Glow-worm Xtrafast 96-120 User Manual

Instructions for Use

Installation and Servicing

To be left with the user

96 120

G.C. No. 47-047-25 G.C. No. 47-047-26

2000221595.11.01

Hab 255a

Fanned Flue Combination Boiler

This is a Cat II

The instructions consist of three parts, User, Installation and Servicing Instructions, which include 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.

Appliance

2H3+

Guarantee Registration

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

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

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:

✔

❑

✔

❑

✔

❑

One Contact Local Service

All replacement parts
All labour charges
All call-out charges

REGISTER YOUR GLOW-WORM APPLIANCE

FOR 1ST YEAR GUARANTEE PROTECTION

CALL 0208 247 9857

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

Hepworth Heating Ltd.,

Nottingham Road, Belper, Derbyshire. DE56 1JT

General/Sales enquiries:

Tel: [phone] Fax: [phone]

Important Information

Testing and Certification

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

Any alteration not approved by Hepworth Heating Ltd., could invalidate the certification, boiler warranty and may also infringe the
current issue of the Statutory Requirements. The requirements are: The installation of this boiler must be carried out by a
competent person in accordance with the current rules in force in the countries of destination at the time of installation.
Manufacture's instructions supplied. Manufacture's instructions must not be taken as overriding statutory requirements.

Note: The boiler serial number is marked on the label attached to the inside of the drop down door. Refer to the
'Introduction' section for a description of the basic functions of the boiler. The 'Users' section describes how to safely operate the
boiler.

Mandatory warning for CEE countries

Warning: This appliance is designed, approved and inspected to meet the requirements of the market. The identification plate

located on the inside of the appliance certifies the origin where the product was manufactured and the country for which it is
intended.
If you see any exception to this rule, please contact your nearest Glow-worm dealer.
Thank you in advance for your assistance.

CE Mark

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

Type test for purposes of Regulation 5 certified by: Notified body ****.
Product/production certified by: Notified body ****.
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.

Substances Hazardous to Health

The adhesives and sealants used in this appliance are cured and give no known hazard in this state.
INSULATION PADS/CERAMIC FIBRE, GLASSYARN, MINERAL WOOL

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

Spare Parts

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

2000221595

2

Contents

CONTENTS DESCRIPTION SECTION PAGE No.

Introduction 4

INSTRUCTION

FOR USE

INSTALLATION

INSTRUCTIONS

Controls and Lighting 5
Clock-timer instructions for use 6
Draining 6
Safety Devices 6
Servicing and Maintenance 7

Technical Data 1 8
Dimensions 2 9
Heating System Design 3 9
Domestic Hot Water System Design 4 10
Boiler Schematic 5 10
Boiler Location, Flue and Ventilation 6 11
Fixing Jig Pack 7 12
Piping System Installation 8 12
Boiler Installation 9 14
Flue Installation 10 14
Electrical Connection 11 17
Commissioning 12 18
Safety Devices 13 22
Changing Gas Type 14 22
Settings 15 23

SERVICING

INSTRUCTIONS

Routine Cleaning and Inspection 17 24
Fault Finding 18 27
Wiring Diagram 19 29
Replacement of Parts 20 30
Spare Parts 21 40

3

2000221595

Introduction

The

XTRAFAST 96 and 120

combination boiler with electronic ignition providing central
heating and instantaneous hot water. The boiler is equipped
with a 4 litre domestic hot water storage vessel that ensures
maximum hot water temperature stability during domestic
demand.

The boiler is of the II
as distributed in the United Kingdom.

The boiler has a fan assisted balanced flue which both discharges
the products of combustion to and draws the combustion air
from the outside of the room.

The boiler is suitable for top outlet flue connection only.
Both the central heating and domestic hot water temperature

are user adjustable from the boiler control panel.
Domestic hot water demand always has priority over heating

demand.
The boiler is designed for use as part of a sealed water central

heating system with fully pumped circulation. The pump,
expansion vessel and associated safety devices are all fitted
within the boiler.

The boiler can be installed against either an external wall or on
an adjacent inside wall, that is, the flue system will pass directly
to the rear or to either side to the terminal fitted on the outside
wall face.

The installation must be carried out by a competent person in
accordance with the relevant requirements of The Building
Regulations, The Water Byelaws, The Building Standards
(Scotland) Regulations and any applicable local regulations.

These instructions should be carefully followed for the safe and
economical use of your boiler.

2H3+

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.

All external wiring between the appliance and the electrical
supply and earthing requirements shall comply with the current
IEE 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

boiler is a wall mounted modulating

category for use with Natural Gas (G20)

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 PVC 85
than 0.75mm

2

(24/0.20mm).

o

C insulated cable, not less

Gas safety (Installation and use) Regulations

In your interests and that of gas safety, it is the law that ALL gas
appliances are installed and serviced by a qualified registered
person in accordance with the above regulations.

Gas leak or fault

If a gas leak or fault exists or is suspected, turn the boiler off and
consult the local gas supply company or your installation/
service company.

Air in the heating system

Persistent air in the heating system may indicate leaks in the
system or corrosion taking place. Call your Installation/Servicing
company.

Overheating safety

In the event of a problem, the overheating safety devices cause
safety shutdown of the boiler. If this happens, call your
Installation/Servicing company.

Boiler controls

The control panel, located at the lower front of the boiler casing,
see diagram 1, allows the boiler to be started, shut down,
controlled and monitored during use.

Flue

Do not obstruct the outside terminal of the boiler.

Ancillary equipment

A range of flue accessories are available including vertical
flues, twin-pipe flues, bends etc.

For further information contact your supplier.

1 - On/Off button
2 - Summer/Winter mode selector
3 - Hot water temperature adjuster
4 - Hot water set point display
5 - Graphic display
6 - Heating temperature adjuster
7 - Heating set point display
8 - Display backlight
9 - Clock-timer

(refer to clock-timer
instructions for use).

Diagram 1

2000221595

1

9900

1.5

4

Controls and Lighting

e

Lighting the boiler :

Make sure that:

• The boiler is connected to the electrical supply.

• The gas service cock is open.
Then follow the instructions below :

Press the On/Off button (1)

A

The pressure must be between 1 and 2 bar. If not, the system must be filled by a competent person.

1.5

bar

To stop the boiler : Press button (1)

mode

IO

1

1

2

4

2

23

3

22

4

21

5

20

6

1
9

7

8

1

8

17

9

1

6

10

15

1

1

14

2

1

13

0
1

Hab 264

Setting to the SUMMER position

(Hot water only)

Appuyer sur mode pour sélectionner la position été

Press the mode button to select the summer symbol

mode

1.5

bar

The flame symbol appears

Apparaît lorsque le brûleur

when the boiler is running

est en fonctionnement

Adjusting the hot water temperature

Press + or - to adjust the maximum temperature

Appuyer sur + ou - pour ajuster la température

of the hot water (38°C to 60°C)

maximale de l'eau chaude sanitaire (38°C à 60°C)

Visual indication of set temperature

Visualisation de la température demandée

Setting to the WINTER position

B

Press the mode button to select the winter symbol

Appuyer sur mode pour sélectionner la position hiver

The actual temperature

Température actuelle

of the heating system

dans le circuit chauffage

Adjusting the heating temperature

C

Press + or - to adjust the maximum temperature

Appuyer sur + ou - pour ajuster la température

of the heating (38°C to 87°C)

maximale souhaitée du circuit chauffage

(Heating + hot water)

°C

10

Visual indication of set temperature

Visualisation de la température demandé

1.5

bar

Illuminates when

Apparaît lorsque le

the boiler lights

brûleur fonctionne

mode

mode

50

°C

mode

60

°C

To obtain domestic hot water, open a hot water tap. Hot water always has priority over central heating.

5

2000221595

Hab 261

Clock-timer instructions for use

The boiler must be conected to the electrical supply and
switched on.

Setting the time

Rotate the clock actuater mechanism clockwise, by hand, until
the current time is indicated by the arrow, see diagram 2.

Note: The time is set in 24 hour format, for example, 1300 for
1pm.

Reg 049

Diagram 2 Diagram 3

Setting the programme "On" and "Off" times

• Select the "On" times by pushing the white tappets to the
outside, see diagram 2.

• Select the 'Off' times by pushing the white tappets to the inside,

see diagram 2.
The clock shown in diagram 2 is set as follows:
ON - 07.00am to 09.00am (7-9)
OFF - 09.00am to 4.00pm (9-16)
ON - 4.00pm to 10.00pm (16-22)
OFF - 10.00pm to 07.00am (22-7)

To override or advance the
clock

The clock has a manual On/
Off switch, see diagram 3,
which operates as follows :

Upper position
Heating On/Off as set by the
tappets.

Middle position
Heating Off continuously

Lower position
Heating On continuously

Reg 050

Draining

Protection against freezing

If the boiler is to be out of use for any long periods during severe
weather conditions, it is recommended that the whole system,
including the boiler, be drained to avoid the risk of freezing.

If in doubt, consult your servicing company.

Safety Devices

Air flow rate safety device

If an obstruction, even partial, of the flue occurs, for any reason,
the built in safety system of the boiler will turn the boiler OFF and
the fan will continue to run. The boiler will be ready to operate
when the fault has been cleared.

Overheat safety

In case of boiler overheating, the overheat thermostat will turn
the boiler off. The thermostat, located on the heat exchanger
flow pipe, will need to be manually reset. To have this done call
a qualified service engineer or Heatcall (Glow-worm’s own
service organisation) using the telephone number behind the
controls cover door or on the front cover of this booklet.

In case of power supply failure

The boiler no longer operates. As soon as power supply is
restored, the boiler will be automatically restarted.

Frost protection

The

XTRAFAST

protects the boiler from freezing. If the boiler is to be left and
there is a risk of frost, ensure that the gas and electrical supplies

has a built in frost protection device that

Draining and filling

Caution: The boiler is installed as part of a sealed system which
must only be drained and filled by a competent person.

are left connected. The frost protection device will light the boiler
when the temperature of the boiler water falls below 6°C. When
the temperature reaches 16°C, the boiler stops.

Note : This device works irrespective of any room thermostat
setting and will protect the complete heating system.

