This is a CAT II2H3+
appliance
USER, INSTALLATION
AND SERVICING
INSTRUCTIONS
Wall hung
combination boilers
SUPPORTED BY
2
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Index
Note
The boiler serial number is marked on the data label attached to the inside of the outer
casing. Refer to the ‘Introduction’ section for a description of the basic functions of the boiler .
The ‘User’ section describes how to safely operate the boiler.
Mandatory warning for CEE countries
WARNING, these appliances were designed, approved and inspected to meet the
requirements of the English market. The identification plate located on the inside of the
appliance certifies the origin where the product was manufactured and the country for
which it is intended.
If you see any exception to this rule, please contact your nearest Stockist.
Thank you in advance for your assistance.
Index
Introduction .......................................... 3
User
instructions ..................................3
Introduction .......................................... 4
Controls and lighting............................. 4
Technical data ..............................7
Installation
instructions ................................ 11
Clearances ......................................... 11
Terminal position ................................ 12
Heating system design....................... 13
Domestic hot water system design..... 13
Boiler connections .............................. 14
Gas connection .................................. 14
Boiler installation ................................ 15
Horizontal flue installation .................. 16
Vertical flue installation....................... 17
Flue configuration ............................... 18
Electrical connection .......................... 19
Commissioning................................... 20
Safety devices .................................... 22
Gas valve setting................................ 23
Adjustments ....................................... 23
Boiler schematic................................. 25
Servicing
instructions ................................26
Routine cleaning and inspection......... 27
Replacement of parts ......................... 28
Schematic wiring diagram .................. 31
3
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User instructions
Introduction
The icon 23 t and icon 28 t boilers are wall mounted combination boilers providing central
heating and instantaneous domestic hot water.
The boilers are of the II2H3+ category for use with Natural gas (G20) as distributed in the United
Kingdom.
These instructions should be carefully followed for the safe and economical use of your boiler.
The boiler has a fan assisted balanced flue which both discharges the product of combustion to,
and draws the combustion air from the outside of the building.
ACCESSORIES
A range of accessories are available including vertical flue components. For further information,
contact you nearest Stockist.
GAS SAFETY (INSTALLATION AND USE) REGULATIONS
In your interests and that of gas safety, it is the law that ALL gas appliances are installed and
serviced by a competent person in accordance with the above regulations.
GAS LEAK OR F AULT
If a gas leak or fault exists or is suspected, turn the boiler off and consult the local gas company or
your Installer/Service Provider.
BOILER CONTROLS
The control panel, located at the lower front of the boiler , allows the boiler to be started, shut down,
controlled and monitored during use, refer to ‘User Instructions’.
User
instructions
4
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User instructions
Introduction
The icon 23 t and icon 28 t boilers are wall mounted combination boilers providing central
heating and instantaneous domestic hot water.
These instructions should be carefully followed for the safe and economical use of your boiler .
GAS LEAK OR F AULT
If a gas leak or fault exists or is suspected, turn the boiler off and consult the local gas company or
your Installer/Service provider.
IN CASE OF POWER SUPPLY F AILURE
The boiler no longer operates.
As soon as power supply is restored, the boiler will restart automatically.
IN CASE OF LOSS OF W ATER IN THE SYSTEM
CAUTION: The boiler is installed as part of a sealed system which must only be drained and
filled by a competent person.
If the pressure shown on the pressure gauge is less than 1 bar the system must be filled up
immediately.
Important notice: A central heating system cannot operate satisfactorily unless it is properly filled
with water and unless the air initially contained in the piping systems has been properly bled off. If
these conditions are not satisfied, air noise will occur within the system.
AIR IN THE HEATING SYSTEM
Persistent air in the heating system may indicate leaks in the system or corrosion taking place. Call
your Installer/Service provider.
OVERHEATING SAFETY
In the event of problem, the overheat safety device causes
safety shutdown of the boiler. If this happens, call your Installer/Service provider.
Controls and lighting
The control panel, located at the lower front of the boiler
casing, see diagram, allows the boiler to be started, shut
down, controlled and monitored during use.
Make sure that:
— The boiler is connected to the electrical supply.
— The boiler gas service cock is open.
— The pressure gauge reads between 1 and 2 bar .
The boiler is now ready to start.
