Saunier duval ECOSY 2 SB 28E 03-01 User Manual

Instructions for Use

Installation and Servicing

T o be left with the user

Ecosy 2

SB 28E

G.C. No. 41-920-30

221879A.03.01

9221

Condensing

System Boiler

This is a Cat I2H Appliance

Reference in these instructions to British Standards and Statutory

Regulations/Requirements apply only to the United Kingdom.

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

For Ireland the rules in force must be used.

Card. The instructions are an integral part of the appliance and must, to comply with the current issue of the Gas Safety

(Installation and Use) Regulations, be handed to the user on completion of the installation.

Guarantee Registration

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

Saunier Duval 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:

✔

All replacement parts

❏

✔

All labour charges

❏

All call-out charges

✔

❏

One Contact Local Service

REGISTER YOUR SAUNIER DUVAL APPLIANCE

FOR 1ST YEAR GUARANTEE PROTECTION

CALL 0208 247 9857

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

Nottingham Road, Belper, Derbyshire. DE56 1JT

Tel: [phone] Fax: [phone]

Hepworth Heating Ltd.,

General/Sales enquiries:

Contents

CONTENTS DESCRIPTION SECTION PAGE No.

INSTRUCTIONS

FOR USE

INSTALLATION

INSTRUCTIONS

Introduction 3
Operating the Boiler 3

General Information 1 5
Boiler Position 2 7
Flue Location and Ventilation 3 8
Heating System 4 10
Installation Preparation 5 12
Flue Preparation 6 13
Boiler Fixing 7 15
Gas, Water and Condensate Conns. 8 15
Electrical Connections 9 16
Commissioning 10 18

SERVICING

Servicing 11 23
Fault Finding 12 27

INSTRUCTIONS

Replacement Parts 13 30

Important Information

General

The Ecosy 2 SB28E can provide room heating as part of a
central heating system. The central heating water temperature
can be adjusted on the boiler.

Domestic hot water can be provided via a hot water cylinder.
Once the controls are set the boiler operates automatically. It

is recommended that a room thermostat and programmer are
used to control the central heating system.

If there is no heating demand for 24 hours then the pump will be
operated to prevent it sticking. A frost protection program is also
included.

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

Gas Category

This boiler is for use only on G20 gas.

Gas Safety (Installation and Use) Regulations

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

Gas Testing and Certification

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

Any alteration not approved by Hepworth Heating Ltd., could
invalidate the certification, boiler warranty and may also infringe
the current issue of the Statutory requirements.

Spare Parts

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.

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 0063.

Product/production certified:

Notified body 0063.

The CE Mark on this appliance shows compliance with:

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

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

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

Control of Substances Hazardous to Health

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

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

221879A

2

Important Information

Insulation Pads/Ceramic Fibre, Glass yarn

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.

Instructions for Use

Gas Leak or Fault

If a gas leak or fault exists or is suspected, turn the boiler mains
electrical supply off and turn off the gas supply at the meter.
Consult your local gas company or your local installation/
servicing company.

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. If not, the boiler safety cut-off may have
operated, please refer to the following section to reset.

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

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.

Reset Button

Refer to diagram 1 which shows the fascia behind the drop
down door.

If the burner goes out check the digital display. Flashing digits
on the display indicate a fault. Allow the boiler to cool down for
at least four minutes then press the ‘reset’ button. This should
restart the boiler.

To obtain service call your installer or Heatcall (Saunier Duval's
own service organisation) using the telephone number given on
the front page of these instructions.

Operating the Boiler

FASCIA

RESET
BUTTON

To Operate the Boiler

1. Check that all isolating valves are open with their slots in line
with the length of the valve, see diagram 7.1.

2. 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 which should read a minimum of 1.0bar, see
diagram 1.

DIGITAL
DISPLAY

MODE

BUTTON

PRESSURE
GAUGE

Diagram 1

3. If you are in any doubt about the boiler being filled with water
contact your installation/servicing company or the local gas
company.

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

5. Set any remote controls as required.

6. If the display is flashing, press the 'reset' button, shown on
diagram 1.

7. The boiler should now operate.

9232

3 221879A

Operating the Boiler

User Controls

The boiler is factory preset to supply central heating up to 70oC.
The operation of the boiler can be altered by using the ‘mode’

button. Temperature Selection and Control Options are detailed
in sections 10.7 to 10.10.

Additional Options

Other modes are available by repeatedly pressing the ‘mode’
button. These cover fault indication and servicing and should
only be accessed by the service engineer. Repeated pressing
of the ‘mode’ button will eventually return the display to show
boiler temperature, see diagram 10.4.

To Turn the Boiler Off

It is preferable to leave the electrical supply on whenever
possible to permit operation of the built-in frost protection (see
‘Protection Against Freezing’ below) and daily pump exercise.

To turn off the central heating use the room thermostat or clock/
timer.

For holiday mode, refer to section 10.7.
To turn off the boiler for servicing, isolate it from the electrical

supply. To turn it on again follow the instructions given in ‘To
Operate the Boiler’.

Maintenance and Servicing

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
on the front cover of this booklet.

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

If the boiler is fitted into a compartment or cupboard do not use
the compartment or cupboard for storage.

Protection Against Freezing

The boiler has a built in frost protection programme as long as
the electricity and gas are left switched on.

This device only protects the boiler. Any other exposed areas
of the system should be protected.

If the mains electricity and gas are to be turned off 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.

If in doubt, contact you installation/servicing company for advice.
As a safety feature the boiler will stop working if the condensate

drain becomes blocked. The display will repeatedly flash ‘

‘8*’. During freezing conditions this may be due to the

then
forming of ice in the condense drain external to the house.
Release an ice blockage by the use of warm cloths on the pipe.
Press the reset button to restart the boiler. Contact your
installation / servicing company if the fault persists.

Draining and Filling

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

If the pressure gauge indicates a loss of system pressure, i.e.
less than 0.7bar, the appliance will shut down showing flashing:

‘1’ then ‘2*’ on the display. YOU MUST CONTACT YOUR

INSTALLER.

Pressure Relief Safety Valve

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, isolate the boiler electrical supply
and contact your installation/servicing company.

Cleaning

This appliance contains metal parts 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

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.

Pluming from flue terminal

All condensing boilers produce a plume of water vapour from
the flue terminal. This is due to the high efficiency and hence
low flue gas temperature. This may increase in wet, damp
weather but is nothing to worry about.

0’

221879A

4

145

1 Installation Instructions

373

208

520

9260

101

CONDENSATE
SIPHON

Condensate Drain
Connection

140

INSIDE WALL
FIXING FACE

140

CAP

1.1 Installation

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

When installing the appliance, care should be taken to avoid any
possibility of personal injury when handling sheet metal parts.

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

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

1.2 Gas Supply

This boiler is for use only on G20 natural gas.
The gas installation must be in accordance with the current

issue of BS6891.
The supply from the governed meter must be of adequate size

to provide a steady inlet working pressure of 20mbar (8in wg) at
the boiler.

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

1.3 Data Label

The data label is on the base panel inside the appliance.

1.4 Electrical Supply

The boiler must be earthed.

All system components shall be of an approved type and all
wiring to current I.E.E. wiring regulations.

The boiler must be connected to a permanent 230V ac, 50Hz
supply.

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

Isolation should be by a double pole switched fused spur box,
with a minimum gap of 3mm for both poles. The fused spur box
should be readily accessible and preferably adjacent to the
appliance. It should be identified as to its use.

118

33

890

C

L

BOILER

REFER TO THE WALL TEMPLATE
FOR PIPE DIMENSIONS

Diagram 1.1

Alternatively connection can be made through an unswitched
shuttered socket and 3A fused 3 pin plug.

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

0.20mm).
The colours of three core flexible cable are, blue - neutral,

brown - live, green and yellow - earth.
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

.

2

(24/

1.5 Condensate Drain

A plastic drain pipe must be fitted to allow discharge of
condensate to a drain.

Condensate should, if possible, be discharged into the internal
household draining system. If this is not practical, discharge can
be made externally into the household drainage system or a
purpose designed soak away, see section 9.4 for more details.

1.6 Boiler Efficiency

The Seasonal Efficiency Domestic Boilers UK (SEDBUK) is:
Ecosy 2 SB28E: 90.2%
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 has been certified by Gastec.

