Saunier Duval SYLVA FF 24 E User guide

Servicing instructions
THIS IS A CAT II2H3+ APPLIANCE
SYLVA
01773 828100
IN WARRANTY
TECHNICAL HELPLINE
01773 828400

2

3
SERVICING INSTRUCTIONS
SYLVA
Note!
The boiler serial number is marked on the label attached to the inside of the door. Refer to the
«Introduction» section page 3 of the Installation and User instructions for a description of the basic
functions of the boiler. The «Users» section describes how to safely operate the boiler.
CONTENTS
Routine cleaning and inspection .................................. Page 4 - 5
Replacement of parts ............................................................... 6 - 9
Domestic hot water thermostat .................................................... 6
Fan .................................................................................................... 6
Air pressure switch .......................................................................... 6
Printed circuit board ...................................................................... 6
Central heating thermistor ............................................................ 6
Central heating temperature control .......................................... 6
Pump ........................................................................................... 6 - 7
Temperature gauge ....................................................................... 7
Pressure gauge ............................................................................... 7
3-way valve head .......................................................................... 7
3-way valve ..................................................................................... 7
Loss of water switch ........................................................................ 7
Gas valve module .......................................................................... 7
Gas valve.................................................................................... 7 - 8
Modulating coil ............................................................................... 8
Central heating safety valve ........................................................ 8
Temperature/pressure relief valve ................................................ 8
Anode .............................................................................................. 8
Heat exchanger ............................................................................. 8
Expansion valve .............................................................................. 8
Central heating expansion vessel ................................................ 9
Domestic expansion vessel ........................................................... 9
High limit thermostat ...................................................................... 9
Combustion chamber insulation .................................................. 9
Burner ............................................................................................... 9
Burner injectors ................................................................................ 9
Ignition/flame sense electrode ..................................................... 9
Boiler schematic ........................................................................... 10
Technical data .............................................................................. 11
Schematic wiring diagram .......................................................... 12
Fault finding ............................................................................ 13 - 16
Spare parts .................................................................................... 16

4
●Remove fan with mounting plate attached by
pulling down and forward out of ‘keyhole’ slots.
●Unscrew and remove two screws securing heat
exchanger inspection plate to flue hood.
●Remove inspection plate by pulling forward and
off 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.
Note:
1) When refitting fan, ensure that it is pushed upwards
as far as the locating lugs will allow.
2) When refitting the ignition and flame detection
leads, the RED lead goes to the REAR electrode and
the WHITE lead goes to the FRONT electrode.
ROUTINE CLEANING AND INSPECTION
To ensure the continued efficient and safe opera-
tion of the boiler it is recommended that it is checked
and serviced at regular intervals. The frequency of
servicing will depend upon the particular installa-
tion 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.
Service Check and Preparation.
●Operate boiler and check for any faults that need
to be put right.
●Isolate boiler from the gas and electrical supplies.
●On completion check all gas carrying parts for
soundness with leak detection fluid.
●The maximum domestic hot water flow rate is 12
litres/minute.
●Remove boiler casing as follows:
Upper front panel
●Remove by pulling free from the spring clips at the
top and bottom.
Side panels
●Remove the four screws securing each panel to the
boiler, two at the top, two at the bottom.
●Lift off panel.
Combustion chamber
●Unclip four toggle clips holding the sealed chamber
cover.
●Unscrew and remove two screws securing sealed
chamber cover to sealed chamber see diag. 1.
●Remove four screws securing combustion chamber
cover to combustion chamber, see diagram 2.
Important: Note position of baffle secured by upper
two combustion chamber cover screws.
●Pull combustion chamber cover down and out of
boiler, taking care not to damage insulating material
on internal faces of combustion chamber.
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
●Disconnect power supply leads from fan by
separating at electrical connector.
●Unscrew, but do not remove, two fan retaining
screws at lower front edge of fan mounting plate.
Diagram. 1
Diagram. 2