5
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User instructions
Controls
1 Safety lockout light
2 Summer/Winter switch
3 Heating temperature control
4 Hot water temperature control
5 Pressure gauge
6 Timeclock
7 Plastic toggles
TO START THE BOILER
Turn selector (2) to the desired Summer
or Winter position.
The green lamp
will light.
TO STOP THE BOILER
Turn selector (2) to the OFF position (0).
If the boiler is to be out of operation for a long period, turn off the gas service cock.
SETTING TO ‘SUMMER’ MODE (HOT W ATER ONLY)
Turn selector (2) to the Summer position
.
Adjust the domestic hot water control
(4) to the desired hot water temperature. The boiler will
operate according to the system requirements.
SETTING TO ‘WINTER’ MODE (HEATING AND HOT WATER)
Turn selector (2) to the Winter position
.
Adjust the heating temperature control
(3) to the desired temperature.
Adjust the domestic hot water control
(4) to the desired hot water temperature. The heating
will operate according to the requirements of the timeclock and room thermostat if fitted or, will
operate according to the system requirements.
Domestic hot water always has priority over central heating.
TO PROGRAM DAIL Y TIMECLOCK (6) (WINTER MODE ONLY)
Set the current time, by turning the dial clockwise until the current time is shown against the
indicator “
”.
Push in plastic toggles (7) against the time you wish the heating to come on.
The timeclock can operate in three positions: automatic “
”, heating off “0”, and heating on “1”.
To select, move the lever to the desired position.
NOTE: In case of failure of electrical supply, timeclock does not operate, having no back-up bat-
tery . Therefore it will be necessary to adjust the current time, once electrical supply is restored.
6
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User instructions
SAFETY LOCKOUT
If, for any reason, the boiler does not operate, check if lockout lamp
(1) is lit. If so, turn
selector (2) to the reset position . The selector is spring loaded and automatically returns to
its’ previous position when released.
Note: This lamp will only light if the boiler has locked out and there is a hot water or central heating
demand at that particular time.
IMPORT ANT: If the safety lockout lamp lights frequently, contact your Installer/Service Provider.
DRAINING AND FILLING
CAUTION: The boiler is installed as part of a sealed system which must only be drained and
filled by a competent person.
Note: If there is persistent loss of system pressure, you must consult your Installer/Service Pro-
vider.
HEA TING SAFETY VALVE
CAUTION: A safety valve with a discharge pipe is fitted to this boiler.
The valve MUST NOT BE TOUCHED except by a competent person. If the valve discharges at any
time, switch the boiler off and isolate it from the electrical supply. Contact your Installer/Service
Provider.
SERVICING/MAINTENANCE
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.
CLEANING
The boiler casing can be cleaned with a damp cloth followed by a dry cloth to polish.
Do not use abrasive or solvent cleaners.
BOILER CASING
CAUTION: Do not remove or adjust the casing in any way , as incorrect fitting may result in
faulty operation.
If in doubt, contact your Installer/Service Provider.
7
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T echnical data
Technical
data
8
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T echnical data
ATADLACINHCETtinU
t32nocit82noci
noitacifitreCEC°n7424TA36005992LB4960
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)sH(tupnItaeH.xaMWk4.8253
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)iH(tuptuOtaeH.xaMWk3.321.82
)iH(tuptuOtaeH.niMWk7.811
YCNEICIFFE
ycneiciffelanimoN%293.29
daol%03taycneiciffE%4.7809
GNITAEH
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lessevnoisnapxEl68
erusserplessevnoisnapxErab1 1
erusserpgnikrow.xaMrab5.25.2
erutarepmetmetsys.xaMC°5858
RETAWTOH
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wolfretaw.niMnim/l5.25.2
erusserpylppus.xaMrab6 6
erusserpylppus.niMrab4.04.0
egnarerutarepmeTC°56-5356-53
ATADLACIRTCELE
ycneuqerf/egatloVzH/V05/03205/032
rewoPW051071
noitcetorpfoleveLPI4444
SNOISNEMID
htdiWmm004054
thgieHmm007007
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teltuo/telniretaWcitsemoDmmmm51mm51
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T echnical data
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DIMENSIONS CONNECTIONS FOR FLUE
10
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T echnical data
HEATING
DOMESTIC
WATER
GAS
BOILER SCHEMATIC
1 By-pass
2 Pump
3 Drain valve
4 Expansion vessel
5 Gas valve
6 Burner
7 Primary heat exchanger
8 Flue hood
9 Air pressure switch
10 Automatic air vent
11 Fan
12 Loss of water switch
13 Heating system safety valve 3 bar
14 Hydraulic 3-way valve
15 Domestic heat exchanger
16 Water valve
RETURN
FLOW
OUTLET
INLET
AVAILABLE PUMP CAPACITY
1–icon 23 t (Automatic By-Pass)
2–icon 28 t (Automatic By-Pass)
Water flow l/h
Pressure m. H
2
O
11
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Installation instructions
Installation
instructions
Clearances
The boiler can be installed with the following clearances:
5 mm either side if the boiler
600 mm to the front of the boiler
150 mm below the boiler
200 mm above the boiler
The above clearances are minimum clearances, consideration must be given to allow adequate
space for servicing.
