Saunier duval SB 30E User Manual

Instructions for Use

Installation and Servicing

To be left with the user

SB30e

Fanned Flue System Boiler

221872B.07.01

7086

G.C. No. 41 920 31

This is a Cat I2H Appliance

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.

Guarantee Registration

Thank you for installing a new Saunier Duval appliance in your home.

Saunier Duval appliances' are manufactured to the very highest standard so we are pleased

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

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

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

to offer our customers' a Comprehensive First Year Guarantee.

return as soon as possible.

Service number 01773 828100.

✔

❑

✔

❑

✔

❑

One Contact Local Service

All replacement parts
All labour charges
All call-out charges

REGISTER YOUR SAUNIER DUVAL 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, see Section 1.4.

CE Mark

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

Type test for purposes of Regulation 5 certified by: Notified body 0086.
Product/production certified by: Notified body 0086.
The CE mark on this appliance shows compliance with:

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

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

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

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.

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.

CONTENTS DESCRIPTION SECTION PAGE No.

INSTRUCTIONS

FOR USE

INSTALLATION

INSTRUCTIONS

Introduction 3
Programmer Settings 4
Lighting the Boiler 5

General Data 1 7
Boiler Position 2 9
Flue and Ventilation 3 10
Water System 4 11
Domestic Hot Water 5 12
Installation Preparation and
Gas/Water Connections 6 13
Flue Preparation 7 13
Mounting the Boiler 8 16
Electrical Connections 9 20
Commissioning 10 22

SERVICING

INSTRUCTIONS

221872B

General Data 11 25
Servicing 12 25
Fault Finding 13 27
Replacement Parts 14 33
Spare Parts 15 43

2

Instructions for Use

Introduction

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

This boiler must have been installed by a competent person in
accordance with the current rules in force in the countries of
destination at the time of installation.

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

The boiler being a fully pumped sealed system is able to provide
room heating as part of a central heating system and indirect
domestic hot water.

The boiler can be fitted with a programmer, which look like this:-

Programmer

DAY HR MIN

IMPORTANT NOTICE:
The User must always adhere to the warnings

given in these instructions and those on the
boiler. Under no circumstances must the
User interfere with any sealed component as
this could result in a potentially dangerous
situation arising.

This boiler is for use only on G20 gas.
Gas Leak or Fault

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

Electrical Supply

WARNING. The boiler must be earthed.
The boiler must be connected to a 230V~50Hz permanent

supply.
Connection of the whole electrical system of the boiler and any

heating system controls to the electrical supply, must be through
one common isolator.

Isolation should preferably be by a double pole switched fused
spur box. The fused spur box should be readily accessible and
preferably adjacent to the appliance. It should be identified as
to its use.

Alternatively a fused 3A 3 pin plug and shuttered unswitched
socket may be used.

The colours of three core flexible cable are, blue - neutral, brown

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

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

marked “N” or “Black”.
The wire coloured brown must be connected to the terminal

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

terminal marked “E” or “Green” or the earth symbol
PVC flexible cable having a conductor size of 0.75mm

0.20mm) must be used within the boiler casing to connect to the
boiler.

Electrical Supply Failure

The boiler will not work without an electrical supply.
Normal operation of the boiler should resume when the electrical

supply is restored.

7809

Note. The boiler safety cutoff may have operated, please refer
to the following section to reset.

Reset any external controls, to resume normal operation of the
central heating.

The digital programmer, has a lithium battery back up and will
not need resetting. Unless it is without power for a considerable
period.

Boiler Safety Cutoff Reset Button

The boiler is fitted with a safety cutoff device to protect the
appliance and the user in the event of a fault occuring.

Should the main burner go out during a demand the red lockout
light “F” will illuminate on the control fascia situated above the
Reset Button “G”, see diagram 2.

The red light will not illuminate if there is no system demand.

Allow the boiler and system to cool down waiting at least
a minimum of four minutes before pressing the Reset
button “G”.

The boiler will take a few seconds to reset after the button is
pressed.

If the problem persists, turn the boiler off and consult your
installation/ servicing company.

The Gas Safety (Installation & Use)
Regulations

In your interests and that of safety it is the law that ALL gas
appliances are installed by competent persons in accordance
with the current issue of the above regulations.

.

2

(24/

3

221872B

Instructions for Use

Setting Instructions for the 7 Day Digital
Programmer

This is a 24 hour programmer, that is 1pm is 13:00, and has two
sets of 8 “ON” and 8 “OFF” daily switching actions
(P1 and P2).

It is fitted with a lithium battery back up which protects the
programme in the event of an electrical failure. The battery
should have a life of several years.

3 SETTINGS SLIDE
SWITCH (AUTO)

DAYS OF THE WEEK
MON. TO SUN.

POINTER

SET 16
PROGRAMMES
BUTTON

DAY HR MIN

DAY OF THE WEEK
AND BLOCK SETTING
BUTTON

TIME HOURS
SETTING BUTTON

Setting the Programmer - Diagram 1

1. With both AUTO and RUN switches set, press R reset button,
the display will flash.

2. Press and hold HR and MIN until display stops flashing.

3. Set day of week or block setting by pressing button DAY.

4. Set time of day by pressing buttons HR and MIN.

5. When set if no buttons are pressed for 15 seconds, colon will
flash, this indicates the programmer is set.

With the programmer set, the factory preset programme shown
below will operate.

MON / SUN

ON - 6:30
OFF - 8:30
ON - 12:00
OFF - 12:00
ON - 16:30
OFF - 22:30

Setting Timed Programmes

With the programmer set to the correct time, see SETTING THE
PROGRAMMER paragraphs 1-4, and then continue as follows:

1. Set RUN switch to P1 or P2, the display will indicate
the 1st (ON) preset programme and the symbol

2. Set day of week to be programmed by pressing the
DAY button.

Note: The days can be selected individually or as
groups:

Mon-Fri., Sat/Sun., Mon-Sat., Mon-Sun.
An arrow or arrows will be displayed under the day

or days selected.

.

3 SETTINGS SLIDE
SWITCH (RUN)

DISPLAY

SOFT
OVERRIDE
BUTTON

TIME MINUTES
RESET
BUTTON

3. Set time of day by pressing the buttons HR and MIN.

4. Press button P to confirm programmes, the

5. Repeat procedures 2, 3 and 4 until desired

6. Set the RUN switch, your appliance will now operate at the

General Notes.

SETTING BUTTON

Diagram 1

display will indicate the 2nd (OFF) preset programme
and subsequently, 3rd to16th.

programmes are set.
Note. It is not a requirement to use the 8 on/off

programmes.

programmed times.

With the AUTO switch in the I position the central
heating will operated constantly ON.

With the AUTO switch in the O position the central
heating will not operate.

Soft Override button indicated by the
symbol
central heating programme for the next available.

ON time programmes are indicated by the symbol

, this function will override the current

7809

.

221872B

4

Instructions for Use

To Light the Boiler

1. Check the two isolating valves are open, the levers in line with
the valve body, see diagram 3.

2. Open the controls cover door and familiarize yourself with the
controls, see diagram 2.

3. Set “C”, programmer (if fitted) and any remote controls as
required.

4. CAUTION. A sealed pressurised system must be filled and
pressurised by a competent person.

Only operate the boiler when you are sure that the system has
been filled and pressurised. Check this by looking at the
pressure gauge “A”, it should read 0.7bar minimum when the
boiler is switched off. If you are in any doubt about the boiler
being filled with water contact your installation/servicing company
or the local gas company.

5. Check that the electrical supply to the boiler is ON at the
external isolator.

6. Set switch “B” to 1, situated on the control fascia, light “E” on
the fascia will illuminate.

7. If the red light “F” comes “ON”, the boiler WILL NOT WORK.
Depress the boiler safety cutoff reset button “G” if the red light
stays “ON”, you MUST contact your installation/servicing
company.

The boiler lighting operation is automatic if the external controls
or programmer, if fitted, are calling for heat.

The fan operates, followed by an ignition spark, the burner lights.
Light “D” on the fascia will illuminate.

When the boiler switches off, the burner will go out.
The automatic lighting sequence will operate again when heat

is required.

8. Adjust the control thermostat knob “J” to desired setting.
Close the controls cover door.

To Turn the Boiler Off

Set switch “B” to 0. To relight follow the lighting sequence given
above.

PRESSURE
GAUGE ‘A’

KEY TO NEON LIGHTS

RESET
BUTTON

CONTROLS
FASCIA

CONTROLS
COVER

‘F’

‘G’

‘D’

‘H’

‘E’

CONTROL
THERMOSTAT

KNOB

PROGRAMMER
IF FITTED

DAY HR MI N

‘J’

‘C’

MAINS
ELECTRIC

SWITCH

7791

‘B’

‘F’ BOILER LOCKOUT

‘H’

LOW WATER PRESSURE

‘D’
‘E’

BURNER IGNITED

POWER ‘ON’

5

Diagram 2

221872B

Instructions for Use

HEATING
FLOW

LEVER (OPEN)
HEATING
FLOW/ RETURN

SAFETY VALVE
DISCHARGE PIPE POSITION

GAS
SERVICE
COCK

SLOT (OPEN)
GAS SERVICE
COCK

HEATING
RETURN

Diagram 3

7790

Protection Against Freezing

The boiler has a 2 stage built in frost protection. Provided power
and gas are available and there is adequate pressure in the
system, if the water temperature within the appliance falls below

o

10

C approx. the pump only will come on. If the water temp
continues to fall to 6
rate until the water in the appliance is greater than 15oC approx.
This function protects the appliance only.

Other system pipework external to the boiler may require frost
protection.

If the boiler is to be out of use for any long periods during severe
weather, it is recommended that the whole system, including the
boiler, should be drained to avoid the risk of freezing. Make sure
that, if fitted, the immersion heater in the cylinder is switched off.

If in doubt, contact you installation/servicing company for advice.

o

C approx. the main burner will fire at min

Draining and Filling

CAUTION. This boiler works in a pressurised system which
must only be drained, refilled and pressurised by a competent
person.

Note: If the pressure gauge indicates a loss of system pressure,
that is, less than 0.7bar, YOU MUST CONTACT YOUR
INSTALLER.

Pressure Relief Safety Valve

CAUTION. A pressure relief safety valve and discharge pipe is
fitted to the boiler. This valve must not be touched. Should there
be any discharge from the pipe, turn the boiler off, isolate from
the electrical supply and contact your installation/servicing
company.

