VOKERA ProCombi 85 HE Quick guide

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Installation & Servicing Instructions
THESEINSTRUCTIONS
TO BE RETAINED
BY USER 0694

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Contents
Design principles and operating sequence Page
1.1 Principle components 4
1.2 Mode of operation (at rest) 4
1.3 Mode of operation (heating) 4
1.4 Mode of operation (DHW) 4
1.5 Safety devices 4
Technical data Page
2.1 Central heating 5
2.2 Domestic hot water 5
2.3 Gas pressure 5
2.4 Expansion vessel 5
2.5 Dimensions 5
2.6 Clearances 5
2.7 Connections 5
2.8 Electrical 5
2.9 Flue details 5
2.10 Efficiency 5
2.11 Pump duty 6
2.12 Appliance 6
General requirements (UK) Page
3.1 Related documents 7
3.2 Location of appliance 7
3.3 Gas supply 7
3.4 Flue system 7
3.5 Air supply 7
3.6 Water circulation 7
3.6.1 Pipework 8
3.6.2 Automatic by-pass 8
3.6.3 Drain cocks 8
3.6.4 Air release points 8
3.6.5 Expansion vessel 8
3.6.6 Fillingpoint 8
3.6.7 Low pressure sealed system 8
3.6.8 Frequent filling 8
3.7 Electrical supply 8
3.8 Showers 8
3.9 Mounting on a combustible surface 9
3.10 Timber framed building 9
3.11 Inhibitors 9
Installation Page
4.1 Delivery 10
4.2 Contents 10
4.3 Unpacking 10
4.4 Preparation for mounting the appliance 10
4.5 Fitting the flue 10
4.5.1 Concentric horizontal flue 10
4.5.2 Concentric vertical flue 11
4.6 Connecting the gas and water 12
4.6.1 Gas 12
4.6.2 Flow and return 12
4.6.3 Cold water inlet 12
4.6.4 Hot water outlet 12
4.6.5 Safety valve 12
4.6.6 Condense pipe 12
4.7 Electrical connections 13
4.7.1 Casing removal 13
4.7.2 Appliance terminal block 13
4.7.3 Connecting the mains (230V) input 13
Commissioning Page
5.1 Gas supply installation 14
5.2 The heating system 14
5.3 Initial filling of the system 14
5.4 Initial flushing 14
5.5 Filling the hot water system 14
5.6 Pre-operation checks 14
5.7 Initiallighting 14
5.7.1 Checking burner pressures 14
5.8 Final flushing of the heating system 14
5.8.1 Inhibitors 14
5.9 Setting the boiler operating temperature 14
5.9.1 Setting the DHW temperature 15
5.10 Setting the system design pressure 15
5.11 Regulating the hot water 15
5.11.1 Changing the flow restrictor 15
5.11.2 Regulating the central heating system 15
5.12 Final checks 15
5.13 Instructing the user 15
5.14 Technical assistance 15
Servicing instructions Page
6.1 General 16
6.2 Routine annual servicing 16
6.3 Replacement of components 16
6.4 Component removal procedure 16
6.5 Pump assembly 16
6.6 Safety valve 16
6.7 Automatic air release valve 16
6.8 Water pressure switch 17
6.9 Pressure gauge 17
6.10 Primary thermistor 17
6.11 High limit thermostat 17
6.12 PCB 17
6.13 Gas valve 17
6.14 Integral time switch 18
6.15 Electrode, burner thermostat, burner & injectors 18
6.16 Flue fan 18
6.17 Main heat exchanger 19
6.18 Air pressure switch 19
6.19 Flow restrictor 19
6.20 DHW flow switch 19
6.21 DHW heat exchanger 20
6.22 Valve actuator 20
6.23 Divertor valve cartridge 20
6.24 DHW thermistor 20
6.25 Automatic by-pass 20
6.26 DHW non-return valve 20
6.27 Expansion vessel 20
6.27.1 Expansion vessel removal (with sufficient clearance above) 20
6.27.2 Expansionvesselremoval (withinsufficientclearanceabove) 21
6.28.1 Latent heat collector 21
6.28.2 Dismantling the latent heat collector 21
6.29 Condense trap removal 21
Checks, adjustments and fault finding page
7.1 Checking appliance operation 22
7.2 Appliance mode of operation 22
7.2.1 Selector switch in the OFF position 22
7.2.2 Selector switch in the hot water only position 22
7.2.3 Selector switch in the heating & hot water position 22
7.2.4 Appliance functions 22
7.2.5 DHW mode 22
7.2.6 Heating mode 23
7.3 Checking & adjusting burner pressure 24
7.3.1 Setting the maximum burner pressure 24
7.3.2 Setting the minimum burner pressure 24
7.3.3 Setting the minimum CH output 24
7.4 Combustion analysis test 24
7.5 Checking the expansion vessel 25
7.6 External faults 25
7.6.1 Installation faults 25
7.7 Electrical checks 25
7.7.1 Earth continuity test 25
7.7.2 Short circuit check 25
7.7.3 Polarity check 25
7.7.4 Reversed polarity or supply fault 26
7.7.5 Resistance to earth check 26
7.8 Fault finding 26
7.8.1 Replacing the main PCB 26
7.9 Fault codes 26
7.10 Fault finding 27-32
Wiring diagrams Page
8.1 External wiring 33
8.2 Typical control applications 33
8.3 Room thermostat 33
8.4 Other controls 33
Functional diagram 34
L.P.G. instructions Page
10.1 Related documents 35
10.2 Technical data 35
10.3 Converting the appliance gas supply 35
10.4 Gas supply 35
10.5 Gas supply installation 35
10.6 Checking & adjusting burner pressure 35
10.6.1 Setting the maximum burner pressure 35
10.6.2 Setting the minimum burner pressure 35