5
ROUTINE CLEANING AND INSPECTION
Flue system
●Check externally to make sure that flue is not
blocked
●Inspect flue system to make sure that all fittings are
secure.
Operation 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.
●Without sealed chamber cover in place, burner
should be automatically prevented from lighting by
air flow detection system.
●Refit sealed chamber cover.
●Check that fan operates when burner lights and
stops when it goes out.
Cold water inlet filter
Drain down hot water circuit of boiler only, as follows:
●Close isolating valve (c) on cold water inlet pipe,
see diagram 3.
Note: This valve is closed when lever is at right angles
to direction of flow.
●Open one or more hot water taps to drain boiler
circuit.
●Undo connecting nut from cold water inlet
connection.
●Clean and inspect filter, replace if necessary.
●With both filter and restrictor in place, reconnect
connecting pipe to inlet connection and tighten.
●Fully open isolating valve on cold water inlet and
check for leaks.
Anode
To inspect anode, it is necessary to drain upper sec-
tion only of storage cylinder, preferably when cold.
●Isolate electrical supply to boiler.
●Close isolating valve (c) on cold water inlet pipe,
see diagram 3.
●Drain upper section only of storage cylinder by
attaching a plastic tube to drain outlet and opening
drain valve knob anticlockwise, see diagram 4. To
assist draining, open one or more hot water taps.
●Remove earth lead from connection on top of
anode.
●Remove anode and inspect for signs of corrosion.
Important note: The anode must be checked at least
once a year and in certain cases more frequent
examination is recommended. If there is any sign of
corrosion causing the diameter of the anode to
reduce significantly, the anode must be replaced.
Corrosion of the anode is a necessary process to
prevent corrosion of the storage cylinder. Failure to
replace the anode, when corroded, may result in
considerable reduction of the life of the storage
cylinder protective lining.
Pla 194
b
c
a
Unvented cylinder safety devices
The unvented cylinder safety devices must be
checked annually for correct operation.
Proceed as follows:
●Ensure that there are no persons in the vicinity of
the boiler safety discharge pipes, outside the building.
●Operate the combined temperature/pressure re-
lief valve, using the manual lever, for a period of FIVE
seconds, ensure that the valve releases safely and
effectively.
Diagram 3
Diagram. 4
Reg 039

6
For replacement of the following components it will
be necessary to remove boiler casing panels as des-
cribed in ‘Routine Cleaning and Inspection’.
WARNING: Before commencing the replacement of
any component, isolate appliance from electrical
supply and turn off gas at service cock.
To replace domestic hot water thermostat
●Locate domestic hot water thermostat phial poc-
ket in underside of storage cylinder.
●Remove wire clip securing thermostat phial into
pocket.
●Remove two screws from front control panel and
open panel.
●Remove two leads from domestic hot water ther-
mostat.
●Remove domestic hot water thermostat knob by
pulling off.
●Using a suitable tool, unscrew and remove nut se-
curing thermostat to control panel.
●Fit replacement control in reverse order to remo-
val.
●Connect leads to terminals 1 and C. The polarity is
not important.
To replace fan
●Remove fan as described in ‘Routine Cleaning and
Inspection’.
●Fit replacement fan in reverse order to removal.
●Reconnect electrical lead.
To replace air pressure switch
●Locate air pressure switch situated outside sealed
chamber on upper right hand side, see diagram 5.
●Remove sealed chamber cover as described in
‘Routine Cleaning and Inspection’.
●Hold air pressure switch and remove two securing
screws.
●Carefully pull off air sensing tubes.
●Disconnect electrical leads to switch.
●Fit leads to terminals of replacement switch.
●Reconnect short air sensing tube to connection
marked H.
●Reconnect long air sensing tube to connection
marked L.
●Fit replacement switch to boiler in reverse order to
removal.
To replace printed circuit board (PCB)
●Remove two screws from front control panel and
open panel.
●Carefully pull off electrical connections to PCB.
●Unscrew and disconnect two incoming mains wi-
res.
●Unscrew and disconnect two mains warning light
wires.
●Remove screws securing PCB to control panel and
lift out PCB.
●Fit replacement PCB in reverse order to removal.
Note: Make sure that PCB connections are fully
pushed onto replacement PCB.
To replace central heating thermistor
Drain down heating circuit of boiler only as follows:
REPLACEMENT OF PARTS
●Close isolating valves on flow and return pipes on
boiler, see diagram 3.
Note: 1) These valves are closed when levers are
at right angles to direction of flow.
2) It is not necessary to drain down entire
heating system to carry out this work.
●Drain boiler by attaching a plastic tube to drain
outlet and opening drain valve knob anticlockwise,
see diagram 4.
●Locate central heating flow thermistor on central
heating flow pipe below automatic air vent.
●Remove electrical connections from thermistor.
●Unscrew and remove thermistor from flow pipe.
●Fit replacement thermistor in reverse order to remo-
val.
●Refit electrical connections.
●Open isolating valves on flow and return connec-
tions, refill, vent and pressurise boiler.
●Check for leaks.
To replace central heating temperature control
●Remove two screws from front panel and open
panel.
●Carefully pull off central heating temperature con-
trol plug from PCB terminal marked A5.
●Carefully pull off two leads to ‘Summer/Winter’
switch.
●Remove central heating temperature adjustment
knob by pushing off with suitable tool through one of
the holes in rear of control panel, see diagram 6.
●Using suitable tool, unscrew and remove nut secu-
ring control to control panel.
●Fit replacement control in reverse order to remo-
val.
To replace pump
●Drain down the heating circuit of the boiler only,
as described previously.
Note: It is not necessary to drain down entire heating
system to carry out this work.
●Undo two pump union nuts and pull pump
forwards.
Diagram. 6
Diagram. 5