5 221879A

1 General Information

TABLE 1 C.H. Max MIN

9261

NOMINAL
HEAT
INPUT kW 32.5 11.7
GROSS Btu/h 110,890 39,920

NOMINAL
HEAT
OUTPUT kW
Btu/h 97,583 34,120

COND.
HEAT
OUTPUT kW 30.0 11.3

Btu/h 102,360 38,556

BURNER
MANIFOLD
SUCTION
PRESSURE
HOT(APPROX)

mbar

wg -1.92 -0.2

28.6 10.0

-4.8 -0.5

SCHEMATIC LAYOUT OF BOILER

Diagram 1.2

TABLE 2

Lift Weight 52kg (114lb)
Total Weight (packed) 56kg (123lb)
Total Weight (installed) 60kg (132lb)

● Gas connection Rc1/2 (1/2in BSPT)

● Heating and return 22mm compression

Safety valve Preset 3bar (43.5lbf/in

Safety valve discharge 15mm copper

Water content (heat exch)

2.7 ltr (0.59 gall)

BURNER
%CO

CASING

2

DOOR ON

CASING
DOOR OFF

9.2-9.6 9.2-9.6

9.0-9.4 9.0-9.4

APPROX.
GAS RATE

m3/h

2.9 1.0

ft3/h 102.4 35.3

■ Maximum heating 130 litres

system water (28.6 gallons)
content using at 750C
fitted expansion average system
vessel, pressurised temperature
at 1bar.

2

)

Electrical supply 230V~50Hz

Electrical rating 115W fused 3A
IP classification IP40

Internal Fuse rating 1) Type 2AF

■ Expansion vessel capacity 7 litres (1.54 gallons)
Charge pressure 0.5bar (7.3lbf/in

2

)

Heating system 0.7bar (10.1lbf/in2)
minimum pressure

● Ball valves are fitted in water and gas connections, plus a drain point on water connections.

■ For larger systems use an additional expansion vessel.

221879A

6

2) Type 2AF

3) Type 3AT

2 Boiler Position

2.1 Location

The boiler is not suitable for fitting outdoors.
Any electrical switch or boiler control using mains electricity

must be positioned so that it cannot be touched by a person
using a bath or shower.

The boiler must be mounted on a flat wall which is sufficiently
robust to take its weight, refer to Table 2.

2.2 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 beneficial around the boiler for

installation and servicing.
For flue installations where external access is not practicable,

consideration should be given for the space required to insert
the flue internally which may necessitate clearance larger than
those specified in diagram 2.1.

9070

5

5

*

† 600

200

*

5

*

5

Increase to 25mm clearance from
combustible material.

*

† A removable compartment door can be
placed at least 5mm in front of the appliance.

Dimensions in millimetres

MINIMUM CLEARANCE FROM
PERMANENT SURFACES

25

200

Diagram 2.1

7 221879A

3 Flue Location and Ventilation

3.1 Flue Position and Length

There are several flueing options available for the
Ecosy 2 SB 28E, e.g. horizontal, vertical and twin flue.

The standard horizontal flue is fitted onto the top of the boiler
using the flue elbow.

See diagrams 3.1 to 3.3 to determine whether a standard flue
can be used.

The standard flue can be extended using 1m long extension kits
and 90° elbows. A maximum of 3500mm of extension pipes plus
3x90° bends can be added to the standard horizontal flue
length.

When extension pipes are used the flue system must be
designed to have a continuous fall to the boiler of at least 2.5°
to allow condensate to run back into the boiler and out via the
drain.

3.2 Internal Flue Installation

The flue can be installed from inside the building, when access
to the outside wall face is not practicable.

3.3 Terminal Position

The minimum acceptable siting dimensions for the terminal
from obstructions, other terminals and ventilation openings are
shown in diagram 3.4.

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

Being a condensing boiler some pluming may occur from the
flue outlet. This should be taken into consideration when
selecting the position for the terminal.

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

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

WALL THICKNESS 'X' = 75 TO 554mm

"X"

REAR FLUE - STANDARD

DISTANCE 'Y' = 307 TO 755mm

Diagram 3.1

6501

6502

DISTANCE 'Y' = 393 TO 755mm

6503

SIDE FLUE - STANDARD Left

221879A

"Y"

Diagram 3.2

SIDE FLUE - STANDARD Right

8

"Y"

Diagram 3.3

3 Flue Location and Ventilation

A

A

F

G

E

A

G

G

G

B,C

B,C

F

F

K

K

K

C

G

L

L

UNDER CAR PORT etc.

H,I

J

D

F

K

3.4 Terminal Guard

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

If a terminal guard is required, it must be positioned to provide
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 3.5.
A suitable guard can be obtained from.
Tower Flue Components
Morley Rd.
Tonbridge
Kent
TN9 1RA.
Their Reference CGD K3 BL.

3.5 Timber Frame Buildings

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

3.6 Room Ventilation

The boiler is room sealed, so when it is installed in a room or
space, a permanent air vent is not required.

3.7 Cupboard or Compartment Ventilation

Due to the high efficiency and hence low casing temperature of
this boiler, cupboard or compartment ventilation is not necessary.

TERMINAL GUARD

Diagram 3.5

M

MINIMUM SITING DIMENSIONS FOR
FANNED FLUE TERMINALS
POSITION

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 200
E FROM VERTICAL DRAIN PIPES AND

SOIL PIPES 75

F FROM INTERNAL 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 300
M FROM EXTERNAL CORNERS 300

Diagram 3.4

2816

* It may be necessary to increase this dimension to prevent

staining of adjacent walls depending on weather conditions.

9 221879A

4 Heating System

4.1 General

The boiler is for use only with sealed central heating systems.
The safety valve is an integral part of the boiler and it cannot be

adjusted.
A pressure gauge is incorporated on the boiler control panel to

indicate the system pressure.
The circulation pump is integral with the boiler.

The Ecosy 2 SB 28E is fitted with a UPS 25-60 pump. A
performance curve is shown in diagram 4.1.

4.2 Expansion Vessel

The boiler has an integral expansion vessel with a capacity of
7 litres (1.54 gallons), with a charge pressure of 0.5bar.

The maximum heating system water content using the fitted
expansion vessel is 130 litres at an average temperature of
75OC, and charge pressure of 1.0bar.

4.3 Flow Rate

The minimum flow rate through the boiler is 1230 litres/hr. This
is equal to 20

The system can be fitted with a lockable balancing valve if
necessary in the main flow or return pipes shown as valve "A"
in diagram 4.2.

O

C differential at maximum heat input.

4.4 Bypass

The boiler is fitted with a manual bypass, see diagram 4.3. This
valve may be adjusted by the installer if necessary to ensure at
least 1230 litres/hr flow through the boiler. The boiler is supplied
with the bypass open by approximately half a turn and is closed
by turning the white screw clockwise. However for systems
completely fitted with thermostatic radiator valves or systems of
high pressure loss an additional bypass valve must be fitted to
the heating circuit to ensure that under no circumstances does
the flow rate drop below this level.

An additional bypass valve “B” is shown in diagram 4.2.

4.5 Filling Sealed Systems

Provision for filling the system at a low level must be made. Two
methods of filling are shown in diagram 4.4. There must be no
permanent connection to the mains water supply, even through
a non-return valve.

Diagram 4.1

9104

221879A

10

4 Heating System

METHOD 1

METHOD 2

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

COMBINED
CHECK VALVE
AND VACUUM
BREAKER

C

C

4.6 Water Treatment

For optimum performance after installation, the boiler and its
associated central heating system should be flushed in
accordance with BS7593:1992 using a cleanser such as Sentinel
X300 or X400, or Fernox Superfloc.

For long term corrosion protection, after flushing, an inhibitor
suitable for aluminium heat exchangers should be used.
Examples are Sentinel X100 and Fernox Copal.

BOILER

OPTIONAL FILLING
ARRANGEMENTS,
SEE DIAGRAM 4.4

C

4.7 Draining Tap

A draining tap must be provided at the lowest points of the
system, which will allow the entire system to be drained.

The flow and return isolation valves are provided with drain
points for boiler heat exchanger drainage, see diagram 7.1.

9262

ADDITIONAL
EXPANSION
VESSEL
(if required)

RETURN

HEATING
CIRCUIT

MANUAL
BYPASS
VALVE

OPTIONAL
BY-PASS
VALVE

'B'

'A'

FLOW CONTROL
VALVE

DRAIN
POINT

Diagram 4.2

Diagram 4.3

7266

6597

Diagram 4.4

11 221879A

5 Installation Preparation

5.1 Wall Mounting Pack

The wall mounting pack contains everything required to pre­plumb the boiler, including the wall mounting jig, hanging
bracket, wall template, screw pack and safety valve discharge
pipe, along with these instructions.

5.2 Wall Template

Remove the wall template from the wall mounting pack and
place in the desired position on a flat wall, giving due consideration
to boiler clearances, see section 2.2.

The wall template supplied covers both the system boiler and
combination boiler versions of the Ecosy 2. When installing a
system boiler please ignore the domestic cold and hot water
connections.

