this collar will mean that the flue lengths will

need to be altered, full instructions are given in the kit.

13

220683B

4.3 Flue Preparation

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

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

For a wall thickness up to 300mm provided there is
sufficient space available, the flue can be fully installed
from the inside.

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

4.4 Rear and Side Flue Application

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

Take the template from the boiler pack and temporarily
position it on the wall, making sure that the minimum
clearances are maintained, see diagram 1.2.

For a rear flue mark the position of the flue as
diagram 4.4.

For a side flue, extend the centre line horizontally left or
right to the corner adjacent surface where the flue is
required to exit to outside. Mark the position of the
centre of the flue and boiler, see diagram 4.4.

4.5 Flue Hole Cutting

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

4.6 Wall Sleeve

If the wall thickness “Q” is less than 300mm cut the wall
sleeve to the required length, see diagram 4.5.

Fit the wall sleeve.
Make good around the wall sleeve at both internal and

external wall faces, through the wall sleeve if internal
access only is available.

If the wall thickness “Q” is greater than 300mm the wall
sleeve must be fitted flush with the INSIDE wall face.
If the inner end of the sleeve sticks out into the cavity
then, if desired, the wall sleeve can be trimmed back to
the depth of the inner skin of brickwork. Make good at
the internal wall face but leave the external wall face
until the flue has been fitted.

Diagram 4.4

SIDE FLUE

REAR FLUE

75mm

115mm
MINIMUM
HOLE

0098M



BOILER
CENTRE LINE

FLUE
CENTRE LINE

14mm

300mm
MAX LENGTH

Q

Q

Diagram 4.5

4443

4 F l u e a n d A p p l i a n c e P r e p a r a t i o n

WALL
SLEEVE

14

220683B

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

Mark the boiler fixing points and mounting bracket
position, see diagram 4.6.

Drill holes and plug, to suit No.12x2in woodscrews, fit
the screws allowing sufficient clearance, about 5mm, to
accept the swing brackets, see diagram 4.6.

Secure the mounting bracket to the wall with No.12x2in
woodscrews and plugs, see diagram 4.6.

4.7 Flue Duct

Mark the duct to the length required, this length allows
for expansion, see diagram 4.7 for rear flue and diagram

4.8 for side flue, then cut square and remove any burrs.

4.8 Air Duct/Terminal

Mark the duct length, see diagram 4.9 for rear flue and
diagram 4.10 for side flue, then cut square and remove
any burrs.

4 F l u e a n d A p p l i a n c e P r e p a r a t i o n

Diagram 4.6

5mm

7 dia.

BOILER
CENTRELINE

7 dia.

NO.
12x2in.

3

/16in. dia.

PLUG

TOP BOILER
MOUNTING
HOLES

TEMPLATE

BOILER
MOUNTING
BRACKET

FLUE
CENTRELINE

MOUNTING
BRACKET FIXING
POINTS

BOILER
CENTRELINE

FLUE
CENTRELINE

4096

NO.
12x2in.

3

/16in. dia.

PLUG

15

220683B

Diagram 4.7

Diagram 4.8

Diagram 4.9

Diagram 4.10

STANDARD FLUE
TERMINAL

Q

BOILER

CENTRE

LINE

BOILER

CENTRE

LINE

Q

T MINUS 188mm

Q PLUS 5mm

LONG FLUE
TERMINAL

LONG FLUE
TERMINAL

STANDARD
FLUE
TERMINAL

FLUE
DUCT

4128

4130

4127

4129

4 F l u e a n d A p p l i a n c e P r e p a r a t i o n

16

220683B

4.9 Air Duct/Terminal and Flue Duct
Assembly

Locate the flue duct into the air duct/terminal, see
diagram 4.11.

Take the flue manifold from the loose items pack
together with the sealant. Place the sealant onto the flue
manifold.

Fully locate the flue manifold in to the air duct/terminal
and flue duct assembly as shown in diagram 4.11, make
sure the correct alignment of the “Top”s.