The recommended servicing clearances are:
50 mm either side if the boiler
600 mm to the front of the boiler
150 mm below the boiler
200 mm above the boiler
CUPBOARD OR COMP ARTMENT VENTILA TION
The boiler can be installed in a cupboard or compartment without the need for high or low level
ventilation
12
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Installation instructions
A
B
P
O
N
C
M
F
E
D
I
H
L
G
Terminal position
The minimum acceptable spacings from the terminal to obstructions and ventilation openings are
shown in the diagram below:
MINIMUM DIMENSIONS (in mm) FOR THE POSITIONING OF FLUE TERMINALS
A Under a window 300
B Under an air vent 300
C Under a gutter 75
D Under a balcony 300
E From an adjacent window 300
F From an adjacent air vent 300
G From vertical drain pipes or soil pipes 75
H From an external corner of the building 300
I From an internal corner of the building 300
L From the ground or from another floor 300
M Between two terminals vertically 1500
N Between two terminals horizontally 300
13
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Installation instructions
Heating system design
The icon 23 t and icon 28 t are compatible with any type of installation.
The heating surfaces may consist of radiators, convectors or fan assisted convectors.
Pipe sectional areas shall be determined in accordance with normal practices, using the pump
curve, refer to ‘Technical Data’. The distribution system shall be calculated in accordance with the
output requirements of the actual system, not the maximum output of the boiler. However, provision shall be made to ensure sufficient flow so that the temperature difference between the flow
and return pipes is less than or equal to 20
o
C. The minimum flow is 420 l/h.
The piping system shall be routed so as to avoid any air pockets and facilitate permanent venting
of the installation. Bleed fittings shall be provided at every high point of the system and on all
radiators.
The total volume of water permitted for the heating system depends, amongst other things, on the
static head in the cold condition. The expansion vessel on the boiler is pressurised at 1 bar (corresponding to a static head of 5m wg.) and allows a maximum system volume of 190 litres for an
average temperature of 75
o
C and a maximum service pressure of 3 bar. This pressure setting can
be modified at commissioning stage if the static head differs.
Provision shall be made for a drain valve at the lowest point of the system.
Where thermostatic radiator valves are fitted, not all radiators must be fitted with this type of valve
and particularly where the room thermostat is fitted.
A suitable WRC approved filling loop must be fitted to enable correct filling of the system.
In all cases, it is ESSENTIAL that the system be thoroughly flushed prior to installing the new
boiler.
Domestic hot water system design
Copper tubing or plastic HeP2O may be used for the domestic hot water system. Unnecessary
pressure losses should be avoided.
The domestic hot water supply pressure must be between 1 and 6 bar. If the pressure exceeds 6
bar, a pressure reducing valve must be fitted.
HARD W ATER AREAS
In areas where the water hardness exceeds 200mg/litre, it is recommended that a suitable scale
reducing device is fitted.
14
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Installation instructions
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Boiler connections
Heating system connections Pipe diameter 22 mm.
Hot water system connections Pipe diameter 15 mm.
Gas connection Pipe diameter 15 mm.
A Heating return
B Heating flow
C Hot water outlet
D Cold water mains inlet
E Safety valve discharge connection
F Gas connection
SAFETY V ALVE DISCHARGE
WARNING: It must not discharge above an
entrance or window or any type of public
access area.