Maintenance and Servicing

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 (Saunier
Duval’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.

Clearances

The boiler requires a clearance in front, below and at the sides
of the casing for safety, servicing and maintenance access, see
diagram 2.1.

Cleaning

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

The boiler casing can be cleaned using a mild liquid detergent
with a damp cloth, then 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 incorrect operation or failure to
operate at all. If in doubt seek advice from the local gas
company or your installation/servicing company.

Replacement Parts

If replacement parts are required apply to your local supplier or
British Gas.

Please quote the name of the appliance.

221872B

6

1 General Data

C

E

D

D

E

L

M

B

N

C

C

L

L

G

9mm

K

J

A

Optional flue kits are available
Horizontal top outlet and Vertical.

F

H

Diagram 1.1

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

7792

450 700 300 100 75 138 142 18 135 110 138 85 115 103

EXTD. EASYFIT

1.1 Installation

Materials and equipment should be fit for their purpose and of
suitable quality and workmanship.

1.2 Important Notice

This boiler is for use only on natural gas, G20.

1.3 Sheet Metal Parts

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

1.4 Requirements

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.

Manufacturer’s instructions, supplied.
Manufacturer’s instructions must not be taken as overriding

statutory requirements.

1.5 Data Label

The data label is on the inner case front, see diagram 1.2.

1.6 Data

See table 1 and diagrams 1.1, 1.2. & 1.3.
The Seasonal Efficiency Domestic Boilers UK (SEDBUK) is

79%.
The value is used in the UK Government’s Standard Assessment

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

TABLE 1

Lift Weight 30Kgs (66Ibs)
Total Weight 39.5Kgs (88Ibs)

Gas connection Ø 15mm compression
Heating and return Ø 22mm compression
Safety valve Preset 3bar (43.5lbf/in
Safety valve discharge Ø 15mm copper
Water content 1.17 litres (.26 gallons)

■ Expansion vessel capacity 6 litres (1.32 gallons)

Heating cold fill 0.7bar
pressure minimum (10.1lbf/in2)

■ Maximum Heating 60 litres

system water (13.2 gallons)
content using with a cold
fitted expansion fill pressure
vessel. of 0.7bar

Electrical supply 230V~50Hz
Electrical rating 150W fused 3A
Internal Fuse rating 1) Type T2A

Approximate gas 3.06m3/h
rate at max input (108.2ft

■ For larger systems use an additional expansion

vessel, see Section 4.

3

/h)

2

)

7

221872B

1 General Data

1.7 Gas Supply

The gas installation shall be in accordance with the rules in force
in the countries of destination.

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

1.8 Electrical Supply

WARNING. This boiler must be earthed.
All system components shall be of an approved type.
The electrical installation shall be in accordance with the current

rules in force in the countries of destination at the time of
installation.

Connection of the whole electrical system of the boiler and any
heating system controls to the electrical supply, must be through
one common isolator.

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

Alternatively, a fused 3A 3pin plug and unswitched socket may
be used, provided they are not used in a room containing a bath
or shower.

The mains supply cable and other cables connected to the
boiler must be the PVC flexible type of at least 0.75mm

2

(24/

0.20mm) .

1.9 Heating System Controls

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

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

Note: All systems must have at least one radiator not fitted with
a thermostatic valve.

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

The appliance flue type is a C
flue where the fan is downstream of the heat exchanger. The C12 is
a horizontal flue termination, and the C32 is a vertical flue termination.

and C32. This refers to a concentric

12

Diagram 1.2

9258

THERMISTOR

OVERHEAT
CUT-OFF

LOW WATER
PRESSURE
SWITCH

FANNED FLUE

HEAT EXCHANGER

MAIN BURNER

GAS VALVE

BYPASS
VALVE

FLOW

HOUSING

GAS

PUMP

RETURN

AUTOMATIC
AIR VENT

SAFETY
VALVE

EXPANSION

VESSEL

SAFETY

VALVE

DISCHARGE

7793

Diagram 1.3

221872B

8

2 Boiler Position

2.1 Location

This boiler must be installed in accordance with the rules in
force in the countries of destination.

This boiler is not suitable for fitting outside.
Any electrical switch must be positioned so that it cannot be

touched by a person using the bath or shower.
The boiler must be mounted on a flat wall which is sufficiently

robust to take its weight, refer to Table 1, “Data”.
Note: It is important that the wall hanging bracket and the

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

If the location of the boiler or any part of the system is subject
to severe cold weather conditions, it is recommended that a
frost thermostat is fitted. Any part of the system that may be
vulnerable to freezing must be protected.

2.2 Boilers in a compartment

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

An existing cupboard or compartment modified for the purpose
may be used, providing minimum clearances are maintained.
Details of essential requirements for cupboard or compartment
design are given in the current issue of BS6798.

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

Where the boiler is fitted in a cupboard or compartment,
permanent ventilation is not required.

Any existing compartment air vents must not be removed or
blocked off.

25 ABOVE THE TOP OF THE BOILER CASE
OR THE FLUE ELBOW IF FITTED

5

150

To achieve minimum "Installation" clearance of 5mm.

The side panels will have to be fitted prior

to boiler mounting.

DIMENSIONS IN MILLIMETRES

450

Diagram 2.1

7087

5

2.3 Clearances

The boiler should be positioned so that at least the minimum
operational and servicing clearances are provided, see diagram

2.1. Additional clearances may be required around the boiler
for installation.

2.4 Timber Frame Buildings

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

9

221872B

3 Flue and Ventilation

3.1 General

The flue must be installed in accordance with the rules in force
in the countries of destination.

3.2 Terminal Position

The minimum acceptable siting dimensions for the terminal
from obstructions, other terminals and ventilation openings are
shown in diagram 3.1.

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

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

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

3.3 Flue Options

There are various flue systems to choose from, as follows:
Easyfit Top Outlet Flue Pack - Pt.No. 232057
Standard Rear Outlet Flue Pack - Pt.No. 230482
Extended Top Outlet Flue Pack - Pt. No. 230487
1 Metre Extension Kit - Pt. No. 230484
Optional Wall Liner Kit No. 900862
A Flue Bend Kit or Vertical Flue Kit can be supplied, see

Hepworth Heating "Flue Options Guide" for configurations
available.

o

Flue Bend Pack - Pt. No. 230485

45

o

90

Flue Bend Pack - Pt. No. 230486
In Line Flue Adapter Kit - Pt. No. 230488
Vertical Flue Kit No. 458115

3.4 Internal Access Flue

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

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

For a wall thickness up to 300mm, provided that there is
sufficient space and the optional wall liner kit is used, the flue
can be installed from the inside.

For a wall thickness of over 300mm the external flue hole will
need to be made good from the outside, this also applies if you
use the flue kit without the optional wall liner kit, irrespective of
wall thickness.

3.5 Terminal Guard

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

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

The guard should be similar to that shown in diagram 3.1 .

3.6 Room Ventilation

Ventilation must be provided in accordance with the rules in
force in the countries of destination. The boiler is room sealed,
so where the boiler is fitted in a room or space, a permanent air
vent is not required.

3.7 Cupboard/Compartment Ventilation

If the boiler is to be fitted in a cupboard or compartment. Refer
to Section 2.2.

L

G

D

F

K

mm

Diagram 3.1

C

K

L

K

MINIMUM
SPACING

A

B,C

K

F

F

G

J

A

F

G

UNDER CAR PORT etc.

B,C

G

A

E

G

H,I

MINIMUM SITING DIMENSIONS FOR
FANNED FLUE TERMINALS
POSITION

A DIRECTLY BELOW, ABOVE OR HORIZONTALLY

TO AN OPENING, AIR BRICK, OPENING
WINDOWS, AIR VENT OR ANY OTHER

VENTILATION OPENING. 300
B BELOW GUTTER, DRAIN/SOIL PIPE 25
C BELOW EAVES 25
D BELOW A BALCONY 25

OR CAR PORT 200
E FROM VERTICAL DRAIN PIPES AND

SOIL PIPES 25
F FROM INTERNAL OR EXTERNAL

CORNERS 25
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 300

TERMINAL GUARD TYPE K3
SUPPLIED BY :

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

2816

221872B

10

4 Water System

7917

4.1 General Notes

The boiler is intended for use in a sealed system only.

4.2 Safety Valve

The safety valve is an integral part of the boiler.
It cannot be adjusted but has a manual test device.

4.3 Pressure Gauge

A pressure gauge is incorporated into the boiler to indicate the
system pressure.

The gauge has a cold fill set pointer.

4.4 Pump

The circulation pump is integral with the boiler.
The remaining circulating pressure head available from the

boiler is shown in diagram 4.1, Saunier Duval pump.

4.5 Expansion Vessel

The boiler has an integral expansion vessel with a capacity of
6 Litres. If the system water content exceeds the maximum
quoted in Table 1, Data, an additional vessel should be connected
into the system as close as possible to the central heating return
connection of the boiler, see diagram 4.2.

The charge pressure shall not be less than the static head at the
point of connection, that is, the height of the top point of the
system above the expansion vessel.

Diagram 4.1

4.6 Flow Rate

A valve must be incorporated in the main flow or return of the
system, valve “A” shown in the flow diagram 4.2. This valve
must be lockable and positioned so that inadvertent closure or
unauthorised interference is not possible.

4.7 Bypass

The bypass is an integral part of the boiler.

4.8 Water Make Up

Provision should be made for replacing water lost from the
system using a make up bottle mounted in a position higher than
the top point of the system, connected through a non-return
valve to the return side of the heating circuit, see diagram 4.2.

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

4.9 Filling Sealed Systems

Provision for filling the system at a low level must be made.
Three methods of filling are shown in diagram 4.3.

There must be no permanent connection to the mains water
supply, even through a non-return valve.

NOTE: It is important that fittings used for connection to potable
water comply with the water undertakers requirements.

11

221872B

ADDITIONAL

METHOD 1

METHOD 2

METHOD 3

SUPPLY STOP
VALVE

SUPPLY
PIPE

HOSE
UNIONS

SERVICING
VALVE

TEMPORARY
HOSE

HEATING
SYSTEM

HEATING
SYSTEM

TEMPORARY
HOSE

HOSE
UNIONS

SERVICING
VALVE

SUPPLY
PIPE

SUPPLY STOP
VALVE

DOUBLE CHECK
VALVE ASSEMBLY

HEATING
SYSTEM

SERVICING
VALVE

SUPPLY
STOP VALVE

SUPPLY
PIPE

HOSE
UNIONS

DOUBLE CHECK
VALVE ASSEMBLY

OVERFLOW

CISTERN

COMBINED
CHECK VALVE
AND VACUUM
BREAKER

PRESSURE
REDUCING
VALVE

EXPANSION
VESSEL
(if required)

HEATING
CIRCUIT

4 Water System

ALTERNATIVE METHODS OF FILLING

7794

BOILER

3132

FILLING
POINT

RETURN

’A’

4.10 Corrosion Inhibitor

If an inhibitor is to be used in the system, contact the inhibitor
manufacturer so that they can recommend their most suitable
product.