5.3 Flue Hole Cutting

The standard horizontal flue is designed with an internal fall
of 35mm/metre towards the boiler for disposal of condensate.
If the standard flue length alone is being used then the flue hole
of diameter 105mm can be cut in the position marked on the wall
template.

For standard side flues the horizontal flue centre line on the
wall template should be extended to the side wall, and the
vertical centre of the flue hole marked at 208mm from the back
wall.

For installations with external access, a 105mm diameter core
drill can be used.

For installations with internal access only a 125mm diameter
core drill should be used.

When using extension pipes with the horizontal rear flue, a core
drill size of 125mm should be used to allow the extension pieces
to slope at 35mm/metre (2.5

For extended side flues, the flue hole centre should be
determined by extending the dashed inclined line on the template
to the side wall. This dashed line is drawn at 35mm/metre (2.5
rise from the boiler. Where this line reaches the side wall, a
horizontal line should be marked. The vertical centre line of the
flue should then be marked at 208mm from the back wall, see
diagram 5.1.

To allow for the flue passing through the wall at this angle a
125mm hole should be drilled irrespective of internal or external
installation.

If necessary remove the wall template whilst drilling the flue
hole.

Extended flue length
Standard flue length

0

) towards the boiler.

2.5˚
Inclined

Horizontal

208

90

Ø 125

0

5.5 Wall Mounting Jig and Hanging Bracket
Fixing

The wall mounting jig supplied is suitable for the system boiler
and combination boiler versions of the Ecosy 2. When installing
a system boiler please remove the domestic cold and hot water
isolation valves, along with their securing brackets and screws.

If previously removed, reposition the wall template over the flue
hole and mark the position of the fixing holes for the jig and the
hanging bracket, see diagram 5.2.

Drill the four fixing holes using a 7mm dia. drill bit and insert wall
plugs supplied.

If gas and/or water pipes are to be plumbed through the rear wall
directly into the wall mounting jig holes, the holes must be drilled
as marked on the wall template prior to fixing of the wall
mounting jig.

Secure the wall mounting jig and hanging bracket using the
screws and washers supplied.

5.6 Pre Plumbing

The wall mounting jig can now be pre-plumbed without the
boiler being mounted if necessary. All water, gas and electric
connections are on the wall mounting jig with the exception of
the condense drain, the position of which is shown on the wall
template for pre plumbing purposes. See sections 8 and 9 for
details of gas, water, condensate and electrical connections.

5.7 Unpacking of Boiler Carton

Cut the straps that secure the carton and the boiler to its transit
pallet and open the top flaps of the carton. Carefully remove the
top packing piece which contains the user control door and
place to one side until required. Remove the carton and edge
packing. To assist in lifting the boiler it is advisable to remove the
casing door by removing the two securing screws.

o

)

WALL
TEMPLATE

WALL PLUG
(2 OFF)

WASHER

6525

(2 OFF)

SCREW
No12 x
50mm
(2 OFF)

HANGING BRACKET

9263

221879A

WALL
TEMPLATE

Diagram 5.1

WALL PLUG
(2 OFF)

12

WALL
MOUNTING JIG

SCREW No12 x 50mm
(2 OFF)

Diagram 5.2

6 Flue Preparation

Y

C

L

BOILER

Y - 483 LEFT FLUE DUCT
Y - 417 RIGHT FLUE DUCT

Y - 493 LEFT AIR DUCT
Y - 427 RIGHT AIR DUCT

OUTSIDE
WALL FACE

SIDE OF
BOILER

AIR DUCT

FLUE
DUCT

125
DIA.
HOLE

6.1 Flue Length

All dimensions are in mm.
For a rear flue, measure the distance from the outside wall face

to the boiler mounting wall. Check that the flue length will be
suitable, see diagram 3.1 for a standard flue system.

For a side flue, measure the distance from the outside wall face
to the flue outlet centre line of the boiler. Check that the flue
length will be suitable, see diagram 3.2 for a left hand flue
system or diagram 3.3 for a right hand flue system.

If the measurement exceeds those shown in diagrams 3.1 - 3.3
then one or more extension pipes are required.

6.2 Rear Flue

Mark the air duct assembly and the flue duct at the lengths
shown in diagram 6.1 then cut to length, cutting square and
removing any burrs.

6.3 Standard Side Flue

Mark the air duct assembly and the flue duct at the lengths
shown in diagram 6.2 then cut to length, cutting square and
removing any burrs.

6.4 Side Flue With Extensions

Measure the distance from the outside wall to the side of the
boiler casing. With the extensions only joined together (i.e.
without standard flue piece fitted) cut the end nearest to the
boiler, to the dimensions shown in diagram 6.3.

OUTSIDE
WALL
FACE

REAR FLUE

X + 196

( AIR DUCT ASSEMBLY)

X

BOILER
MOUNTING
WALL

X + 271

( FLUE DUCT )

Diagram 6.1

Y + 297 LEFT FLUE DUCT
Y + 363 RIGHT FLUE DUCT

Y + 222 LEFT AIR DUCT
Y + 288 RIGHT AIR DUCT

AIR DUCT

6505

9292

6.5 Flue Assembly

The flue assembly is an entirely push fit design.
The rubber seals should be lubricated prior to assembly.
Remove all burrs from cut pipes.
Diagram 6.4 shows the components supplied in the standard

flue kit.
Having cut the air and flue ducts as described in sections 6.1 -

6.4, assemble the flue as follows: the flue can be assembled
externally and internally by following sections A & C, or entirely
from inside by following sections B & C.

A. External fitting - Fit the rubber sealing collar ‘D’ into the
groove at the outer end of the air pipe ‘B’.

Push the air pipe ‘B’ into the wall until collar ‘D’ is pushed up
against the outside face of the wall.

Ensure that the ‘up’ label on air pipe ‘B’ is at the top, i.e. the tab
protruding into the hole at the outer end of the pipe is uppermost.

B. Internal fitting - Fit the rubber sealing collar ‘D’ into the
groove at the outer end of the air pipe ‘B’.

Fit spacer piece ‘E’ over air pipe ‘B’.
Push the air pipe ‘B’ through the wall until collar ‘D’ is clear of the

outside face of the wall.
Pull the air pipe ‘B’ to ensure that collar ‘D’ is pulled up to the

outside wall face.
Ensure spacer piece ‘E’ is pushed into the wall, see diagram

6.1.
C. Fitting Completion - Fit sealing flange ‘F’ over the air pipe

and against the inside wall face.
From inside fit flue pipe ‘A’ into the air pipe ‘B’ ensuring that the

groove on the outer end engages in the air pipe tab.
Fit the flue pipe spacer ‘C’ over the flue pipe ‘A’ and push inside

air pipe ‘B’.
Attach any extension pieces necessary.

FLUE
DUCT

C

Y

OUTSIDE
WALL FACE

SIDE OF
BOILER

SIDE DUCT -STANDARD FLUE

SIDE FLUE EXTENSION

13 221879A

L

BOILER

Diagram 6.2

6554

Diagram 6.3

6 Flue Preparation

6.6 Flue Attachment To Boiler

Refer to section 7 and fix the boiler in position prior to completing
the flue installation.

Pull off the wire clip on the flue adaptor pipe inside the boiler, see
diagram 6.5. Push the flue adaptor pipe downwards into the flue
pipe.

Refer to diagram 6.4. Fit rubber dome ‘J’ to the base of the flue
elbow ‘G’ and place securing ring ‘H’ over the elbow to rest
around the bottom flange of the rubber dome.

‘D’

LABEL

‘B’

‘A’

GROOVE

‘C’

Fit flue elbow ‘G’ to air pipe ‘B’ and flue duct ‘A’. A small amount
of lubricant can be applied to the rubber seals in the elbow to
facilitate this.

Secure the rubber dome ‘J’ to the top of the boiler with securing
ring ‘H’ and screws provided.

Push the flue adapter pipe up onto the inner duct of the elbow
and secure with wire clip.

‘F’

‘G’

SCREW

(4 OFF)

‘E’

‘H’

‘J’

6507

FLUE
ADAPTOR
PIPE

TAB

BOILER FLUE
OUTLET PIPE

GROOVE

Diagram 6.4

6551

WIRE CLIP

Diagram 6.5

221879A

14

7 Boiler Fixing

Boiler Fixing

Having previously secured the wall mounting jig and hanging
bracket to the wall, lift the boiler into position in the following
manner. To assist in the lifting of the boiler, remove the front
panel.

Lean the top of the boiler slightly to the wall and position just
above the hanging bracket. Allow the boiler to slowly move
downwards until engaged in the hanging bracket.