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INTRODUCTION
Fig.1GeneralLayout
1 Dischargevalve
2 Gas valve
3 Modulatorcoil
4 Pressureswitch
5 Condensetrap
6 Ignitiontransformer
7 Expansion vessel
8 Electrode
9 Mainburner
10 Mainheatexchanger
11 Latentheatcollector
12 Flue gas analysis test point
13 Flueoutlet
14 Air intake
15 Differentialpressureswitch
16 Siliconepressuretube(-)
17 Siliconepressuretube(+)
18 Fanassembly
19 CHNTCsensor
20 High limit thermostat
21 Combustionchamber
22 Condensatepressureswitch
23 Auto air vent (AAV)
24 Pump
25 DHWflow switch
26 DHWsensor
27 Domestichotwaterheatexchanger
28 Divertervalve motor
29 Pressuregauge
30 DHWposition
31 Mode selector switch
32 Faultindicatorled
33 CHposition
34 Timeclock
The PROCombiHE range ofappliancesis comprised of
2modelsofhigh-efficiency combination boiler with inputs
to heating & DHW of 25, 29 kW respectively.Each appli-
ance - by design - incorporates electronic ignition, circu-
lating pump, expansion vessel, safety valve, pressure
gaugeand automatic by-pass.
The PRO Combi HE range is produced as room sealed,
category II2H3P appliances, suitable for internal wall
mountingapplications only. Theyare provided with a fan
poweredflueoutletwithanannularcoaxialcombustionair
intake that can be rotated - horizontally - through 360
degreesforvarioushorizontalorverticalapplications. The
PROCombiHErangeisapprovedforusewithC12&C32
type flue applications.
These appliances are designed for use with a sealed
system only; consequently they are not intended for use
on open vented systems
Fig. 1 29 30 31 33 34
32

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SECTION 1 DESIGN PRINCIPLES AND OPERATING SEQUENCE
Fig. 2
1.1 PRINCIPLE COMPONENTS
●A fully integrated electronic control board fea-
turing electronic temperature control, anti-cy-
clecontrol,pumpover-run, LED fault indicator,
full gas modulation.
●Low-water-content, copper heat exchanger.
●Electronic ignition with flame supervision.
●Integral high-head pump.
●Fan.
●Air pressure switch.
●Expansion vessel.
●Water pressure switch.
●Two-stage gas valve.
●Pressure gauge.
●Safety valve.
●Condense switch.
1.2 MODE OF OPERATION (at rest)
When the appliance is at rest and there are no
requests for heating or DHW, the following func-
tions are active:
●Frost-protection system: the frost-protection
system protects the appliance against the risk
offrostdamage.Shouldthetemperatureofthe
appliance fall to 5 °C, the boiler will function in
the heating mode at minimum power until it
reaches 35°C.
●Anti-blockfunction:theanti-blockfunctionena-
blesthepumpanddivertorvalveactuator,tobe
energised for short periods, when the appli-
ancehasbeeninactiveformorethan19-hours.
1.3 MODE OF OPERATION (Heating)
Whenthereisarequestforheatviathetimeclock
and/oranyexternalcontrol,thepumpandfanare
started, the fan will then prove the air pressure
switch. At this point an ignition sequence is
enabled.
Ignition is sensed by the electronic circuitry to
ensure flame stability at the burner. Once suc-
cessfulignitionhasbeenachieved,theelectronic
circuitry increases the gas rate to 75% for a
period of 15 minutes. Thereafter, the boiler’s
output will either be increase to maximum or
modulate to suit the set requirement.
When the appliance reaches the desired tem-
perature the burner will shut down and the boiler
will perform a three-minute anti-cycle (timer de-
lay).
Whentherequest for heat hasbeen satisfied the
appliancepumpandfanmaycontinuetooperate
to dissipate any residual heat within the appli-
ance.
1.4 MODE OF OPERATION (DHW)
When there is a request for DHW via a hot water
outletortap,thepumpandfanarestarted,thefan
will then prove the air pressure switch. At this
point an ignition sequence is enabled.
Ignition is sensed by the electronic circuitry to
ensure flame stability at the burner. Once suc-
cessfulignitionhasbeenachieved,theelectronic
circuitry increases the gas rate to maximum or
willmodulateoutputtostabilisethetemperature.
In the event of the appliance exceeding the
desired temperature the burner will shut down
until the temperature drops.
WhentherequestforDHWhasbeensatisfiedthe
appliancepumpandfanmaycontinuetooperate
to dissipate any residual heat within the appli-
ance.
1.5 SAFETY DEVICES
When the appliance is in use, safe operation is
ensured by:
●A water pressure switch that monitors system
water pressure and will deactivate the pump,
fan and burner should the system water pres-
sure drop below the rated tolerance.
●A high limit thermostat that over-rides the tem-
perature control circuit to prevent or interrupt
the operation of the burner.
●An air pressure switch that requires the fan to
prove operation before the gas valve is ener-
gised.
●A pressure switch that interrupts the operation
ofthe appliance if the condensepipe becomes
blocked.
●Asafetyvalvewhichreleasesexcesspressure
from the primary circuit.
Automatic
by-pass
DHWnon
returnvalve
Safetyvalve
DHW
temperature
sensor
Diverter
valvemotor
Water
pressure
switch
AAV
latent heat
collector
Flue
outlet Air intake
Pressure
switch
Mainheat
exchanger
Gasvalve
Main
burner
CH NTC
sensor
Expansion
vessel
Pump
DHWheat
exchanger
DHW
flowswitch
CH
return
CH
flow DHW
outlet Domesticcold
water inlet