Connect the safety valve discharge pipe to the valve, the discharge must be extended using not
less than 15 mm o.d. pipe, to discharge in a visible position outside the building, facing downward,
preferably over a drain. The pipe must have a continuous fall and be routed to a position so that any
discharge of water, possibly boiling or steam, cannot create any danger to persons, damage to
property or external electrical components and wiring. Tighten all pipe connection joints.
Gas connection
The supply from the governed meter must be of adequate size to provide a constant inlet working
pressure of 20 mbar (8 in wg).
To avoid low pressure problems, it is recommended that the supply is taken to the boiler using 22
mm pipe as far as possible.
On completion, the gas installation must be tested using the pressure drop method and purged in
accordance with the current issue of BS6891.
WARNING: While connecting gas inlet pipe of the boiler to the pipe coming from gas network,
it is MANDATORY to insert a TIGHT GASKET, whose dimensions and material must be
adequate. Connection is NOT suitable for hemp, teflon strip or similar materials.
GAS SAFETY (Installation and Use) REGULATIONS.
In your interests and that of gas safety, it is the law that ALL gas appliances are installed and
serviced by a competent person in accordance with the above regulations.
15
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Installation instructions
ST A TUTOR Y REQUIREMENTS
The installation of this boiler must be carried out by a competent person in accordance with the
relevant requirements of the current issue of:
— The Gas Safety (Installation and Use) Regulations
— The Building Regulations
— The local water company Bylaws
— The Building Standards Regulations (Scotland)
— The Health and Safety at Work Act
SHEET META L PARTS
WARNING: When installing or servicing this boiler , care should be taken when handling the
edges of sheet metal parts to avoid the possibility of personal injury.
INST ALLING THE BOILER
Prior to starting work, the system must be thoroughly flushed to eliminate any foreign bodies and
contaminents such as filings, solder, particles, oil, grease etc.
Note: Solvent products could cause damage to the system.
Boiler installation
To install the boiler, proceed as follows:
— Allowing sufficient clearances for servicing/repair ,
place the template on the wall (see diagram below).
— Determine the position of the flue hole and drill
hole for flue, preferably using a 120 mm core drill.
— Drill two 8mm holes for the wallplugs (supplied).
— Screw fixing screws (supplied) into wallplugs, leave
proud by approx. 10 mm.
Note: Boiler fixing holes are keyhole type slots to al-
low easy hanging of boiler.
— Remove template.
— Hang the boiler on the screws and tighten screws.
— Connect system pipework and gas connection.
Note:
1. The template is only used as a guide, it can be
removed prior to fitting the boiler.
2. Remove the plastic caps from the boiler connec-
tions prior to connecting boiler to the pipework.
P
P
PP,FRQW
PP,FRQW
P
P
PP
PP,FRQ W
PP,FRQ W
PP,FRQ W
PP,FRQ W
PP
),;,1*+2/(6PP
,FRQ W
,FRQ W
BOILER TEMPLA TE
16
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Installation instructions
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Horizontal flue installation
A Gasket
B 90
°
bend
D ‘O’ ring
E Collar
F Clamp
H Screws
I Air inlet pipe
M External sealing collar
N T erminal
O Screws
P Inner elbow
Q Inner pipe
R Clip
— Fit gasket (A) onto underside of flue elbow (B).
— Fit elbow onto top of boiler ensuring it locates correctly onto fan outlet.
— Carefully insert ‘O’ ring (D) into inner elbow (P).
— Fit external sealing collar (M) onto air inlet pipe (I).
— Fit flue through hole in wall and pull up so that external collar (M) is flush against outside wall.
— Fit collar (E) and clamp (F) to flue and assemble into elbow (B) making sure that both inner and
outer pipes are sealed properly.
NOTE: Maximum horizontal length with no additional bends is 3m.
— Tighten up clamp using screws and nuts provided (H & G).
Note: Should it be necessary to cut the flue, always cut equal amounts from both inner and outer
pipes. Always cut the end furthest from the terminal.
For each 90o flue bend fitted, reduce overall flue length by 1 m.
For each 45o flue bend fitted, reduce overall flue length by 1/2 m.
Flue accessory Cat No.
C Flue extension kit 885117
D90
o
bend kit 885118
E45
o
bend kit 885119
17
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Installation instructions
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Vertical flue installation
A Gasket
B Vertical adaptor
D ‘O’ ring
E Collar
L Terminal
M Screws
— Fit gasket (A) onto underside of vertical adaptor (B).