Slowly swing the base of the boiler to the wall mounting jig
ensuring that the copper tails on the boiler fit into the gas and
water isolation valves on the jig, see diagram 7.1. If necessary
the gas and water isolation valve clamps can be loosened to
ease fitting. Make sure that the isolation valves are secured
with the clamps after making good the connections.

Connect the two electrical connector plugs hanging from the
boiler into the sockets on the wall mounting jig. The white mains
electrical supply socket on the left hand side of the jig and the
black auxiliary electrical socket on the right hand side of the jig.

Please refer to condensate connection before proceeding,
see section 8.4.

Attach the flue as described in section 6.6.

DRAIN
POINT

CENTRAL
HEATING
VALVES

GAS
SERVICE
COCK

SLOTS SHOWN IN
CLOSED POSITION

BOILER
MOUNTING
FRAME

SECURING

SCREW

CLAMP

DRAIN
POINT TO
FRONT OF
APPLIANCE

CENTRAL
HEATING
RETURN

GAS & WATER ISOLATION VALVES

CENTRAL
HEATING

PRESSURE RELIEF
VALVE PIPE

FLOW

9264

GAS
ISOLATION
VALVE

Diagram 7.1

8 Gas, Water, and Condensate Connections

8.1 Gas Connection

The gas supply can be connected from below or through the
wall at the rear of the boiler, the position is shown on the wall
template.

Refer also to section 1.2.
Make the gas supply connection to the gas isolation valve.

Slacken or remove the clamp, as desired, whilst making the
connection. Do not subject the gas isolation valve to heat, see
diagram 7.1.

8.2 Water Connections

Provision is made for the water connections to be made from
below or through an internal wall at the rear of the boiler, the
position is shown on the wall template. Copper tail pieces are
supplied in the wall mounting pack if required.

Flush out the heating system before connecting to the boiler.
Make the connections to the heating system by way of the

isolating valves, see diagram 7.1
Slacken or remove the clamps, as desired, while making the

connections. Do not subject any of the isolating valves to heat.

15 221879A

8 Gas, Water, and Condensate Connections

Make sure that the drain points on the isolating valves are
positioning towards the front of the boiler, also that the drain and
operating screw heads are accessible.

8.3 Safety Valve Discharge

The pipe from the safety valve must not discharge above an
entrance, window or any type of public access area.

A short discharge pipe is supplied loose in the wall mounting
pack. This must be extended, using not less than 15mm o.d.
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.

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

CONDENSATE
SIPHON

9057

CAP

8.4 Condensate Drain Connection

The condensate drain connection is at the bottom of the boiler,
to the left of the wall mounting jig, see diagram 8.1. 21.5mm
plastic overflow pipe should be used to fit into the drain connection
on the condensate siphon and discharge condensate to a drain.
The drain pipe should have a fall of a least 2.5
boiler.

Condensate should, if possible be discharged into the household
internal drainage system. If this is not practicable, discharge
can be allowed into the external household drains or a purpose
designed soak away.

It is recommended that any external condensate drain pipe is
insulated and also preferably of 32mm diameter, to prevent
freezing in adverse weather conditions.

The condensate is discharged periodically in ‘slugs’ by siphonic
action.

o

away from the

9 Electrical Connections

9.1 Supply Cable Connection

This appliance must be earthed.
It is essential that the polarity is correct.

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

The boiler requires a permanent mains supply through an
isolator, see section 1.4.

Any heating system controls must not interrupt the permanent
mains electrical supply to the boiler.

Unscrew the mains electrical supply cover plate, situated on the
left hand side of the wall mounting jig, see diagram 9.1.

DRAIN
CONNECTION

DRAIN PIPE

It is recommended that the condense siphon is prefilled by
pouring 250ml (1/2 pt) of water into the boiler flue outlet pipe
prior to commissioning, see diagram 6.4.

It is not necessary to provide air breaks or extra traps in the
discharge pipe as there is already a trap inside the boiler. Fitting
an extra trap may cause the boiler siphon to work incorrectly.
Refer to British Gas publication “Guidance notes for the
Installation of Domestic Condensing Boilers” for advice on the
disposal of the boiler condensate.

Remove the white mains electrical connector socket from the
fittings pack and push on to the bracket on the left hand side of
the wall mounting jig with the socket pins pointing upwards.
Remove the two securing screws and cover from the socket.
Using PVC cable of suitable length and rating as stated in
section 1.4, connect the mains supply cable to the appropriate
terminals of the plug, see diagram 9.2.

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

The electrical mains supply cable outer insulation must not be
cut back external to the connector.

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

Diagram 8.1

221879A

16

9 Electrical Connections

9.2 Heating System Controls

Mains electricity must NOT be connected to the black
electrical connector plug.

All heating system controls must be low voltage or potential
free.

Under no circumstances must connection be made to the
terminal strip under the boiler with the red/white and blue/
white wires connected to it.

It is recommended that the boiler is controlled by a programmer
and room thermostat. Thermostatic radiator valves may be
installed in addition to the room thermostat.

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

All system controls are wired into the black electrical connector
plug situated on the right hand side of the wall mounting jig.

If electrical controls are being used the blue link between
terminals should be removed as necessary as shown in diagram

9.3.
If electrical controls are not being used, DO NOT REMOVE the

red and blue links between terminals 1 and 2, and 2 and 3 in the
black electrical connector plug.

9.3 Frost Thermostat

This boiler has its own frost protection device to protect the
boiler. Additional frost protection may be required for exposed
pipework. If required, connect a single pole frost thermostat to
the appropriate terminals of the black electrical connector plug
as shown in diagram 9.3.

9.4 Outside Sensor

An outside sensor can be supplied as an optional extra, see
section 10.10. If required, connect to the red and black wire tails
which are pre-wired to terminals 4 and 5 of the control module.

9.5 Cable and Connector Securing

After completing all the connections to the wall mounting jig
electrical connectors, secure the cables with the covers, using
the screws previously removed.

Connect the boiler connector, and replace the cover plate over
the white mains connector, see diagram 9.4.

9.6 Electrical Connections - Testing

Carry out preliminary electrical system checks as below:

1. Test insulation resistance to earth of mains cables.

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

3. Test the polarity of the mains.

6571

MAINS ELECTRICAL
COVER PLATE

MAINS ELECTRICAL
SUPPLY SOCKET

SECURING
SCREW

Diagram 9.1

BRACKET

6531

FROST THERMOSTAT

EXTERNAL
CONTROLS

RED LINK

WARNING : Mains electricty must not be connected to
the black auxiliary control plug.

BLUE LINK

Diagram 9.3

APPLIANCE
PLUG

COVER
PLATE

SCREW

9380

6596

EARTH

(L) LIVE

(N) NEUTRAL

Diagram 9.2

MAINS IN
SUPPLY PLUG

17 221879A

Diagram 9.4

10 Commissioning

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

10.1 Filling the Heating Circuit

Open the two central heating isolating valves, slots in line with
the length of the valve, see diagram 7.1.

Flush, fill and vent the system refering to sections 4.5 and 8.2.
Make sure that the automatic air vent is operating correctly, see

diagram 10.1, and that the black cap is loosely fitted to allow air
to escape.

Pressurise the system until the pressure gauge reads at least

1.0bar (14.5lbf/in
Check the heating system and boiler for water soundness.

2

), see diagram 1.

AUTOMATIC
AIR VENT

Diagram 10.1

10.2 Preparation for Lighting

Isolate the boiler from the mains electrical supply.
Test for gas soundness and purge air from the gas supply. Turn

on the gas isolation valve, slot in line with the length of the valve,
see diagram 7.1.

10.3 Initial Lighting

The lighting procedure of the boiler is fully automated. Check
that all external controls are calling for heat.

Turn on the mains electrical supply. After a short delay the
digital display on the fascia should illuminate, see diagram 1 in
Instructions for Use.

The fan should start and after a few seconds the ignition will
commence.

If the burner fails to light the fan will stop and the display will flash

'0' and then '2*'. This indicates the boiler has failed to light,

which initially may be due to air in the gas supply line.
Press the ‘reset’ button and the boiler will restart, see diagram

1 in Instructions for Use.

Flashing digits indicate a fault. Refer to fault finding if any fault
persists, see section 12.

The boiler will continue firing in central heating mode until the
user controls; ie. time clock or room thermostat are satisfied.

10.4 Gas Pressure

The gas valve is factory set and should need no adjustment. It
should be checked that the supply pressure is 20mb when the
boiler is firing at full rate, measured on the gas valve as shown
in diagram 10.2.

See section 10.7 on how to run the boiler at maximum heat
input.