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SECTION 2 TECHNICAL DATA
Ref. Condition 15 °C , 1013,25 mbar, dry gas
NOTE: L.P.G. data refer to section 10
85 HE 100HE
2.1Centralheating
Heatinput(kW) 25.00 29.00
Maximumheatoutput@80/60°C(kW) 24.35 28.30
Minimumheatoutput@80/60°C(kW) 14.25 14.28
Maximumheatoutput@50/30°C(kW) 25.90 29.93
Minimumheatoutput@50/30°C(kW) 14.85 14.75
Minimumworkingpressure 0.5bar 0.5bar
Maximumworkingpressure 2.7bar 2.7bar
Minimumflowrate 350l/h 350l/h
2.2 Domestic hot water
Minimumoutput(kW) 9.50 9.90
Flowrate(35 °C rise) 10.2l/min 11.9l/min
Maximuminletpressure 6.0bar 6.0bar
Minimuminletworkingpressure 0.15bar 0.15bar
Minimumflowrate 2l/min. 2l/min.
2.3Gaspressures
Inlet pressureG20 20.0mbar 20.0mbar
Maximumburnerpressure 9.40mbar 9.20mbar
Minimumburnerpressure(centralheating) 3.50mbar 2.70mbar
Minimumburnerpressure(domestichotwater) 1.50mbar 1.20mbar
Grossrate(centralheating,max-min) 2.64-1.59 m3/h 3.07-1.59m3/h
Injectorssize 12x1.35mm 14x1.35mm
2.4Expansionvessel
Capacity 8litres 10litres
Maximumsystemvolume 76litres 91litres
Pre-chargepressure 1.0bar 1.0bar
2.5Dimensions
Height 780mm 780mm
Width 400mm 450mm
Depth 332mm 332mm
Dryweight 40kg 44 kg
2.6Clearances
Sides 12mm 12mm
Top 150mmfromcasingor25mmaboveflueelbow,whicheverisapplicable
Bottom 150mm 150mm
Front 600mm 600mm
2.7Connections
Flow&return 22mm 22mm
Hot&coldwaterconnections 15mm 15mm
Gas 15mm 15mm
Safetyvalve 15mm 15mm
Condense 21mm 21mm
2.8Electrical
Voltage 230V/~50hz 230V/~50hz
Powerconsumption 153W 153W
Internalfuse 2A 2A
Externalfuse 3A 3A
2.9Fluedetails(concentric)
Maximumhorizontalfluelength(60/100mm) 4.5m 4.0m
Maximumverticalfluelength(60/100mm) 5.5m 5.0m
2.10Efficiency
SEDBUK 86.9Band“B” 86.7Band“B”

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2.11 PUMPDUTY
Fig. 3 shows the flow rate available - after allowing for pressure loss through the appliance - for system
requirements. When using this graph, apply only the pressure loss of the system. The graph is based on a
20 ºC temperature differential.
Fig. 4
SECTION 3 GENERAL REQUIREMENTS
Key Location Minimum distance
A Below an opening (window, air-brick, etc.) 300 mm
B Above an opening (window, air-brick, etc.) 300 mm
C To the side of an opening (window, air-brick, etc.) 300 mm
D Below gutter, drain-pipe, etc. 25 mm
E Below eaves 25mm
F Below balcony, car-port roof, etc. 25 mm
G To the side of a soil/drain-pipe, etc. 25 mm
H From internal/external corner or boundary 300 mm
I Above ground, roof, or balcony level 300 mm
J From a surface or boundary facing the terminal 1200 mm
K From a terminal facing a terminal 1200 mm
L From an opening in the car-port into the building 1200 mm
M Vertically from a terminal on the same wall 1500 mm
N Horizontally from a terminal on the same wall 300 mm
P From a structure to the side of the vertical terminal 500 mm
Q From the top of the vertical terminal to the roof flashing As determined by the fixed collar
of the vertical terminal
2.12Appliance
NOx 94ppm-166mg/kWh 92 ppm-162mg/kWh
CO(max-min) 80ppm-80 ppm 100ppm-60 ppm
CO2(max-min) 6.75 - 3.90% 7.05- 3.50 %
CO/CO2ratio (max) 0.001to1 0.001to1
CO/CO2ratio(min) 0.002to1 0.002to1
85 HE 100HE
0,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
4,0
4,5
5,0
0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300
first speed
second speed
third speed
85 HE - 100 HE