Drill two 3mm diameter holes through the air duct/
terminal to the flue manifold secure with the two self
tapping screws supplied in the loose items pack.

It should now not be possible to remove the manifold.

4.10 Wall thickness up to 300mm

Fit the self adhesive foam seal provided in the loose
items pack around the air duct/terminal at the position
shown in diagram 4.12.

4.11 Wall thickness over 300mm

Fit the self adhesive foam seal around the air duct/
terminal such that, when installed, the seal will be within
the wall sleeve, see diagram 4.12.

4.12 Flue Assembly - Installation

If the boiler is not to be fitted for some time cover the
hole in the wall.

On limited access installations push the flue assembly
into and through the wall sleeve and hole such that it is
within the wall sleeve and does not stick out into the
room. see diagram 4.13. Do not push the flue assembly
too far into the holes as it has to be pulled back into the
boiler and secured.

Note that the foam seal is a tight fit in the wall sleeve, so
either the wall sleeve will need to be rigidly fixed in the
wall, that is, the cement has fully set or it can be held
from the other side whilst inserting the flue assembly.

4 F l u e a n d A p p l i a n c e P r e p a r a t i o n

17

220683B

4131

4 F l u e a n d A p p l i a n c e P r e p a r a t i o n

Diagram 4.12

10mm

Q

WALL THICKNESS­UP TO 300mm

Q-25mm

Q

WALL THICKNESS­OVER 300mm

FOAM
SEAL

FOAM
SEAL

4132

Diagram 4.11

Diagram 4.13

GASKET
(PRE-ATTACHED)

WALL
SLEEVE

4082

FLUE DUCT

5mm

3mm
DRILL SIZE

FLUE
MANIFOLD

SEALANT

AIR DUCT/TERMINAL
ASSEMBLY

18

220683B

WASHER

FRONT
COVER

NUT

CONTROLS
COVER

FRONT
COVER

WING
NUT

4115

5.1 Boiler Preparation

With the boiler still in the bottom tray, slide the controls
tray upwards and remove it as shown in diagram 5.1.

Remove the front cover by undoing (and keeping) the
screw and wing nuts and lifting the front cover off, see
diagram 5.1.

Remove the packing piece from inside the front cover.
Place front cover on one side until required.
Fit suitable compression fittings to the boiler

connections.

5.2 Mounting the Boiler

As necessary, fit the blanking plate, see diagram 5.2.
Now make sure that the top, swing brackets are

UPRIGHT.
Lift the boiler into position, hooking over the mounting

bracket.
Swing the brackets over the two screws at the top.

Hold the swing bracket(s) in place whilst tightening the
screw(s) on to it, see diagram 5.3.

Remove the blue and red electrical connections from the
fan, see diagram 5.4.

Break the air pressure switch tube connections, see
diagram 5.4.

Remove the fan assembly by removing the screws at the
front, slackening the screws at the rear and sliding it out,
see diagram 5.4. Taking care not to damage the gasket.

Secure the flue assembly to the boiler using the
previously fitted dogpoint screws noting that these are
keyhole fixings, see diagram 5.5.

Make sure of the correct fitting of the flue to the boiler.
For a side outlet cut the fan duct extension to the length

required, see diagram 5.6.
Remove any burrs and fit as diagram 5.6.
Fit the fan duct extension to the elbow and assembly to

the fan, see diagram 5.6
Do not secure at this point with the screw.
Position the fan assembly and engage the fan duct

extension over the flue manifold. Make sure, by pushing
in the flue duct extension that a secure seal is made.
Mark the final position of the fan duct extension in the
screw hole on the elbow, remove the assembly, seal with
sealant, supplied in the loose items pack and secure with
the screw as diagram 5.6.

Secure the elbow to the fan outlet with the Jubilee clip.
For rear outlet cut and fit the fan duct extension as

shown in diagram 5.6.
Fit fan assembly by engaging the fan duct extension over

the flue manifold spigot, see diagram 5.7.