When fitting the boiler into an existing system, special care
should be taken to drain the entire system, including radiators,
then thoroughly cleaning out before fitting the boiler whether or
not adding an inhibitor.

4.10 Draining

A draining tap must be provided at the lowest points of the
system, which will allow the entire system to be drained. An
additional draining tap MUST be fitted close to the boiler.

The flow and return isolation valves are provided with drain
points for boiler heat exchanger drainage.

General

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

5.1 Domestic Hot Water Cylinder

SINGLE FEED INDIRECT CYLINDERS ARE NOT SUITABLE
AND SHOULD NOT BE USED.

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

FLOW
CONTROL
VALVE

DRAIN
POINT

Diagram 4.2

Diagram 4.3

5 Domestic Hot Water

5.2 Domestic Hot Water System - Unvented

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

If fitting into an existing system the local authority should be
informed.

221872B

12

6 Installation Preparation and Gas / Water Connections

The installation requires the following components :-

1. Plumbing jig Carton

2. Boiler Carton

3. Flue Pack

6.1. Plumbing Jig

Remove from the wall template, then follow the instructions
given on the template.

Note: Leaving the service cock bracket (lower jig) fixing screws
loose will make the fitting of the boiler service elbows on to the
service cocks easier. Once the service connections are made,
tighten service cock bracket (lower jig) fixing screws. It is
important that the wall hanging bracket and the service cock
bracket (lower jig) are fitted to a flat and true wall area for correct
alignment with the boiler. If this cannot be achieved it is
acceptable to pack out the service cock bracket (lower jig) to
obtain the correct alignment with the wall hanging bracket.

6.2 Gas Connection

Provision is made for the gas supply to be connected from
below the boiler, see diagrams 1.1 and 6.1 for position.

Refer also to “Gas Supply”, Section 1.7.
Make the gas supply connection to the gas service cock. While

making the connection, do not subject the gas service cock to
heat as you may damage the seals.

6.3 Water Connections

Provision is made for the flow and return pipes to be connected
from below or through an internal wall at the rear of the boiler,
see diagram 1.1 and 6.1 for position. Provision is also made for
the flow and return to be connected from above, passing down
either side of the boiler. Take care that any pipework connected
from above will clear the expansion vessel. Refer to the wall
template. If connecting from above a piping kit 457620 is
available and is recommended.

NOTE: Top rear flue outlet is not possible with a vertical
piping kit.

Refer also to Section 4.11.
If necessary, temporarily fit the boiler.
Flush out the system before connecting the boiler.
Make the connections to the flow and return by means of the

isolating valves, see diagram 6.1.
While making the connections. Do not subject any of the

isolating valves to heat as you may damage the seals.

SAFETY DISCHARGE PIPE
ROUTING POSITION

HEATING
FLOW

LEVERS (OPEN)
HEATING
FLOW/ RETURN

Make sure that the drain and operating screw heads on the
isolating valves are accessible.

GAS
SERVICE
COCK

HEATING
RETURN

SLOT (OPEN)
GAS SERVICE
COCK

Diagram 6.1

6.4 Safety Valve Discharge

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

A short discharge pipe is supplied loose with the boiler, which
when fitted to the safety valve, will end below the boiler the
position is next to the heating return, for position see diagram

6.1.
This must be extended, using not less than 15mm od metal

pipe, to discharge, in a visible position, outside the building,
facing downwards, 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.

Note. To ease future servicing it is advisable to use a compression
type fitting to extend the discharge pipe.

7795

7 Flue Preparation

7.1 Flue Position and Length

Determine flue application, length and terminal position before
starting, refer to diagram 7.1.

Note: The Easyfit Top Outlet Flue Pack and the Extended Top
Outlet Flue Pack contains a flue duct extension piece complete
with "O" rings, this should be discarded.

If you are using a Flue Bend or a Vertical Flue Kit, please follow
the instructions supplied with the kit.

To make a neat finish to the flue outlet a flue collar kit, part No.
443286, with instructions, is available, see diagram 7.2.

Note: If required an optional wall liner kit, part no. 900862, is
available complete with instructions.

7.2 Flue Assembly

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

7.1.
Carefully drill though air duct pilot hole and secure with self

tapping screw provided in fittings pack, see diagram 7.1.
Seal the joint with the tape provided.
If the flue system requires the addition of flue extension kits,

drill, seal and secure them with the self tapping screw and tape
provided.

Note: Should any one of the flue sections require cutting to
obtain desired flue system length, cut at the end opposite the
expanded end.

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

13

221872B

7 Flue Preparation

9359

m

W

TOP OUTLET FLUE PACK

EXTENDED
'X' plus 254mm (RH) = flue length
'X' plus 10mm (LH) = flue length

EASYFIT
'X' plus 282mm (RH) = flue length
'X' plus 38mm (LH) = flue length
(must include 50mm min.
side clearance)

54mm*

5mm*

FLUE LENGTH

MAX 840mm (extended)

MAX 570mm (easyfit)

15mm

239mm*

SCREW

TOP OUTLET/
SIDE FLUE

'X'

& T APE

TOP OUTLET/
REAR FLUE

EXTENDED 'Y' plus 69mm = flue length

*EXTENDED flue only

EASYFIT 'Y' plus 97mm = flue length

EASYFIT/EXTENDED TOP OUTLET FLUE PACK & 1 METRE EXTENSION KIT

3 x 1 metre extension kits may be joined together.

Note: Remove heat exchanger baffle over 2.5m.

15mm

VIEW 'B'

SCREW
& T APE

'Y'

SCREW
& T APE

'X'

SIDE FLUE

EXTENDED
'X' plus 254mm (RH) = flue length
'X' plus 10mm (LH) = flue length
EASYFIT: 'X' plus 282mm (RH) 'X' plus 38mm (LH) = flue length

REAR FLUE

EXTENDED 'Y' plus 69mm = flue length
EASYFIT 'Y' plus 97mm = flue length

REAR OUTLET FLUE PACK

FLUE LENGTH

REAR OUTLET FLUE PACK & 1 METRE EXTENSION KIT

2 x 1 metre extension kits may be joined together.

510mm MAX.

FLUE LENGTH

MAX 840mm (extended)

MAX 570mm (easyfit)

15mm

SCREW
& T APE

'Y'

SCREW
& T APE

VIEW 'B'

15mm

80mm

FOAM
SEAL

'Y'

SCREW
& T APE

'Y' plus 95mm = FLUE LENGTH

FLUE

PACKS

EASYFIT

REAR
SIDE R.H.
SIDE L.H.

TOP EXTD.

REAR
SIDE R.H.
SIDE L.H.

REAR STD.

REAR 75 170 510 415 -

MINIMUM

WALL

THICKNESS

MINIMUM

LENGTH

75
75
75

75
75
75

FLUE

144
334

90

144
334

90

MAXIMUM

FLUE

LENGTH

570
570
570

840
840
840

BOILER MOUNTING FACE

TO EXTERNAL WALL FACE

80mm

FOAM
SEAL

'Y' plus 95mm = FLUE LENGTH

MAXIMUM DISTANCE FROM

"Y"

500

-

-

770

-

-

BOILER CASING TO

EXTERNAL WALL FACE

"X"

316
560

586
830

SCREW

15m

& T APE

'Y'

SCRE
& T APE

NOTE :

IF IT IS NECESSARY TO CUT THE DUCTS
TO ACHIEVE THE "FLUE LENGTH" MAKE SURE
THAT THE OVERLAPS ARE AS FOLLOWS :­THE OVERLAP FOR AIR DUCT = 25mm

-

-

THE OVERLAP FOR FLUE DUCT = 50mm
THE MAXIMUM LENGTHS CAN BE INCREASED

BY AN ADDITIONAL 2 METRES WITH THE USE
OF THE 1 METRE EXTENSION KITS.
NOTE :THIS APPLIES TO STANDARD KITS ONLY.

9360

Diagram 7.1

221872B

14

7 Flue Preparation

7.3 Internal Access Flue

If access to the outside wall is not practical, the flue system can
be installed from inside. Use of the optional wall liner kit is
required.

7.4 Rear Outlet Flue Fixing

Fit the self adhesive foam seal provided in the flue pack around
the air duct at the position shown in diagram 7.1.

Make good around the flue outside after installation of the boiler.
Important: If the wall liner kit is used, the self adhesive foam seal

included in the wall liner kit must be used in place of the one
supplied with the flue pack, see diagram 7.3 for position of self
adhesive seal.

7.5 Top Outlet Side or Rear Flue Fixing

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

Important: If the wall liner kit is used, the self adhesive foam seal
included in the wall liner kit must be used in place of the one
supplied with the flue pack, see diagram 7.3 for position of self
adhesive seal.

7.6 Flue Positioning

Push the flue assembly into and through the hole such that it is
within the wall, and does not stick out into the room. Do not push
the flue assembly too far into the hole as it has to be pulled back
into the boiler and secured.

WITH WALL LINER KIT ONLY

WALL THICKNESS­UP TO 300mm

FOAM SEAL

Q

15mm

7148

OPTIONAL
FLUE
COLLAR

Diagram 7.2

7102

FOAM SEAL

Q-35mm

WALL THICKNESS­OVER 300mm

Q

Diagram 7.3

15

221872B

8 Mounting the boiler

8.1 Boiler Mounting

Remove the inner case front, secured by two clamps at the
bottom lift up and unhook from the threaded lugs at the top, see
diagram 8.1.

Remove the combustion chamber panel transit screws, see
diagram 8.2. (It will not be necessary to refit these).

Slide the combustion chamber panel upwards to disengage
from the retaining lugs, pull forward to remove, see diagram

8.2.
Remove the fan electrical connections by pulling the plastic

boots not the wires. Remove the tubes from fan, noting the
colour tubes positions. see diagram 8.3.

Remove the fan and flue collector assembly by pulling it forward
see, diagram 8.3.