Note that the burner pressure cannot be measured at the gas
valve as it is altered by the suction of the fan and modulated
according to demand.

9265

10.5 Testing - Heating System

Check that all remote controls are calling for heat. The boiler will
fire automatically. Fully open all radiator valves, flow control
valve ‘A’ and additional bypass valve ‘B’ if fitted, see diagram

4.2.
Balance the radiators as required and if fitted adjust valve ‘A’ to

give the required system differential. Turn off all radiators that
can be shut off by the user and adjust the boiler bypass if
necessary to achieve less than the maximum differential allowed
of 20°C across flow and return.

If this is not possible, a separate system bypass must be fitted
and adjusted to achieve less than maximum differential. Refer
to section 4.3 and diagram 4.2.

Allow the system to reach maximum temperature then switch
off the boiler by isolating from the electrical supply.

Drain the entire system rapidly whilst hot, using the drain tap at
the lowest part of the system. Fill and vent the system as
described previously in section 10.1.

Lock or remove the handles from controls valve ‘A’ and bypass
valve ‘B’ if fitted to prevent unauthorised adjustment.

10.6 User Control Door - Fitting

Take the control door, which was removed from the top of the
boiler carton and fit the the two brass lugs. Push the lugs into the
slots at the bottom of the fascia to engage, see diagram 10.3.

10.7 User Controls and Options

The Ecosy 2 SB 28E has a multifunctional single digit display
and two control buttons labelled ‘mode’ and ‘reset’, see diagram
1 in Instructions for Use.

The ‘reset’ button is used to restart the boiler after a fault
condition has occurred, ie. ignition failure, low water pressure or
high water temperature.

The ‘mode’ button allows the user to view the operating conditions
of the boiler, or if necessary change the central heating
temperatures to a preferred setting. The boiler is factory pre-set
to supply central heating up to 70°C.

221879A

18

10 Commissioning

Repeated pressing of the 'mode' button gives the display
sequence shown in diagram 10.4.

If a different option is required, repeatedly press the ‘mode’
button until the required symbol is shown, and then press and
hold the ‘mode’ button for two seconds. The decimal point will
flash to confirm selection.

Note: If no buttons are pressed the display reverts to show boiler
temperature after approximately two minutes.

Temperature Display

The boiler normally shows the operating temperature of the unit
on the digital display. However, because the display consists of
only one digit, temperature is represented in blocks of ten
degrees as follows.

DISPLAY TEMPERATURE RANGE (°C)

0 Min - 5

1 6-15

2 16 - 25

3 26 - 35
4 36 - 45
5 46 - 55
6 56 - 65

7 66 - 75
8 76 - 85
9 86 - Max

9059

PRESSURE
TEST
POINT

ELECTRICAL
CONNECTIONS

Temperature Options

There are four central heating options to choose from. These
options are shown on the digital display by repeated pressing of
the ‘mode’ button. The sequence is shown in diagram 10.4. The
selected options are indicated by a flashing decimal point.

6566

Only one central heating option can be selected at any one time.
For adaptive control, see section 10.9.

PROTECTIVE
CAP

Diagram 10.2

The decimal point after the digit signifies that the boiler is firing.
This information is also supplied on the inside of the control

door.

CONTROL
DOOR

9251

BRASS
LUGS

Diagram 10.3

19 221879A

10 Commissioning

Control Options

There are two control options available: Normal mode and
Holiday mode, see diagram 10.4.

Normal mode uses the central heating temperatures selected.
Holiday mode shuts down the central heating. However, frost

protection and pump exercise programme remain active. To
resume normal operation after a holiday period, select ‘Normal
Mode’,

If an external frost thermostat is fitted ‘Holiday Mode’ should not
be selected during periods of cold weather. Turn the central
heating off at the programmer or reduce the room thermostat
temp to a low setting. This will allow the external frost thermostat
to operate the boiler, see section 10.13 for 'frost protection'.

.

10.8 Servicing Options

There are four options available to the service engineer,which
are not to be used by the user, see diagram 10.4. They are as
follows:

Installation Mode

This allows interrogation of the appliance by an authorised
engineer, via the connection of a P.C.

After using the installation mode, normal operation of the
appliance can be resumed by reselecting
'Normal mode', .

Operating Function

The current function that the boiler is performing is shown by a
number with a flashing decimal point, see table below.

Minimum Input Lock

This function allows the service engineer to lock the appliance
into delivering minimum heat input to enable accurate combustion
analysis.

Maximum Input Lock

This function allows the service engineer to lock the appliance
into delivering maximum heat input to enable accurate
combustion analysis.

See section 11.6 for details of checking combustion.
Both input locks are not permanent and revert to normal

operation after approximately 15 minutes. The boiler can be
manually reverted at any time by pressing the ‘Reset’ button.

The display automatically reverts to show temperature after
approximately two minutes.

10.9 Adaptive Control

Adaptive Control is an advanced control feature that requires
the interaction of a room thermostat. It is used in two out of the
four central heating options and allows the boiler to optimise the
heat output. This enables the boiler to operate at much lower
temperatures and hence be more fuel efficient.

If a room thermostat is not fitted when using these modes the
boiler will revert to standard modulation at the temperatures
given in diagram 10.4.

When the boiler fires from cold with the adaptive control active,
it fires at low rate for ten minutes before ramping up to full rate.

For details of wiring in a room thermostat refer to section 9.2 and
diagram 9.3.

OPERATING FUNCTION

DISPLAY ACTION

No demand.
Boiler fan is purging the system.
Ignition phase.
Boiler is suppyling central heating.
Waiting for the fan to run up to speed.
Boiler is off after reaching temperature.
Central heating pump overrun.
Boiler safety shut down.

10.10 Outside Sensor

9381

If an outside sensor is fitted the boiler adjusts the flow temperature
to compensate for variations in external temperature. Only two
central heating options are available which are different to those
in diagram 10.4, these are:

The outside sensor optimises the boiler
flow temperature to suit demand. Normal on/off control is
retained but a room thermostat is required. This is the preferred
option.

For use in systems with a programmer but no room
thermostat. Sets the boiler flow temperature depending on
external temperature. During “off” periods on the programmer
the flow temperature is reduced by 10OC.

10.11 Operating Sequence

Refer to diagram 10.4 and press the ‘mode’ button until the
Operating function is displayed.

221879A

20

10 Commissioning

NOTE:- The SYMBOL (flashing decimal point) indicates the selected options

to

Press 'mode' -

Press 'mode' -

BOILER
TEMPERATURE (Decimal Point illuminated means boiler is firing)

Do not use

Press 'mode' -

Press 'mode' -

Press 'mode' -

Press 'mode' -

O

55 C with adaptive control

O

70 C with adaptive control

Central heating
options

Press 'mode' -

O

85 C

(select one only)

9266

Press 'mode' -

Press 'mode' -

Press 'mode' -

Press 'mode' -

Press 'mode' -

Press 'mode' -

Press 'mode' -

O

85 C with continuous
pump operation

Normal mode

Holiday mode

Installation mode

to

Operating function

Minimum input lock

Maximum input lock

Control options

Servicing options

Press 'mode'

Sequence Chart for Digital Display

to

Returns to temperature display

Diagram 10.4

21 221879A

10 Commissioning

The operating sequence of the appliance during central heating
can be checked against the following table.

CENTRAL HEATING SEQUENCE TABLE

DISPLAY ACTION
(Operating
function)

No demand.
Create demand by switching on

timer or room thermostat.
Three way valve switches to

central heating
(approx. 15 seconds).

Pump and fan start.

Fan running up to speed.
Gas valve opens

and ignitor sparks for 3 seconds.
Burner ignites.

Burner runs at ignition rate (70%)
for 10 seconds.
Rate drops to minimum for
60 seconds.
Input adjusts according to heating
option selected.

10.14 Instruct the User

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

Instruct on and demonstrate the operation of any heating
system controls.

6572

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

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

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

Advise the user that, like all condensing boilers this appliance
will produce a plume of condensation from the flue terminal in
cool weather. This is due to the high efficiency and hence low
flue gas temperature of the boiler.

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

Advise the user that the permanent mains electrical supply
SHOULD NOT be switched off, as the built in frost protection
and pump exercise program would not be operable.

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

End of heating demand
i.e. room thermostat satisfied.

Burner shuts down and timed
pump overrun commences.

No demand.
3 way valve switches back
to domestic position
(approx 15 seconds).

10.12 Pump Exercise Program

After a power cut or every 24 hours in holiday mode, the pump
will run for one minute to prevent it from sticking. This will also
occur during normal operating if there is no central heating
demand for more than 24 hours.