5 B o i l e r I n s t a l l a t i o n

Diagram 5.1

4617

GASKETNUT (3)

BLANKING
PLATE

Diagram 5.2

Secure the fan assembly with the screws previously
slackened and removed.

Reconnect the blue and red electrical connections to the
fan, the polarity of the connections is not important.

Reconnect the air pressure switch tubes as shown in
diagram 5.4.

19

220683B

5.3 Water Circulation System

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

5.4 Safety Valve Discharge

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

5.5 Gas Connection

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

Check for leaks using a suitable leak detection fluid.

5.6 Control Box Removal

Remove the electrical control box securing screws, see
diagram 5.8. Slide the box forward and release, hook it
onto the lip bracket at the front, see diagram 5.8.

5 B o i l e r I n s t a l l a t i o n

0167(A)M

Diagram 5.3

5mm

Pipe
omitted
for clarity

MOUNTING
BRACKET

SECURING
SCREWS (2)

SWING
BRACKET

LOCATION
PLUG

GASKET

RED

CLEAR

REAR SECURING SCREW (2)
(SLACKEN)

KEYHOLE

5874

4134

ELECTRICAL CONNECTIONS

Diagram 5.4

Diagram 5.5

AIR
PRESSURE
TUBES

SECURING
SCREWS (2)

20

220683B

Diagram 5.6

REAR

RIGHT

LEFT

Cutting 'MARK' lengths.
Lefthand flue does not require cutting.

SEALANT

FAN

DUCT

EXTENSION

REAR

3mm
dia.
drill

Diagram 5.7

FLUE ELBOW

JUBILEE
CLIP

SCREW
(2)

SEALANT

FAN DUCT
EXTENSION

FLUE
MANIFOLD
SPIGOT

VERTICAL

4089

4093

5.7 Electrical Connection

WARNING. This boiler must be earthed.
Take care not to damage any internal wiring and

capillaries.
Take plastic cable retaining clip, from the loose items

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

Using heat resistant (to 85oC) cable of at least 0.75mm

2

(24/0.2mm) to the current issue of BS6500 Table 16 and
of suitable length, thread through cable clamps, secure
into the plastic clips and connect to appropriate
terminals, see diagram 5.9 and 9.5.

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

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

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

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

SIDE
LEFT

SIDE
RIGHT

5 B o i l e r I n s t a l l a t i o n

FAN
DUCT
EXTENSION

(REAR FLUE OUTLET ILLUSTRATED)

21

220683B

5.8 Pump Connection

The pump must be connected directly to the control box,
as shown in diagram 5.9 threading the cable through the
cable clamp in the side of the control box.

5.9 External Controls

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

Make sure that the supply cable and all external cables
are secured and away from hot surfaces.

5.10 Testing

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

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

1. Test insulation resistance to earth.

2. Test continuity and short circuit of all cables,

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

the user of the controls scheme used with the boiler.

Diagram 5.9

FIXING SCREWS

Diagram 5.8

LIP BRACKET

PUMP
CABLE

4619

4620

3310

5 B o i l e r I n s t a l l a t i o n

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

CABLE
CLAMPS

IGNITION
LEAD

MAINS
CABLE

22

220683B

6 C o m m i s s i o n i n g

6.1 All Systems

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

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

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

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

6.2 Sealed Water Systems Only

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

Check the operation of the safety valve, by allowing the
water pressure to rise until the valve opens. The valve
should open within +/-0.3bar (+/-4.3lbf/in2) of the preset
pressure. Where this is not possible conduct a manual
check and test.

Release cold water to initial system design pressure.
The set pointer on the pressure gauge should be set to

coincide with the indicating pointer.

6.3 Initial Lighting and Testing

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

Make sure that all naked lights and cigarettes are out.
Identify the controls by reference to diagram 6.1.
Check that the boiler is isolated from the electrical

supply.
Makes sure that the control thermostat is turned to “O”

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

soundness as follows:
Disconnect the ignition lead from the PCB, see

diagram 5.9.