Remove the rear outlet restrictor plate and retain if using the
rear flue outlet, see diagram 8.4.

REAR FLUE ONLY Fit the flue spigot supplied separately, see
diagram 8.5.

TOP FLUE ONLY Remove the blanking plate and foam gasket
from the top of the boiler and use to blank the hole where the rear
restrictor plate (discard) was fitted.

Note: Should the side clearances be less than 30mm. It will be
necessary to fit the side panels before mounting the boiler.
Refer to Section 10.6 for fitting.

Remove the protective caps from the boiler water pipes.
Fit the sealing washers (supplied in the fittings pack) to the

boiler water pipes by inserting them into the tubing nuts (the
nipples on the washers will hold them in position), see diagram

8.8.
Lift the boiler into position on the top mounting brackets use

hand holes provided, see diagram 8.6.

RETAINING
LUG (4)

TRANSIT
SCREW (2)

AIR PRESSURE TUBE (3)

ELECTRICAL
CONNECTIONS

COMBUSTION
CHAMBER PANEL

Diagram 8.2

7011

REDCLEAR

6984

THREADED
LUG (2)

SECURING
CLAMP (2)

INNER CASE
FRONT

Diagram 8.1

6965

RETAINING LIP
AT REAR

FAN

Pull
Forward

Diagram 8.3

221872B

16

8 Mounting the boiler

8.2 Water and Gas Connections

Locate the boiler water pipes and gas supply pipe making sure
the washers are retained in the tubing nuts onto the isolation
valves, fully push the boiler back, see diagram 8.8.

Ensure the bottom boiler bracket is sitting on top of the service
cock bracket, see diagram 8.6.

3

Secure all the tubing nuts finger tight, plus
Connect the gas pipe to the isolation valve ensuring that the

sealing washer (supplied fitted) is in position.

/4 turn maximum.

8.3 Boiler Securing

Secure the boiler to the service cock bracket with the screws
provided in the fittings pack, see diagram 8.6.

An anti theft kit is available, Kit No. 457110.

8.4 Discharge Pipe

Fit the short discharge pipe to the safety valve using the nut and
sealing washer supplied in the fittings pack, see diagram 8.9.

Extend the discharge pipe, using only a compression type fitting
to join the discharge extension, refer also to Section 6.4 “Safety
Valve Discharge”.

8.5 Rear Outlet Flue Fixing

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

Fit the air duct into the flue spigot by pulling the air duct into the
flue spigot, locating cutouts. Turn the air duct anticlockwise to
lock into the cutouts, see diagram 8.10.

RETAINING LUG

7796

BOILER

TOP MOUNTING
BRACKET

RESTRICTOR
PLATE

SECURING
SCREW (3)

GASKET

Diagram 8.4

FLUE
SPIGOT

SECURING
SCREW (4)

HAND
HOLES

7644

7304

Diagram 8.5

17

BOILER BRACKET
(On Top)

SECURING SCREW

SERVICE COCK
BRACKET

Diagram 8.6

221872B

8 Mounting the boiler

Note: It is important the correct restrictor plate is fitted or refitted,
see restrictor table.

Fit the flue connecting sleeve onto the fan, see diagram 8.11.
Fit the fan to the flue ducting, see diagram 8.11.
Fit the fan and flue collector the electrical connections and air

pressure tubes to the fan.
Refit the combustion chamber panel.
Make the outer wall weatherproof. A Flue Collar Kit Part No.

443286 is available.

8.6 Top Outlet Side or Rear Flue Fixing

Position the restrictor plate. Fit the gasket on top of the restrictor
plate. Fit the flue elbow on top of the gasket and secure to the
boiler using the four screws supplied, see diagram 8.7.

Tighten the four screws of the flue elbow evenly to ensure a
good seal at the gasket.

7798

PRESSURE
GAUGE
CONNECTION

SAFETY
VALVE
DISCHARGE

SEAL

DISCHARGE
PIPE

UNION CONNECTION

FLUE ELBOW
(REAR FLUE
SHOWN)

GASKET

RESTRICTOR
PLATE

ELBOW

UNION
NUT

CENTRAL
HEATING
FLOW
ISOLATION
VALVE

SEALING
WASHER (2)
(INSERT INTO
TUBING NUT)

GAS SUPPLY

GAS
SERVICE
COCK

SECURING
SCREW (4)

PRODUCTS
PROBE

Diagram 8.7

ELBOW

UNION
NUT

CENTRAL HEATING

RETURN ISOLATION

UNION
NUT

Diagram 8.8

VALVE

7405

DISCHARGE
PIPE

8081

TAB (2)

CUTOUT (2)

Note: It is important the correct restrictor plate is fitted or omitted
where instructed. For top flue outlet be sure to use the correct
restrictor plate, all restrictors are supplied with the appliance,
see restrictor table.

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

Remove the fan from the flue collector, secured with a screw
and retaining lip.

Diagram 8.9

7305

AIR
DUCT

FLUE
SPIGOT

Diagram 8.10

221872B

18

8 Mounting the boiler

RESTRICTOR TABLE

FLUE OUTLET

Case Rear

Top LHS

Top RHS

Top Rear

Fit the flue connecting elbow onto the fan, see diagram 8.12.
Fit the fan to the flue ducting, Holding it up in position fit the flue

collector, see diagram 8.13.
Secure the fan to the flue collector with the securing screw and

retaining lip, see diagram 8.14.
Fit the electrical connections and air pressure tubes to the fan.
Refit the combustion chamber panel.
Make the outer wall weatherproof. A Flue Collar Kit Part No.

443286 is available.

FLUE
CONNECTING
SLEEVE

FAN

Max. flue length Restrictor Plate Max. flue length Restrictor Plate

Up to 2.5M
Up to 2.5M
Up to 2.5M
Up to 2.5M

FLUE
DUCTING

G
C
C
C

7308

2.5 to 3.5M

2.5 to 3.5M

2.5 to 3.5M

7307

FLUE
CONNECTING
SLEEVE

FAN
(Push up
to fit)

FLUE
DUCTING

N/A

N/A

Non

D
D

RETAINING
LIP

Push
to fit

FLUE
CONNECTING
ELBOW

FAN

Diagram 8.11

Diagram 8.12

7865

FLUE
COLLECTOR

FLUE
DUCTING

AIR
PRESSURE
TUBE (2)

FLUE
CONNECTING
ELBOW

CLEAR

SECURING
SCREW

Diagram 8.13

ELECTRICAL
CONNECTIONS

FAN

RETAINING
LIP

Diagram 8.14

7901

RED

19

221872B

9 Electrical Connections

9.1 Supply Cable Connection

CAUTION: To prevent an induced current from switching the
appliance on, when not required, it is important that the system
control cables are separated from the other mains supply
cables.

Open the controls cover door. Remove the two screws securing
the controls facia, see diagram 9.1.

Hinge the control fascia open.
The boiler requires a permanent mains supply through an

external isolator which must also isolate any heating system
controls, see diagram 9.2.

Any heating system controls must not interrupt the permanent
mains supply to the boiler, as this would prevent frost protection
from operating.

Using PVC cable of a suitable length and rating as stated in
Section 1.8 “Electrical Supply”, route the mains supply cable
and connect to the appropriate terminals of the connector block,
restrain with the cable clamp supplied, see diagram 9.2.

Standard colours are, Brown - Live, Blue - Neutral, Green and
Yellow - Earth.

Make the earth cable of a greater length so that if the cable is
strained the earth would be the last to become disconnected.

CAUTION: It is ESSENTIAL to make sure that the polarity is
correct.

9.4 Frost Thermostat

If the installation requires protection by a “frost thermostat”,
connect a single pole type, to the appropriate terminals of the
connector.

Keep all cables away from hot surfaces.

9.5 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.
Refit the control fascia.

9.2 Heating System Controls

All external controls and wiring are required to provide a
minimum of reinforced insulation at 250Vrms between the parts
of those devices operating at mains hazardous voltage and the
user accessible parts at those devices.

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

If electrical controls are not to be used to regulate the heating
system, fit a link cable between LP and LS on the mains supply
connection block, see diagram 9.2 for positional reference.

When any form of external electrical control is being used to
regulate the system, connect the external system controls to
L.s. on the connection block on the mains terminal block
bracket, see diagram 9.2.

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

9.3 Programmer Kit (if applicable)

Open the controls cover door. Remove the two screws securing
the controls facia, see diagram 9.1.

Hinge the control fascia open.
Remove the programmer cover and blanking plate, see diagrams

9.1 and 10.2.
Fit the programmer with the three screws supplied, see diagram

13.2.
Fit the programmer bracket with the two screws supplied, see

diagram 9.2.
Fit the connection block, see diagram 9.2.
Connect the wires to the connection block and programmer,

see diagrams 9.2 and 14.24.
Connect the programmer plug, see diagram 13.4.

CONTROLS
FASCIA

CONTROLS COVER

SECURING
SCREW (2)

BLANKING
PLATE

7799

Diagram 9.1

221872B

20

9 Electrical Connections

PROGRAMMER PLUG

PROGRAMMER

SCREW (2)

SCREW (2)

CONNECTION
BLOCK

PROGRAMMER

BRACKET

CONNECTION
BLOCK

SCREW (2)

MAIN TERMINAL
BLOCK BRACKET

CABLE

7847

CLAMP

MAINS
CABLE

GROMMET

MAIN TERMINAL
BLOCK BRACKET

MAINS SUPPLY
ROUTING

Diagram 9.2

21

221872B

10 Commissioning

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

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

10.1 System Commissioning

Check that the boiler is isolated from the electrical supply, at the
external isolator.

Take care not to splash any of the electrical components.
Fully open the two water isolating valves, levers in line with the

length of the valves, see diagram 6.1.
Make sure that the automatic air vent is operating correctly by

loosening the cap, ensuring hole is directed away from controls.
Flush out the whole system.
Refill the system, refer to Section 4.9 and diagram 4.3, check the

operation of the safety valve, by allowing the water pressure to
rise until the valve operates. The valve should open within +/-

0.3bar of the 3 bar preset pressure. Where this is not possible
carry out a manual check by turning the safety valve knob in the
direction of the arrow.

Clear any air locks and check the system for water soundness.
Release the water pressure to the initial system design pressure.

10.2 Initial Lighting, testing and Adjustment

Check the boiler is Isolated from the electrical supply, at the
external isolator.

Turn on the gas service cock, slot in line with the length of the
cock, see diagram 6.1.