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This appliance must be installed by a competent
personinaccordancewiththeGasSafety(Instal-
lation & Use) Regulations.
3.1 RELATED DOCUMENTS
The installation of this boiler must be in accord-
ance with the relevant requirements of the Gas
Safety(Installation & Use) Regulations, the local
building regulations, the current I.E.E. wiring
regulations, the bylaws of the local water under-
taking, the Building Standards (Scotland) Regu-
lation and Building Standards (Northern Ireland)
Regulations.
Itshould be in accordancealso with anyrelevant
requirements of the local authority and the rel-
evant recommendations of the following British
Standard Codes of Practice.
3.2 LOCATION OF APPLIANCE
The appliance may be installed in any room or
internal space, although particular attention is
drawn to the requirements of the current I.E.E.
wiring regulations and in Scotland, the electrical
provisions of the Building Regulations, with re-
specttotheinstallationoftheapplianceinaroom
or internal space containing a bath or shower.
Whenanapplianceisinstalledinaroomorinternal
spacecontainingabathorshower,theappliance
or any control pertaining to it must not be within
reach of a person using the bath or shower.
Thelocationchosenfortheappliancemustpermit
the provision of a safe and satisfactory flue and
termination. The location must also permit an
adequate air supply for combustion purposes
and an adequate space for servicing and air
circulation around the appliance. Where the in-
stallation of the appliance will be in an unusual
location special procedures may be necessary,
BS 6798 gives detailed guidance on this aspect.
A compartment used to enclose the appliance
must be designed and constructed specifically
for this purpose. An existing compartment/cup-
board may be utilised provided that it is modified
to suit.
Details of essential features of compartment/
cupboarddesignincludingairingcupboardinstal-
lationsaregiveninBS6798.Thisapplianceisnot
suitable for external installation.
3.3 GAS SUPPLY
The gas meter - as supplied by the gas supplier
-mustbecheckedtoensurethatitisofadequate
size to deal with the maximum rated input of all
the appliances that it serves. Installation pipes
must be fitted in accordance with BS 6891.
Pipe work from the meter to the appliance must
be of adequate size. Pipes of a smaller size than
the appliance gas inlet connection must not be
used. The installation must be tested for sound-
ness in accordance with BS6891.
Ifthegassupplyservesmorethanoneappliance,
it must be ensured that an adequate supply is
maintained to each appliance when they are in
use at the same time.
3.4 FLUE SYSTEM
Theterminalshouldbelocatedwherethedisper-
sal of combustion products is not impeded and
withdueregardforthedamageanddiscoloration
thatmayoccurtobuildingproductslocatednearby.
Theterminalmustnotbelocatedinaplacewhere
it is likely to cause a nuisance (see fig. 4).
Watervapourwillcondenseonleavingthetermi-
nal and the effect of such pluming must be
considered.
BS5440 PART 1 FLUES
BS 5440 PART 2 FLUES & VENTILATION
BS5449 PART 1 FORCEDCIRCULATIONHOTWATERSYSTEMS
BS5546 INSTALLATION OF GAS HOT WATER SUPPLIES FOR DOMESTIC PURPOSES
(2ND FAMILY GASES)
BS 6798 INSTALLATION OF BOILERS OF RATED INPUT NOT EXCEEDING 60kW
BS 6891 LOW PRESSURE INSTALLATION PIPES
BS 7074 PART 1 APPLICATION, SELECTION AND INSTALLATION OF EXPANSION VESSELS AND
ANCILLARY EQUIPMENT FOR SEALED WATER SYSTEMS
If installed less than 2m above a pavement or
platform to which people have access (including
balconies or flat roofs) the terminal must be
protected by a guard of durable material. The
guard must be fitted centrally over the terminal.
Refer to BS 5440 Part 1, when a terminal is sited
less than 1m below a plastic gutter, or less than
500mm below a painted surface, a suitable one
metre long heat shield should be fitted.
3.5 AIR SUPPLY
The following notes are intended for general
guidance only.
Thisapplianceisaroom-sealed,fan-fluedboiler,
consequentlyit doesnot require a permanent air
vent for combustion air supply.
When installed in a cupboard or compartment,
ventilation for cooling purposes is also not re-
quired.
3.6 WATER CIRCULATION
Detailedrecommendationsaregivenin BS 5449
Part 1 and BS 6798. The following notes are for
general guidance only.

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Fig. 5a
3.6.7 LOW PRESSURE SEALED SYSTEM
An alternative method of filling the system would
be from an independent make-up vessel or tank
mounted in a position at least 1 metre above the
highest point in the system and at least 5 metres
above the boiler (see fig. 5a).
The cold feed from the make-up vessel or tank
must be fitted with an approved non-return valve
and stopcock for isolation purposes. The feed
pipe should be connected to the return pipe as
close to the boiler as possible.
3.6.8 FREQUENT FILLING
Frequent filling or venting of the system may be
indicative of a leak. Care should be taken during
the installation of the appliance to ensure all
aspects of the system are capable of withstand-
ing pressures up to at least 3 bar.
3.7 ELECTRICAL SUPPLY
The appliance is supplied for operation on 230V
@ 50Hz electrical supply; it must be protected
with a 3-amp fuse. The method of connection to
the mains electricity supply must allow for com-
plete isolation from the supply. The preferred
method is by using a double-pole switch with a
contact separation of at least 3mm. The switch
must only supply the appliance and its corre-
sponding controls, i.e. time clock, room thermo-
stat, etc. Alternatively an un-switched shuttered
socket with a fused 3-pin plug both complying
with BS 1363 is acceptable.
3.8 SHOWERS
Iftheapplianceisintendedforusewithashower,
the shower must be thermostatically controlled
andbe suitableforusewitha combinationboiler.
3.6.1 PIPEWORK
ItisrecommendedthatcoppertubingtoBS2871
Part 1 is used in conjunction with soldered capil-
lary joints.
Where possible pipes should have a gradient to
ensureairiscarriednaturallytoairreleasepoints
and that water flows naturally to drain cocks.
Exceptwhereprovidingusefulheat,pipesshould
beinsulatedtoavoidheatlossandinparticularto
avoid the possibility of freezing. Particular atten-
tion should be paid to pipes passing through
ventilated areas such as under floors, loft space
and void areas.
3.6.2 AUTOMATIC BY-PASS
The appliance has a built-in automatic by-pass.
However it may be necessary to fit an external
bypass should the design of the heating system
require such. In any case, the design of the
system should be such that it prevents boiler
‘cycling’.
3.6.3 DRAIN COCKS
Thesemust be located in accessible positions to
facilitate draining of the appliance and all water
pipes connected to the appliance. The drain
cocks must be manufactured in accordance with
BS 2879.
3.6.4 AIR RELEASE POINTS
Thesemustbepositionedatthehighestpointsin
thesystemwhereairislikely to be trapped. They
should be used to expel trapped air and allow
complete filling of the system.
3.6.5 EXPANSION VESSEL
The appliance has an integral expansion vessel
to accommodate the increased volume of water
when the system is heated. It can accept up to 8
litres(25kW)or10litres(29kW)ofexpansionfrom
within the system, generally this is sufficient,
howeverifthesystemhasanunusuallyhighwater
content,itmaybenecessarytoprovideadditional
expansioncapacity (see 6.19).
3.6.6 FILLINGPOINT
Anapprovedmethodforinitialfillingofthesystem
and replacing water lost during servicing etc. is
required (see fig. 5). This method of filling must
comply with the current Water Supply (Water
Fittings) Regulations 1999 and Water Bylaws
2000 (Scotland).
Fig. 5
control valve
temporary
connection control valve
supply pipe
double check
valve
flow/return
pipe
Make-up vessel
or tank
Automatic
air-vent
Non-return
valve Stopcock
5.0 metres minimum
Heating
return