Heating safety valve

CAUTION: A heating safety valve with a discharge pipe is fitted

to this boiler.
The valve MUST NOT BE TOUCHED except by a qualified

registered person. If the valve discharges at any time, switch the
boiler off and isolate it from the electrical supply. Contact your
installation/service company.

Pressure relief valve

CAUTION: A domestic hot water pressure relief valve, with a

discharge pipe is fitted to this boiler.
The valve MUST NOT BE TOUCHED except by a qualified

registered person. If the valve discharges at any time, switch the
boiler off and isolate it from the electrical supply. Contact a
qualified service engineer or Heatcall (Glow-worm’s own service
organisation) using the telephone number behind the controls
cover door or on the front cover of this booklet.

2000221595

6

Servicing and Maintenance

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

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

Servicing/maintenance should be carried out by a competent
person in accordance with the rules in force in the countries of
destination.

To obtain service, please call your installer or Heatcall (Glow­worm’s own service organisation) using the telephone number
behind the controls cover door.

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.

1 Technical Data

Cleaning

WARNING: This appliance contains metal parts (components)
and care should be taken when handling and cleaning with
particular regard to edges of sheet metal parts to avoid any
possiblity of personal injury.

The boiler casing can be cleaned using a mild liquid detergent
with a damp cloth, followed by a dry cloth to polish.

Do not use any form of abrasive or solvent cleaner as you
may damage the paint work.

Boiler casing

CAUTION. Do not remove or adjust the casing in any way, as

incorrect fitting may result in faulty operation. If in doubt, consult
your installation/service company.

Heating

Heating output ajustable from ... (kW) 10,4 11,7

to ... (kW) 27,6 34,6

from ... (BTU/H) 35,485 39,920

to ... (BTU/H) 94,170 118,053
Efficiency (%) ** **
Maximum heating temperature (°C) 87 87
Expansion vessel effective capacity (l) 7 12
Expansion vessel charge pressure (bar) 0,5 0,5
Maximum system capacity at 75°C (l) 160 275
Safety valve,

maximum service pressure (bar) 3 3
Products outlet diameter (mm) 60 60
Fresh air inlet diameter (mm) 100 100

Hot water

Hot water output

automatically variable from ... (kW) 10,4 11,7

to ... (kW) 27,6 34,6

from ... (BTU/H) 35,485 39,920

to ... (BTU/H) 94,170 118,053
Maximum hot water temperature (°C) 60 60
Specific flow rate (for 30°C temp rise)

(l/min.) 13,2 16,5
Threshold flow rate (l/min.) 1 1
Nominal water flow rate (l/min.) 11,3 16,5
Maximum supply pressure (bar) 8 8
Minimum operating pressure (bar) 0,7 0,7

XTRAFAST 96

XTRAFAST 120

Natural Gas (G20)

Ø Burner injector (mm) 1,20 1,20
Inlet pressure (mbar) 20 20
Burner pressure (mbar) 13,8 14,1
Gas rate maximum (m3/h) 3,20 3,98
Gas rate minimum (m3/h) 1,32 1,48

Electrical supply (V) 230 230
Maximum absorbed power (W) 220 220
Level of protection IP44 IP44

Fuse rating 125mAT 125mAT

XTRAFAST 96

XTRAFAST 120

Xtrafast 96 Xtrafast 120
Lift weight 51.2kg (112.9lb) **.*kg (**.**lb)
Total weight
(inclusive water) **.*kg (**.**lb) **.*kg (**.**lb)

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

The value is used in the UK Government's Standard
Assesssment Procedure (SAP) for energy rating of dwellings.
The test data from which it has been calculated have been
certified by B.S.I.

7

2000221595

60

1 Technical Data

PUMP 96

50

1

2

3

40

30

20

10

Available pressure (kPa) between

heating supply and return lines

0

(10 kPa = 1 m WG)

80

4

5

Pom 010 a

120010008006004002000

Flow rate through heating system (I/h)

PUMP 120

70
60

1

50

3

4

5

2

40
30
20
10

Available pressure (kPa) between

heating supply and return lines

0

120010008006004002000

(10 kPa = 1 m WG)

Bypass fully shut Open 1/4 turn Open 1/2 turn Open 1 turn Open 2 turns

1

2

Flow rate through heating system (I/h)

3 4

5

Pom 058

2000221595

Diagram 4

8

The

XTRAFAST

packages:

- the boiler

- the fixing jig

- the flue system

Lifting Weight:
51,2 kg

2 Dimensions

is delivered in three separate

234

890

7422

65

X = 470 (96)
552 (120)

X

3 Heating System Design

• The

XTRAFAST

• Heating surfaces may consist of radiators, convectors or fan
assisted convectors.

• The

XTRAFAST

heating system without the need for a mixing bottle. The
maximum central heating flow temperature can be set to
53°C.on the boiler printed circuit board during commissioning.

• Pipe sectional areas shall be determined in accordance with
normal practices, using the output/pressure curve (diagram

4). The distribution system shall be calculated in accordance
with the output requirements of the actual system, not the
maximum output of the boiler. However, provision shall be
made to ensure sufficient flow so that the temperature difference
between the flow and return pipes be less than or equal to
20°C. The minimum flow is 400 l/h.

• The piping system shall be routed so as to avoid any air
pockets and facilitate permanent venting of the installation.
Bleed fittings must be provided at every high point of the
system and on all radiators.

is compatible with any type of installation.

can be piped directly to an underfloor

380

Diagram 5

• The total volume of water permitted for the heating system
depends, amongst other things, on the static head in the cold
condition. The expansion vessel on the boiler is pressurised at
0,5 bar (corresponding to a static head of 5 m w.g.) and allows
a maximum system volume of 160 litres for an average
temperature of 75°C and a maximum service pressure of 3 bar.
This pressure setting can be modified at commissioning stage
if the static head differs. An additional expansion vessel can be
fitted to the system if required, see diagram 8.2.

• Provision shall be made for a drain valve at the lowest point of
the system.

• Where thermostatic radiator valves are fitted, not all radiators
must be fitted with this type of valve, and in particular, where the
room thermostat is installed.

• In the case of an existing installation, it is ESSENTIAL that the
system is thoroughly flushed prior to installing the new boiler.

Filling the system

A filling device must be provided to fill the system, see diagram

8.2.

9

2000221595

4 Domestic Hot Water System Design

• Copper tubing or plastic hep2o may be used for the domestic
hot water system. Unnecessary pressure losses should be
avoided.

• A flow restrictor limiting the flow through the boiler to a
maximum of 12 l/min is fitted to the boiler.

• The boiler will operate with a minimum supply pressure of 0,7

5 Boiler Schematic

1 - Domestic thermistor
2 - Three way valve
3 - Gas valve
4 - Ignition module
5 - Heating element
6 - Micro accumulation vessel
7 - Burner
8 - Ignition electrode
9 - Combustion chamber
10 - Micro accumulation vessel thermistor
11 - Main heat exchanger
12 - Air pressure switch
13 - Heating safety valve (3 bar)
14 - Electronic control (PCB)
15 - Domestic water flow sensor
16 - Bypass
17 - Domestic heat exchanger
18 - Pump
19 - Expansion vessel
20 - Heating thermistor
21 - Overheat safety thermostat
22 - Flame sense electrode
23 - Fan
24 - Domestic safety valve (10 bar)
25 - Loss of water sensor
A - Heating return
B - Cold water inlet
C - Heating flow
D - Domestic hot water outlet
E - Gas

19

21

bar, but under reduced flow rate. Best operating comfort will be
obtained from a supply pressure of 1 bar.

'Hard Water Areas'
In areas where the water is 'hard', more than 200mg/litre, it is

recommended that a proprietary scale reducer is fitted in the
cold water supply to the boiler.

23

12

11

9

22

7

8

4

18

20

3

2

16

17

1

10026

10

6

5

2000221595

25

AB

10

15

13

14

C

24

D

E

Diagram 5.1

6 Boiler Location, Flue and Ventilation

If the appliance has to be stored for any length of time before
installation it should be kept in a safe place where it will not be
a hazard to persons or obstruct any access. Care should be
taken when handling or moving the appliance taking note of the
trucking points on the sides of the carton.

6.1 Clearances

The position of the boiler must be such that there is adequate
space for servicing.

The recommended clearances are:
20 mm either side of the boiler.
600 mm at the front of the boiler.
300 mm below the boiler.
25 mm above the flue elbow.
Note: The boiler must be mounted on a flat wall which is

sufficiently robust to take its weight when full, that is, ** kg. If in
doubt, expert advice should be obtained. In the event of the wall
being found not suitable.

Note: It is permissible to install the boiler with smaller clearances
than those quoted above PROVIDING that adequate
consideration is given for Servicing/Repairs at a later date. If
any doubt exists, contact the Glow-worm Technical Helpline

01773 828100.

The minimum acceptable spacings from the terminal to
obstructions and ventilation openings are shown in diagram

6.1.

The boiler must be installed so that the terminal is exposed to
the external air.

Should any doubt exist as to the permissible position of the
terminal, contact the Glow-worm Technical Helpline 01773

828100.

6.2 Terminal guard

A terminal guard is required if persons could come into contact
with the terminal or the terminal could be sublject 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
to be central over the terminal.

Teminal guard type K3 supplied by:

Tower flue components Ltd.
Morley road
Tonbridge
Kent
TN9 1RA

6.3 Flue options

There are various flue systems to choose from as follows:
Standard horizontal flue pack.
Standard horizontal extended flue pack.
Vertical flue pack.
Twin flue pack.
Extentions, 90° and 45° bends.
Flue options and accessories.
For detailed information refer to flue guide Part No. 223278.

6.4 Cupboard or compartment ventilation

The boiler can be fitted in a cupboard or compartment without
the need for permanent ventilation.

MINIMUM SITING DIMENSIONS FOR THE
POSITIONING OF FLUE TERMINALS MM

A DIRECTLY BELOW, ABOVE OR
HORIZONTALLY TO AN OPENING, AIR
BRICK, OPENING WINDOWS, AIR VENT, OR
ANY OTHER VENTILATION OPENING 300
B BELOW GUTTER, DRAIN/SOIL PIPE 75
C BELOW EAVES 200
D BELOW A BALCONY OR CAR PORT 300
E FROM VERTICAL DRAIN PIPES AND

SOIL PIPES 300

F FROM INTERNAL CORNERS AND

EXTERNAL CORNERS 300

G ABOVE ADJACENT GROUND OR

BALCONY LEVEL 300

H FROM 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 600

A

A

F

G

UNDER CAR PORT etc.