10.13 Frost Protection

During periods of no demand the boiler is protected by a frost
protection procedure. If the heating outlet temperature falls to
7°C the pump will start. If the heating outlet temperature
continues to fall to 3°C the burner is ignited. The burner is
extinguished when the heating outlet reaches 10°C, the pump
will run for a further 15 minutes. This function primarily protects
only the boiler.

If an additional frost thermostat is fitted, switching of this will
operate the boiler.

221879A

22

11 Servicing

11.1 General

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

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

Measurement of the products of combustion can be achieved
by connection of a probe to the flue elbow or alternatively to the
sample point at the base of the flue outlet pipe inside the boiler,
see diagram 12.1.

Before commencing with a service or replacement of parts the
boiler should be isolated from the electrical supply and the gas
supply should be turned off at the gas isolation valve, see
diagram 8.1.

All routine servicing requirements can be achieved by the
removal of the front panel only. To remove, simply lower the
control door and remove the two screws at the bottom of the
front panel.

Unless stated otherwise any part removed during servicing
should be replaced in the reverse order to removal.

Servicing should always include the removal of any debris from
the condensate pipe and siphon.

After completing any servicing of gas carrying components,
ALWAYS test for gas soundness and carry out a functional test
of the controls.

11.4 Spark Electrode

Remove the spark plug lead and two securing screws. Withdraw
the spark electrode and viewing window from the combustion
chamber, see diagram11.3.

Inspect the tips for damage.
Clean away any debris and check the spark gap is 3.5

see diagram 11.7.
Check the electrode gasket for signs of leakage and replace if

necessary.

FLUE ELBOW

ALTERNATIVE
PROBE
POSITIONS

+

0.5mm,

6527

11.2 Combustion Chamber and Heat
Exchanger

The Combustion Chamber and Heat Exchanger do not require
cleaning during routine servicing. See section 11.9 for major
servicing.

11.3 Burner and Fan

Undo the union nut on the injector tube. Lift the tube clear of the
injector on the gas valve and then twist the tube and pull
downwards to disengage from the fan inlet flange, see diagram

11.2.
Remove Air pressure switch tube, see diagram 11.2.
Remove spark plug lead, see diagram 11.3.
While supporting the fan, remove the wing nut and screw and

pull out the fan securing plate, see diagrams 11.3 & 11.4.
Gently lower the fan and burner assembly out of the combustion

chamber.
Disconnect the electrical lead from the fan.
Inspect the burner for any signs of damage.
The burner can be cleaned if necessary by washing in warm

soapy water and rinsing with clean water. DO NOT use wire or
sharp instruments to clean the holes of the burner.

Clean the inlet holes of the fan inlet flange with a soft brush or
vacuum cleaner, see diagrams 11.2 and 11.5.

Examine the fan inlet and outlet seals and replace if necessary.
When refitting the fan securing plate, ensure that the dimples

are uppermost and that the fork on the plate engages onto the
ledge on the Heat Exchanger, see diagram 11.6.

When refitting the injector tube make sure the ‘O’ ring seal is
fitted.

VENT
PIPE

FLUE
OUTLET
PIPE

Diagram 11.1

AIR
PRESSURE
SWITCH TUBE

FAN INLET
FLANGE

INJECTOR
TUBE

6528

INJECTOR

23 221879A

“O” RING SEAL

Diagram 11.2

11 Servicing

SPARK ELECTRODE
SECURING SCREW
(2 OFF)

SECURING
PLATE

WING
NUT

SECURING

6526

PLATE

SPARK
PLUG
LEAD

Diagram 11.3

11.5 Condensate Siphon

Place a container beneath the drain cap on the condensate

9048

siphon.
Carefully remove the cap at the base of the condensate drain

trap, see diagram 8.1.
Remove any solids found.
Check for any debris in the outlet pipe of the condensate drain

and clean as necessary.
When refitting the cap ensure that a water tight seal is achieved,

but do not use excessive force.
Ensure that the flexible pipe between the heat exchanger and

siphon is not kinked.
Fill the condensate trap as recommended in section 8.4.

11.6 Combustion Check.

Connect a CO2 combustion analyser to the test point on the flue
elbow if fitted, or alternatively to the sample point at the base of
the flue outlet pipe inside the boiler casing, see diagram 11.1.

Turn on the gas isolation valve, see diagram 7.1.
Turn on the electricity supply.
Set all external controls to give a heating demand and the boiler

should fire automatically.
Repeatedly press the 'mode' button on the boiler fascia until the

symbol

appears.

FAN

Diagram 11.4

FAN INLET
FLANGE

FAN

Press and hold the 'mode' button for greater than one second
until the decimal point is flashing on the display.

The boiler is now locked at minimum input.
Allow the boiler to stabilise for a few minutes and then check the

value. See Table 1.

CO

2

If adjustment proves necessary then proceed as follows.
Any adjustment to the gas valve should only be carried out by

a qualified person. The CO
minimum input.

Remove the protective cap from the Gas Valve. See diagram

10.2.
Turn the adjuster until the correct CO
To check the combustion at full rate repeatedly press the mode

button on the boiler fascia until the symbol
and hold the mode button until the decimal point on the display

flashes.

6544

The boiler is now locked at maximum input.
The CO

mode, see above for adjustment at minimum input.
Check the combustion levels of CO and CO
If the combustion is excessive, see fault finding section 12.4.
Press the Reset button to remove the minimum or maximum

input lock. Replace caps on sample point and gas valve.

level should not be adjusted in maximum input lock

2

value can only be adjusted at

2

value is attained.

2

.

2

appears. Press

221879A

Diagram 11.5

24

11 Servicing

11.7 Casing Panel Removal

During major servicing or replacement of parts it may be
necessary to remove the boiler side panels to gain access.

Remove the front panel and the control door. See section 10.6.
To remove a side panel undo and remove the four screws

securing the lower panel brackets to the boiler.
Remove the brackets along with the control door.
Undo and remove the four screws securing each side panel to

the boiler, two at the bottom and two at the top.
Pull the panel out at the bottom and off at the top of the boiler.

11.8 Draining of Boiler Heating Circuit

Drain down the heating circuit of the boiler by closing the
heating flow and return isolating valves on the wall mounting jig,
see diagram 7.1. These valves are closed when the slots are at
right angles to the direction of flow.

Lift the head of the pressure relief valve on the underside of the
boiler by twisting and allow the boiler circuit to drain. Complete
draining by removing the drain screws from the isolating valves
and drain the water into a suitable receptacle.

After servicing or replacing parts, open the heating flow and
return isolating valves and refill, vent and pressurise the heating
circuit. See section 10.1.

Check for leaks.

SECURING
PLATE

Ensure the securing plate forks
are supported on the ledge.

Fan removed for clarity

ELECTRODE
GASKET

6545

LEDGE

Diagram 11.6

6550

SPARK
ELECTRODE
SECURING
SCREW (2 OFF)

SPARK
ELECTRODE

SPARK GAP

+

3.5

0.5mm

Diagram 11.7

25 221879A

11 Servicing

11.9 Heat Exchanger - Major Servicing

Refer to Fault Finding sections 12.1, (fault code 0 and 8.) and

12.4 before carrying out a major service of the heat exchanger.
If it is suspected that the heat exchanger has become partially

blocked internally, proceed as follows.
Remove the burner and fan as described in section 11.3.
Remove the wire clip from the internal flue adaptor, see diagram

6.5.
Push the adaptor pipe downwards into the boiler flue pipe,

disengaging it from the flue elbow.
Remove the boiler flue pipe.
Check for any blockage in the boiler flue pipe and remove any

debris.
Check for any blockage in the casting flue outlet orifice and

remove any debris.
Place a suitable container below the condense drain and

remove the cap. See section 11.5.
Using a suitable torx screwdriver, remove the heat exchanger

top panel screws, see diagram 11.8. Take care when removing
the screws and washers, not to drop them behind the heat
exchanger.

Carefully prise open the boiler top.
Replace the boiler flue pipe.
Place a water hose into the top of the heat exchanger, taking

care not to damage the insulation to the rear, see diagram 11.9.
Thoroughly flush the heat exchanger from above and collect the

water and any debris in the container beneath the condense
drain.

Flush the heat exchanger until the water appears clear at the
condense drain.

Check the condition of the heat exchanger top gasket and
replace if necessary.

Rebuild the boiler.
Repeat the combustion test as detailed in section 11.6.
If the combustion is still unacceptable then the heat exchanger

will need to be replaced. Refer to section 13.15 and remove the
heat exchanger.