Diagram 6.1

Diagram 6.2

NOTE:

DO NOT ADJUST ANY
OTHER SETTING SCREWS

MAIN BURNER
PRESSURE TEST
SCREW

MULTI­FUNCTIONAL
CONTROL

OVERHEAT
SAFETY
CUT OFF

GAS SERVICE COCK
(SHOWN OFF)

SETTING

POINT

CONTROL
THERMOSTAT
KNOB

PLASTIC
COVER

4085

4108

GAS

PRESSURE

ADJUSTMENT

SCREW

23

220683B

Remove the combustion chamber front, see diagram 6.3.
WARNING. The fan operates on mains voltage,

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

controls are calling for heat.
Check that the pump is circulating water through the

system.
To complete the test it is necessary to operate the boiler

without its case, but UNDER ALL OTHER
CIRCUMSTANCES the case must be correctly fitted
and sealed.

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

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

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

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

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

diagram 6.4.
Turn the control thermostat knob to “O” and isolate the

boiler from the electrical supply.
Fit the combustion chamber front.
Reconnect the ignition lead to the PCB.
Stick the self adhesive arrow indicator to the data label,

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

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

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

heating system, neon 1 will light.

Diagram 6.3

VIEWING
WINDOW

SECURING
SCREW (4)

4138

6 C o m m i s s i o n i n g

Diagram 6.4

SPARK GAP
2 to 4mm

10 to 20mm FLAME LENGTH

NOTE:

PILOT SHIELD
REMOVED FOR
CLARITY

4146

4139

24

220683B

6.4 Testing - Electrical

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

The lighting sequence is automatic as follows:
The fan operates
The spark ignition operates Neon 3 will light
The pilot solenoid opens

The pilot burner lights
The ignition spark stops
The main solenoid opens
and after a short period of time the main burner will

light, look through viewing window, see diagram 6.3.
Very cold weather may delay the operating sequence.

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

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

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

Neons 1, 2 and 3 should stay alight.

3. If the above does not happen, refer to fault finding
Section 9.1.

4. To carry on turn gas service cock “On” see
diagram 6.1.

When the boiler switches “Off”, both the pilot and main
burner go out. The automatic lighting sequence will
work again when heat is required.

6.5 Testing - Gas

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

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

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

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

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

}

}

Neon 4 will light

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

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

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

Refit the electrical controls box, see diagram 5.8.
Note. The neon indicator lights on the printed circuit

board are an aid to fault finding, for details refer to
Section 9.

6.6 Testing - Open Vented

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

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

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

6.7 Adjustment - Fully Pumped Open
Vented and Sealed Water Systems

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

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

6 C o m m i s s i o n i n g

25

220683B

6 C o m m i s s i o n i n g

Diagram 6.6

Diagram 6.5

WING
NUT

NUT

TOP
SEAL

SIDE
SEAL

WASHER

CONTROLS
COVER

SLIDERS

4140

4088

NOTE: MAKE SURE
OF CORRECT
ENGAGEMENT

6.8 Sealed Water Systems ONLY

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

6.9 Thermostatic Radiator Valves

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

6.10 Operational Checks and Completion

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

Do not attempt to adjust the thermostat calibration
screw.

Operate the boiler again on full service and check that
the balancing is satisfactory, making adjustments as
necessary.

Fit the front cover by hooking it under at the top and
securing with the wing nut, washer and nut previously
removed, refer to diagram 6.5.

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

6.11 Protection Against Freezing

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

26

220683B

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

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

Draw attention, if applicable, to the current issue of the
Gas Safety (Installation and Use) Regulations, Section
35, which imposes a duty of care on all persons who let
out any property containing a gas appliance.

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

Advise the user of the precautions necessary to prevent
damage to the system and building in the event of the
heating system being out of use during frost and freezing
conditions.

Reminder, leave these instructions with the user.

7 I n s t r u c t i o n s t o t h e U s e r

27

220683B

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

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

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

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

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

8.1 Access

Refer to diagram 6.6 and slide the controls cover
forwards and off.

Remove the outer case, see diagram 6.5.
Note. As an aid to servicing the air pressure switch tube

connection can be used to obtain a products of
combustion reading.