2816

C

B,C

G

A

E

G

H,I

B,C

K

F

F

G

J

K

K

L

L

K

G

D

F

Diagram 6.1

11

2000221595

7 Fixing Jig Pack

The fixing jig is made up, from left to right, as follows:
A - Heating return fitting with isolating valve(v) and
drain knob (u).
B - Cold water inlet fitting with isolating valve (m)and

factory fitted flow regulator and filter (not shown).
C - Heating flow fitting with isolating valve (q), drain
knob (r) and safety valve (s1).
D - Domestic hot water outlet fitting with safety valve
(s2).
E - Gas fitting.

SCREW
(4 OFF)

A

u

ISOLATING
VALVE PLATE

B

v

m

s1

Other components within the fixing jig pack.

F - Hanging bracket
G - wall template
H - copper connections
J - sealing washers
K - sealant (putty)

F

K

9959

C

r

D

E

q

G

J

9880

COPPER

LEFT
HAND
SUPPORT
BRACKET

THE FIXING JIG SHOWN ASSEMBLED

H

CONNECTIONS
AND WASHERS
(7 OFF)

8 Piping System Installation

8.1 Fixing jig

• Remove the contents of the fixing jig pack.

• Secure the left and right hand support brackets to the isolating
valve plate with the securing screws (4 OFF) supplied, see

diagram 7.1.

• Connect the six copper connections and sealing washers to
the isolating valves, see diagram 7.1.

• Heating system connections - Pipe diam. 22mm

• Hot water system connections - Pipe diam. 15mm

• Gas connection - Pipe diam. 22mm

• Domestic safety valve connection - Pipe diam.15mm

• Heating safety valve connection - Pipe diam. 15mm

8.2 Wall template

• Remove the wall template, follow the instructions given on the
wall template.

• Note: It is important the hanging bracket and service cock

s2

RIGHT
HAND
SUPPORT
BRACKET

Diagram 7.1

bracket are fitted to a flat and true wall area for correct alignment
with the boiler. If this is cannot be achieved it is acceptable to
pack out the service cock bracket to obtain the correct alignment.

• Position the wall template, see diagram 8.1.

• Mark the position of the holes for the hanging bracket and jig.

• Drill, plug and fix the hanging bracket to the wall using suitable
screws.

• Check that the hanging bracket is level.

• Drill plug and fix the fixing jig to the wall.

• For horizontal flue system, mark the position for the flue hole
as follows:

8.3 Flue to rear of boiler

• Mark correct position of hole from template.

8.4 Flue to side of boiler

• Mark the horizontal centre line for the hole on the rear wall.
Extend the horizontal centre line to the side wall and mark the
vertical centre line of flue hole as shown in diagram 8.1.

2000221595

12

8 Piping System Installation

8.5 Cutting the flue hole

• Making allowance for the slope of the flue, cut hole in external
wall, preferably using a core drill. For installations with internal
and external access use a 105 mm diameter core drill.

For installations with internal access only use a 125 mm
diameter core drill.

9684

105

8.6 Important

When cutting the flue hole and when extending the flue centre
line to a side wall, remember that the flue system must have a
fall of about 35 mm per metre of flue DOWNWARD towards the
terminal. There must NEVER be a downward incline towards
the boiler.

8.6 Terminal position

The minimum acceptable spacings from the terminal to
obstructions and ventilation openings are shown in diagram

6.1.

The boiler must be installed so that the terminal is exposed to
the external air.

Should any doubt exist as to the permissible position of the
terminal, contact the Glow-worm Technical Helpline 01773

828100.

8.7 Water connection

Connect the system pipework to the copper connections on the
fixing jig observing the correct flow and return format as shown
in diagram 8.2. Do not subject the isolating valves to heat.

8.8 Heating safety valve and domestic safety
valve discharge, refer to diagram 8.3.

Tee the domestic safety valve outlet pipe to the heating safety
valve outlet pipe and extend horizontally to the outside wall.

WARNING. It must not discharge above an entrance or window
or any type of public access area.

Connect the safety valve discharge pipe to the outlets of both
the heating safety valve and the domestic water safety valve,
the discharge must be extended using not less than 15mm.
pipe, to discharge in a visible position outside the building,
facing downward preferably over a drain.

The pipe must have a continuous fall and be routed to a position
so that any discharge of water, possibly boiling or steam, cannot
create any danger to persons, damage to property or external
electrical components and wiring. Tighten all pipe connection
joints.

65

890

Additional
expansion
vessel
(if required)

470 (96)
552 (120)

Boiler

20

234

Diagram 8.1

Domestic

water

Hot

Cold supply

8.9 Gas connection

• The supply from the governed gas meter must be of adequate
size to provide a constant inlet working pressure of 20 mbar (8
in w.g.).

To avoid low gas pressure problems, it is recommended that the
gas supply is connected using 22 mm pipe.

• On completion, the gas installation must be tested using the
pressure drop method and purged in accordance with the
current issue of BS6891.

8.10 Gas Safety (Installation and use)
Regulations

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

Return

Heating
circuit

HEATING SAFETY
VALVE 3 bar)

13

Flow

control valve

Bypass

valve

Filling device

Drain point

Sch 173a

Diagram 8.2

DOMESTIC
SAFETY
VALVE
(10bar)

Diagram 8.3

2000221595

9 Boiler installation

9.1 Statutory requirements

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

The Gas Safety (Installation and Use) Regulations
The Building Regulations
The local water company Byelaws
The Building Standards Regulations (Scotland)
The Health and Safety at Work Act

9.2 Sheet metal parts

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

9.3 Installing the boiler

Prior to starting work, the system must be thoroughly flushed
using a propriety cleanser such as Sentinel X300 to eliminate
any foreign matter and contamination e.g. metal filings, solder
particles, oil, grease etc.

Note. Solvent products could cause damage to the system.
The boiler pack consists of the boiler, base panel, literature,

sealing washers and securing screws.

• Lay boiler on its back.

• Remove all packaging from around the boiler.

• Remove front panel, put in a safe place to avoid damaging it.

• Ensure the plastic plugs are removed from water and gas
pipes. NOTE: There will be some spillage of water.

• Remove transportation timber support bar from bottom rear of
boiler.

• If required the boiler can be stood upright supported by
extending the legs at the front bottom of the boiler.

• Engage boiler upper part onto the hanging bracket.

• Fit the washers between the boiler pipes and the inlet and
outlet fittings on the fixing jig and connect the various couplings
between the boiler and jig.

• Fit the base panel, hook in at the rear secure with the four self
tapping securing screws at the front.

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14

10 Flue Installation

10.1 Top outlet flue - kit 86285

The boiler is only suitable for top outlet flue connection.

10.2 Rear flue systems

(Refer to diagram 10.1). To calculate the length when flueing to

the rear measure wall thickness e plus 160 mm for the outer air
duct and e plus 244 mm for the inner flue duct measurement.

10.3 Flue systems Right or Left

(Refer to diagram 10.1). To calculate the length when flueing to
the side measure wall thickness e plus inside of wall to side of

boiler a add 145(mm) for the outer air duct and wall thickness e
plus inside of wall to side of boiler a add 229(mm) for the inner flue
duct measurement.

• Refer to diagram 10.2 (Table A) for cutting lengths of both flue
duct and air duct pipes for each of the various flue options
available.

Important: All flue cutting lengths must be measured from the
terminal end of the flue pipes, see diagram 10.2 (D).

When the dimension X measured on site is greater than that given
in diagram 10.2 ( Table B ), extensions will be required as
necessary.

Calculation of flue cutting lengths for extended flue

•Using the correct number of extension kits as (Table B), measure
dimensions a and e, see diagram 10.1. Cut both the flue duct and
air duct pipes to the dimensions given in (Table C)

Important: All cutting lengths should be measured from the push
fit joint end of the extension pipe. Do not leave any burrs or sharp
edges on the cut ends of the pipes. Note : maximum horizontal
flue length without bends is 3.5m.

70mm 70mm

a

X

9659

a

X

Diagram 10.1

ee

Rear flue
Air Duct pipe : e + 160, Flue duct pipe : e + 244

Note : maximum distance 'x' without extension 756 mm

Side flue (right or left)
Air Duct pipe : e + a + 145, Flue duct pipe : e + a + 229

Note : maximum distance 'x' without extension 990 mm

Table B: Number of extension kits required

Flue option Dimension 'X' No. of

extension kits

Side flue 991 to 1991 mm 1

(left or right) 1991 to 2991 mm 2

Note: Maximum flue length for 120 model is 2 metres

Table C: Flue extention cutting lengths (mm)

Rear flue option

Air Duct pipe : e + a - 755, Flue duct pipe : e + a -755

Note : maximum distance 'x' without extension 990 mm

(D)Table A: Flue cutting lengths (mm)

AIR DUCT PIPE

Outer pipe

Ven 089

Cutting length

FLUE DUCT PIPE

Inner pipe

Cutting length

Diagram 10.2

15

2000221595

10 Flue Installation

10.4 Installation of flue assembly

• Fit rubber sealing collar (F), see diagram 10.3, into groove
at the outer end of pipe (A).

• Fit air duct pipe (A) into wall with groove to the outside.

• Pull pipe inwards to bring rubber sealing collar hard up
against external wall, see diagram 10.4.

• Fit internal plastic flange (G) onto air duct pipe. Push along the
pipe until engaged against internal wall.

• From inside, insert flue duct pipe (B) into air duct pipe.

• Fit both ‘O’ rings (J) into the flue elbow (C), one at the inlet,
one at the outlet. By necessity, they are a loose fit, apply a small
amount of silicone grease to each ‘O’ ring when fitting.

• Fixing collar (D) over air duct pipe (A) and elbow (C) ensuring
it is the correct way round (Note: the fixing collar can only be
fitted one way due to different diameters of the flue elbow and
air duct).

• Take hold of the flue duct pipe and push gently onto the elbow
outlet taking care not to tear the ‘O’ ring.