— Fit vertical adaptor onto top of boiler ensuring it locates correctly onto fan
outlet.
— Carefully insert ‘O’ ring (D) into vertical adaptor inner spigot.
— For flat roof installation, fit flat roof flashing collar (part no. 885121)
— Fit flue terminal (L) onto roof ensuring flashing makes a watertight joint.
— For pitch roof installation, fit pitch roof flashing collar (part no. 885120)
— Fit flue terminal (L) onto roof ensuring flashing makes a watertight joint.
— Fit collar (E) to vertical flue pipes and assemble between terminal (L)
and vertical adaptor (B) making sure that both inner and outer pipes
are sealed properly.
NOTE: Maximum vertical height with no bends is 4m.
— Tighten up clamp using screws provided (H).
Note: Should it be necessary to cut the flue, always cut equal amounts
from both inner and outer pipes.
For each 90o flue bend fitted, reduce overall flue height by 1 m.
For each 45o flue bend fitted, reduce overall flue height by 1/2 m.
Vertical flue kit 885116
Flue accessory Cat. No.
A Pitched roof flashing 885120
B Flat roof flashing 885121
C Flue extension kit 885117
D90
o
bend kit 885118
E45
o
bend kit 885119
18
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Installation instructions
Flue configuration
ATTENTION
If coaxial system would have a total length lower than 2 linear meters (n°1 additional bend = 0.5 linear meters), it will
be necessary to install the diaphragm supplied with the
gas boiler , as indicated in the figure besides
'LDSKUDJP
19
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Installation instructions
Electrical connection
It is important that the mains supply is wired with correct polarity: brown to LIVE, blue to
NEUTRAL.
Warning: This boiler must be earthed.
All system components must be of an approved type.
Connection of the whole electrical system and any heating system controls to the electrical supply
must be through a common isolator.
Isolation should preferably be by a double pole switched fuse spur box having a minimum contact
separation of 3 mm on each pole. The fused spur box should be readily accessible and preferably
adjacent to the boiler. It should be identified as to its use.
A fused three pin plug and shuttered socket outlet may be used instead of the fused spur box,
provided that:
a) They are not used in a room containing a bath or shower.
b) Both the plug and socket comply with the current issue of BS1363.
The mains electrical supply must be maintained at all times in order to provide domestic hot water .
DO NOT INTERRUPT THE MAINS SUPPL Y TO THE BOILER WITH A TIME SWITCH OR PROGRAMMER.
The icon 23 t and icon 28 t are delivered with an integral mains supply lead AND an integral
external controls lead.
EXTERNAL CONTROLS
The boiler will work for heating AS
DELIVERED without a room ther-
mostat fitted provided the two wires
on the integral external controls
lead REMAIN LINKED TO-
GETHER (as supplied).
If a room thermostat is required, it
must be connected to the external
controls lead as shown below, using a suitable electrical connection.
ANY ROOM THERMOST A T MUST
BE OF THE VOL T AGE FREE TYPE.
Note: For further information, see The Building Regulations 1991 – Conservation of fuel and power –
1995 edition – Appendix G, table 4b.
ON NO ACCOUNT MUST ANY ELECTRICAL VOLTAGE BE APPLIED TO EITHER OF THE
TERMINALS OF THE WHITE EXTERNAL CONTROLS LEAD
WARNING: This boiler must be wired in accordance with these instructions. Any fault arising from incorrect wiring may invalidate the terms of the guarantee.
BOILER
BLACK MAINS LEAD WHITE EXTERNAL CONTROL LEAD
FUSED MAINS
SPUR OR
FUSED 3 PIN
PLUG
VOLTAGE FREE
ROOM THERMOST A T
617
icon 23 t
icon 28 t
20
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Installation instructions
Commissioning
The commissioning and first firing of the boiler must only be carried out
by a competent person.
ACCESS FOR ADJUSTMENT
1. Remove the lower grille, remove two screws securing outer casing. Re-
move casing by lifting up and forwards.
2. Unscrew 6 screws securing inner casing and remove casing.
3. After commissioning, replace all items in reverse order to removal.
GAS INST ALLATION
It is recommended that any air is purged from the supply at the gas inlet test
point on the gas valve, see diagram below .
FILLING THE SYSTEM
— Open isolating valves (see “Boiler connections”, items A,
B and D) and cap on automatic air vent inside sealed chamber .