7
REPLACEMENT OF PARTS
Diagram. 7
Diagram. 8
Reg 018
●Undo and remove screw securing electrical cover
onto pump housing and remove cover.
●Disconnect electrical connections from pump.
●Connect electrical connections to replacement
pump and refit cover.
●Fit replacement pump in reverse order to removal.
●Open isolating valves on flow and return connec-
tions, refill, vent and pressurise boiler.
●Check for leaks.
To replace temperature gauge
●Gain access to rear of control panel.
●Remove clip securing temperature gauge bulb
to heating flow pipe.
●Remove temperature gauge from front panel by
squeezing together plastic locating tabs and
pushing gauge through hole in panel.
●Fit replacement gauge in reverse order to
removal.
Note: 1) Apply heat sink compound to bulb of
replacement gauge prior to fitting.
2) Carefully route capillary to ensure it
doesn’t become crushed or damaged.
To replace pressure gauge
●Drain down heating circuit of boiler only as
described previously.
●Gain access to rear of control panel.
●Unscrew and remove nut securing pressure gauge
capillary to hot water pipe, see diagram 7.
●Remove pressure gauge from front panel by
squeezing together plastic locating tabs and pushing
gauge through hole in panel.
●Fit replacement gauge in reverse order to removal.
●Open isolating valves on flow and return connec-
tions, refill, vent and pressurise boiler.
●Check for leaks.
Note: Carefully route capillary to ensure it doesn’t
become crushed or damaged.
To replace 3-way valve head
●Locate three way valve on left hand side of boiler,
below sealed chamber.
●Depress valve head locating button, and turn valve
head 1/8th turn anti-clockwise to release from valve
body.
●Pull out electrical plug.
●Fit replacement valve head in reverse order to
removal.
Note: It is not necessary to drain boiler to carry out
this work.
To replace 3-way valve
●Drain down heating circuit of boiler only as
described previously.
Note: It is not necessary to drain down entire heating
system to carry out this work.
●Remove 3-way valve head as described previously.
●Unscrew three nuts securing 3 - way valve to
pipework and lift out 3 -way valve, making note of
the position of valve port ‘A’.
●Fit replacement valve in reverse order to removal,
fitting valve port ‘A’ in the correct position.
●Open isolating valves on flow and return connec-
tions, refill, vent and pressurise boiler.
●Check for leaks.
To replace loss of water switch
●Drain down heating circuit of boiler only as
described previously.
Note: It is not necessary to drain down entire heating
system to carry out this work.
●Locate loss of water switch on heating flow pipe to
right of pump.
●Disconnect electrical connections from switch.
●Undo switch from pipe using suitable spanner.
●Fit replacement switch into pipe, do not overtighten.
●Refit electrical connections
●Open isolating valves on flow and return connec-
tions, refill, vent and pressurise boiler.
●Check for leaks.
To replace gas valve module
●Locate gas valve module attached to side of gas
valve.
●Remove screw securing cover onto gas valve mo-
dule, see diagram 8.
●Remove cover
and disconnect
multi-plug from mo-
dule.
●Disconnect ignition
and flame sense
leads from module.
●Withdraw module
from gas valve.
●Fit replacement
module, ensuring it is
of the correct type
for the boiler, in re-
verse order to removal.
●Reconnect ignition and flame sense leads, the con-
nections are uniquely sized to ensure correct repla-
cement.
●Reconnect multi-plug onto replacement module.
●Refit cover ensuring all sealing grommets are
correctly located in module body.
To replace gas valve
●Ensure that gas supply to boiler is turned off at gas
cock.
●Remove gas valve module as described previously.
●Disconnect electrical connections to gas valve
modulating coil, see diagram 8.
●Undo main gas supply nut from main burner.
Note: The washer must be kept for use on reassembly.
●Undo main gas union nut between gas valve
supply pipe and gas inlet valve at right hand rear
of boiler.
Note: The washer must be kept for use on reassembly.
●Unscrew and remove two screws securing gas valve
fixing bracket to boiler frame.