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3.9 MOUNTINGONACOMBUSTIBLESURFACE
If the appliance is to be fitted on a wall of
combustible material, a sheet of fireproof mate-
rial must protect the wall.
3.10 TIMBER FRAMED BUILDING
If the appliance is to be fitted in a timber framed
building,itshouldbefittedinaccordancewiththe
Institute of Gas Engineers publication (IGE/UP/
7) ‘Guide for Gas Installations in Timber Frame
Buildings’.
3.11 INHIBITORS
Itisrecommendthataninhibitor-suitableforuse
with copper and aluminium heat exchangers - is
used to protect the boiler and system from the
effects of corrosion and/or electrolytic action.
The inhibitor must be administered in strict ac-
cordance with the manufacturers instructions*.
*Watertreatmentofthecompleteheatingsystem
- including the boiler - should be carried out in
accordance with BS 7593 and the Domestic
Water Treatment Association’s (DWTA) code of
practice. Fig. 6a
Fig. 6

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Using the template provided, mark and drill a
115mm hole for the passage of the flue pipe. The
hole should be drilled level to ensure any con-
densefluidthatformswilldrainbacktotheboiler.
The fixing holes for the wall-mounting bracket
should now be drilled and plugged, an appropri-
ate type and quantity of fixing should be used to
ensure that the bracket is mounted securely.
Once the bracket has been secured to the wall,
mount the appliance onto the bracket.
FITTING THE HORIZONTAL FLUE KIT
Carefullymeasurethedistancefromthecentreof
the appliance flue outlet to the edge of the fin-
ished outside wall (dimension X). Add 65mm to
dimensionXtogiveyoudimensionY(seefig7A).
Measure dimension Y from the terminal end of
the concentric flue pipe and cut off the excess
from the 100mm pipe ensuring any burrs are
removed. Using the cut-off piece of 100mm pipe
as a guide, mark and cut the same length of pipe
from the inner 60mm pipe (the 60mm should
always project past the 100mm pipe by 30mm).
Pass the concentric flue pipe through the previ-
ously drilled hole. Fit the flue bend to the boiler
flue outlet and insert the concentric flue pipe into
the flue bend ensuring the correct seal is made.
Usingtheclamps,gaskets,andscrewssupplied,
secure the flue bend to the appliance flue spigot
and the flue terminal.
NOTE
Fit the internal (White) trim to the flue assembly
prior to connecting the flue pipe to the bend.
Fig. 7
Boiler
outer
clamp
Terminalor
extension
SECTION 4 INSTALLATION
4.1 DELIVERY
Duetotheweightoftheapplianceitmaybenecessary
for two people to lift and attach the appliance to its
mounting.Theapplianceiscontainedwithinaheavy-
dutycardboardcarton.Laythecartononthefloorwith
the writing the correct way up.
4.2 CONTENTS
Contained within the carton is:
●the boiler
●the wall bracket
●appliance template
●anaccessoriespackcontainingapplianceserv-
ice connections and washers
●the instruction pack containing the installation
& servicing instructions, user instructions,
Benchmarklogbook,guaranteeregistrationcard
and a 3-amp fuse.
4.3 UNPACKING
At the top of the carton pull both sides open - do
notuseaknife-unfoldtherestofthecartonfrom
around the appliance, carefully remove all pro-
tective packaging from the appliance and lay the
accessories etc. to one side. Protective gloves
shouldbeusedtolifttheappliance,theappliance
back-frame should be used for lifting points.
4.4 PREPARATION FOR MOUNTING THE APPLI-
ANCE
The appliance should be mounted on a smooth,
vertical,non-combustiblesurface,whichmustbe
capable of supporting the full weight of the appli-
ance. Care should be exercised when determin-
ing the position of the appliance with respect to
hidden obstructions such as pipes, cables, etc.
When the position of the appliance has been
decided - using the template supplied - carefully
mark the position of the wall- mounting bracket
(see fig. 6) and flue-hole (if applicable).
4.5 FITTING THE FLUE
The top flue outlet permits both horizontal and
vertical flue applications to be considered.
4.5.1 CONCENTRIC HORIZONTAL FLUE
(For concentric vertical flue, see section 4.5.2).
The appliance flue outlet elbow can be rotated
through 360º on its vertical axis. In addition the
fluemaybeextendedfromtheoutletelbowinthe
horizontalplane (see2.9). A reduction must also
be made to the maximum length (see table
below) when additional bends are used.
Bend Reduction in maximum flue length for each bend
45º bend 0.5 metre
90º bend 1.0 metre
Reduction for additional bends
Part No. Description Min-Max Length
489 Telescopic flue terminal kit 350/500mm
491 Horizontal flue kit for use with 1000 mm
add. bends & extensions
492 0.5m extension 500 mm
493 1.0m extension 1000 mm
494 2.0m extension 2000 mm
495 45º bend (pair) N/A
496 90º bend N/A
499 Wall bracket N/A
Horizontal flue terminals and accessories