— Fill system by opening system filling loop until a pressure
of between 1 and 2 bar is shown on the boiler pressure
gauge.
— Bleed each radiator until a continuous jet of water is ob-
tained.
— Do not close automatic air vent cap.
— Open various hot water taps to bleed system.
— Make sure that pressure gauge reads between 1 and 2
bar. Re-pressure as necessary.
Important: When venting air from boiler, do not touch the
schrader valve on the expansion vessel, it is NOT a vent.
ST ARTING THE BOILER
Before starting the boiler check that:
— The gas meter tap is open.
— The boiler gas service cock is open.
— The water isolating cocks are open.
— The boiler is connected to the electrical supply.
1 Outlet test point
2 Inlet test point
3 Vent
21
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Installation instructions
FIRST STARTING UP
— Set boiler to run in central heating as described in ‘Users Instructions’.
— Set heating temperature control to maximum temperature and check that any external con-
trols, if fitted, are calling for heat.
— Allow the temperature to rise to the maximum value, with all radiator valves open. The tem-
perature rise will cause release of the gases contained in the water of central heating system.
• Gases driven towards the boiler will be automatically released through the automatic air
vent.
• The gases trapped at the highest point of the system must be released by bleeding the
radiators.
— On reaching maximum temperature, the boiler should be turned off and the system drained
as rapidly as possible whilst still hot.
— Refill system to a pressure of 1 bar and vent as before.
— Restart boiler and operate until a maximum temperature is reached. Shut down boiler and vent
heating system. If necessary , top up heating system and make sure that a pressure of 1 bar is
indicated on the pressure gauge when system is COLD.
GAS PRESSURES
— Shut down boiler.
— Undo screw on gas inlet test point ‘2’ on gas valve.
— Connect a suitable pressure gauge.
— Start boiler as described in “Users Instructions”.
— Check that there is a constant pressure of 20 mbar. If the pressure is insufficient, it is neces-
sary to check the gas supply/pipework and correct any fault.
— Shut down boiler.
— Remove pressure gauge, tighten up test point screw and check for gas soundness.
ACCESS FOR ADJUSTMENT
1. Remove the lower grille, remove two screws se-
curing outer casing. Remove casing by lifting up
and forwards.
2. Unscrew 6 screws securing inner casing and re-
move casing.
3. Loosen, but do not remove, the two knurled nuts
securing controls housing to boiler (behind control
panel).
4. Lift controls housing from bracket and remove rear
cover.
5. After commissioning, replace all items in reverse
order to removal.
22
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Installation instructions
SETTING THE CENTRAL HEATING OUTPUT
The central heating output must be set in accordance with the system requirements. To adjust the
burner pressure, proceed as follows, referring to the tables listed in ‘Technical Data’:
— Gain access to the PCB, see diagram above.
— Set the “summer/winter” switch to the “winter” position
— Light the burner and check the gas pressure
— Adjust the pressure using potentiometer P1 on the PCB.
— Refit cover to controls housing.
DOMESTIC HOT WATER FLOW ADJUSTMENT
The domestic hot water flow rate is factory set. However , after installation, it may be necessary to
adjust the domestic hot water flow rate, proceed as follows:
— Fully open a domestic hot water tap.
— Using a suitable water flow gauge, adjust water flow by turning the adjuster screw on the water
valve (item G, page 27)
— Nominal water flow rate is 9.6 l/min.
Safety devices
OVERHEAT SAFETY
In the event of problem, the overheat safety device causes safety shutdown of the boiler. In the
event of this, the lockout warning light will illuminate. To clear this, turn the summer/winter switch
fully to the right or left as appropriate. This resets the boiler.
PCB CONTROLS HOUSING
23
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Installation instructions
Gas valve setting
All boilers are tested and factory set during manufacture. Should it be necessary to reset a gas
valve, for example after replacement, proceed as follows:
MAX/MIN. DOMESTIC HOT W ATER OUTPUT ADJUSTMENT
Check that the Inlet pressure is correct for the type of gas being used.
— Set “Summer/Winter” switch to “Summer” position.
— Open the domestic hot water tap fully , wait for 10 seconds and check gas burner pressure on
test point ‘1’, refer to “Technical data”
To adjust the settings, proceed as follows:
— Verify that the modulation coil is energised
— Remove protection cap (C).