8
REPLACEMENT OF PARTS
●Withdraw gas valve assembly.
●Using old gas valve as a guide, transfer gas pipes
from old gas valve to replacement gas valve.
●Fit replacement gas valve into boiler.
●Reconnect gas pipes in reverse order to removal.
●Refit electrical connections in reverse order to
removal, the polarity of the wires to the modulating
coil is not important.
To replace modulating coil
●Ensure that gas supply to boiler is turned off at gas
cock.
●Disconnect electrical connections to gas valve
modulating coil, see diagram 8.
●Undo two screws securing modulating coil to gas
valve and remove coil.
●Fit replacement coil in reverse order to removal.
●Refit electrical connections in reverse order to
removal, the polarity of the wires to the modulating
coil is not important.
To replace central heating safety valve
If safety valve seating is damaged, it will be necessary
to replace safety valve as a complete unit, repair is
not possible.
●Drain down heating circuit of boiler only as
described previously.
Note: It is not necessary to drain down entire heating
system to carry out this work.
●Disconnect safety valve discharge pipe from safety
valve.
●Remove safety valve from boiler pipework, see
diagram 7.
●Fit replacement safety valve in reverse order to
removal.
●Open isolating valves on flow and return connec-
tions, refill, vent and pressurise boiler.
●Check for leaks.
To replace temperature/pressure relief valve (T&P
valve)
To replace T&P valve, it is necessary to drain upper
section only of storage cylinder, preferably when cold.
●Isolate electrical supply to boiler.
●Close isolating valve (c) on cold water inlet pipe,
see diagram 3.
●Drain upper section only of storage cylinder by
attaching a plastic tube to drain outlet and
opening drain valve knob anticlockwise, see
diagram 4. To assist draining, open one or more hot
water taps.
●Locate T&P valve on upper part of storage
cylinder.
●Disconnect T&P valve discharge pipe.
●Unscrew and remove T&P relief valve.
●Fit replacement T&P valve in reverse order to
removal using a Water Research Centre approved
sealant suitable for potable water.
●Open isolating valve (c) on cold water inlet
connection on fixing jig, see diagram 3.
●Refill storage tank and vent cylinder.
●Check for leaks.
To replace anode
To replace anode, it is necessary to drain upper sec-
tion only of storage cylinder, preferably when cold.
●Isolate electrical supply to boiler.
●Close isolating valve (c) on cold water inlet pipe,
see diagram 3.
●Drain upper section only of storage cylinder by
attaching a plastic tube to drain outlet and
opening drain valve knob anticlockwise, see
diagram 4. To assist draining, open one or more hot
water taps.
●Remove earth lead from connection at top of
anode.
●Unscrew and remove anode from storage
cylinder.
●Fit replacement anode in reverse order to
removal.
●Open isolating valve (c) on cold water inlet pipe,
see diagram 3.
●Refill storage tank and vent cylinder.
●Check for leaks.
To replace heat exchanger
●Drain down heating circuit of boiler only as
described previously.
Note: It is not necessary to drain down entire
heating system to carry out this work.
●Remove fan as described in ‘Routine Cleaning
and Inspection’.
●Undo two nuts securing heating flow and return
pipes to sealed chamber bulkhead fittings, see
diagram 9.
●Undo nuts on heating flow and return connec-
tions on heat exchanger.
●Undo nuts securing sealed chamber bulkhead
fittings to sealed chamber and remove pipes and
fittings from boiler.
Note: Keep washers for use on reassembly.
●Remove spring clip securing flue hood to heat
exchanger pipe and withdraw flue hood forwards
and out of boiler.
●Disconnect electrical connectors from high limit
thermostat.
●Lift heat exchanger up and out of combustion
chamber and remove from boiler.
●Fit replacement heat exchanger in reverse order
to removal.
●Reconnect electrical connections to high limit
thermostat, the polarity is not important.
●Reconnect heating connections using new
washers supplied.
●Replace flue hood and fan in reverse order to
removal.
●Open isolating valves on flow and return connec-
tions, refill, vent and pressurise boiler.
●Check for leaks.
To replace expansion valve
●Close isolating valve (c) on cold water inlet pipe,
see diagram 3.
●Locate expansion valve at base of
●Disconnect pipework to expansion valve and
remove valve from boiler.
●Fit replacement expansion valve in reverse order
to removal.
●Open isolating valves on flow and return connec-
tions, refill, vent and pressurise boiler.
●Check for leaks.