• Open fixing collar (D) and locate between elbow and air duct
pipe (A). Close fixing jig.

• Engage the two fixing clips (E) onto the collar (D) and press
down to lock into position. Secure clips with screws provided.

Important: If the flue has been cut, ensure that there are no
burrs that could damage the ‘O’ ring.

• For flue systems less than 1,5 m long, leave the restrictor (a)
fitted in the fan outlet, see diagram 10.5.

• Remove the backing from the self adhesive gasket (H) and
carefully fit gasket to base of flue elbow.

• Fit elbow onto boiler and secure with the four screws (I).

A

B

E

C

D

H

The flue kit 86285 is 1000 mm long and comprises:

- Air duct pipe .......................................................... A

- Flue duct pipe ........................................................ B

- Flue elbow .............................................................. C

- Fixing collar............................................................. D

- Locking clips ............................................................ E

- External rubber sealing collar ............................... F

- Internal flange ....................................................... G

- Gasket ..................................................................... H

- Screws ....................................................................... I

- 'O' rings..................................................................... J

F

I

J

Diagram 10.3

G

Pho 451

Pho 087

Diagram 10.4

Concentric flue system

The maximum permissible length (L) for the
concentric flue system is 3.5 m. For flue systems up to 1,5 m length, the restrictor (a) supplied fitted to the boiler,
inside the fan outlet, must be left in place. For longer flue systems, the restrictor must be removed.
For each 90° flue elbow used, (or two 45° elbows) the maximum permissible length (L) must be reduced by 1
metre.

L

Gasket

a

65

234

Hab 249a

2000221595

Diagram 10.5

16

11 Electrical Connection

Warning. This boiler must be earthed

The boiler is supplied with a mains lead attached.
Standard colours are Brown - Live, Blue - Neutral, Green and
Yellow - Earth.

All system components must be of an approved type.
Electrical components have been tested to meet the equivalent

requirements of the BEAB.
Connection of the whole electrical system and any heating

system controls to the electrical supply must be through a
common isolator.

Isolation should preferably be by a double pole switched fused
spur box having a minimum contact separation of 3 mm on each
pole. The fused spur box should be readily accessible and
preferably adjacent to the boiler. It should be identified as to its
use.

A fused three pin plug and shuttered socket outlet may be used
instead of a fused spur box provided that:

a) They are not used in a room containing a fixed bath or shower.
b) Both the plug and socket comply with the current issue of

BS1363.
The mains electrical supply must be maintained at all times in

order to provide domestic hot water.
Do not interrupt the mains supply with a time switch or programmer.

WARNING: ON NO ACCOUNT MUST ANY EXTERNAL
VOLTAGE BE APPLIED TO ANY OF THE TERMINALS ON
THE HEATING CONTROLS CONNECTION PLUG.

Warning: This appliance must be wired in accordance with these

instructions. Any fault arising from incorrect wiring cannot be put
right under the terms of the Glow-worm guarantee.

9881

The boiler is supplird with a mains lead
attached. Connect this to the electrical supply.

Diagram 11.1

10036

SIDE CLIPS

Diagram 11.2

Leave link in place for no external controls.

11.1 External controls

The

XTRAFAST

efficiency at all times, but will be most efficient and economical
when connected to a room thermostat.

To gain access to the external control connections, unclip side
clips and hinge up control panel cover, see diagram 11.2.

The boiler will work for heating without a room thermostat being
connected provided that the wire link fitted between the two
terminals of the connector (E) is left in place, see diagram 11.3.

Alternatively, a 230V room thermostat can be used but do not
make any connection to the compensating resistor, see diagram

11.3.
ON NO ACCOUNT must any electrical voltage be applied to any

of the terminals of the external controls plug.

Remote Control

A remote control is available for the Xtrafast. Part no. xxxxxx. If
the remote control is fitted the wire link must be in place on
connector (E), and the Switch SW3 must be adjusted, see

diagram 11.4.

boiler is designed to operate at maximum

11.2 Electrical test

Carry out preliminary electrical system checks as below:

1. Test insulation resistance to earth of mains cables.

2. Test earth continuity and short circuit of all cables.

3. Test the polarity of the mains.
Note: For further information, see the building regulations 1991

- Conservation of Fuel and Power - 1995 edition - appendix G,
Table 4b.

E

9878

Set 1 & 2 OFF
for normal
operation

9879

IMPORTANT

VOLTAGE FREE

With

room thermostat

Without room

°C

thermostat

E

E

Diagram 11.3

SW3

ON

12

TOGGLES

ON OFF
1 - Remote Control with without
2 - Parameters open locked

Diagram 11.4

10023

17

2000221595

12 Commissioning

d

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

The commissioning and first firing of the boiler must only be
done by a qualified registered person.

Gas valve settings. Refer to Section 15 "Settings".

Gas installation

It is recommended that any air is purged from the supply at the
gas inlet test point on the gas valve, see diagram 12.1.

9323

Filling the system 1 to 8

Press the mains 'On/Off' button

1

The warning light will illuminate

➜

v

m

➜

GAS INLET
TEST POINT

The display will indicate 0 bar pressure in the system

2

3

4

5

6

7

8

9

10

1

1

12

0.0

mode

bar

Undo cap on
automatic air
vent on top of
pump and

q

leave undone.

Diagram 12.1

Hab 265

IO

1

24

2

3

2

2

21

2

0

1
9

18

1

7

1

6

15

14

13

0
1

3

2

Open the system filling loop and fill the

4

system until the pressure indicated
on the display is between 1 and 2 bar.

2000221595

Open the boiler isolating valves
(v and q), the slot of the screw
corresponds to flow direction.
Fully open valve m by turning
anti-clockwise.

Reg 008

The pressure must be between 1 and 2 bar

mo

1.5 bar

18

Hab 265

12 Commissioning

Bleed each radiator to

5

remove the air, re-tighten

Leave the cap on the

6

pump auto air vent open.

bleed screws.

➜

➜

Reg 008

Ins 061

Make sure the display indicates a system pressure of between 1 and 2 bar. Re-fill

8

system as necessary. (The warning light will extinguish at 1 bar).

The pressure must be between 1 and 2 bar

1

2

4

2

2

3

3

22

4

21

5

20

17

9

1

6

0

1

15

1

1

14

12

13

mode

6

7

8

Open various hot water

7

taps to bleed system.

Ins 062

Hab 265

IO

1
9

18

0
1

1.5

bar

19

2000221595

12 Commissioning

e

Lighting the boiler:

Make sure that:

• The boiler is connected to the electrical supply. • The gas service cock is open.
Then follow the instructions below :

A

Press the On/Off button (1)

The pressure must be between 1 and 2 bar. If not, the system must be filled by a competent person.

IO

1

24

2

2

3

3

2

2

4

21

5

20

1
9

8

18

17

9

1

6

10

15

1

1

1

4

2

1

13

0
1

1

1.5

bar

mode

6

7

Hab 264

To stop the boiler: Press button 1.

Setting to the WINTER position

(Heating + hot water)

B

Appuyer sur mode pour sélectionner la position hiver

The actual temperature

Température actuelle
dans le circuit chauffage

of the heating system

Press the mode button to select
the winter symbol

°C

10

1.5

bar

Illuminates when the

Apparaît lorsque le
brûleur fonctionne

boiler lights

Adjusting the heating temperature

C

Press + or - to adjust the maximum

Appuyer sur + ou - pour ajuster la température

temperature of the heating (38°C to 87°C)

maximale souhaitée du circuit chauffage

Visual indication of set temperature

Visualisation de la température demandé

mode

• Adjust heating temperature to maximum 87°C.

• Check that any external controls, if fitted, are calling for heat
(set room thermostat to maximum).

• Allow the temperature to rise to the maximum value, with all
radiator valves open. The temperature rise will cause release
of the gases contained in the water of the central heating
system.

• Gases driven towards the boiler will be automatically released
through the automatic air vent.

• The gases trapped at the highest point of the system must be
released by bleeding the radiators. Check the burner gas rate
required, ten minutes from lighting. Refer to Data Label on
electrical controls box. Should there be any doubt about the
gas rate it should be checked at the meter.

On reaching maximum temperature, the boiler should be
turned off and the system drained as rapidly as possible whilst
still hot.

• Refill system to a pressure of between 1 and 2 bar and vent
as before.

• Restart boiler and operate until a maximum temperature is
reached. Shut down boiler and vent heating system. If necessary,
top up heating system and make sure that a pressure of at least
1 bar is indicated when system is COLD.

2000221595

60

°C

mode

Hab 261

20

13 Safety Devices

The

XTRAFAST

fault conditions, should they occur.
In the event of a fault, the display will indicate, by means of

pictograms and/or letters and numbers, exactly in which area
the fault lies.

Should the boiler fail to operate during Commissioning, the
most likely fault is that the gas supply to the boiler has not been
turned on or purged sufficiently or that there is no pressure in the
heating system. These are indicated as follows :

13.1 No gas supply

• Switch off the boiler at the On/Off
push button.

• Rectify the gas supply problem.

• Restart the boiler by pressing the
On/Off button.

13.2 Insufficient system pressure

13.3 Other faults

These are indicated on the display by a fault code and a
telephone symbol. Further information on the fault codes can
be found in the 'Section 17 Fault Finding'.

incorporates a visual display that indicates

➜

This will be indicated on the
display as a pictogram of a
spark. To rectify this, proceed
as follows:

IO

1

This will be indicated on the
display as a flashing warning

0.3

bar

indicating the system pressure
is low. To rectify this the system
must be re-filled, refer to

'Section 12 Commissioning'.

General safety devices

13.4 Air flow rate safety device

If an obstruction, even partial, of the flue occurs, for any reason
whatsoever, the built in safety system of the boiler will turn the
boiler OFF and the fan will continue to run.

The boiler will be ready to operate when the fault has been
cleared.

13.5 Overheat safety

In case of boiler overheating, the overheat thermostat will turn
the boiler off. The thermostat will need to be manually reset. To
do this remove the front panel and sealed chamber cover,
locate the reset button on the heat exchanger flow pipe, refer

to Sections 16.3, 16.4, 16.5 and diagram 19.15.

13.6 In case of power supply failure

The boiler no longer operates.
As soon as power supply is restored, the boiler will be

automatically restarted.