Supplied By www.heating spares.co Tel. [phone]
11
Using the dimensions given in fig. 9 as a refer-
ence, mark and cut a 107mm hole in the ceiling
and/or roof.
4.5.1.1 EXTENDINGTHE FLUE
Connect the bend - supplied with the terminal kit
- to the top of the boiler using clamp (supplied)
seefig.7.Theadditionalbends&extensionshave
push-fit connections, care should be taken to
ensure that the correct seal is made when as-
sembling the flue system. Connect the required
number of flue extensions or bends (up to the
maximum equivalent flue length) to the flue ter-
minal (see fig. 7 & 8).
Theholeshouldbedrilledleveltoensurethatany
condense fluid drains back to the appliance.
NOTE
Whencuttinganextensionto the requiredlength,
you must ensure that the excess is cut from the
plain end of the extension (see fig. 7 & 8). Re-
move any burrs, and check that all seals are lo-
cated properly.You must ensure that the entire
fluesystemisproperlysupportedand connected.
Seal the flue assembly to the wall using cement
or a suitable alternative that will provide satisfac-
tory weatherproofing.
4.5.2 CONCENTRIC VERTICAL FLUE
The vertical flue terminal can be connected di-
rectly to the appliance flue outlet. Alternatively,
Fig. 9
Bend Reduction in maximum flue length for each bend
45º bend 0.5 metre
90º bend 1.0 metre
Reduction for bends
Part No. Description Min-Max Length
490 Vertical flue terminal
497 Pitchedroofflashingplate N/A
498 Flatroofflashingplate N/A
492 0.5mextension 500mm
493 1.0mextension 1000mm
494 2.0mextension 2000mm
495 45º bend(pair) N/A
496 90ºbend N/A
499 Wallbracket N/A
Vertical flue terminal and accessories
145
Fig. 8
Fig. 7a
FLUERESTRICTORRING(horizontalflue)
To ensure maximum efficiency of the appliance,
it may be necessary to fit one of the supplied
flue restrictor rings to the appliance flue outlet
(see tables below).
Total flue length Restrictor required
Less than 1.2 metre 82.5mm diameter (fitted)
Less than 3.0 metres 88mm diameter
Less than 4.5 metres not required
Total flue length Restrictor required
Less than 2.0 metres 84mm diameter (fitted)
Less than 4.0 metres not required
100 HE
an extension or bend can be connected to the
appliance flue outlet if desired (see 4.4.2), how-
ever if additional bends are fitted, a reduction
must be made to the maximum flue length (see
table below).
FLUERESTRICTORRING(verticalflue)
To ensure maximum efficiency of the appliance,
it may be necessary to fit one of the supplied
flue restrictor rings to the appliance flue outlet
(see tables below).
Total flue length Restrictor required
Less than 2.0 metre 82.5mm diameter (fitted)
Less than 4.0 metres 88mm diameter
Less than 5.5 metres not required
85 HE
Total flue length Restrictor required
Less than 2.8 metres 84mm diameter (fitted)
Less than 5.0 metres not required
100 HE
85 HE

Supplied By www.heating spares.co Tel. [phone]
12
Fit the appropriate flashing plate to the roof and
insert the vertical flue terminal through the flash-
ingplatefromtheoutside,ensuringthatthecollar
on the flue terminal fits over the flashing.
The fixing holes for the wall-mounting bracket
should now be drilled and plugged, an appropri-
ate type and quantity of fixing should be used to
ensure that the bracket is mounted securely.
Once the bracket has been secured to the wall,
mount the appliance onto the bracket.
IMPORTANT
Theverticalflueterminalcannotbecut;therefore
it may be necessary to adjust the height of the
appliance to suit or use a suitable extension.
Connecttheverticalflueassemblytotheboilerflue
spigot using the 60mm & 100mm clips, gaskets &
screws (supplied), ensuring the correct seal is
made. The flue support bracket (supplied with the
vertical flue kit) can now be fitted.
If the vertical flue requires extension/s or addi-
tional bend/s, connect the required number of
flue extensions or bends (up to the maximum
equivalent flue length) between the boiler and
vertical flue assembly (see fig. 8).
Ensure that any horizontal sections of the flue
system have a minimum 1º fall back to the boiler
(17mm per 1000mm).
NOTE
Whencuttinganextensionto the requiredlength,
you must ensure that the excess is cut from the
plain end of the extension (see fig. 8). Remove
any burrs, and check that any seals are located
properly. You must ensure that the entire flue
system is properly supported and connected.
4.6 CONNECTING THE GAS AND WATER
Theapplianceissuppliedwithanaccessorypack
that includes service valves.
The service valves are of the compression type.
Theaccessorypackcontainssealingwashers’etc,
for use with the service valves. When connecting
pipe work to the valves, tighten the compression
end first then insert the sealing washers before
tightening the valve to the appliance.
NOTE
It will be necessary to hold the valve with one
spanner whilst tightening with another
4.6.1 GAS (fig. 6 & 10)
The appliance is supplied with a 15mm service
valve, connect a 15mm pipe to the inlet of the
valve and tighten both nuts.
NOTE
It will be necessary to calculate the diameter of
the gas supply pipe to ensure the appliance has
an adequate supply of gas.
4.6.2 FLOW & RETURN (fig. 6 & 10)
The appliance is supplied with 22mm service
valves for the flow and return connections, con-
nect a 22mm pipe to the inlet of each valve and
tighten both nuts.
NOTE
Depending on system requirements, it may nec-
essarytoincreasethesizeoftheflow&returnpipe
work after the service valve connections.
4.6.3 COLD WATER INLET (fig. 6 & 10)
Theapplianceissuppliedwitha15mmstopcock,
connect a 15mm pipe to the inlet of the stopcock
and tighten both nuts.
4.6.4 HOT WATER OUTLET (fig. 6 & 10)
The appliance is supplied with a 15mm outlet
connection, connect a 15mm pipe to the outlet
connection and tighten both nuts.
4.6.5 SAFETY VALVE (fig. 6 & 10)
Connectthesafety valve pipetothesafetyvalve
outletandtighten.Thedischargepipemusthave
a continuous fall away from the appliance to
outsideandallowanywatertodrainawaythereby
eliminating the possibility of freezing. The dis-
chargepipemustterminateinapositionwhereany
water-possiblyboiling-dischargessafelywithout
causing damage or injury, but is still visible.
4.6.6 CONDENSE PIPE (fig. 6 & 10)
Duringnormaloperationtheboilerproducescon-
dense which is collected in a trap located in the
lowerpartoftheboiler.Aflexiblepipe(condense
outlet pipe) is connected to the outlet of the trap.
The flexible pipe must be connected to a plastic
wastepipeonly.Theplasticwastepipemusthave
a minimum of a 3º fall towards the drain. Any
externalrunofpipeshouldbeinsulatedtoprevent
the risk of freezing.
CONNECTINGTHECONDENSATEOUTLET
Gentlypullthecondenseoutletpipedownfromits
location inside the boiler until approximately it
protrudes from the underside of the boiler. Con-
nect a suitable plastic (not copper) pipe (no less
than21mmdiameter)totheoutletpipeandensure
it discharges in accordance with local building
regulationsor other rules in force.
Fig. 10
flow return
gas
DHW
outlet DHW
inlet
condense