9
Front panel:
Lift front insulation panel free from retaining lug on
combustion chamber cover.
Rear panel:
●Lift rear insulation panel free from retaining lug at
rear of combustion chamber by tilting forward.
Side panels:
●Lift side panels free from retaining lugs on combus-
tion chamber sides by tilting slightly.
●Fit replacement insulation panels in reverse order
to removal
●Refit combustion chamber cover, heat exchanger,
flue hood and fan in reverse order to removal.
To replace burner
●Remove burner as described in 'Routine Cleaning
and Inspection'.
Assemble replacement burner, supplied in parts, as
follows:
●Fit burner injectors to burner injector bar and tighten.
Note: Make sure that injector size, marked on each
injector, is the same as that given in ‘Technical Data’
for the type of gas being used.
●Fit injector bar into burner, secure using four screws.
●Fit replacement burner into boiler in reverse order
to removal.
To replace burner injectors
●Remove burner as described in 'Routine Cleaning
and Inspection'.
●Unscrew and remove four injector bar retaining
screws and separate injector bar from burner.
●Unscrew and remove injectors from injector bar.
●Fit replacement injectors to injector bar and tighten.
Note: Make sure that injector size, marked on each
injector, is the same as that given in ‘Technical Data’
for the type of gas being used.
●Reassemble burner and fit into boiler in reverse order
to removal.
To replace ignition/flame sense electrode
●Remove burner as described in ‘Routine Cleaning
and Inspection’.
●Undo and remove screw securing electrode onto
burner.
●Fit replacement electrode onto burner in reverse
order to removal.
●Refit burner into boiler in reverse order to removal.
REPLACEMENT OF PARTS
To replace central heating expansion vessel
●Drain down heating circuit of boiler only as
described in 'To replace pump'.
Note: It is not necessary to drain down entire heating
system to carry out this work.
●Isolate electrical supply to boiler.
●Undo pipe coupling at base of expansion vessel.
●Supporting expansion vessel, unscrew and remove
screws securing expansion vessel to boiler.
●Lift vessel out of boiler.
●Fit replacement vessel to boiler in reverse order to
removal, ensuring that sealing washer is fitted to pipe
connection before tightening.
●Ensure that expansion vessel charge pressure is 1,0
bar (15 psi) using a pressure gauge. If necessary,
increase pressure using a car or cycle tyre pump
connected to the Schrader valve.
●Open isolating valves on flow and return connec-
tions, refill, vent and pressurise boiler.
●Check for leaks.
To replace domestic expansion vessel
To replace domestic expansion vessel it is necessary
to drain entire storage cylinder, preferably when cold.
●Isolate electrical supply to boiler.
●Close isolating valve (c) on cold water inlet pipe,
see diagram 3.
●Drain upper section only of storage cylinder by
attaching a plastic tube to drain outlet and opening
drain valve knob anticlockwise, see diagram 4. To
assist draining, open one or more hot water taps.
●Undo pipe coupling to expansion vessel.
●Undo nut securing expansion vessel to boiler.
●Lift expansion vessel out of boiler.
●Fit replacement vessel to boiler in reverse order to
removal, ensuring that sealing washer is fitted to pipe
connection before tightening.
●Ensure that expansion vessel charge pressure is 3
bar (45 psi) using a pressure gauge. If necessary,
increase pressure using a car or cycle tyre pump
connected to the Schrader valve.
●Open isolating valves on flow and return connec-
tions, refill, vent and pressurise boiler.
●Check for leaks.
To replace high limit thermostat
●Locate high limit thermostat on left hand side of
heat exchanger below central heating flow
connection, see diagram 9.
●Disconnect two electrical connectors from thermos-
tat
●Unscrew and remove two self tapping screws
securing thermostat to heating flow pipe.
●Remove thermostat.
●Fit replacement thermostat in reverse order to
removal using heat sink compound supplied.
●Reconnect two leads to thermostat, the polarity is
not important.
To replace combustion chamber insulation
●Remove fan, flue hood and heat exchanger as
described in ‘To replace heat exchanger’.
●Unscrew and remove four screws securing combus-
tion chamber cover to combustion chamber.
●Remove combustion chamber cover.
Diagram. 9