13.7 Frost protection

The XTRAFAST has a built in frost protection device that
protects the boiler from freezing. If the boiler is to be left and
there is a risk of frost, ensure that the gas and electrical supplies
are left connected. The frost protection device will light the boiler
when the temperature of the boiler water falls below 6°C. When
the temperature reaches 16°C, the boiler stops.

Note : This device works irrespective of any room thermostat
setting and will protect the complete heating system.

21

2000221595

14 Changing Gas Type

Should it become necessary to change the gas type, a
modification kit will be required.

This modification must only be carried out by a suitably qualified
engineer.

Conversion natural Gas (G20) to G30/G31 Part No. 86216.

15 Settings

Bypass

The

XTRAFAST

adjusted according to the requirements of the system, refer to
the flow rate pressure curve (diagram 4). The boiler is supplied
with the built-in bypass open a half a turn. It is adjusted by
turning the bypass screw (a), see diagram 15.1. Turn the screw
clockwise to close the bypass. When using thermostatic
radiator valves (TRV’s) on all of the radiators, it is essential that
a separate, adjustable bypass of 15 mm minimum diameter is
fitted between the flow and return of the heating circuit, see
diagram 8.2. Any bypass must be fitted before system controls.

boiler has a built-in bypass. This must be

9669

a

Diagram 15.1

2000221595

22

16 Routine Cleaning and Inspection

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

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

All parts are replaced in reverse order to removal.

16.1 Products of combustion check, refer to
diagram 16.1

Note: To obtain a products of combustion reading, unscrew the
left hand sampling point cap on the flue elbow, located on top
of boiler.

Connect the analyser tube onto sampling point.
Switch on the electrical supply and gas supply, then operate

the boiler.
On completion of the test switch off the electrical supply and the

gas supply, remove analyser tube and replace sampling point
cap.

10022

9318

PRODUCTS
SAMPLING
POINT

Diagram 16.1

16.2 Service Check and Preparation.

• Operate boiler and check for any faults that need to be put
right.

• Isolate boiler from the gas and electrical supplies.

• On completion check all gas-carrying parts for soundness with
leak detection fluid.

• Remove boiler casing as follows:

16.3 Front panel

• Unscrew and remove the two front panel retaining brackets
from the top of the boiler.

• Remove panel by lifting up and forward.

16.4 Control panel

• Lift control panel up and lower forwards to gain access to lower
part of boiler.

16.5 Sealed chamber cover

• Unclip the two toggle clips holding the sealed chamber cover,
see diagram. 16.2.

• Lift cover up and off boiler.

Diagram 16.2

9950

Diagram 16.3

16.6 Side panels

• Unscrew and remove the four screws securing lower grille
onto boiler. Unhook grille from rear of boiler and remove.

• Remove three screws from front of each side panel.

• Unclip the toggle clip at the top of each side panel.

• Lift each panel up and then forward to remove.

(For ease of access if required)

16.7 Combustion chamber cover

• Unscrew the two screws securing combustion chamber cover
to combustion chamber then unclip the two toggle clips, see
diagram 16.3.

• Remove combustion chamber cover from boiler.

23

2000221595

16 Routine Cleaning and Inspection

16.8 Burner, refer to diagram 16.4.

• Undo main gas supply nut from under the sealed chamber.
Note: The washer between main burner and main burner gas

supply must be kept for use on reassembly.

• Pull off ignition leads from gas control valve.

• Slacken but do not remove, two burner support screws at rear
of burner chamber using a long blade screw driver.

• Ease burner from boiler by lifting up from key hole slots,
threading the gas supply and ignition leads through the grommets
and pulling forwards, (taking care not to damage the insulation).
Before you completly remove the burner pull off flame sense
lead from flame sense electrode.

• Clean burner by washing in soapy water. Dry thoroughly
before refitting.

• When refitting burner ensure that the burner locates and seals
correctly through the grommets.

Note: To gain access to injectors for removal, refer to Section,

19.24 in Replacement of Parts.

9661

GROMMETS

16.9 Heat exchanger, refer to diagram 16.5.

• Disconnect electrical leads from fan.

• Unscrew and remove two fan retaining screws from the right
hand side edge of fan mounting plate.

• Remove fan with mounting plate attached by pulling forward
and out of boiler.

• Remove air pressure switch sensing tube from sensing probe
on flue hood.

• Remove screws securing flue hood to rear panel

• Lift flue hood clear of heat exchanger and examine for debris.

• Using a soft brush or vacuum clean as required.

DO NOT USE ANY TOOL LIKELY TO DAMAGE PAINTED
FINISH OF HEAT EXCHANGER.

Note: When re-fitting fan, make sure that the two lugs on the fan
mounting plate engage in the flue hood

FAN RETAINING SLOTS

9670

9664

BURNER
SECURING
SCREWS

MAIN GAS
SUPPLY NUT

9344

IGNITION
LEADS

9665

9662

9663

2000221595

9667

IGNITION
ELECTRODE
ASSEMBLY

FLAME SENSE
ELECTRODE

Diagram 16.4

9660

Diagram 16.5

24

16 Routine Cleaning and Inspection

16.10 Spark and Sense Gaps

• Check that the spark and sense gaps as shown in diagram

16.6.

16.11 Flue system

• Check externally to make sure that flue is not blocked

• Inspect flue system to make sure that all fittings are secure.

16.12 Operation of fan

• Switch on electrical supply and turn on gas.

• Light burner by opening a hot water tap.

• Check that fan operates when burner lights and stops when it
goes out.

16.13 Cold water inlet filter

Drain down domestic hot water circuit of boiler only, as follows:

• Close isolating valve/throttle (m) on cold water isolating cock,

see diagram 7.1.
Note: This valve is closed when screwed fully clockwise.

• Undo connecting nut from boiler cold water inlet connection.

• Clean and inspect filter, replace if necessary, see diagram

16.7.

• With both filter and restrictor in place, reconnect connecting
pipe to inlet connection and tighten.

• Fully open isolating valve/throttle on cold water inlet and check
for leaks.

4mm

9877

4mm

SPARK GAP

9876

5mm

SENSE GAP

FLOW
RESTRICTOR
AND COLD
WATER INLET
FILTER

Diagram 16.6

9875

Diagram 16.7

25

2000221595

17 Fault Finding

Fault finding must be carried out by a competent person.
WARNING. Always isolate the boiler from the electrical supply

before carrying out any electrical replacement work.
On completion of a fault finding task that has required the

disconnection and making of electrical connections then check
for earth continuity, polarity and resistance to earth must be
carried out.

If any gas-carrying components are disturbed, removed or
replaced it will be necessary on completion to check for gas
soundness with leak detection fluid.

Before trying to operate the boiler make sure that :

• All gas supply cocks are open and that the gas supply has
been purged of air.

Table 2

Voltage Measured value Measuring point

230 Volt 230 V AC Between terminals H8.1 and H8.2

24 Volt maximum 33V DC Between terminals B2.4 and B2.7

minimum 20V DC

15 Volt 15V + 0.5V Between terminals B2.4 and B2.2

Display 5V + 0.5V Between terminals B2.4 and B4.2

• There is a permanent mains supply to the boiler.

• The heating system pressure is at least 1 bar.

• The fuse on the PCB is intact.
Preliminary electrical system checks, as outlined in a multimeter

instruction book, are the first checks to be carried out during a
fault finding procedure.

Should there be any doubt about the voltage supply to any of
the components, it is possible to carry out a simple electrical
test to ensure all is operational in that area.

To carry out the electrical test, gain access to the main Printed
Circuit Board (PCB) , and measure the voltages according to
table 2.

The In-board fault diagnostic system. Should a fault
occur on the boiler, the warning LED at the top of the
user display will illuminate and the LCD display will
indicate the precise area where the fault has occurred.

Sec 052

09 FF

A fault code is displayed on the left hand side of the LCD display, whilst at the same time, the letters appear with a
telephone symbol.

Thermistor values

The following table applies to the central heating,
domestic hot water and storage vessel thermistors:

Temperature (°C) Resistance (Ω)

0 ...................................... 32565

5 ...................................... 25345

10 ..................................... 19875

15 ..................................... 15700

20 ..................................... 12500

25 ..................................... 10000

30 ...................................... 8060

35 ...................................... 6535

40 ...................................... 5330

45 ...................................... 4370

50 ...................................... 3605

55 ...................................... 2989

60 ...................................... 2490

65 ...................................... 2085

70 ...................................... 1755

75 ...................................... 1480

80 ...................................... 1260

85 ...................................... 1070

90....................................... 920

95....................................... 785

100...................................... 680

System pressure sensor

The resistance of the sensor at various pressures is
as follows :

0 bar ...................... between 280 Ω and 320 Ω

1 bar ...................... between 195 Ω and 220 Ω

3 bar ...................... between 93 Ω and 143 Ω

2000221595

26

17 Fault Finding

TO AID FAULT FINDING REFER TO DIAGRAMS 5.1 AND 18.1.

CODE CHECKDISPLAY SYMBOL

00

02

04

05

06

or

07

or

08

09
12

TYPE OF FAULT

NO FAULT

AIR FLOW SAFETY

NO IGNITION

Note: MAX. IGNITION TIME

= 7 SECONDS

OVERHEATING

HEATING THERMIST OR

ON FLOW PIPE

DOMESTIC THERMISTOR

ON DHW PIPE

TEMPERATURE ON

STORAGE VESSEL

LOSS OF WATER

PRESSURE SENSOR.

USER INTERFACE

NO FAULT

THIS SYMBOL IS NOT INSTANTANEOUS BUT IF IT APPEARS
AFTER 40 SECONDS, CHECK

• THE FLUE SYSTEM FOR A BLOCKAGE, EXCESS LENGTH.

• CHECK THE AIR PRESSURE SWITCH.

• CHECK THE ELECTRICAL CONNECTIONS.
IF THE BURNER LIGHTS WITH A TRAIN OF SPARKS

AND GOES OUT AFTER 7 SECONDS.

• REVERSE LIVE AND NEUTRAL TO THE ELECTRICAL PLUG.

• CHECK THE ELECTRODE AND ITS CORRECT CONNECTION.

• CHECK IGNITION BOX.