Purge the gas supply and test for soundness.
Lower the controls fascia by removing the two securing screws,

see diagram 9.1.
Loosen the burner pressure test point screw , see diagram 10.1,

and connect a suitable pressure gauge.
Switch on the electrical supply at the external isolator and check

all remote controls, thermostats and programmers are switched
on and are calling for demand.

Set the mains electrical switch “B” to 1, located on the controls
fascia, see diagram 2. (Instructions for Use).

If the red light “F” comes “ON”, the boiler will not work. Depress
the boiler safety cutoff reset button “G”, see diagram 2.
(Instructions for Use).

The pump will circulate water through the appliance and the
burner will light.

10.3 Burner Pressure

The burner pressure is factory preset and no adjustment should
be required.

The burner pressure should be checked with the system cold to
prevent any modulation of the gas pressure and the inner case
front fitted.

Remove the three plastic plugs on the rear of the controls fascia,
using the adjustment tool supplied turn the maximum burner
pressure potentiometer on the control board (P.C.B.) to minimum
(fully anticlockwise). Check the minimum burner pressure is

2.3 mbar +/-0.2 mbar. Adjust the pressure if required by adjusting
the minimum burner pressure potentiometer, see diagram 10.2.

Turn the maximum burner pressure potentiometer to maximum,
(fully clockwise).

Check that the maximum burner pressure is 14.3 mbar +/-0.2
mbar. Adjust the pressure if required by removing the screw
cap and turning the maximum rate adjustment screw on the gas
control valve, see diagram 10.1.

10.4 Ignition Rate

Set the mains electrical switch “B” to 0, located on the controls
fascia, see diagram 2. (Instructions for Use).

Disconnect the sensing lead at the connection, see diagram

10.2.
Set the mains electrical switch “B” to 1. The electrode will

continue to spark for (10 seconds approx.) to enable the ignition
to be set and checked before going to lockout. Check the
ignition rate is set to 6.0 mbar +/-1.0 mbar, adjust if required by
turning the ignition rate setting potentiometer using the
adjustment tool supplied, If this is not achieved before the boiler
goes to lockout the process can be repeated as required by
pressing the rest button “G”, see diagram 2. (Instructions for
Use). When set, switch the mains electrical switch “B” to 0.
Reconnect the sensing lead.

Set mains electrical switch “B” to 1, depress the rest button “G”
if required. Check the appliance operates correctly.

Isolate the boiler from the electrical supply.
Replace plastic plugs, screw cap and adjusting tool.
Disconnect the pressure gauge, tighten the burner pressure

test point screw . Test for gas soundness. Take care not to
splash any of the electrical components.

10.5 System - Commissioning

Fully open all radiator valves.
Set the heating system in operation and balance the radiators.
Refer to Section 4.6 and diagram 4.1.
Allow the system to reach maximum temperature then switch

off, isolate the boiler from the electrical supply and drain the
system rapidly whilst still hot.

Remove the inner case front.
Fill and vent the system as described in Section 10.1. Add

inhibitor, if applicable, refer to Section 4.10.
Fit the inner case front.

10.6 Completion

Fit the side panels, hook into the threaded lugs at the top, see
diagram 10.4.

Refit controls fascia fastening through holes in the side panels,
secure with four screws in the base

Fit the case base, slide back to engage the rear lugs, secure
with two screws, see diagram 10.3.

Fit the outer case front by locating it on one side then wrap it
around locating it on the opposite side, slide down locating on
to the threaded lugs at the top and behind the controls cover at
the bottom, secure all the panels with nuts , see diagram 10.5.

Set the boiler and any remote control to the desired settings,
then close the control cover door.

221872B

22

10 Commissioning

10.7 Instruct the User

Instruct and demonstrate the lighting procedure, then advise
the user of the efficient and safe operation of the boiler.

Instruct and demonstrate the operation of any heating system
controls.

Advise the user on the use and maintenance of any scale
reducer and pass on any relevant instructional documents.

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

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

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

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

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

GAS
CONTROL VALVE

6989

IGNITION
LEADS (2)

CONNECTION

CHASSIS
EARTH LEAD

IGNITION
RATE SETTING
POTENTIOMETER

MAXIMUM RATE
ADJUSTMENT
SCREW
(Cap removed)

CABLE ENTRY
COVER

PLASTIC
PLUG

MINIMUM RATE
ADJUSTMENT

BURNER

SCREW

PRESSURE
TEST POINT

SECURING SCREW (2)
Slacken do not remove

PROGRAMMER
COVER

MINIMUM RATE
POTENTIOMETER

Diagram 10.1

7811

SENSING
LEAD

SECURING
SCREW (4)

CONTROL BOARD
COVER

BURNER PRESSURE
ADJUSTING TOOL

23

MAXIMUM BURNER
PRESSURE
POTENTIOMETER

Diagram 10.2

221872B

10 Commissioning

CASE
BASE

CUTOUT

SECURING SCREWS

CUTOUT

Diagram 10.3

SIDE
PANEL

7802

7021

DATA
LABEL

WRAP AROUND

7020

SECURING
NUT (6)

OUTER
CASE
FRONT

SECURING
SCREW (2)

221872B

SECURING
SCREW (4)

Diagram 10.4

Diagram 10.5

24

11 General Data

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.

11.1 Servicing or Replacing Parts

To ensure the continued efficient and safe operation of the
boiler it is recommended that it is checked and serviced as
necessary at regular intervals.

The frequency of servicing will depend upon the particular
installation conditions and usage, but in general once a year
should be enough.

The servicing of this boiler must be carried out by a competent
person in accordance with the rules in force in the countries of
destination.

NOTE: To obtain a products of combustion reading, remove
the rubber cap from probe positioned on the top of the boiler,
see diagram 12.7. Connect the analyser tube after use replace
the screw.

Typical values for this boiler at maximum demand is:- CO

- 7.3% and CO < 0.0070%. These are based on a 300mm
length rear flue.

Make sure the appliance does not modulate whilst checking
combustion and allow the appliance to warm up for 15 minutes
before taking a reading.

Unless stated otherwise, parts removed or renewed during
servicing should be fitted in the reverse order to removal.

After completing any servicing, or renewing of gas carrying
components, ALWAYS test for gas soundness and carry out
functional checks of controls.

2

= 6

Dispose of all used sealing washers, gaskets and “O” rings
when renewing components.

Use the new ones supplied with the replacement.

11.2 Data Label

The data label is positioned on the inner case front, refer to
diagrams 10.5 and 1.2.

11.3 Isolation of Boiler

Before starting any servicing or the replacement of parts, isolate
the boiler from the electrical supply at the external isolator.

When servicing or replacing any components containing water
close all water cocks and drain appliance.

Close the gas service cock, see diagram 6.1.
BEFORE DRAINING THE BOILER, REFER TO SECTION

11.6.

11.4 Outer Case Front Removal

Remove the two nuts securing the outer case front then lift up
unhook the case at the top from the threaded lugs, pull it off on
one side to release then remove, see diagram 10.5.

11.5 Inner Case Front

Remove the inner case front, secured by two clamps at the
bottom lift up and unhook at the top, see diagram 8.1.

11.6 System Pressures and Draining

After replacing any water containing part of the circuit, make up
the water loss, vent all air and pressurise the system. Refer to
“Commissioning” in the Installation Instructions.

Check for water soundness and that the safety valve seats
without leaking.

12 Servicing

12.1 Isolation and Access REAR FLUE ONLY

Before commencing, refer to Section 11.
Remove the combustion chamber panel, unhook and lift off,

see diagram 8.2.
Remove the fan electrical connections by pulling the boots not

the wires and air pressure switch tubes, see diagram 8.3.
Remove the fan and flue collector assembly by pulling it forward

see, diagram 8.3.
Disconnect the three electrode leads, see diagram 12.1 (White

lead sensing electrode).
Remove the left hand section of the burner base baffle, secured

with two screws, see diagram 14.24.
Remove the burner retaining bracket by sliding it out, see

diagram 12.4.
Carefully pull the burner forward to remove, see diagram 12.5.
Take care not damage the combustion chamber insulation.

12.2 Isolation and Access HORIZONTAL TOP
FLUE OUTLET ONLY

Before commencing, refer to Section 11.
Remove the combustion chamber panel unhook and lift off, see

diagram 8.2.

Remove the fan electrical connections by pulling the boots not
the wires and air pressure switch tubes, see diagram 12.2.

Remove the fan.
Remove flue collector assembly by pulling it forward, see

diagram 12.3.
Disconnect the three electrode leads, see diagram 12.1 (White

lead sensing electrode).
Remove the left hand section of the burner base baffle, secured

with two screws, see diagram 14.24.
Remove the burner retaining bracket by sliding it out, see

diagram 12.4.
Carefully pull the burner forward to remove, see diagram 12.5.
Take care not damage the combustion chamber insulation.

12.3 Cleaning Heat Exchanger

Place a sheet of paper or similar in the combustion chamber, to
act as a collector for deposits removed.

Brush the heat exchanger with a suitable brush, remove paper
together with any debris.

Take care not to damage the insulation.
Do not use a brush with metallic bristles.
Ensure the baffle is refitted correctly to top of heat exchanger.

25

221872B

12 Servicing

12.4 Cleaning Main Burner

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

Do not use a brush with metallic bristles.

12.5 Service Checks

Inspect the spark and sensing electrodes, Clean or renew if
necessary, refer to Sections 14.4 and 14.5.

Check the injector, cleaning or renewing as necessary, refer to
Section 14.3.

SENSING
ELECTRODE

EARTH
ELECTRODE

IGNITION
ELECTRODE

Before replacing any of the parts removed during servicing,
inspect the condition of all seals and joints, renewing them as
necessary.

Check the condition of the combustion chamber insulation.
If renewing, refer to Section 14.22.

BURNER
RETAINING
BRACKET

9408

Pull bracket
forward to
remove

6962

SECURING
SCREW (3)

BURNER

ELECTRICAL CONNECTIONS

SECURING SCREW

FAN

LEADS (3)

Diagram 12.1

AIR PRESSURE
TUBE (2)

Diagram 12.2

SILICONE
SLEEVE (3)

FAN

7306

7307

GUIDE

RIGHT HAND SIDE OF BURNER

BURNER
GUIDE

When refitting
make sure the
bracket is located
in the guide
and fitted properly.

SECURING
LIP

Diagram 12.4

7808

FLUE
COLLECTOR

221872B

Diagram 12.3

LEFT HAND SIDE OF BURNER

26

When refitting
make sure the
burner is located
in the burner guide
and fitted properly.