10
BOILER SCHEMATIC
Diagram 10
SYLVAFF 24 E
17 - Expansion valve (6 bar)
18 - Domestic expansion vessel
19 - Drain valve
20 - Fan
21 - Air pressure switch
22 - Temperature/pressure relief valve (7 bar)
23 - Tundish
24 - Non-return valve
A - Heating return
B-Cold water inlet
C-Heating flow
D-Domestic hot water flow
F-Gas supply
1-3-way valve
2-Loss of water switch
3-Pump
4-CVI unit
5-Gas valve
6-Ignition electrode
7-Injector manifold
8-Flame detection electrode
9-Heat exchanger
10 - Bleed valve
11 - Thermistor
12 - Expansion vessel
13 - Anode
14 - Cylinder
15 - Domestic thermostat
16 - Overheat safety thermostat
Shy 115UK
H
L
21
10
11
19
20
21
13
14
15
6
7
8
9
AB
CD
F
12
12
3
4
5
17
18
16
23
22
24

11
TECHNICAL DATA
Heating output
adjustable from 10,8 kW to 24 kW
36,850 BTU/H to 81,890 BTU/H
Efficiency 81 %
Maximum heating temperature 90 °C
Expansion vessel effective capacity 7,5 l
Expansion vessel charge pressure 1,0 bar
Maximum system capacity at 75°C 170 l
Safety valve, maximum service pressure 3 bar
Products outlet Ø 60 mm
Fresh air inlet Ø 100 mm
Hot water output
automatically variable from 10,8 kW to 24 kW
36,850 BTU/H to 81,890 BTU/H
Storage capacity 60 l
Maximum hot water temperature 65 °C
Specific flow rate (for 30°C temperature rise) 13,6 l/min.
Nominal water flow rate 10 l/min.
Expansion vessel effective capacity 2 l
Expansion vessel charge pressure 3 bar
Maximum supply pressure 10 bar
Maximum operating pressure 3,5 bar
Temp./press. relief valve opening pressure 7 bar
Temp./press. relief valve opening temperature 90 °C
Cylinder heat up time 7 min.
Time to reheat 70% of storage to 65°C 3 min.
Expansion valve setting 6 bar
Weight when full 144 kg
Electrical supply 230 V
Maximum absorbed power 165 W
Level of protection IP44
Natural Gas Butane Propane
(G20) (G30) (G31)
Burner injector 1,20 mm 0,77 mm 0,77 mm
Inlet pressure 20 mbar 28 mbar 37 mbar
Gas rate (maximum) 2.81 m3/h 2,10 kg/h 2,06 kg/h
Gas rate (minimum) 1,32 m3/h 0,98 kg/h 0,97 kg/h
Gas (reference 15°- 1013 mbar)
Burner pressures : burner pressures, as listed in the table below, must be checked after the boiler has been
operating for 3 minutes.
Table 1
0
10
20
500 1000 1500
30
40
50
Pression disponible (kPa)
entre départ et retour chaffage
Débit dans le circuit chaufage (l/h)
(10 kPa = 1 mCE)
0
30
35
30 60 90 120 150 180 210 240
40
45
50
55
60
65
Température de soutirage en °C
Quantité d'eau soutirée en litres
Water draw off temperature in °C
Flow rate through heating system (l/h)
Available pressure between
heating flow and return (kPa)
10 kPa = 1 mWG Water draw off in litres
Pump : Domestic hot water production :
Temperature of cold water = 15°C
Temperature of stored water = 60°C
Drawing off at 12 l/min.
Diagram. 11
Heat output
(kW) 10,8 11 12 13 14 15 16 17 18 19 20 21 22 23 24
(Btu/h) 36850 37532 40944 44356 47768 51180 54592 58004 61416 64828 68240 71652 75064 78476 81888
Heat input
(kW) 13,9 14,1 15,3 16,6 17,8 19,0 20,2 21,4 22,6 23,8 24,9 26,1 27,3 28,4 29,6
(Btu/h) 47389 48115 52326 56510 60668 64800 68907 72989 77045 81077 85084 89067 93026 96961 100872
GAS
G 20 (mbar) 3,1 3,4 3,5 4,1 4,7 5,4 6,1 6,8 7,6 8,4 9,2 10,1 11,1 12,0 13
G 30 (mbar) 5,8 6,3 6,9 8,1 9,3 10,6 12,0 13,5 15,0 16,6 18,3 20,0 21,9 23,7 25,7
G 31 (mbar) 7,6 8,0 9,1 10,6 12,3 14,0 15,8 17,7 19,8 21,9 24,1 26,4 28,8 31,3 33,9