• CHECK THERE IS MORE THAN 40V BETWEEN LIVE AND EARTH.

IF THE TRAIN OF SPARKS DOES NOT LIGHT THE BURNER, CHECK .

• THE GAS TAP ON THE INSTALLATION IS OPEN.

• THE GAS CONTROL VALVE.

• CHECK THE IGNITON BOX.

• PUMP BLOCKED OR ITS CONDENSER OUT OF SERVICE.

• ISOLATING COCKS CLOSED ON JIG.

• DEFECTIVE OVERHEAT THERMOSTAT.

• BLEED OUT AIR.

• CHECK THE ELECTRICAL CONNECTIONS.

• CIRCUITS OPEN OR SHORT CIRCUIT.

• CHECK RESISTANCE OF THE THERMISTOR. (12500 ohms AT
20°C. 1750 ohms AT 70°C).

• UNCLIP THE THERMISTOR FROM THE PIPE, IF THE BOILER
RE-LIGHTS WHEN THE THERMISTOR IS OPEN CIRCUIT.
REPLACE THE THERMISTOR.

• SENSOR IN SHORT CIRCUIT OR HAS ISOLATION FAULT.

• CHECK THE ELECTRICAL CONNECTIONS.

• INTERFACE MAY BE DAMP. DRY IT OUT OR REPLACE.

13

14

20

MAIN CONTROL BOARD

(PCB)

TEMPERATURE LIMITER.

CONTROLLED BY THE

HEATING THERMIST OR

ON FLOW PIPE.

COMMUNICATION FAULT

OTHER FAULTS NOT DISPLAYED BY FAULT CODE

NO HEATING

NO HEATING.

NO DISPLAY OF

RADIATOR SYMBOL.

WATER NOT HOT ENOUGH,

OR UNEVEN FLOW FROM

TAP. THERE IS A

HOT W A TER DEMAND.

WATER NOT HOT ENOUGH,

OR UNEVEN FLOW FROM

TAP. NO DISPLAY OF

TAP SYMBOL.

THE BURNER COMES ON

WHEN COLD WATER

IS DRAWN OFF.

THIS FAULT MAY BE INTERMITTENT.

• SWITCH (OFF), WAIT APPROXIMATLEY 5 SECONDS, SWITCH (ON).

• IF FAULT PERSISTS. REPLACE MAIN CONTROL BOARD (PCB).

• CHECK HEATING THERMISTOR (MAY BE UNCLIPPED) OR
THREE WA Y V ALVE FAUL TY .

• FAULTY PUMP.

• LOW HEATING FLOW RATE.
THIS FAULT MAY BE OCCASIONAL AND CAUSED BY

• ELECTROMAGNETIC INTERFERENCE. OTHERWISE

• CHECK THE MAIN CONTROL BOARD (PCB).

THERE IS DEMAND BY THE ROOM TEMPERATURE THERMOSTAT.

• CHECK THE CONNECTIONS.
IF FAULT PERSISTS, REPLACE MAIN CONTROL BOARD (PCB).

• CHECK THAT CONTACT 1 IS ON 1. OR MEASURE A RESISTANCE
< 10 ohms BETWEEN B5.1 AND B5.2.

• CHECK ROOM THERMOSTAT CONNECTIONS OR MEASURE A
RESISTANCE < 50 ohms BETWEEN B3.1 AND B3.2.

• CHECK THREE WA Y V AL VE.

• CHECK THREE WA Y V AL VE MOTOR (SWITCHING).

• CHECK THE DIRECTION OF

• CLIP ON THREE WAY VALVE (READABILITY OF SYMBOL ).

• MEASURE THE MICROFAST RESISTANCE = 1000 ohms
BETWEEN H4.1 AND H4.3.

• READ THE VALUE OF FLOW RATE DETECTOR ON CODE 07 OF
INFO MENU. IT WILL READ HOT WATER OUTPUT (L/MIN.)(x10)
VALID RANGE 00,,,199 NOTE: DIVIDE THE VALUE BY 10.
IF = 0 THE DETECTOR IS BLOCKED OR FAILED. IF = 0 THE
DETECOR IS BLOCKED OR THE
MAIN CONTROL BOARD (PCB) HAS FAILED.

• CHECK THAT THE HOT WATER CIRCUIT HAS BEEN BLED
PROPERLY (ANY AIR BUFFER MAY ACTIVATE THE FLOW RATE
DETECTOR WHEN THE T APS ARE TURNED ON).

R

O
K

27

2000221595

18 Wiring Diagram

FAN

g

p

w

FAN
SENSOR

AIR PRESSURE

WATER
PRESSURE
SENSOR

g

or

w

OVERHEAT
THERMISTOR

bk
bk

THERMISTOR

w

w

CH

w

g

PLUG

THERMISTOR

DHW

rr

SWITCH

ww

3
1

bk
bk

STORAGE VESSEL

THERMISTOR

IGNITION
ELECTRODES

bg/y br

FLOW SENSOR

wg

p

SENSE
ELECTRODE

GAS

CONTROL

VALVE

THREE-WAY

CLOCK-TIMER

bk

VALVE

IGNITION

MODULE

CHASSIS

EARTH

bk

4

3

2
1

HEATING

ELEMENT

USER INTERFACE

NOTE 'E'

J2

J19

J4

230V~50Hz

PERMANENT

MAINS SUPPLY

FUSED AT 3A

br

g/y

J3

NOTE 'F'

b

J16

CHASSIS
EARTH

g/y g/y g/y

J6

S2

ON/OFF
SWITCH

bk
bk

H2

H8

H5

H4
J5
J9

J8

SW3

S1

H1

H3

H6

FUSE
125mAT

NOTE 'E' VOLTAGE FREE room thermostat connection or link.
NOTE 'F' Optional remote control unit with

programmable room stat connection Part No. 86774

PUMP CH

b
br

bk- BLACK
w- WHITE
or- ORANGE
g/y- GREEN/

bk bk
br
b

bk
br
b

g/y

b

br
br

g/y

b

KEY

YELLOW

br - BROWN
b- BLUE
p- PINK
g- GREY
r- RED

Diagram 18.1

9683

2000221595

28

19 Replacement of Parts

IMPORTANT INFORMATION

WARNING: Before commencing the replacement of any

component, isolate appliance from electrical supply and turn off
gas at service cock.

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

When replacing components it may be necessary to renew
sealing washers, gaskets and 'O' rings. If new ones are
supplied with replacement components they must be used.

All parts are replaced in reverse order to removal.
If any gas-carrying components are disturbed, removed or

replaced it will be necessary on completion to check for gas
soundness with leak detection fluid.

19.1 Domestic hot water thermistor, refer to
diagram 19.1

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Locate domestic hot water thermistor on hot water flow pipe on
right hand side of boiler adjacent to gas control valve.

• Unclip thermistor from pipe.

• Disconnect leads from thermistor.

• Fit leads to replacement thermistor and fit thermistor to pipe.
The polarity is not important.

19.2 Central heating thermistor, refer to
diagram 19.2

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Locate central heating thermistor on heating flow pipe on
centre of boiler.

• Unclip thermistor from pipe.

• Disconnect leads from thermistor.

• Fit leads to replacement thermistor and fit thermistor to pipe.
The polarity is not important.

19.3 Fan, refer to diagram 19.3

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Remove the sealed chamber cover, refer to Section 16.5.

• Disconnect power supply leads and earth lead from fan.

• Unscrew and remove two fan retaining screws at front edge of
mounting plate.

• Remove fan with mounting plate attached by pulling forwards
out of the boiler.

• Remove fan from mounting plate.
Note: When re-fitting, make sure that the two lugs on the fan

mounting plate engage in the flue hood.

• Reconnect electrical leads.

9672

9671

➜

DOMESTIC
HOT WATER
THERMISTOR

Diagram 19.1

CENTRAL
HEATING
THERMISTOR

➜

Diagram 19.2

➜

➜

➜

➜

FAN
RETAINING
SLOTS

19.4 Fan sensor, refer to diagram 19.3

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Remove the sealed chamber cover, refer to Section 16.5.

• Remove the 2 fan sensor retaining screws.

• Remove the fan sensor and disconnect the electrical
connection, avoid straining the cables.

Diagram 19.3

➜

9670

➜

29

2000221595

19 Replacement of Parts

19.5 Air pressure switch, refer to diagram 19.4

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Remove the sealed chamber cover, refer to Section 16.5.

• Locate air pressure switch situated inside combustion chamber
on top right hand side.

• Remove air pressure switch tube.

• Disconnect air pressure switch electrical connections.

• Undo screws on top of boiler securing air pressure switch to
boiler and remove switch.

19.6 Domestic water flow sensor, refer to
diagram 19.5.

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Drain down domestic hot water circuit of boiler only, refer to
relevant part of Section 16.13.

• Locate flow sensor on cold water inlet pipe to boiler inside
controls area.

• Carefully pull off electrical connector from flow sensor.

• Pull out slotted metal clip securing cold water inlet pipe to flow
sensor disconnect union nut securing cold water inlet pipe to
isolating valve and remove.

• Pull out slotted metal clip securing flow sensor to pump
mounting, remove sensor.

19.7 Printed circuit board (PCB), refer to
diagram 19.6

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Gain access to rear of control panel.

• Unclip side clips and hinge up control panel cover to gain
access to PCB, see diagram 11.2.

• Carefully pull off electrical connections to PCB.

• Unclip and lift out PCB.
Note: Make sure that PCB connections are fully pushed onto

replacement PCB.

19.8 Central heating pump, refer to diagram

19.7.

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Drain down central heating water circuit of the boiler only, as
follows:

• Close isolating valves (q) and (v) on central heating isolating
cocks (A) and (C) ,see diagram 7.1.

10037

9674

➜

➜

➜

➜

➜

➜

➜

➜

➜

➜

AIR PRESSURE
SWITCH

Diagram 19.4

WATER
FLOW
SENSOR

Diagram 19.5

Diagram 19.6

CENTRAL
HEATING
PUMP

➜

Diagram 19.7

9673

9680

2000221595

30

19 Replacement of Parts

Note: These valves are closed when slots are at right angles to
direction of flow.

• Drain boiler by opening drain valves (r) and (u), see diagram

7.1.