Pull burner
forward to
remove

Diagram 12.5

12 Servicing

4mm

3.5mm

IGNITION
ELECTRODE

EARTH
ELECTRODE

4mm

12.6 Spark Gap

Check that the spark and sensing gaps are as shown in diagram

9372

12.6.

12.7 Operational Checks

Light the boiler, carry out operational checks and any necessary
adjustments as described in “Commissioning” in the Installation
Instructions.

12.8 Completion

Slide the outer case front on secure with the nuts previously
removed.

PRODUCTS

PROBE

7076

SENSING
ELECTRODE

SPARK GAPS

Diagram 12.6

13 Fault Finding

13.1 Initial Checks

If the boiler fails to operate, first check the following:-

1) That the electrical supply is available at the boiler and the
fuses are in order.

NOTE: THE BOILER CONTROL BOARDS CAN BE DAMAGED
BY INCORRECT TESTING OF COMPONENTS AND WIRING
WITH THE POWER ON.

2) Make sure that the system pressure gauge registers 0.7bar,
minimum, and that the automatic air vent works. Refer to
Installation Instructions, Section 10.1.

3) That the gas supply is available at the boiler and purged of
air.

4) Check that all heating system controls, if fitted, are working
correctly and calling for heat. If not isolate the boiler from the
electrical supply.

Diagram 12.7

Test for continuity, at mains.
If this is satisfactory proceed with the detailed fault finding as

Section 13.3.

27

221872B

13 Fault Finding

13.2 Electrical

Preliminary electrical system checks, as outlined in a Multimeter
Instruction book, are the first checks to be carried out during a
fault finding procedure.

Isolate the boiler from the electrical supply, refer to Section

11.3.
Gain access to the boiler controls by removing the outer case

front, refer to diagram 10.5.
Remove the two screws securing the controls facia, see diagram

9.1.
Hinge the control facia forward.
Remove the controls board cover by slackening the cable entry

cover screws, see diagram 10.2.
Remove the covers.
Ease the cover up and clear.
Check that all cables, multipin connectors and connectors are

secure on the board.

ON/OFF
SWITCH

brown

PUMP

AIR

PRESSURE

SWITCH

SPARK

ELECTRODES

PERMANENT
MAINS 230V-50HZ

brown

X3

F1 T2A

X3

X3

X2

TERMINAL

BLOCK

L

brown

red
black

grey

grey

Test the fuse on the main control board and renew as necessary.
Fuse 1 type (2AT). If a fuse fails repeatedly or the initial fault­finding checks described in Section 13.1 indicate a boiler fault,
check the boiler electrical circuits and follow the fault finding
procedures, see diagrams 13.1, 13.2, 13.3 and for programmer
fault finding, diagram 13.5.

NOTE: Only replace fuse with correct type.
On completion of a fault finding task that has required the

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

Before replacing any part please read points below:­Replacement of parts must only be carried out by a competent

person.

1. Refer to Section 11.1.

2. Always isolate the boiler from the electrical supply and as
required, the gas supply, as Section 11.3.

3. On completion, make good any water loss and pressurise the
system to initial design pressure, refer to “Commissioning” in
the Installation Instructions.

THERMISTOR

WATER

PRESSURE

SWITCH

orange
orange

black

N/C

C

white

grey

N/O

X5
X5

X4
X4
X4

PCB

7836

CONTROL BOARD

LOW VOLTAGE FUNCTIONAL FLOW

X2

X2

X2

X2

X2

CONTROL BOARD

X1
X1
X1
X1

X3

X3

X3

X3

brown

blue

yellow

white

red
blue

black
white

yellow
yellow

blue

grey

MAINS FUNCTIONAL FLOW

FAN

OVERHEAT

CUTOFF

PRESSURE

DIFFERENTIAL

GAS

VALVE

PROGRAMMER
SUPPLY
PLUG

N

EXTERNAL

Ls

X3

CONTROLS

black

Diagram 13.1

221872B

28

13 Fault Finding

TO TEST FOR COMPONENT OPERATION / FAILURE
Power to the appliance :- Test for 230V~ across live (brown) and earth (yellow and green), 230V~ across live and neutral (blue),

and zero potential across neutral and earth.

Thermistor :- With the power off unplug the connector and test resistance is 10kΩ at 25°C
Differential pressure switch :- With the power off separate the in-line connector and test for continuity across male end. Restore

the power and with demand off, open circuit, demand on closed circuit.

Overheat thermostat :- With the power off unplug the connectors and test for continuity (zero resistance).
Power to the gas control valve :- With a demand on test for voltages of 24 to 50V~ across the black and white cable connectors

and 130V~ across the red and blue cable connectors.

Power to the fan :- With a demand on and the front cover removed test for 230v~ at the fan connectors.
Fan failure :- with the power off and the supply leads to the fan disconnected (pull the boots only) the resistance across the fan

coil should not be greater than 50Ω.
Pump :- With the power off. Restore the power and check that there is 230V~ between live (red) and neutral (black) or live and

the appliance earth.
Air pressure switch :- With the power off and the front cover removed pull one of the supply cables from the fan and ensure

it is electrically safe. Restore the power establish a demand, check that there is 230v~ at one of the APS cables but not at the
other. Turn the power off, refit the fan cable, restore the power and check that there is now 230V~ at both the APS connectors
(Caution, the appliance will light unless the spark leads are temporarily unplugged from the electrodes and laid where they cannot
spark and ignite the gas and are electrically safe). This indicates that the APS changes state when the fan is run.

29

221872B

13 Fault Finding

Boiler Fault Finding

Check gas,water and electricity are available at the boiler. Before commencment of test, isolate the boiler

electricity supply, ensure that the remote controls are not calling for duty.

Check appliance installation and that it is mechanically correct, ensure all circuit valves are open.

Refer to tests for component operation/falure for individual checks.

Remove the outer case, lower the control housing and remove cable restraints. Check all connections on the

control board and the boiler components, rectify or renew as necessary. A spare fuse is provided.
YES

Switch on main supply. Do mains LEDs illuminate?

YES

Does low water

pressure LED flash?

NO

YES

Is there enough

system pressure?.

Re-pressurise

system.

NO

YES

Is the fuse on

the P.C.B. OK?.

YES

Is there continuity between common and

N/O? on the low water presure switch?.

Replace low water

pressure switch.

NO

Replace P.C.B.

NO

Replace the fuse.

Replace P.C.B.

7918

YESNO

Set all controls to call for a demand.

Does pump run?.

YES

Does the fan start?.

YES

NO

Is there 230V at

the fan terminals?.

Replace fan.

NO

Is there 230V

at the pump?.

YES

Check the pump

is not stuck.

NO

YES YES

NO

differential switch functioning?.

thermostat functioning?.

Replace P.C.B.

NO

Is the water pressure

Replace pump.

Is the air pressure

switch functioning?.

Is the overheat

Is the thermistor

functioning?.

YES

YES

YES

NO

NO

NO

NO

Replace water pressure

air pressure switch.

Replace overheat

differential switch.

Replace

thermostat.

Replace

thermistor

221872B

Continue

Replace P.C.B.

Diagram 13.2

30

Boiler Fault Finding Continued

13 Fault Finding

7919

Does the ignition electrode

begin to spark?

YES

Does the gas control valve open to

ignition rate between (5 and 7mbar)?.

YES

Does the burner pressure

increase to full rate?.

NO

NO

Is the air pressure

switch functioning?.

YES

Change P.C.B.

NO

Does the appliance

go to lockout?.

Is the voltage at the

gas control valve correct?.

gas control valve.

NO

YES

Replace

NO

Replace

air pressure switch.

NO

Is the thermistor

functioning?.

YES

Replace P.C.B.

Replace P.C.B.

NO

Replace

thermistor.

Disconnect sensing lead from P.C.B.

Is there continuity along lead and electrode?.

YES

Allow system to heat up.

Does the burner pressure modulate?.

YES

Remove demand does

boiler go out?.

YES

NO

Replace P.C.B.

YES

Is the burner

cross lighting?.

YES

YES

Replace P.C.B.

NO NO

decrease in resistance as the temperature rises?.

NO

Disconnect the thermistor connectors. Is there a

Replace

burner.

NO

YES

Replace P.C.B.

Replace sensing

electrode and lead.

Replace

thermistor

OK.

31

Diagram 13.3

221872B

13 Fault Finding

13.2 Programmer

If the programmer has failed it can be bypassed by disconnecting
the plug, see diagram 13.4.

Gain access by removing the two screws securing the controls
facia, see diagram 9.1.

Hinge the control facia forward.
Remove the programmer cover, see diagram 10.2.
Disconnect the programmer wiring harness plug.
This is a temporary measure and the programmer should be

repaired or replaced as soon as possible.

Check continuity of programmer harness, ensure an electrical supply is available,
ensure that remote controls are calling for heat.

Isolate the boiler from electrical supply remove outer case.

YES

Switch on electrical supply, is there a display on programmer?

YES

Central heating. Advance programmer until a demand is indicated,
is there 230V AC between common and heating on (pin 5).

ELECTRICAL
CONNECTION (2)

BROWN

12 3

LN

PLUG

BLUE

NO

NO

ORANGE

RED

BLACK

4

5

Faulty programmer.
Replace.

Faulty programmer.
Replace.

7850

PROGRAMMER

SECURING
SCREW (3)

Diagram 13.4

7937

YES

Domestic hot water. Advance programmer until a demand is indicated,
is there 230V AC between common and hot water (pin 3).

YES

Is there 230V AC between switched live incomming and neutral.

NO

NO

Faulty programmer.
Replace.

Check system
controls.

Diagram 13.5

221872B

32

14 Replacement of Parts

14.1 Fan

Before starting refer to Section 11.
Disconnect the two electrical connectors at the fan by pulling the

boots not the wires, see diagram 14.1.
Remove the two flexible tubes from the fan, noting their colour

and positions, see diagram 14.1.
Remove the fan, secured with a screw at the front, ease the fan

outlet from the flue duct and retaining lip at the rear, see diagram

14.1.
Note: To fit the fan, locate it into the flue duct and rear retaining

lip, push fully up to ensure a good seal, then secure the fan with
the screw, see diagram 14.1.

The polarity of the two electrical connectors is not important.