12
SCHEMATIC WIRING DIAGRAM
Diagram. 12
1110 9 8 7 6 55 4321654321 987654321 4321
CTN
EV1 K5
E/H TH
TA
V2
P
IG
230V
N
L
L.alim.
P1
L2 L1 L3
P3
A5
654321
A2
A4
A7
A3
A1
F1 - 4A
Rel3
Rel2
Rel4
SW2
TRA
Rel1
F2 - 125mA
F3
315mA
Pr
EX
NO
C
NC
+-
EV
FA
FL
BR
LK4
K4
ACF
ACF .................................... Flame control circuit
A1 ...................................... 230V Connector
A3-A5 ................................ 24V Connectors
A7 ...................................... Clock option connector
BR ....................................... Reset button
CTN .................................... Thermistor
EV1 ..................................... Modulating valve
EV ....................................... Main gas valve
EX ....................................... Fan
E/H ..................................... ‘Summer/Winter’ switch
F1, F2, F3 ............................ Fuses
FA ....................................... Ignition elctrode
FL ........................................ Flame sense electrode
IG ....................................... Mains ON/OFF switch
K4 ....................................... Overheat thermostat
K5 ....................................... Loss of water switch
LK4 ..................................... Safety reset light
L.alim ................................. Mains supply light
L1,L2,L3 .............................. Diagnostic LED's
P ......................................... Pump
Pr ........................................ Air pressure switch
P1 ....................................... Heating temperature control
P3 ....................................... Heating range rating adjuster
Rel1,Rel2,Rel3,Rel4 ........... Relays
SW2 .................................... Fan option shunt
TA ....................................... Room thermostat
TH ....................................... Cylinder thermostat
V2....................................... Three way valve

13
FAULT FINDING
Before trying to operate the boiler make sure that :
●All gas supply cocks are open and that the gas
supply has been purged of air.
●The heating system pressure is at least 1 bar.
●There is a permanent mains supply to the boiler.
●The fuses on the PCB are intact.
●The ‘Summer/Winter’ switch is in the heating or
heating and hot water position.
The fault finding charts will enable the majority of
faults to be diagnosed. To use the charts effectively,
it is necessary to determine exactly which aspects
of the boiler are working correctly and which are
not.
For example:
If the domestic hot water works but the heating
doesn’t, refer to chart No. 1.
If heating works correctly but the hot water doesn’t,
refer to chart No. 2.
IMPORTANT: Always adopt a logical, step by step
procedure starting at the beginning of the
appropriate fault finding chart.
WARNING. Always isolate the boiler from the
electrical supply before carrying out any electrical
replacement work.
Always check for gas soundness after any service
work.
T (°C) 0 3 6 9
0.................... 33242 ..................28409 .............. 24361............. 20958
10...................19947 ..................17233 .............. 14934............. 12979
20...................12394 ..................10813 ............... 9459............... 8297
30.................... 7947 ....................6995 ................ 6171............... 5458
40.................... 5242 ....................4651 ................ 4136............... 3685
50.................... 3548 ....................3171 ................ 2840............... 2548
60.................... 2459 ....................2212 ................ 1994............... 1800
70.................... 1740 ....................1580 ................ 1428............... 1297
80.................... 1256 ................... 1143 ................ 1042 ................ 952
90.....................932 ......................845.................. 774................. 710
100....................690 ......................634 .................. 584................. 538
Thermistor values
Example : At 36°C, the thermistor resistance will be 6171 Ω
At 80°C, the thermistor resistance will be 1256 Ω