Note: it is not necessary to drain down the entire heating system
to carry out this work.

• For ease of access if required remove the left hand side panel,
refer to Section 16.6.

• Undo two fixing screws and remove pump retaining bracket
from front of pump.

• Pull out slotted metal clip securing pump outlet hose connection
to pump.

• Remove pump from pump block by lifting up at front and pulling
forward.

• Gain access to the pump electrical connection box and remove
cover.

• Disconnect pump cable from pump (avoid straining cables).

• Transfer automatic air vent to replacement pump.

• Re-connect electrical connection.

• Open isolating valves on flow and return connections, refill,
and pressurise boiler.

• Check for leaks.

PLATE TO PLATE
HEAT EXCHANGER

➜

9677

➜

➜

➜

PIPE
CONNECTION

➜

Diagram 19.8

9682

19.9 Hot water plate to plate heat exchanger,
refer to diagram 19.8.

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Drain down central heating and domestic hot water circuits of
boiler only ,refer to relevant parts of Sections 16.13 and 19.8.

• To gain access to the left hand securing screw. Disconnect the
domestic water flow sensor at the plate to plate heat exchanger
and cold water inlet. Remove the domestic hot water flow
sensor, refer to Section 19.6.

• Supporting domestic heat exchanger, unscrew and remove
two screws securing it onto pump mounting and 3-way valve/
bypass housing.

• Remove plate to plate heat exchanger from boiler.

• Fit replacement plate to plate heat exchanger using new seals,
supplied.

Note: Plate to plate heat exchanger mounting screws are offset
to ensure correct fitting of replacement.

THREE WAY
VALVE

9956

➜

➜

➜

Diagram 19.9

➜

➜

THREE WAY
VALVE/BYPASS
HOUSING

9785

THREE WAY VALVE
ACTUATOR

31

9955

Diagram 19.10

2000221595

19 Replacement of Parts

19.10 Three-way valve head, refer to diagram

19.9.

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Locate 3- way valve in centre of lower controls area.

• Remove electrical plug from valve head.

• Pull out slotted metal clip from valve body and remove valve
head from body.

• Fit replacement valve head.
Note :

1) When refitting clip, ensure that letters OK are as shown.

2) It is not necessary to drain boiler to carry out this work.

19.11 Three-way valve actuator, refer to
diagram 19.10.

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Drain down central heating and domestic hot water circuit of
boiler only, refer to relevant parts of Sections 16.13 and 19.8.

Note: It is not necessary to drain down entire heating system to
carry out this work.

• Remove three-way valve head, refer to Section 19.10.

• Pull out slotted metal clips and remove bypass pipe.

• Remove three-way valve actuator from three-way bypass
valve housing.

• Fit replacement three-way valve actuator into three-way
bypass valve housing.

9675

➜

➜

➜

➜

➜

➜

9951

Diagram 19.11

9893

➜

19.12 Bypass, refer to diagram 19.11.

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.
Drain down central heating water circuit and drain the boiler,

refer to relevant part of Section 19.8.
Note: it is not necessary to drain down the entire heating system

to carry out this work.
Pull out slotted metal clips and remove bypass pipe.
Pull out slotted metal clip securing bypass into bypass housing,

ease up and out bypass valve using a screw driver.

SYSTEM WATER
PRESSURE SENSOR

Diagram 19.12

19.13 System water pressure sensor, refer to
diagram 19.12.

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

.Drain down central heating water circuit and drain the boiler,
refer to relevant part of Section 19.8.

• Locate system water pressure sensor at front left hand side of
boiler.

• Pull off slotted metal clip and remove sensor from boiler, take
care not to strain cables.

• Remove electrical connection from sensor.

2000221595

32

19 Replacement of Parts

19.14 Gas control valve stepper motor, refer to
diagram 19.13.

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Locate gas control valve stepper motor attached to front of gas
valve.

• Disconnect multi-plug from stepper motor.

• Remove screws securing stepper motor onto gas valve body.

• Withdraw stepper motor from gas valve body.

• Fit replacement stepper motor in reverse order to removal
taking care not to damage the ‘O’ ring.

19.15 Gas Control valve assembly, refer to
diagram 19.13.

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Disconnect multi-plug from stepper motor.

• Disconnect electrical connections from spark ignition unit
above gas control valve assembly.

• Disconnect electrical connection from R/H side of gas control
valve assembly mounting bracket.

• Undo main gas supply nut from main burner, see diagram

16.4.
Note: The washer must be kept for use on reassembly.

• Undo main gas union nut between gas control valve supply
pipe and gas inlet valve.

Note: The washer must be kept for use on reassembly.

• Unscrew and remove screw securing gas control valve mounting
bracket to boiler frame.

• Withdraw gas control valve assembly, pipes and bracket,
taking care not to strain the electrical connection at the rear of
the gas control valve.

• While supporting the gas control valve assembly disconnect
the electrical connection at the rear of the gas control valve, see
diagram 19.13.

• Using old gas control valve as a guide, transfer gas pipes and
bracket from old gas control valve to replacement gas control
valve.

• Refit electrical connector to the rear of the gas control valve
assembly.

• Fit replacement gas control valve assembly into boiler.

• Reconnect gas pipes.

• Refit electrical connections in reverse order to removal.

SPARK IGNITION UNIT

➜

➜

➜

➜

➜

➜

➜

➜

➜

➜

➜

➜

GAS CONTROL
VALVE ASSEMBLY

9325

33

➜

➜

10028

GAS SAFETY VALVE

Diagram 19.13

2000221595

19.16 Gas safety valve, refer to diagram 19.13.

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Remove gas control valve assembly, refer to Section 19.15.

• Locate gas safety valve on the rear of the gas valve.

• Unscrew and remove the 2 screws securing the gas safety
valve to the gas control valve.

• Fit replacement gas safety valve in reverse order to removal
taking care not to damage the ‘O’ ring.

• Refit electrical connections, the polarity of the wires to the
modulating coil is not important.

• Refit electrical connector to the gas safety valve.

• Fit replacement gas control valve assembly into boiler.

• Reconnect gas pipes.

• Refit electrical connections in reverse order to removal.

19.17 Spark ignition unit, refer to diagram

19.13.

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Disconnect electrical connections from spark ignition unit.

• Remove screw securing spark ignition unit to gas valve
mounting bracket.

• Replace spark ignition unit.

19.18 Heating safety valve (3 bar), refer to
diagram 19.14.

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.
If safety valve seating is damaged, it will be necessary to

replace safety valve as a complete unit, repair is not possible.
Drain down central heating water circuit and drain the boiler,

refer to relevant part of Section 19.8.

• Remove the base panel, secured with four screws and hooked
in at the rear.

• If lt is not possible to remove the safety valve securing pin
(without straining the pipe work), to remove the safety valve.
Continue following the removal instructions below.

• Remove the heating flow isolating valve by disconnecting the
two union nuts and removing the securing clip.

• Disconnect the heating flow union nut at the safety valve
housing.

• Disconnect safety valve discharge pipe from safety valve.

• Remove the safety valve and housing.

• Remove safety valve securing pin.

• Remove safety valve.

• Fit replacement safety valve.

Note: Apply a small quantity of silicon grease to the safety valve
'O' ring prior to fitting.

• Open isolating valves on flow and return connections, refill,
vent and pressurise boiler.

• Check for leaks.

19.19 Domestic safety valve (10 bar), refer to
diagram 19.14.

Before starting refer to the front of Section 19 Important
information.

If safety valve seating is damaged, it will be necessary to
replace safety valve as a complete unit, repair is not possible.

• Remove the base panel, secured with four screws and hooked
in at the rear, see diagram 19.14.

Drain down the boiler, refer to relevant part of Section 19.8.

• Disconnect safety valve discharge pipe from safety valve.

• Remove wire clip securing safety valve to domestic hot water
outlet fitting and remove safety valve.

• Fit replacement safety valve.
Note: Apply a small quantity of silicon grease to the safety valve

'O' ring prior to fitting.

• Open isolating valves on flow and return connections, refill,
vent and pressurise boiler.

• Check for leaks.

19.20 Main heat exchanger, refer to diagram

16.5 and 19.15.

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Remove the sealed chamber cover, refer to Section 16.5.

• Remove the combustion chamber cover, refer to Section

16.7.

Drain down central heating water circuit and drain the boiler,
refer to relevant part of Section 19.8.

• Disconnect power supply leads and earth lead from fan.

• Unscrew and remove two fan retaining screws from the right
hand side edge of fan mounting plate.

• Remove fan with mounting plate attached by pulling forward
and out of boiler.

• Remove air pressure switch sensing tube from sensing probe
on flue hood.

• Remove screws securing flue hood to rear panel

• Lift flue hood clear of heat exchanger.

• Unclip overheat thermostat from heating flow pipe.

• Pull out slotted metal clips securing pipes from heat exchanger.

• Lift heat exchanger up and forwards to remove from boiler
taking care not to damage insulation.

DO NOT DAMAGE PAINTED FINISH OF HEAT EXCHANGER.

• Fit replacement heat exchanger.
Note: When re-fitting fan, make sure that the two lugs on the fan

mounting plate engage in the flue hood.

2000221595

34

19 Replacement of Parts

• Open isolating valves on flow and return connections, refill,
vent and pressurise boiler.

• Check for leaks.

19.21 Overheat thermostat, refer to diagram

19.15.

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Remove the sealed chamber cover, refer to Section 16.5.

• Locate high limit thermostat on heating flow pipe on left hand
side of boiler

• Disconnect electrical connection from thermostat

• Unclip thermostat from heating flow pipe.

• Fit replacement thermostat in reverse order to removal. (Use
heat sink compound supplied).

• Refit connection to thermostat.

19.22 Combustion chamber insulation

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Remove the sealed chamber cover, refer to Section 16.5.

• Remove the combustion chamber cover, refer to Section

16.7.

• Remove main heat exchanger, refer to Section 19.20.

• Remove fan and loosen flue hood, refer to relevant parts of
Sections 19.3 and 16.9.

9957

➜

DOMESTIC SAFETY VALVE (10 bar)

➜

➜

➜

➜

➜

➜

HEATING SAFETY VALVE (3 bar)

OVERHEAT

RESET
BUTTON

THERMOSTAT

➜

➜

9958

➜

Diagram 19.14

9687

Front panel insulation

• Lift front insulation panel free from retaining lugs on combustion
chamber cover.