14.2 Burner

Before starting refer to Section 11.
Remove as relevant parts of Servicing Section 12.1.
Remove the spark electrode assemblies from the burner secured

by three screws see diagram 12.1.
Fit spark electrode assemblies to new burner. Check setting.
Taking care fit new burner.

14.3 Injector

Before starting refer to Section 11.
Remove the burner as relevant parts of Servicing Section 12.1.
Unscrew the injector.
When fitting the new injector, fit the new copper sealing washer,

supplied, to ensure gas soundness, see diagram 14.2.

14.6 Boiler Overheat Cutoff

Before starting refer to Section 11.
Disconnect the electrical connections, unclip to remove the

overheat cutoff, see diagram 14.3.

14.7 Thermistor

Before starting refer to Section 11.
Remove the two screws securing the controls cover door and

controls facia, see diagram 9.1.
Hinge the assembly forward.
Remove the electrical connection, unclip to remove the

thermistor, see diagram 14.3.

RED

ELECTRICAL
CONNECTION
(2)

AIR PRESSURE
TUBES

CLEAR

7893

14.4 Ignition, Earth and Sensing Electrodes

Before starting refer to Section 11 General Data.
For easier access remove the burner as relevant parts of

Servicing Section 12.1.
Remove the electrode lead and silicone sleeve, remove the

securing screw and electrode, see diagram 12.1.
Check setting of new one when fitted.

14.5 Ignition, Earth and Sensing Lead

Before starting refer to Section 11.
Disconnect the silicone sleeve and lead at the electrode, see

diagram 12.1. (White to sensing electrode).

Important Note : If replacing one of the ignition leads it will
be necessary to disconnect both from their electrodes and
untwist them from one another and the earth lead. Make
sure when replacing the two ignition leads that they are
tightly twisted together again, and the earth lead is twisted
round the pair, see diagrams 10.2 and 12.1.

Disconnect leads from the two retaining clips at the side of case.
Remove the two screws securing the controls facia, see diagram

9.1.
Hinge the control fascia open.
Remove the control board cover, see diagram 10.2.
Remove the lead on the control board and withdraw from

grommet, see diagram 14.7.

RETAINING
LIP

COPPER
SEALING
WASHER

SECURING
SCREW

FAN

Diagram 14.1

6961

INJECTOR

MANIFOLD

Diagram 14.2

33

221872B

14 Replacement of Parts

14.8 Pressure Gauge

Before starting refer to Section 11.
Remove case base, see diagram 10.3.
Open the controls cover door. Remove the two screws securing

the controls facia, see diagram 9.1.
Hinge the control fascia open.
Release the water pressure and drain the boiler, refer to Section

11.3 and 11.6.
Disconnect the pressure gauge connection from the safety

valve, discard the washer, see diagram 14.4.
Remove the pressure gauge, see diagram 14.5.
Locate the supplied washer under the pressure gauge connection

when refitted to the safety valve.

14.9 Control Board

Before starting refer to Section 11.
Remove the two screws securing the controls facia, see diagram

9.1.
Hinge the control fascia open.
Remove the cable entry covers, see diagram 10.2.
Disconnect the multi-pin connectors retained by clips, see

diagram 14.6.
Remove the controls board cover, see diagram 10.2.
Disconnect the remaining multi-pin connector retained by a clip.
Remove the control board securing screw and the control board

from the support posts, see diagram 14.7.
THE MAIN CONTROL BOARD MUST BE KEPT IN THE ANTI

STATIC HOLDER UNTIL IMMEDIATE REQUIREMENT.
When replacing the main control board check and if necessary

adjust the main burner gas pressure. Refer to “Commissioning”
in the Installation Instructions.

14.10 Gas Control Valve

Before starting refer to Section 11.
Remove the two screws securing the controls cover door and

controls fascia, see diagram 9.1.
Hinge the assembly open.
Disconnect multi-pin connector
Support the gas control valve, remove the eight screws at the

sides of the gas control valve, see diagram 14.8.
Separate the valve from the pipes, noting the fitted position.
Discard the “O” rings and fit the new ones supplied.
Check and adjust the main burner gas pressures, refer to

“Commissioning” in the Installation Instructions.

THERMISTOR
CENTRAL
HEATING

RETURN
FLOW
PIPE

7803

CLIP

UNION
NUT

SECURING

7026

SCREW (2)

PRESSURE
GAUGE

GAS CONTROL
VALVE

ELECTRICAL
CONNECTORS

UNION NUT

SAFETY

WASHER

VALVE

FACSIA

CLIP

7994

OVERHEAT
CUTOFF

Diagram 14.3

EXPANSION
VESSEL PIPE

DISCHARGE
PIPE

UNION
NUT

Diagram 14.4

RETAINING
BRACKET
(2)

Diagram 14.5

221872B

34

14 Replacement of Parts

SECURING SCREW

6982

CONTROL
BOARD

IGNITION LEADS

MULTI PIN

LEAD

7894

CONNECTORS

CAREFULLY BEND THE
RETAINING CLIPS FORWARD
TO RELEASE MULTI PIN

SENSING

CONNECTORS

Diagram 14.6

14.11 Pump

Before starting refer to Section 11.
Remove the two screws securing the controls facia, see diagram

9.1.
Hinge the assembly open.
Release the water pressure and drain the boiler, refer to Section

11.3 and 11.6.
Remove the electrical plug at the pump, see diagram 14.9.
Remove the four cap head screws, see diagram 14.9.
Make sure that the new pump is fitted in the correct orientation.
The pump adjuster on the new pump should be set to that of the

original, refer also to Section 4.4.
The flow rate should be controlled by means of a valve in the

heating flow, refer to Section 4.6.

GAS
CONTROL
VALVE

MANIFOLD

SPACER

PLUG

SUPPORT
POSTS (4)

MULTI PIN
CONNECTOR

GAS SUPPLY
PIPE)

Diagram 14.7

SECURING
SCREWS (8)

Diagram 14.8

TERMINAL
COVER SCREW

PUMP
ADJUSTER

7813

7814

14.12 Low Water Pressure Switch

Before starting refer to Section 11.
Remove the two screws securing the controls cover door and

controls fascia, see diagram 9.1.
Hinge the assembly open.
Release the water pressure and drain the boiler, refer to Section

11.3 and 11.6.

35

CAP HEAD
SECURING
SCREW (4)

END
SCREW

PUMP

SPINDLE

Diagram 14.9

221872B

14 Replacement of Parts

Remove the clip to remove the water pressure switch, see
diagram 14.10

Remove the plastic cover.
Remove the electrical connectors.
Refer to wiring diagram 14.24 when fitting.

14.13 Safety Valve

Before starting refer to Section 11.
Remove the two screws securing the controls cover door and

controls fascia, see diagram 9.1.
Hinge the assembly open.
Remove the case base, see diagram 10.3.
Release the water pressure and drain the boiler, refer to Section

11.3 and 11.6.
Disconnect the union nut and clip to release the safety valve,

see diagram 14.4.

14.14 Pressure Differential Micro Switch

Before starting refer to Section 11.
Remove the two screws securing the controls cover door and

controls facia, see diagram 9.1.
Hinge the assembly open.
Disconnect the inline connector to the pressure differential

micro switch.
Remove the micro switch securing clip, ease the micro switch

from its housing, see diagram 14.11.

14.15 Hydro Block Assembly Left hand side
(see diagram 14.12)

Before starting refer to Section 11.
Remove the case base refer to Section 10.6 and diagram 10.3.
Remove the two screws securing the controls cover door and

controls fascia, see diagram 9.1.
Hinge the assembly open.
Release the water pressure and drain the boiler, refer to Section

11.3 and 11.6.
Remove the low water pressure switch, refer to Section 14.11.
Disconnect the pressure differential micro switch inline electrical

connector, refer to Section 14.14.
Unplug gas control valve multi pin connector.
Remove the left hand side bypass tube retaining pin, see

diagram 14.13.
Disconnect the union nut to the central heating flow service

cock, refer to diagram 14.3.
Remove securing pins 1, 2, 3, elbow and the support plug, see

diagram 14.12.
Ease the hydro block back to release the central heating flow

pipe and bypass tube, see diagram 14.14.
Remove the left hand side of the hydro block.
Ensure all ”O“ rings and seals are fitted when reassembling.

14.16 Hydro Block Assembly Right hand side
(see diagram 14.12)

Before starting refer to Section 11.
Remove the case base refer to Section 10.6 and diagram 10.3.
Remove the two screws securing the controls cover door and

controls fascia, see diagram 9.1.
Hinge the assembly open.
Release the water pressure and drain the boiler, refer to

Section 11.3 and 11.6.
Disconnect the discharge pipe and expansion vessel pipe, see

diagram 14.4.
Disconnect the union nut to the central heating return service

cock, refer to diagram 8.8 and 14.12.
Remove the left hand side bypass tube retaining pin, see

diagram 14.13.
Remove the main terminal block bracket with programmer

bracket if fitted to ease hydro block removal, for position refer
to diagram 9.2.

Unplug pump multi pin connector.
Remove the pump and spacer, refer to Section 14.11 and

diagram 14.9.
Remove securing pins 4, 5, 6, elbow and the support plug, see

diagram 14.12.
Take care the heating return filter may fall out.
Twist the hydro block and ease forward to release the central

heating return pipe and bypass tube, see diagram 14.15.
Remove the right hand side of the hydro block.
See inset on diagram 14.12 to remove heating return filter.
Ensure all ”O“ rings, seals and heating return filter are fitted

when reassembling.

RETAINING
CLIP

LOW WATER
PRESSURE
SWITCH

LEFT HAND
HYDRO BLOCK

RETAINING
CLIP

PLASTIC
COVER

Diagram 14.10

7815

221872B

36

14 Replacement of Parts

14.17 Bypass Tube

Before starting refer to Section 11.
Remove the two screws securing the controls cover door and

controls fascia, see diagram 9.1.
Hinge the assembly open.
Release the water pressure and drain the boiler, refer to Section

11.3 and 11.6.
Remove the left hand side bypass tube retaining pin, see

diagram 14.13.
Remove the right hand hydro block as relevant parts of Section

14.16.
Remove the bypass tube, refer to diagram 14.15 .
Refer to diagram 14.16 for rear view and position.

14.18 Bypass Valve

Before starting refer to Section 11.
Remove the two screws securing the controls cover door and

controls fascia, see diagram 9.1.
Hinge the assembly open.
Release the water pressure and drain the boiler, refer to Section

11.3 and 11.6.
Remove the left hand side bypass tube securing pin, see

diagram 14.13.
Remove the bypass valve retaining pin, see diagrams 14.13.

and 14.17.
Remove bypass valve.