14
FAULT FINDING
CHART N°1
NO CENTRAL
HEATING
CHART N°2
NO DOMESTIC
HOT WATER
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
YES
Does burner fire?
Refer to chart No.3.
Set controls to call for heat.
Are external controls wired?
Rectify wiring.
Is burner pressure correct? -
Refer to technical data.
Heating ok.
Is the range rating potentiometer
correctly adjusted?
Adjust potentiometer to required
setting - does potentiometer
adjust burner pressure?
Faulty potentiometer - replace
PCB.
YES
YES
Does burner fire when a hot tap
is opened for approximately 3
minutes ?
Is plug to the external controls
connected to the boiler ?
Connect external controls plug.
Remove leads from central
heating thermistor. Check its
resistance in accordance with
diagram 17 - is central heating
thermistor OK ?
Remove potentiometer connec-
tor from A5 on PCB. Check resis-
tance of heating potentiometer
between white and black leads
- does it adjust between 0-1 kΩ?
Replace central heat-
ing potentiometer
Replace central
heating thermistor
Faulty PCB - replace
Are heating controls calling for heat ?
NO
NO
NO
NO
NO
YES
DHW ok.
Replace domestic hot water
thermostat
Replace 3 - way
valve head
Refer to
chart N°5
NO
NO
NO
YES
YES
YES
YES
YES
YES
With the "Summer/winter" switch in the
winter, hot water and central heating
position - does the burne fire for central
heating ?
Refer to chart No.3.
Remove domestic hot water thermostat
connector from A3 on PCB. Turn thermos-
tat up maximum - Is there continuity bet-
ween the two thermostat leads ?
Check PCB - replace if necessary
Replace domestic hot water thermostat
Is the hot water hot enough ?
Adjust domestic hot water
thermostat
Is the domestic hot water
thermostat set to the desired
position ?
Check operation of 3 - way valve
- is there flow of hot water to
storage cylinder flow pipe ?
Is domestic hot water thermostat
working correctly, that is, by
turning to maximum does burner
fire, by turning to minimum does
burner go out ?
Operate 3 - way valve
manually - is there flow
of hot water to storage
cylinder flow pipe ?
Does the burner fire when a hot tap is
opened for aproximately 3 minutes ?

15
FAULT FINDING
CHART N°3
BURNER WILL
NOT FIRE
(AFTER REFER-
RING TO
CHART 1 OR 2)
NO
YES
YES
YES
NO
NO
Does fan run ?
Fan OK
Faulty PCB-replace
Faulty fan-replace
Chek PCB - is there 230 V ac between
PCB connections A.2.1 and A2.2 ?
Check fan wiring loom - is there 230 V
ac at fan motor ?
Faulty fan wiring loom - rectify/replace
as necessary
CHART N°4
FAN NOT
RUNNING
NO
YES
YES YES
YES
YES
YES NO
NO
YES NO
NO
NO
NO
NO
Does burner fire on central heating or
hot water ?
is the flue corrctly fitted and
free of obstructions ?
Check for correct fit of
sealed chamber cover
Is pump running at full speed ?
Does burner remain on for less than 5
seconds ?
Is fan running at full speed ?
Refer to chart N°4
Refer to chart N°5
Is there circulation in the heating
circuit?
Check :
- Boiler isolating valves are open.
- Radiator valves are open (or system
bypass is fitted)
- No air is trapped in system
Rectify flue
Check air pressure switch - is there 230
V ac between PCB connections
A2.4 and A1.2
Check for 230 V ac at gas valve -is
there 230 V ac between PCB
connections A1.1 and A1.2 ?
Does burner light and then go out ?
Replace air pressure switch
Replace gas valve
Faulty PCB - replace
Boiler ok.
YES

16
FAULT FINDING
When ordering spare parts, quote the part number and description, stating
the appliance model number and serial number from the data badge.
Short parts list
No. Description Part No.
1 Domestic hot water thermostat 56013
2 Fan 56118
3 Air pressure switch 56008
4 Printed circuit board 56254
5 Central heating thermistor 56014
6 Pump 56128
7 Temperature gauge 56010
8 Pressure gauge 56005
9 3-way valve head 51335
10 Gas valve module 56024
11 Central heating safety valve 56110
12 Expansion valve (6bar) 56029
13 T&P relief valve (7bar) 56108
14 Anode 56000
15 High limit thermostat 56012
16 Ignition/flame sense electrode 56002
85890 B 07/97
CHART N°5
PUMP NOT
RUNNING
SPARE PARTS
NO
NO NO
NO
YES
YES
YES
NO
NO
Does pump run?
Remove cap on front of pump.
Using screwdriver, press in and
rotate the slotted shaft clockwise -
do not hit shaft.
Open auto air vent
on pump.
Check PCB - is there 230 V ac between
PCB connections A1.3 and A1.4
Faulty pump wiring loom -
rectify/replace as necessary.
Faulty PCB - replace
Faulty pump - replace Is there 230 V ac at pump motor ?
Pump ok.
Is pump free to rotate?
Is there air in pump?
YES