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

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

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

8.2 Cleaning Heat Exchanger Flueways

Disconnect the air pressure tubes, see diagram 5.4.
Remove the violet and red electrical connections from

the fan, see diagram 5.4.
Remove the fan complete with fan duct extension taking

care not to damage the gasket, see diagram 5.4.
Vertical Flue Only, carefully remove the restrictor plate

and additional gaskets.
Remove the flue hood, noting that there are keyhole slots

at the rear, see diagram 8.1.
Remove the combustion chamber cover, see diagram 6.3.
Remove the burner as Section 8.3.
Place a sheet of paper in the base of the combustion

chamber.
Remove the baffles, note, when replacing they are

marked “Front”, see diagram 8.2.
Clean the heat exchanger flueways with a suitable stiff

brush.
Remove the paper together with any debris.

Diagram 8.2

Diagram 8.1

Diagram 8.3

SECURING
SCREW (4)

GASKET

FLUEHOOD

SECURING NUT AND
SHAKEPROOF
WASHER

PILOT PIPE

ELECTRODE AND
LEAD ASSEMBLY

UNION
CONNECTOR

BAFFLE (4)

80FF Illustrated

41164109

4087

8 S e r v i c i n g

28

220683B

8.3 Main Burner

Disconnect the pilot pipe union connector and pilot
burner, securing nut and shakeproof washer together
with the pilot shield. Remove the pilot burner assembly
taking care not to damage the electrode and lead
assembly, see diagram 8.3.

Remove the securing screw from the burner support
bracket, see diagram 8.4.

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

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

Continue cleaning heat exchanger as Section 8.2.
Note. On refitting and after cleaning the heat exchanger

make sure the burner is fitted correctly, that is, located
on the main injector and horizontal.

8.4 Main Injector

With the main burner removed the main injector can be
inspected and cleaned as necessary, see diagram 8.5.

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

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

8.5 Pilot Burner/Electrode and Pilot Injector

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

diagram 8.6.
When removing and replacing the pilot injector from the

pilot burner take care not to damage the electrode, see
diagram 8.6, clean the injector by blowing through it.

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

8.6 Operational Checks

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

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

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

8 S e r v i c i n g

Diagram 8.4

Diagram 8.5

Diagram 8.6

SECURING SCREW

BURNER SUPPORT
BRACKET

MAIN BURNER
INJECTOR

PILOT
INJECTOR

ELECTRODE

PILOT
BURNER

SPRING
CLIP

4112

4111

4143

29

220683B

9.1 Electrical

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

Refer to neon indicators “An Aid to Fault Finding”
diagram 9.1, Boiler Fault Finding diagram 9.2, Pump
Overrun Fault Finding diagram 9.3, the Functional Flow
diagram 9.4 , and the Pictorial Wiring diagram 9.5.

9.2 Electrical Supply Failure

Failure of the electrical supply will cause the burner to
go out.

Operation will normally resume on restoration of the
electrical supply. If the burner does not relight after an
electrical supply failure the overheat device may need
resetting.

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

If the cutoff operates at any other time press the rest
button and the burner should relight. If the fault persists
refer to fault finding chart.

9 F a u l t F i n d i n g

Diagram 9.1

Neon Indicators - An Aid to Fault Finding

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

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

Is neon 1 lit? Fault with mains supply or PCB fuse

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

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

YES

YES

YES

YES

YES

NO

NO

NO

NO

NO

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

- see detailed fault finding chart.

Is neon 2 lit?

Is neon 4 lit?

System satisfactory

Is neon 3 lit?

Is main burner operating?

Multi-functional control/harness problem

- see detailed fault finding chart.

NEON
INDICATORS

3324

30

220683B

9 F a u l t F i n d i n g

Diagram 9.2

Is neon 1 lit?

YES

YES

Is neon 2 lit?

YES

NO

Correct power supply problem.

NO

YES

Is there 240V~
between 6 on thermostat and N ?

Replace thermostat.