PRESSURE
DIFFERENTIAL
MICRO SWITCH

SECURING
CLIP

7830

SECURING
PIN 1

RETAINING CLIP

LOW WATER
PRESSURE
SWITCH

LEFT
HAND

PRESSURE
DIFFERENTIAL
MICRO SWITCH

INLINE
ELECTRICAL
CONNECTOR

UNION NUT CENTRAL
HEATING FLOW
SERVICE COCK

GAS CONTROL VALVE
MULTI PIN CONNECTOR

SECURING
PIN 3

SUPPORT
PLUG

SUPPORT

PLUG
SECURING
PIN 2

UNION NUT CENTRAL
HEATING RETURN
SERVICE COCK

PLUG

SECURING
PIN 4

ELBOW

SECURING
PIN 6

HYDRO BLOCK
ASSEMBLY

FILTER

Diagram 14.11

7831

RIGHT
HAND

PUMP

SECURING
PIN 5

7077

Diagram 14.12

37

221872B

14 Replacement of Parts

14.19 Expansion Vessel

Before starting refer to Section 11.
Remove all panels refer to the relevant parts of Section 10.
Renewal of the expansion vessel requires the boiler to be

removed from the wall. As an alternative, a separate expansion
vessel of the same specification may be connected as close as
possible to the boiler on the return side of the system, leaving the
original in position, refer to the Installation Instructions.

Release the water pressure and drain the boiler, refer to Section

11.3 and 11.6.
Remove the case base refer to Section 10.6 and diagram 10.3.
Disconnect the boiler water connection and gas supply union

nuts at the front of the isolating valves, see diagram 8.8 .
Disconnect the safety valve discharge pipe from the boiler, see

diagram 8.9.
Disconnect the mains supply cable at the connector block and

slacken the cable clamp to release the cable. Refer to diagram

9.2 for position.

CENTRAL
HEATING
RETURN
PIPE

RIGHT HAND
SIDE HYDRO BLOCK
(Twist and ease down,
pull forward to remove)

BYPASS
TUBE

7897

Diagram 14.15

LEFT HAND SIDE
HYDRO BLOCK

BYPASS VALVE
HOUSING

BYPASS VALVE
SECURING PIN

BYPASS TUBE
SECURING
PIN

BYPASS TUBE

CENTRAL
HEATING
FLOW PIPE

Diagram 14.13

7895

7896

'O' RING (2)

BYPASS
TUBE

REAR OF THE
BOILER

SECURING
PIN (2)

Diagram 14.16

SECURING
PIN

7832

7833

221872B

LEFT HAND
SIDE HYDRO BLOCK
(Ease back and down)

BYPASS
TUBE

Diagram 14.14

LEFT HAND SIDE
HYDRO BLOCK

REAR OF THE
BOILER

38

BYPASS
VALVE

'O' RING

Diagram 14.17

14 Replacement of Parts

Remove the two screws at the service cock bracket, see
diagram 8.6. Ease the boiler from the isolating valves. Unhook
the boiler at the top, easing the boiler from the flue outlet and lift
off.

Carefully lay the boiler down on its side for access to the
expansion vessel.

Disconnect the union nut connection, see diagram 14.18 and
discard the sealing washer for the new one supplied.

Remove the expansion vessel, secured with two clamping
screws.

Connect the union nut, when fitting the expansion vessel,
before clamping it.

Refer to Sections 8, 9 and 10 when mounting the boiler.

14.20 Automatic Air Vent

Before starting refer to Section 11.
Remove the two screws securing the controls cover door and

controls fascia, see diagram 9.1.
Hinge the assembly open.
Release the water pressure and drain the boiler, refer to Section

11.3 and 11.6.
If you have access to the right remove the automatic air vent

securing pin, see diagram 14.19.
Remove the automatic air vent cap and body.
SLACKEN THE SMALL CAP ON THE AIR VENT. THIS MUST

NOT BE RE-TIGHTENED.
If you have minimum clearances remove the right hand hydro

block as Section 14.16 to gain access to the automatic air vent.

EXPANSION VESSEL

SECURING
SCREW (2)

UNION
NUT CONNECTION

Diagram 14.18

7834

AIR VENT
CAP

AUTOMATIC
AIR VENT

PUMP

7835

SECURING
PIN

Diagram 14.19

39

221872B

14 Replacement of Parts

14.21 Heat Exchanger

Before starting refer to Section 11.
Unhook the combustion chamber front, see diagram 8.2.
Remove the fan and flue collector, refer to Section 14.1.
Remove the burner see Section 14.2.
Refer to diagram 14.20 and remove the two side insulation

pieces.
Remove the securing clips on the inlet and outlet pipes.
Remove the combustion chamber main panel securing screws.
Remove the heat exchanger/combustion chamber assembly.
Remove heat exchanger front retaining clips.
Remove the heat exchanger from its retaining tabs positioned

at the rear by easing it forward and up.
Replace heat exchanger making sure that it is correctly engaged

on the retaining lugs at the back of the combustion chamber,
carefully refit the pipe securing clips and front retaining clips.

14.22 Combustion Chamber Insulation

Remove outer case front as section 11.4.
Remove the inner case front as Section 11.5.
Unhook the combustion chamber front, see diagram 8.2.
Remove the burner see section 14.2.
Remove the front insulation piece and slide out both side

insulation pieces, see diagram 14.21.
Pull the lower rear insulation forwards, then slide the upper rear

insulation down from behind the heat exchanger, see diagram

14.21.

HEAT
EXCHANGER

SIDE
INSULATION (2)

COMBUSTION
CHAMBER MAIN
PANEL

SECURING
SCREWS (2)

BASE
BAFFLE

BEADING

BAFFLE

9376

FRONT
RETAINING CLIP
(2)

SECURING

SCREW (4)
PIPE
SECURING
CLIP (2)

221872B

'O' RINGS

Diagram 14.20

40

COMBUSTION
CHAMBER
FRONT PANEL

SIDE
INSULATION

14 Replacement of Parts

9379
REAR
INSULATION

SIDE
INSULATION

FRONT
INSULATION

Diagram 14.21

14.23 Viewing Window

Before starting refer to Section 11.
Remove the old self adhesive aluminium foil gasket and the old

mica window. Replace with the new mica window, see diagram

14.22. Peel off the backing paper and secure with the new self
adhesive aluminium foil gasket. Ensure no air bubbles are
trapped underneath the foil.

Important

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

14.24 Air Pressure Switch

Before starting refer to Section 11.
Disconnect the two electrical connectors at the air pressure

switch, see diagram 14.23.
Remove the flexible tubes from the switch.
Remove the air pressure switch, secured with two screws.
When replacing the tubes to the air pressure switch make sure

that the red tube from the fan connects to the upper connection
of the switch.

The polarity of the electrical connections is important, refer to
diagram 14.24.

14.25 Programmer if fitted

Before starting refer to Section 1 General Data.
Isolate the boiler from the electrical supply.
Remove outer case front as section 11.4.
Remove the two screws securing the controls cover door and

controls facia, see diagram 9.1.
Hinge the assembly forward.
Remove the programmer cover, see diagram 10.2.
Disconnect the programmer wiring harness plug, remove the

programmer and electrical connections, see diagram 13.4.

MICA WINDOW

SELF ADHESIVE
ALUMINIUM FOIL
GASKET

AIR PRESSURE
SWITCH

SECURING
SCREW (2)

ELECTRICAL
CONNECTION (2)

OPENING
(BOILER INNER
CASE FRONT)

PEEL OFF
BACKING
PAPER

Diagram 14.22

AIR
PRESSURE
SWITCH
TUBE (2)

RED

CLEAR

Diagram 14.23

7002

6980

41

221872B

14 Replacement of Parts

w- WHITE
b- BLUE
bk- BLACK
br - BROWN
g/y- GREEN/

YELLOW

PRESSURE
DIFFERENTIAL
MICRO SWITCH

GAS VALVE

bk
w

KEY

g- GREY
or- ORANGE
r- RED
y- YELLOW
p- PURPLE

PLUG

BOILER
OVERHEAT
CUT-OFF

bk

w

b

br

THERMISTOR

Programmer (If fitted)

y

r

b

bk

w

MAINS SUPPLY

FUSED AT 3A

FAN

5
4
3

SWITCHED LIVE

FROM EXTERNAL

230V-50Hz

PERMANENT

g

Ls

To System

SOURCE

E
N
Lp

or
or

Controls

r

AIR PRESSURE
SWITCH

g/y

PUMP

NOTE

br

MAINS
SWITCH

bk

7806

gg

br

EARTH

ELECTRODE

IGNITION

ELECTRODE

WATER
PRESSURE
SWITCH

NOTE

N/O
N/C
C

g/y

CHASSIS
EARTH

SENSING
ELECTRODE

g
w

bk

g/y

X9

b

FUSED

AT 2A

y
y

PLUG

Programmer

(If fitted)

X5X4X3X1X2

CONTROL BOARD

bk

r

or

1

5

432

L

N

Switched live from external source.
CAUTION :- This wiring will remain live when the mains switch on the controls facsia is isolated.

221872B

Diagram 14.24

42

15 Spare Parts

15.1 Part Identification

The key number in diagram 15.1 and the first column of the list will help identify the spare part.

15.2 Ordering

When ordering any spare part, please quote the part number and the description from the list together with the model name and serial
number information from the data label.

The data label is positioned on the inner case front, see diagram 8.1 and 10.5 Installation Instructions.

Key No Part No Description GC No

1 457077 Fan assembly E27122
2 205768 Injector assembly ********
3 202641 Spark electrode (2) ********
4 202641 Sensing electrode ********
5 202579 Boiler over heat cut off assy E27159
6 204546 Pressure gauge assembly E26680
7 227095 Control board ********
8 227004 Thermistor assembly-Heating ********

9 801192 Pump (Not illustrated) E27211
10 202226 Fuse - not illustrated 278136
11 230510 Gas control valve E27124
12 227129 Air pressure switch assy ********
13 801208 Safety valve assembly E27115
14 ******** Water inlet filter ********
15 457068 Low water pressure switch ********
16 227060 Mains switch E26675
17 ******** Automatic air vent assembly ********
18 ******** Pressure differential micro switch ********

5

8

1

12

17

7807

3

4

14

18

11

7

2

13

15

16

6

Diagram 15.1

43

221872B

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

221872B

44