— Set maximum pressure by turning knob (B) with 10 mm span-
ner . Clockwise to increase, anti-clockwise to decrease.
— Remove electrical connector on modulation coil.
— Keeping knob (B) locked, adjust minimum pressure unscrew-
ing screw (A) very slowly, using a 4 mm spanner
— Refit electrical connector and check settings.
— Lock the adjustement device after any setting operation.
Adjustments
SLOW OPENING REGULA TION
Should ignition of the burner be noisy , it will be necessary to adjust the slow opening setting of the
gas valve. This adjustment is made on the PCB.
To adjust the slow opening, proceed as follows:
— Switch off the boiler and isolate from the mains supply.
— Remove control housing cover as described previously.
— Remove jumper S1
— Connect a suitable pressure gauge to the gas valve outlet test point ‘I’
— Switch on the boiler and open an hot water tap, the burner will ignite. The gas pressures should
be as follows:
• NATURAL GAS= 3 mbar (30 mm w.g.)
— Turn potentiometer P3 (clockwise to increase pressure and counterclockwise to decrease
pressure) until the required value is obtained.
— Refit jumper S1.
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Installation instructions
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Installation instructions
1 Air pressure switch
2 Overheat thermostat
3 Expansion vessel
4 Ignition and flame sense electrodes
5 Domestic heat exchanger
6 Gas valve
7 Water valve
8 Hydraulic 3-way valve
9 N/A
10 Drain valve
11 N/A
12 Thermistor
13 Burner
14 Primary heat exchanger
15 Automatic air vent
16 Fan
17 Sealed chamber
18 Pump
19 Loss of water pressure switch
Boiler schematic
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Servicing instructions
Servicing
instructions
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Servicing instructions
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.
It is the law that any servicing is carried out by a competent person.
Routine cleaning and inspection
— Operate boiler and check for any faults that need to be put right.
— Isolate boiler from the gas and electrical supplies.
— On completion check all gas carrying parts for soundness with leak detection fluid.
— Remove boiler casing as follows:
OUTER CASING
Remove the lower grille, remove two screws securing outer casing. Remove casing by lifting up
and forwards.
COMBUSTION CHAMBER
— Unscrew and remove 6 screws securing sealed chamber cover to boiler. Pull cover forward
and off boiler.
BURNER
— Undo main gas supply nut from burner.
— Pull main burner forward, pull off the ignition and flame
sense leads from the electrodes and remove burner
from boiler.
Note: The washer between main burner and main burner
gas supply must be kept for use on reassembly.
— Remove ignition and flame sense electrodes from
burner.
— Unscrew and remove four injector bar retaining screws and separate injector bar from burner .
— Examine and clean injectors as necessary.
Note: DO NOT use a wire or sharp instrument on the holes.
HEAT EXCHANGER
— Locate the heat exchanger inside the sealed chamber .
— Gain acces to heat exchanger by removing fan and flue hood.
— Examine heat exchanger for any blockages or build up of deposits.
— Clean heat exchanger with soft brush or vacuum cleaner.
REASSEMBLY OF PARTS REMOVED FOR SERVICING
All parts are replaced in reverse order to removal.
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Servicing instructions
FLUE SYSTEM
— Check externally to make sure that flue is not blocked
— Inspect flue system to make sure that all fittings are secure.
OPERA TION OF FAN
— Switch on electrical supply and turn on gas.
— Set selector switch to “Winter”
position.
— Light burner by operating external controls (if fitted) to call for heat.
— Do not light the boiler without the sealed chamber cover fitted
— Check that fan operates when burner light and stops when it goes out.
Replacement of parts
TO REPLACE F AN
— Slide flue sensing probe insulating boot away from fan.
— Pull off both red and white sensing probe tubes.
— Disconnect power supply and earth leads to fan.
— Slacken, but do not remove, two screws securing fan to rear of flue hood.
— Supporting fan, unscrew and remove two screws securing fan to front of flue hood.
— Lower fan from top of boiler then tilt base of fan to right hand side. Gently ease fan forwards
and out of boiler.
— Transfer flue sensing probe assembly onto replacement fan.
— Fit replacement fan in reverse order to removal.
Note: Ensure white air sensing tube is connected to upper probe and red tube to lower probe.