NO

YES

NO

Is neon 3 lit?

Is there 240V~ between
"N/C" on air pressure switch and N ?

YES

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

YES

NO

Is there 240V~ between "C" on air
pressure switch and N ?

Replace air pressure switch.

Does fan run?

YES

NO

NO

YES

Replace fan.

YES

Replace printed circuit board.

Does fan Hunt?

NO

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

NO

Is there 240V~between "N/O" on air
pressure switch and N ?

NO

NO

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

YES

With pilot lit does spark stop?

NO

Replace main solenoid

YES

Replace multi-functional control.

YES

Is Neon 4 lit?

NO

Does main burner light?

System satisfactory

NO

YES

NO

YES

YES

NO

NO

Is there 240V~ between SL and
N and between L and N ?

Is there 240V~ between yellow connection
on overheat device and N ?

YES

Is there 240V~ between motor connections on fan?

YES

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

Before detailed checking of electrical components ensure that remote controls are calling for heat. Check the gas supply is free of obstructions and purged of
air. Check the overheat cutoff has not operated. For fully pumped systems only. Isolate the electrical supply and physically check ALL cables, connections
and the printed circuit board fuse. Check the air tubes to the air pressure switch. Switch on the electrical supply and check for correct polarity. Turn the
boiler thermostat to its maximum setting. Also check fuses.

Check overheat reset.
If satisfactory replace overheat device.

Is there a spark at pilot burner?

Check lead continuity and inspect electrode and
lead for damage.

Check for pilot jet blockage, incorrect electrode
adjustment isolate supply. Remove plug from
multifunctional control. Check continuity of pilot
solenoid between EV1 and COM, continuity OK?

Does pilot light?

NO

Replace
multifunctional
control

Replace pilot
solenoid.

NO

YES

Isolate supply. Remove plug from the
multifunctional control. Check continuity
of main solenoid between EV2 and COM.
Continuity OK?

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

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

31

220683B

Diagram 9.3

Pump overrun Operation

The Control Thermostat has a pump overrun facility built into it, when the Control Thermostat is set at maximum only, the pump overrun will keep the

pump running to allow the boiler to cool down after which it will stop, providing the remote controls are NOT calling for heat.

YES

NO

NO

Faulty Pump overrun.
Replace Control Thermostat

YES

Is there 240V~ on L ?

NO

Pump overrun in order.

NO

NO

Faulty pump / wiring ? Replace or
repair as necessary.

Is there 240V~ on 9 connection
on thermostat?

Is there 240V~ on P for pump?

Faulty connections between thermostat
and terminal strip. Repair.

Faulty internal wiring between main
terminal strip and thermostat.
Repair.

Faulty permanent live feed.
Replace.

YES

YES

YES

Turn off remote controls, does the
pump stop after a short period
of time?

Fault Finding

Turn boiler Control Thermostat to maximum, with the remote controls calling for heat,

does the pump continue to run after the appliance has shut down on boiler control thermostat?

9 F a u l t F i n d i n g

32

220683B

9 F a u l t F i n d i n g

Diagram 9.4

FUSE
TYPE F1A
1 AMP

AIR PRESSURE SWITCH CONNECTIONS

0097M

SPARK
ELECTRODE

O/H CUTOFF

CONTROL STAT

FAN

AIR
PRESSURE
SWITCH

PILOT
SOLENOID

MAIN
SOLENOID

N

N

N

N

N

N

N

(N/O) (C)

(N/C)

L

K2

K1

6

3

N

N

b
w

w

br

y

y

y

r b

r

bk

b

y

br b

b

bk

b

KEY

bk BLACK
br BROWN
b BLUE

w WHITE
r RED
y YELLOW

SL

MAIN TERMINAL STRIP CONNECTIONS
CONTROL THERMOSTAT CONNECTIONS
PRINTED CIRCUIT BOARD CONNECTIONS

FULLY PUMPED OPEN VENTED
OR SEALED WATER SYSTEM

PN

9

9

8

7

P

L

PUMP

br b

br

r

brbr

THERMOSTAT

PUMP

OVERRUN

PURPLE

b

b

*

RED

LINK

*

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

33

220683B

Diagram 9.5

r

FULLY PUMPED OPEN
VENTED OR SEALED
WATER SYSTEM

KEY:

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

g/y

FAN

MULTI-FUNCTIONAL
CONTROL

ELECTRODE

PLUG

AIR
PRESSURE
SWITCH

C

NO

NC

y

r

b

bk

g/y

CHASSIS
EARTH

✽ Remove red link between 9 and SL when fitting

a time control etc (If no switch is fitted, link
will make the circulation pump run constantly)

CHASSIS EARTH

L
N

CIRCULATION
PUMP

E

E

N

L

240~50Hz
PERMANENT
MAINS
SUPPLY
FUSED
AT 3-AMP

N

L

9

8

7

SL

g/y

p

b

br

br

3-PLUGS

br
b

r

br

y

w
y

6

8

9

7

3

COMBINED THERMOSTAT
AND PUMP OVERRUN

OVERHEAT
CUTOFF

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

✽ SEE NOTE

4117

9 F a u l t F i n d i n g

F1A
1 AMP
FUSE

g/y

SEQUENCE
BOARD

g/y

br

b

br

b

g/y

34

220683B

1 0 R e p l a c e m e n t o f P a r t s

CONTROL
KNOB

RETAINING
CLIP

SPLIT
GROMMET

Diagram 10.1

SHAKEPROOF
WASHERS AND
SCREWS

CONTROL
THERMOSTAT

ELECTRICAL
CONNECTIONS
BROWN 9
RED 8
PURPLE 7
YELLOW 6 & 3

LOCKNUT

ELECTRICAL
CONNECTIONS

4113

10 Replacement of Parts

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

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

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

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

10.1 Access

Gain access as Section 8.1.

10.2 Control Thermostat/Pump Overrun ­diagram 10.1 and 10.2

Remove and support the electrical control box, refer to
Section 5.6.

Remove the control knob. Remove the electrical
connections from the thermostat body.

Release the thermostat body by unscrewing the two
screws and shakeproof washers in the front of the control
box.

Remove the split pin and withdraw the thermostat phial
from its pocket. Release the capillary from the base and
plastic retaining clip then remove it from the split
grommet. Release the capillary from its clips. Remove
the thermostat complete from the boiler.

Reassembly note. When fitting the thermostat, make
sure that the thermostat phial is covered with heat sink
compound then fully inserted into the phial pocket and
that the capillary is within the gland seal, see diagram

10.2. Remake the electrical connections. There must be
no kinks or sharp bends in the capillary.

10.3 Over Heat Cutoff Device - diagram

10.1, 10.2 and 10.2A

Remove and support the electrical control box, refer to
Section 5.6.

Remove the overheat cutoff electrical connections.
Disconnect the air pressure switch plug from the PCB.
Remove the locking nut from the overheat cutoff.
Release the capillary from the retaining clips then

remove it from the split grommet.
Remove the split pin and then the phial.
When refitting use the heat sink compound supplied.

35

220683B

10.4 Control Board (PCB) - diagram 102A

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

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

Release the main terminal strip and plastic label.
Carefully pull the board away from its supports.
When refitting refer to wiring diagram 9.5.

10.5 Pilot Burner and Pilot Injector

Proceed as Section 8.3 and 8.5.

10.6 Electrode

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

box.

Diagram 10.2 Diagram 10.2A

1 0 R e p l a c e m e n t o f P a r t s

PHIAL
POCKET

THERMOSTAT

PUMP

OVERRUN

PHIAL

ELECTRICAL PLUGS

OVERHEAT
CUTOFF
ELECTRICAL
CONNECTION
"WHITE"
CABLE

CHASSIS
EARTH
CONNECTION

MAIN
TERMINAL
STRIP
SECURING
SCREW (2)

ELECTRICAL
CONNECTION

SL BROWN CABLE

PLASTIC
RETAINING
CLIP

ELECTRICAL
CONNECTION

N BLUE CABLE

SPLIT
PIN

GLAND SEAL
(Right hand illustrated)

SUPPORT
POST (4)

IGNITION
LEAD

SPLIT
PIN

PHIAL
POCKET

RETAINING
CLIP

4110

BOILER
THERMOSTAT
ELECTRICAL
CONNECTION
NO.6
"YELLOW"
CABLE

3328

OVERHEAT
CUTOFF
DEVICE
PHIAL

NOTE: All capillaries and
cables should be situated
within the "Gland Seal".