Supplied By www.heating spares.co Tel. [phone]
13
4.7 ELECTRICALCONNECTIONS
Theboilerissuppliedwitha2-metrefly-lead.This
lead can be used for connection to the electrical
supply. Connect the fly-lead to a fused plug or
fused isolator in the following way:
●brown wire to LIVE supply
●blue wire to NEUTRAL supply
●green/yellow to EARTH connection.
Insert the supplied 3-AMP fuse into the fused
isolator or fused plug.
Should the fly-lead be unsuitable, refer to 4.7.3
fordetailsonhowtoconnecttheelectricalsupply
directly to the boiler.
The electrical supply must be as specified in
section 3/3A. A qualified electrician should con-
nect the appliance to the electrical supply. If
controls-externaltotheappliance-arerequired,
a competent person must undertake the design
of any external electrical circuits, please refer to
section 8 for detailed instructions. ANY EXTER-
NALCONTROLORWIRINGMUSTBESERVED
FROM THE SAME ISOLATOR AS THAT OF
THE APPLIANCE. The supply cable from the
isolator to the appliance must be 3-core flexible
sized0.75mmtoBS6500orequivalent.Wiringto
the appliance must be rated for operation in
contact with surfaces up to 90 ºC.
4.7.1 CASINGREMOVAL
Togaininternalaccesstotheapplianceyoumustfirst
remove the casing, proceed as outlined below:
●locate and unscrew the 3-screws (A) that se-
cure the outer casing to the appliance (see fig.
11)
●lift the casing upward to disengage it from the
top locating hooks and then remove
●store the casing and screws safely until re-
quired. Re-fit in the reverse order
●gently lower the control fascia until it rests.
4.7.2 APPLIANCE TERMINAL BLOCK
The appliance terminal block is located on the
left side of the control fascia (see fig.11).Locate
and remove the screw that secures the terminal
block cover.
NOTE
The appliance comes with a factory fitted clock
toallowbasic operationof theboiler.If it is antici-
pated that additional controls - such as a room
thermostat - will be required please refer to the
wiring diagrams in section 8 for more detailed
information.
4.7.3 CONNECTINGTHE MAINS (230V) INPUT (see
fig. 12)
Lifttheterminalblockcoveras described in 4.7.2.
Passthecablethroughthecableanchoragepoint.
At the terminal block on the extreme left, there
are 3 terminals from left to right they are:
LIVE - NEUTRAL - EARTH
Connectthesupplycablewires(LIVE,NEUTRAL
&EARTH)totheircorrespondingterminalsonthe
applianceterminalblock(seefig.13).Ensurethat
the EARTH wire is left slightly longer than the
others,thiswill prevent strain ontheEARTHwire
should the cable become taut.
The securing screw on the cable anchorage
should now be tightened. This must be done
before the control fascia is re-fitted in the upright
position. The appliance casing and screws can
now be re-fitted.
Controlpanel screws andcasing screws
Fig. 11
A
Fig. 12
Fig. 13

Supplied By www.heating spares.co Tel. [phone]
14
5.1 GASSUPPLYINSTALLATION
Inspect the entire installation including the gas
meter,testforsoundnessandpurge.RefertoBS
6891 for specific instruction.
5.2 THE HEATING SYSTEM
The appliance contains components that may
becomedamaged orrenderedinoperablebyoils
and/or debris that are residual from the installa-
tion of the system, consequently it is essential
thatthesystembeflushedinaccordancewiththe
following instructions.
5.3 INITIAL FILLING OF THE SYSTEM
Ensure both flow and return service valves are
open, remove appliance casing as described in
4.7.1,identifytheautomaticairreleasevalveand
loosen the dust cap by turning the cap anti-
clockwise one full turn. IMPORTANT, THERE
ARE NO MANUAL AIR RELEASE VALVES LO-
CATEDONTHEAPPLIANCE.Ensureallmanual
air release valves located on the heating system
areclosed.Connectthefillingloop(notsupplied)
and slowly proceed to fill the system. As water
enters the system the pressure gauge will begin
torise.Oncethegaugehasreached1BARclose
the filling loop and begin venting all manual air
release valves, starting at the lowest first. It may
benecessarytogobackandtop-upthepressure
untiltheentiresystemhasbeenfilled. Inspectthe
systemforwatersoundness,rectifyinganyleaks.
5.4 INITIAL FLUSHING
Thewholeoftheheatingsystemmustbeflushed
both cold and hot as detailed in 5.8. Open all
radiatoror heating valves and the appliance flow
& return service valves. Drain the boiler and
system from the lowest points. Open the drain
valve full bore to remove any installation debris
from the boiler prior to lighting. Refill the boiler
and heating system as described in 5.3.
5.5 FILLING THE HOT WATER SYSTEM
Close all hot water outlets, turn appliance stop-
cocktothenormal operating position (fullycoun-
ter clockwise), slowly open each outlet until air
hasbeenexpelledandclearwaterisdischarged.
Check pipe-work etc. for water soundness.
5.6 PRE-OPERATION CHECKS
Before attempting the initial lighting of the appli-
ance, the following checks must be carried out:
●ensureall gas service valves from the meterto
theapplianceareopenandthesupplypipehas
been properly purged
●ensure the proper electrical checks have been
carried out, (see 7.7) particularly continuity,
polarity and resistance to earth
●ensure the 3 AMP fuse - supplied with the
appliance - has been fitted
●ensure the system has been filled, vented and
the pressure set to 1 BAR
●ensurethefluesystemhasbeenfittedproperly
and in accordance with the instructions
●ensure all appliance service valves are open.
SECTION 5 COMMISSIONING
5.7 INITIALLIGHTING
Ensure the electrical supply to the appliance is
switched on. Move the selector switch to the
Heating & Hot Water position, ensure the time
clock is switched to an ‘ON’ position and ensure
any other external controls (room thermostat for
example) are also calling for heat.
The appliance will now operate in the mode as
described in 1.2. Should the appliance fail to
ignite, refer to 5.6 and/or section 7 (faultfinding).
5.7.1 CHECKINGTHEBURNERPRESSURE
Although the burner pressure is factory set, it is
necessarytocheckitduringcommissioning.Isolate
theappliancefromtheelectricalsupplyandattach
asuitablemanometertothegasvalveoutlettest-
point(seefig.14).Lighttheboilerasdescribedin
5.7, turn the Hot Water temperature selector to
maximum,andopenfullyaDHWoutlet(preferably
the bath), allowing the appliance to stabilise.
Comparethereadingon the manometer with the
value described in 2.3. If adjustment is required,
follow the detailed instructions in section 7 (7.3).
Oncetheburnerpressurehasbeenchecked,close
the DHW outlet, isolate the appliance from the
electrical supply, remove the manometer and
tighten the gas valve outlet test nipple.
5.8 FINAL FLUSHING OFTHE HEATING SYSTEM
The system shall be flushed in accordance with
BS 7593. Should a cleanser be used, it must be
suitableforCopperandAluminiumheatexchang-
ers.Itshallbefromareputablemanufacturerand
shallbeadministeredinstrictaccordancewiththe
manufacturers’ instructions and the DWTA code
of practice.
5.8.1 INHIBITORS
Seesection3“Generalrequirements”.
5.9 SETTINGTHEBOILEROPERATINGTEMPERA-
TURE
The flow outlet temperature can be adjusted be-
tween 40 ºC - 80 ºC via the Heating thermostat
knob (see fig.1).
Fig. 14
Protective
cap
Outlet
test-point
Inlet
test-point