TORX
SCREWS
(6 OFF)

HEAT
EXCHANGER

Air Vent Pipe
removed for clarity

HOSE

Air Vent Pipe
removed for clarity

Diagram 11.8

INSULATION

Diagram 11.9

9065

9066

221879A

26

12 Fault Finding

Red r
Black b
Blue bl
Brown br
Green gr
Yellow y
Green/Yellow g/y
White wh
Orange or
Grey gy
Red/White r/wh
Blue/White bl/wh

P.C INTERFACE

Do NOT connect

*

to these terminals

*

Ribbon cable

KEY

r/wh
bl/wh

X7

X4

X8

FLAME IGNITION AND
IONISATION ELECTRODE

AUTOMATIC CONTROL MODULE

INTERNAL
FUSES

F1=2AF

F3=3AT

F2=2AF

X1-1
X1-2
X1-3
X1-4
X1-5

br

br

PUMP

230V/50Hz
WHITE
MAINS PLUG

bl

CHASSIS
EARTH POINT

bl

g/y

9267

BLACK LOW
VOLTAGE PLUG
Room thermostat
Clock/timer
Frost thermostat

g/y

g/y

CONTROL PANEL

FLOW N.T.C.
THERMISTOR

RETURN N.T.C.
THERMISTOR

b

OUTSIDE
SENSOR

X2-1

X2-2

X2-3

X2-4

X2-5

X3-1

X3-2

X3-3

X3-4

X3-5

X3-6

b

r

b

b

D.C. FAN

AIR
PRESSURE
SWITCH

wh

bl

r

1 gr

3 gr

X2-6

X2-7

X2-8

X2-9

X2-10

X2-11

X2-12

X2-13

y

gy

r

wh

b

or

gr

r/wh

br

GAS
CONTROL
VALVE

bl

r

RESISTOR
220Ω / 7W

Schematic Wiring Diagram

Diagram 12.1

27 221879A

12 Fault Finding

12.1 Digital Display - Fault Codes

If a fault has occurred during operation of the boiler the display
will start flashing. Two numbers will alternate to show what type
of fault has occurred. The second number has a decimal point
after it.

After correcting the fault, press the ‘reset’ button to restart the
boiler.

Fault Code = 0 and 0.

There is a flame signal without there being a flame present.
Press the 'reset' button.
If the fault recurs, check the ignition electrode and wire.
Check to see if there is 24V a.c. on the gas valve.
If there is 24V a.c. at the gas valve then replace the Automatic

control module, see section 13.4.
After replacing the Automatic Control Module, press the 'reset'

button and check that the boiler functions correctly. Check that
flames extinguish correctly and that after heating demand is
complete there is not 24V a.c. present at the gas valve.

Fault Code = 0 and 2.

There is no flame ionisation.
This fault code may appear on commissioning the boiler and

may simply due to the presence of air in the gas line.
Press the 'reset' button and the ignition phase will be repeated.
If the problem recurs, then proceed as follows:
Check that the gas supply to the boiler is turned on.
Check that during the ignition phase there are sparks present at

the electrode.
Check that the spark gap of the electrode is correct, see section

11.4.
Check that the resistance of the ignition wire is less than 1000

ohms. If the resistance is too high, change the lead. See section

13.3.
Re-check to see if sparks are present at the electrode. If not

check the electrode and change if necessary, see section 13.2.
If there is still no spark at the electrode then the Automatic

Control Module needs replacing, see section 13.4.
If the burner lights but the flame is not detected, the CO

may be too low to sustain combustion. Refer to section 11.6. Try
turning the adjustment screw clockwise to increase the CO
content. If the burner flame is still not detected, then the
Automatic Control Module needs replacing. Refer to section

13.4.
If the gas valve setting has been adjusted in any way, the CO

value must be reset to the correct value. See section 11.6.

Fault Codes = 0 and 3., 0 and 5., 0 and 6., 0 and 7., 1 and

1

., 1 and 3., 1 and 4., 1 and 5.,1 and 6., 1 and 7., 4 and 1., 4 and

2

. and 6 and 0.

There is an internal fault in the Automatic Control Module.
Try pressing the 'reset' button.
If the fault is not cleared, the Automatic Control Module should

be replaced. Refer to section 13.4.

Fault Codes = 0 and 4.

Power supply has been interrupted.
This fault code may appear on first commissioning the boiler, or

if the power is interrupted while the boiler is in operation.

level

2

Press the 'reset' button.
If the fault code is not removed then an internal fault has

occurred in the Automatic Control Module.
Refer to section 13.4 and replace the module.

Fault Code = 2 and 4.

The heating flow thermistor and heating return thermistor are
connected the wrong way round.

Exchange the thermistor positions or their wiring.

Fault Code = 3 and 0.

There is excessive temperature difference between the flow
and return thermistors.

Check that the pump is functioning correctly.
Check that the system is not air locked.
Check that the flow rate through the installation is high enough.

Refer to section 4.3.

Fault Code = 3 and 1.

The heating flow thermistor is short circuited.
Check the wiring between the thermistor and the Automatic

Control Module for a short circuit.
If the wiring is sound, change the thermistor. Refer to

section 13.5.

Fault Code = 3 and 2.

The heating return thermistor is short circuited.
Check the wiring between the thermistor and the Automatic

Control Module for a short circuit.
If the wiring is sound, change the thermistor. Refer to

section 13.6.

Fault Code = 3 and 6.

The heating flow thermistor is too resistant.
Check that the wiring has not become disconnected
If the wiring is sound, change the thermistor. Refer to

section 13.5.

Fault Code = 3 and 7.

The heating return thermistor is too resistant.
Check that the wiring has not become disconnected.

2

If the wiring is sound, change the thermistor. Refer to
section 13.6.

Fault Code = 0 and 8.

The Air pressure switch has not closed.

2

Check that the air pressure switch is functioning correctly.
Switch off the electrical supply to the boiler. Remove the
sensing pipe from the fan elbow and gently suck on the pipe.
The air pressure switch should click shut. Immediately crimp the
sensing pipe and note whether the air pressure switch holds
pressure. A new air pressure switch is required if under these
conditions the switch drops to open circuit within a few seconds
of crimping the pipe. See section 13.16 for replacement.

Reconnect the sensing pipe to the fan elbow and switch on the
electric mains supply. If the boiler does not fire check the
following.

Check that the condense drain is not blocked and backing up
into the heat exchanger. See section 11.5 for instructions on
cleaning.

Check for any obstruction to the flue system internally.
Check the fan and burner cleanliness as in section 11.3.

221879A

28

12 Fault Finding

If after checking all previous points the error code is still present,
this suggests that the heat exchanger has become partially
blocked. See section 11.9 for major service of heat exchanger.

Fault Code = 2 and 8.

The fan is stationary or there is no fan speed signal.
Check the wiring to the fan.
Check the fan and replace as necessary. See section 11.3 for

fan removal.

Fault Code = 2 and 9.

The fan is stationary and open circuit.
Check the wiring to the fan.

Fault Code = 1 and 8.

The heating flow thermistor is detecting a temperature in
excess of 100°C.

Check that the pump is functioning correctly.
Check that the system is not air locked.
Check that the flow rate through the installation is high enough.

Refer to section 4.3.

Fault Code = 1 and 9.

The heating return thermistor is detecting an excessive
temperature.

Check that the pump is functioning correctly.
Check that the system is not air locked.
Check that the flow rate through the installation is high enough.

Refer to section 4.3.

Fault Code = 2 and 5.

The rate of temperature rise measured by the heating flow
thermistor is too high.

Check that the pump is functioning correctly.
Check that the system is not air locked.
Check that the flow rate through the installation is high enough.

Refer to section 4.3.

12.2 Central Heating

If the central heating fails to operate, or the temperature
provided is poor, check the following:

Check that all external controls are calling for heat.
Check that the boiler controls are set correctly, see section 10.

Increase temperature or return to 'Normal mode'
if necessary.

,

12.3 Thermistor Characteristics

Both thermistors used on the boiler can be checked for accuracy
against the chart below if their performance is suspect.

Temperature ˚C Resistance (Ohms)
0 35400
10 22500
20 14700
25 12000
30 9835
40 6712
50 4672
60 3311
70 2388
80 1749
90 1300
100 980
110 749

The thermistors should be checked at both hot and cold
temperatures.

12.4 Combustion

If the combustion CO2 measured during servicing in section

11.6 is too high and cannot be adjusted, or the CO levels
measured at full rate are unacceptable, then the following
possibilities should be investigated and cured.

A. Check the flue system has been correctly installed and that
both air and flue ducts are unobstructed internally, see section

6.5.
B. Ensure that correct terminal clearances are observed and

that product recirculation is impossible, see section 3.3.
C. Ensure that the condensate drain is not blocked. Refer to

section 11.5 for cleaning of the condensate drain and section

13.17 for removal if faulty.
D. Check the condition of the burner and clean or replace as

directed in section 11.3.
E. Check and clean the air inlet to the fan and check that the

seals are in good condition as directed in section 11.3.
F. If after checking all previous points the heat exchanger may

have become partially blocked, see section 11.9 for major
servicing of the heat exchanger.