36

220683B

1 0 R e p l a c e m e n t o f P a r t s

10.7 Multifunctional Control - diagram 10.3

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

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

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

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

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

10.8 Solenoid - diagram 10.3

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

10.9 Main Burner

Remove the main burner as Section 8.3.

10.10 Main Injector

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

10.11 Insulation - 10.4

Combustion Chamber Front
Remove the retaining screw then the insulation.

Sides

Slide the insulation out.

Rear

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

Diagram 10.3

SOLENOIDS

SECURING
SCREW

PILOT PIPE
TUBING NUT

RESTRICTOR

ELECTRICAL
PLUG

EXTENDED
SCREW (8)

4123

10.12 Viewing Window - diagram 10.5

Remove the push on fixes and then the window.
When replacing take care not to damage the gasket.

10.13 Air Pressure Switch - diagram 10.6

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

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

tubes and electrical connections are made as shown in
diagram 9.5 and 10.6.

10.14 Fan - diagram 5.4

Remove the electrical connections and disconnect the air
pressure tubes.

Remove the fan assembly securing screws at the front
and slacken those at the rear and withdraw the assembly.

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

The polarity of the other connections is not important.

37

220683B

Diagram 10.4

Diagram 10.5

Diagram 10.6

RED

CLEAR

AIR PRESSURE
SWITCH TUBES

ELECTRICAL
CONNECTIONS

CONTROL
BOX

FRONT INSULATION

RETAINING
SCREW

SIDE INSULATION

REAR INSULATION

AIR
PRESSURE
SWITCH

PUSH
ON FIX

RETAINING
PLATE

GASKET

VIEWING WINDOW

SECURING
POINTS

SECURING
SCREWS

4118

4095

4122

1 0 R e p l a c e m e n t o f P a r t s

38

220683B

11.1 Part Identification

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

11.2 Ordering

When ordering any spare parts please quote the number
and description from the list together with the model
name and serial number.

If ordering from British Gas also quote the GC number
of the appliance and part.

1 1 S p a r e P a r t s

1 800442 Multifunctional control 278 021
2 208040 “O” ring 334 592
3 205710 Injector 80FF 278 024
3 205701 Injector 70FF 313 393
4 203432 Pilot burner 278 023
5 411194 Sight glass 355 153
6 800421 Fan assembly 278 008
7 202626 Spark electrode and lead 313 998
8 K3580 Clip 390 983
9 202552 Thermostat 278 009
10 202201 Air pressure switch 313 992
11 800275 Control knob 313 609
12
13 202015 Fuse 334 750
14 900817 Control board PCB 313 301
15 800479 Overheat cutoff device 278 188

Key No. Part No. Description GC Part No.

39

220683B

1 1 S p a r e P a r t s

Diagram 11.1

4

6

2

1

9

10

5

7

8

11

3

13

14

15

4119

40

220683B

Control of Substances Hazradous to Health

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

INFORMATION FOR THE INSTALLER AND SERVICE ENGINEER.

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

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

THERMOSTATS

These contain very small amounts of xylene in the sealed phial and capillary.
If broken, under normal circumstances the fluid does not cause a problem, but in case of skin

contact, wash with cold water.
If swallowed drink plenty of water and seek medical attention.

CUT-OFF DEVICES

These contain activated charcoal and a very small amount of chlorodifluormethane in the sealed
phial and capillary.

If broken, under normal circumstances the fluid does not cause a problem.
If there is irritation to the eyes or skin then seek medical attention.