TO REPLACE AIR PRESSURE SWITCH
— Locate air pressure switch in upper right hand corner of sealed chamber.
— Pull off plastic tubes from base of switch.
— Remove electrical connections from switch.
— Unscrew and remove two screws securing switch to upper panel and remove switch.
— Fit electrical connections to replacement switch as follows:
NO - RED
NC - BLACK
C - BLUE
— Fit replacement switch in reverse order to removal.
Important: Refit red tube to right hand connector and white tube to left hand connector .
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Servicing instructions
TO REPLACE PUMP
— Drain down heating circuit only of boiler as follows:
— From below boiler , close isolating valves on flow and return connections to boiler.
— Open boiler drain valve to right of pump.
Note: It is not necessary to drain down entire
heating circuit to carry out this work.
— Unscrew, but do not remove, knurled nuts
at rear of controls housing and lift housing
off bracket and clear of pump.
— Pull off electrical connection to pump.
— Supporting pump, unscrew pump connec-
tion nuts at top and rear of pump. Remove
pump by lifting forward and out of boiler .
— Fit replacement pump in reverse order to
removal.
— Open isolating valves on flow and return connections,
— Refill, vent and pressurise boiler . Check for leaks.
TO REPLACE GAS V AL V E
— Isolate boiler from gas supply.
— Remove controls housing as described in ‘To re-
place pump”.
— Remove clear plastic sensing pipe from gas valve.
— Unscrew and remove upper screw holding gas
valve ignition box onto gas valve body .
— Carefully pull off ignition box, leaving electrical wir-
ing connected, and move clear of gas valve.
— Remove electrical connections to gas valve modu-
lating coil.
— Disconnect gas inlet cock from boiler.
— Undo nuts on gas valve to burner supply pipe and
swing pipe clear of gas valve.
— Unscrew and remove two screws securing gas valve to boiler lower frame.
— Fit replacement gas valve in reverse order to removal.
Note: When refitting electrical connections to gas valve modulating coil, the polarity is not impor-
tant.
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Servicing instructions
TO REPLACE DOMESTIC HEAT EXCHANGER
— Drain down heating circuit of boiler as described previously.
— Drain down hot water circuit of boiler as follows:
— From below boiler, close cold water inlet
isolating valve.
— Open a hot tap to drain hot water circuit.
— Remove clip (A) and pull off microswitch
assembly
— Undo connections (B), (C), (D) and (F) on
3 way valve
— Grasp 3 way valve and lift upwards releas-
ing ‘O’ ring joint (E)
— Remove 3 way valve and domestic heat
exchanger assembly from boiler .
Important: Take care not to drip water into
pub housing when removing assembly .
— Fit replacement heat exchanger in reverse
order to removal.
— Open isolating valves on flow and return connections, refill, vent and pressurise boiler . Check
for leaks.
— Open cold water isolating valve. Check for leaks.
TO REPLACE THERMISTOR
— Locate thermistor clipped onto flow pipe behind pump.
— Pull off clip from flow pipe.
— Remove electrical connections from thermistor.
— Fit replacement thermistor in reverse order to removal.
Note: 1) No heat sink compound is required.
2) The polarity of the connections is not important.
TO REPLACE OVERHEA T THERMOST A T
— Locate overheat thermostat on left hand side of main heat exchanger at rear.
— Remove electrical connections from overheat thermostat.
— Unscrew and remove two screws securing overheat thermostat to heat exchanger .
— Fit replacement overheat thermostat in reverse order to removal.
Note: 1) No heat sink compound is required.
2) The polarity of the connections is not important.
A
F
BC
EGD
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Servicing instructions
Schematic wiring diagram
IG Mains switch
C Pump
E/I Summer/winter selector
PSA Loss of water pressure switch
MOD Modulating coil
S Thermistor
MP Water valve microswitch
CA Ignition and flame control unit
EA Ignition electrodes
ER Flame sense electrode
LN Mains lamp
TS Overheat thermostat
R Lockout reset switch
LB Lockout warning light
MV Fan
MPV Air pressure switch
MO Timeclock
CO Timeclock microswitch
Colours
abbreviations:
BK Black
BN Brown
BU Blue
GN Green
GNYE Green-Yellow
GY Grey
OG Orange
RD Red
VT Violet
WH White
02/2000 COD. 982160005 / REV. 06
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