12.5 Operating Procedure

Refer to sections 10.7 to 10.11 if necessary to check for correct
operation of the central heating.

29 221879A

13 Replacement of Parts

13.1 General

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

Before replacing any parts the boiler should be isolated from the
mains electric supply and the gas should be turned off at the
service cock on the boiler, see diagram 7.1.

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

After replacing any parts always test for gas soundness and if
necessary carry out functional test of the controls.

For replacement of parts the front casing of the boiler will need
to be removed, see section 11.1.

13.2 Spark Electrode

Replace the spark electrode as described in section 11.4.

13.3 Ignition Lead

Pull the spark plug style connector off the spark electrode and
the spade connector connected to the top of the grey ignition
coil.

13.4 Automatic Control Module

Pull the spark plug style connector of the ignition lead off the
spark electrode.

Carefully remove the ribbon wire from the display connection on
the front face of the unit.

Undo and remove the retaining screw from the top corner of the
module.

Pull the Automatic control module forwards and upwards out of
its bracket and remove the electrical connections from the
underside of the module.

Remove the ignition lead from the module and push onto
replacement unit.

Note that the electrical connections are unique to prevent
incorrect fitting.

The Ribbon wire connection must be fitted to the lower socket
on the module marked ‘DISPLAY’.

HEATING FLOW
THERMISTOR

SCREW

ELECTRICAL
CONNECTION

(2 OFF)

SECURING
BRACKET

Diagram 13.1

ELECTRICAL
CONNECTION

(2 OFF)

THERMISTOR
CLIP

9063

6567

13.5 Heating Flow Thermistor

Refer to diagram 13.1.
The heating flow thermistor is situated on the front of the

combustion chamber directly above the spark electrode.
Remove the electrical connections from the thermistor.
Undo and remove the screw and securing bracket.
Fit the replacement thermistor using the heat sink compound

supplied.
Note that the polarity of the wiring to thermistors is unimportant.

13.6 Heating Return Thermistor

Refer to diagram 13.2.
The heating return thermistor is located on the pipe running

from the pump to the heat exchanger.
Remove the thermistor clip by pulling it forwards from beneath

the pipe.
If this thermistor clip is tight it may be necessary to remove the

pump for easier access. See section 13.11.
Remove the thermistor and clip from the boiler.
Disconnect the electrical connections from the thermistor.
Push the thermistor out of its clip.

HEATING RETURN
THERMISTOR

Push the replacement thermistor into the clip and apply heat
sink compound supplied.

Ensure that the thermistor is correctly located on the flat on the
return pipe and push the thermistor clip into place.

Note that the polarity of the wiring to thermistors is unimportant.

Diagram 13.2

13.7 Gas Injector

Remove the injector pipe as described in section 11.3.
Undo and remove the injector from the outlet of the Gas valve,

see diagram 11.2.
Fit replacement injector into gas valve using a suitable sealant.
Do not over tighten.

13.8 Gas Valve

Remove the injector pipe as described in section 11.3.
Remove the gas injector as described in section 13.7.
Remove the electrical connections from the gas valve, see

diagram 10.2.
Undo the gas pipe nut from beneath the base panel.

221879A

30

13 Replacement of Parts

Undo and remove the two securing screws from beneath the
base panel.

Remove the gas valve.
After replacing the gas valve the combustion CO

be checked and adjusted if necessary, see section 11.6.

will need to

2

13.9 Fan

Remove fan as described in section 11.3.

13.10 Burner

Remove fan and burner as described in section 11.3.

13.11 Pump

Refer to section 11.8 and drain the boiler heating circuit.
Undo the pump union nuts.
Unscrew the electrical cover from the pump and remove wiring.
Fit the new pump and refill, vent and pressurise the boiler.
Check for leaks.

13.12 Pressure Relief Valve

Refer to section 11.8 and drain the boiler heating circuit.
Undo the pressure relief valve unions and remove from the

pipework.
Fit new pressure relief valve.
Refill, vent and pressurise the boiler.
Check for leaks.

13.13 Pressure Gauge

Refer to section 11.8 and drain the boiler heating circuit.
Undo the union to the return pipe.
Push the pressure gauge out of the controls fascia while

depressing the retaining lugs behind the fascia, see diagram

13.3.
When replacing the gauge, ensure that the location pin engages

in the slot in the fascia.
Refill, vent and pressurise the boiler.
Check for leaks.

RETAINING
LUGS

SLOT

PRESSURE
GAUGE

Remove the ignition electrode as described in section 11.4.
Remove the pump as described in section 13.11.
Remove the automatic control module as described in section

13.4.
Remove the air pressure switch as described in section 13.16.
Remove the wire clip on the internal flue adaptor pipe and pull

the adaptor pipe down into the flue outlet pipe, see diagram 6.5.
Pull the flue outlet pipe out of the heat exchanger.
Remove the automatic air vent pipe from the top right hand side

of the heat exchanger.
Pull the condensate pipe off the top of the condensate siphon.
Unscrew the heat exchanger condense pipe from the base of

the heat exchanger.
Undo the heat exchanger flow pipe connection from the bottom

left hand side of the boiler.
Undo and remove the return pipe locking plate from the rear

panel below the heat exchanger and pull the return pipe down
and out of the casting.

Prise open the heat exchanger retaining clips on the back panel
of the appliance and remove the heat exchanger.

After refitting the heat exchanger , fill, vent and pressurise the
boiler and check for leaks.

LOCATION
PIN

Diagram 13.3

9253

13.14 Expansion Vessel

Refer to section 11.8 and drain the boiler heating circuit
Undo the coupling at the base of the vessel.
While holding the vessel undo the securing bolt on the top panel

of the boiler. Remove the expansion vessel from the boiler
taking care not to lose the securing bolt spacer from the top of
the unit.

Fit the replacement unit ensuring that the securing bolt spacer
is in position and the securing bolt passes through it.

Refill, vent and pressurise the boiler.
Check for leaks.

13.15 Heat Exchanger

Refer to section 11.8 and drain the boiler heating circuit.
The right hand casing panels should be removed as described

in section 11.7.
Remove the gas valve as described in section 13.8.
Remove the fan and burner as described in section 11.3.
Remove the central heating flow thermistor as described in

section 13.5.

13.16 Air Pressure switch

Remove the sensing tube from the air pressure switch.
Disconnect the wires. Unclip the air pressure switch from its
plastic retaining clip. Fit the new air pressure switch with the
sensing pipe connections downwards, see diagram 13.4.

13.17 Condensate siphon

See diagram 8.1.
Unscrew the drain cap on the siphon and drain off the

condensate. Disconnect the drain pipe from the outlet of the
siphon. From underneath the baseplate, unscrew the two
condensate siphon securing screws. Pull the condensate siphon
trap away from the bottom of the appliance and disconnect the
heat exchanger condensate pipe.

Check the condensate siphon gasket and if necessary replace
prior to refitting the assembly.

Insert the heat exchanger condensate pipe onto the trap and
siphon assembly prior to fixing to the boiler base. Ensure pipe
is not kinked after trap/siphon has been refitted.

Refill the condensate siphon as recommended in section 8.4.

31 221879A

13 Replacement of Parts

13.18 Display PCB

Unscrew the two securing screws, one on the top front edge of
the base panel and the second on the bottom edge of the base
panel. Carefully remove the ribbon wire plug from the display
PCB. Unclip the PCB from its four retaining pillars on the PCB
cover.

When refitting the PCB and cover to the appliance base panel
be careful not to trap the ribbon wire behind the cover. The
ribbon wire should exit from the right hand side of the cover.

13.19 Control Door

Open the control door and pull the brass lugs out of their
locations in the fascia, see diagram 10.3.

13.20 Spare Part LIst

Key No. Part No. Description GC Part No.

1 801145 Gas control valve E24434
2 ********* Automatic control module *********
3 801029 Ignition lead E24243
4 801112 Electrode E24371
5 801049 Pump E24288
6 801034 Heating flow thermistor /Heating return thermistor E24250
7 801074 Air pressure switch E24309
8 801142 Burner E24426
9 801275 Injector *********

10 801040 Fan E24259

CLIPS

SENSING
TUBE

AIR PRESSURE
SWITCH

ELECTRICAL
CONNECTIONS

Diagram 13.4

6565

9268

1

2

9

7

8

5

6

4

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

10

3

221879A

32