Rear panel insulation

• Pull rear insulation panel free from retaining lug at rear of
combustion chamber by tilting forward.

• Fit replacement insulation panels in reverse order to removal

• Refit combustion chamber cover.

Side Panels

Note: Rear panel must be removed first.

• Pull out side panels free from retaining lugs at side of
combustion chamber by tilting sideways.

• Fit replacement insulation panels in reverse order to removal.

• Refit combustion chamber cover.

➜

➜

➜

➜

Diagram 19.15

35

2000221595

19 Replacement of Parts

19.23 Burner

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Remove the sealed chamber cover, refer to Section 16.5.

• Remove the combustion chamber cover, refer to Section

16.7.

• Remove burner, refer to Section 16.8.
Assemble replacement burner, supplied in parts, as follows:

• Fit burner injectors to burner injector bar and tighten.
Note: Make sure that injector size, marked on each injector, is

the same as that given in ‘Section 1 Technical Data’ for the
type of gas being used.

• Fit injector bar into burner, secure with retaining rods.

• Fit replacement burner.

19.24 Burner injectors, refer to diagram 19.16.

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Remove the sealed chamber cover, refer to Section 16.5.

• Remove the combustion chamber cover, refer to Section

16.7.

• Remove burner, refer to Section 16.8.

• Remove injector bar retaining nuts and separate the injector
bar from the burner.

• Remove and renew injectors as required from injector bar.
Note: Make sure that injector size, marked on each injector, is

the same as that given in ‘Section 1 Technical Data’ for the
type of gas being used.

• Assemble the burner in reverse order to removal taking care
to engage all parts correctly.

19.25 Ignition electrode assembly, refer to
diagram 16.4

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Remove the sealed chamber cover, refer to Section 16.5.

• Remove the combustion chamber cover, refer to Section

16.7.

• Pull off ignition leads from gas control valve.

• Ease ignition leads through the grommet.

• Undo and remove screws securing electrode assembly onto
burner.

• Fit replacement electrode assembly onto burner in reverse
order to removal.

• When refitting ensure that the grommet locates and seals
correctly.

INJECTOR BAR

9689

RETAINING
NUT (2 OFF)

INJECTOR BAR

9686

INJECTORS

Diagram 19.16

19.26 Flame sense electrode, refer to diagram

16.4

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Remove the sealed chamber cover, refer to Section 16.5.

• Remove the combustion chamber cover, refer to Section

16.7.

• Pull off flame sense lead from flame sense electrode.

• Undo and remove screws securing flame sense electrode onto
burner.

• Fit replacement flame sense electrode onto burner.

9688

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19 Replacement of Parts

19.27 User interface board assembly, refer to
diagram 19.17.

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Gain access to rear of control panel.

• Unclip side clips and hinge up control panel cover, see

diagram 11.2.

• Carefully pull off electrical connection from the user interface
board to PCB at (B4).

• Remove the two securing screws to release the control panel
fascia.

• Remove the two user interface board assembly securing
screws to remove the user interface board assembly.

• Fit replacement user interface board.

19.28 Clock-timer, refer to diagrams 19.17 and

19.18.

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Gain access to rear of control panel.

• Unclip side clips and hinge up control panel cover, see

diagram 11.2.

• Carefully pull off electrical connection from the clock-timer to
PCB at (B5).

• Remove the two securing screws to release the control panel
fascia.

• Remove the two clock-timer securing screws to remove clock­timer.

• Fit replacement clock-timer.

9892

➜

B4 B5

USER INTERFACE BOARD

➜

MAINS POWER
SWITCH

9891

Diagram 19.17

9890

19.29 Mains power switch, refer to diagram

19.17.

Before starting refer to the front of Section 19 Important
information.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Gain access to rear of control panel.

• Unclip side clips and hinge up control panel cover, see

diagram 11.2.

• Slide back and up to remove the mains power switch.

• Carefully pull off electrical connections from the mains power
switch.

• Fit replacement mains power switch.

CLOCK-TIMER

Diagram 19.18

37

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19 Replacement of Parts

19.30 Domestic Hot water storage vessel, refer
to diagram 19.19.

For this operation the boiler must be removed from the wall.
Before starting refer to the front of Section 19 Important

information.

• Drain down central heating and domestic hot water circuit of
boiler only, refer to relevant parts of Sections 16.13 and 19.8.

Note: It is not necessary to drain down entire heating system to
carry out this work.

• Disconnect flue system.

• Remove the base panel, secured with four screws and hooked
in at the rear.

• Disconnect boiler pipes onto fixing jig.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Gain access to rear of control panel.

• Unclip side clips and hinge up control panel cover, see

diagram 11.2.

• Disconnect mains cable and any external controls cables.

• Carefully pull off electrical connection at (H4) from the PCB.
Unclip to release the cable back to the storage vessel.

• Remove the sealed chamber cover, refer to Section 16.4.
Remove the two side panels, refer to Section 16.6. Using the
two lifting handles positioned bottom left of the controls and to
the center right of the combustion chamber lift the boiler off the
hanging bracket and away from the wall.

• From rear of boiler, disconnect domestic pipes from the bottom
of the storage vessel.

• Disconnect electrical connections from vessel.

• Unclip vessel from boiler frame and remove from boiler.

CLIP
POSITIONS
(2 OFF)

➜

➜

➜

9882

➜

DOMESTIC
HOT WATER
STORAGE
VESSEL

9883

➜

➜

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➜

DOMESTIC HOT WATER
STORAGE VESSEL

Diagram 19.19

38

19 Replacement of Parts

19.31 Storage vessel thermistor, refer to
diagram 19.20.

For this operation the boiler must be removed from the wall.
Before starting refer to the front of Section 19 Important

information.

• Drain down central heating and domestic hot water circuit of
boiler only, refer to relevant parts of Sections 16.13 and 19.8.

Note: It is not necessary to drain down entire heating system to
carry out this work.

• Disconnect flue system.

• Remove the base panel, secured with four screws and hooked
in at the rear.

• Disconnect boiler pipes onto fixing jig.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Gain access to rear of control panel.

• Unclip side clips and hinge up control panel cover, see

diagram 11.2.

• Disconnect mains cable and any external controls cables.

• Remove the sealed chamber cover, refer to Section 16.4.
Remove the two side panels, refer to Section 16.6. Using the
two lifting handles positioned bottom left of the controls and to
the center right of the combustion chamber lift the boiler off the
hanging bracket and away from the wall.

• Remove the insulation from around the storage vessel

• Locate thermistor.

• Disconnect the electrical connection to the thermistor.

• Peel off the self adhesive thermistor.

• Clean the surface prior to fitting the replacement thermistor in
same position as old thermistor.

• Refit vessel.

• Refit boiler onto fixing jig, tighten all connections ensuring that
all sealing washers are fitted before tightening.

• Reconnect flue making sure that all joints are properly
connected.

DOMESTIC HOT
WATER STORAGE

➜

VESSEL

INSULATION

INSULATION

DOMESTIC HOT
WATER STORAGE
VESSEL

9887

Diagram 19.20

9888

➜

Diagram 19.21

19.32 Storage vessel heating element, refer to
diagram 19.21.

For this operation the boiler must be removed from the wall and
the storage vessel removed, refer to Section 19.30.

• Remove the insulation from around the storage vessel

• Locate heating element.

• Peel off the heating element, secured with self adhesive tape.

• Clean the surface prior to fitting the replacement heating
element in same position as old heating element.

• Refit vessel in reverse order to removal.

• Refit boiler onto fixing jig, tighten all connections ensuring that
all sealing washers are fitted before tightening.

• Reconnect flue making sure that all joints are properly
connected.

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19 Replacement of Parts

19.33 Expansion vessel, refer to diagram

19.22.

For this operation the boiler must be removed from the wall.
Before starting refer to the front of Section 19 Important

information.

• Drain down central heating and domestic hot water circuit of
boiler only, refer to relevant parts of Sections 16.13 and 19.8.

Note: It is not necessary to drain down entire heating system to
carry out this work.

• Disconnect flue system.

• Remove the base panel, secured with four screws and hooked
in at the rear.

• Disconnect boiler pipes onto fixing jig.

• Remove the front panel, refer to Section 16.3.

• Lower the control panel, refer to Section 16.4.

• Gain access to rear of control panel.

• Unclip side clips and hinge up control panel cover, see

diagram 11.2.

• Disconnect mains cable and any external controls cables.

• Remove the sealed chamber cover, refer to Section 16.4.
Remove the two side panels, refer to Section 16.6. Using the
two lifting handles positioned bottom left of the controls and to
the center right of the combustion chamber lift the boiler off the
hanging bracket and away from the wall.

• Supporting expansion vessel unscrew and remove expansion
vessel retaining nut and screw.

• Remove expansion vessel.

• Fit replacement expansion vessel.
Note: Check that expansion vessel pressure is correct, see

‘Section 1 Technical Data’.

UNION NUT

RETAINING
NUT

➜

EXPANSION
VESSEL

Diagram 19.22

20 Spare Parts

When ordering spare parts, quote the part number and description, stating the appliance model number and serial number
from the data label.

Short parts list

No. ...... Description ......................................... Part No. .......... G. C. No.

1 .......... Domestic hot water thermistor ........ 57213 .............. ******

2 .......... Central heating thermistor ............... 57215 .............. ******

3 .......... Storage vessel thermistor ................. 57250

4 .......... Fan ...................................................... 57238

5 .......... Air pressure switch ............................. 57237

6 .......... Domestic water flow sensor ............. 57202

7 .......... Printed circuit board ......................... 57248

8 .......... Pump .................................................. 57207

9 .......... 3-way valve head ............................. 57206

10 ........ System pressure sensor ..................... 57205

11 ........ Gas valve module ............................ 57079

12 ........ Central heating safety valve ........... 57228

13 ........ Domestic safety valve ...................... 57229

14 ........ Overheat thermostat ........................ 57212

15 ........ Ignition electrode .............................. 57194

16 ........ Flame sense electrode ..................... 57195

16 ........ Clock-timer ........................................ 57245

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

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