Supplied By www.heating spares.co Tel. [phone]
15
5.9.1 SETTING THE DOMESTIC HOT WATER TEM-
PERATURE
The DHW outlet temperature can be adjusted
between 40 ºC - 65 ºC via the Hot Water thermo-
stat knob (see fig.1).
5.10 SETTING THE SYSTEM DESIGN PRESSURE
The design pressure should be a minimum of 1
BAR and a maximum of 1.5 BAR.
The actual reading should ideally be 1BAR plus
the equivalent height in metres (0.1 BAR = 1
metre) to the highest point in the system above
the base of the appliance (up to the maximum of
1.5 BAR total).
N.B. The safety valve is set to lift at 3 BAR/30
metres/45 psig.).
To lower the system pressure to the required
value, water can be drained from the heating
system drain cock or from the boiler drain cock.
5.11 REGULATING THE HOT WATER
The appliance is fitted with a flow rate restrictor
that limits the maximum flow rate that can be
drawnthroughtheappliance.
The restrictor eliminates the need to manually
adjust the DHW flow rate. However if it is felt
necessary to further increase or decrease the
availableflowrate,sparerestrictorsareincluded
in the accessory pack.
The spare flow rate restrictors can be fitted to
either increase or decrease the maximum flow
rate.Thetablesabovedenotethesizeofrestrictor
fitted and the spare restrictors supplied in the
accessory pack. Each restrictor is colour-coded
to enable identification.
5.11.1 CHANGING THE FLOW RESTRICTOR
Referto6.19 for detailedinstructiononchanging
the flow restrictor.
5.11.2 REGULATINGTHECENTRAL HEATING SYS-
TEM
Fully open all radiator and circuit valves and run
theapplianceforbothheatingandhotwateruntil
heatedwateriscirculating.Ifconditionsarewarm
remove any thermostatic heads. Adjust radiator
returnvalvesandanybranchcircuitreturnvalves
until the individual return temperatures are cor-
rect and are approximately equal.
5.12 FINALCHECKS
●ENSUREALLTESTNIPPLESONTHEAPPLI-
ANCE GAS VALVE HAVE BEN TIGHTENED
ANDCHECKEDFORSOUNDNESS.
●ENSURE THE APPLIANCE FLUE SYSTEM
ISFITTED CORRECTLY ANDIS PROPERLY
SECURED.
●ENSURE ALL PIPE WORK IS RE-CHECKED
FOR SOUNDNESS.
●RE-FIT APPLIANCE CASING.
●COMPLETE BENCHMARK CHECKLIST.
Complete details of the boiler, controls, installa-
tionandcommissioninginthe Benchmark check-
list at the back of this book. It is important that
the Benchmark checklist is correctly completed
and handed to the user. Failure to install and
commission the appliance to the manufacturers
instructions may invalidate the warranty.
5.13 INSTRUCTING THE USER
Hand over all documentation supplied with this
appliance - including these instructions - and
explainthe importance of keeping them in a safe
place.
Explain to the user how to isolate the appliance
from the gas, water and electricity supplies, and
the locations of all drain points.
Show the user how to operate the appliance and
any associated controls correctly.
Showtheuserthelocation of the filling valveand
howtotop-upthesystempressurecorrectly,and
showthelocationofallmanualairreleasepoints.
Explaintotheuserhowtoturnofftheappliancefor
both long and short periods and advise on the
necessaryprecautions to preventfrost damage.
Explain to the user that for continued safe and
efficient operation, the appliance must be serv-
iced annually by a competent person.
5.14 TECHNICALASSISTANCE
Shouldyourequiretechnicaladviceorassistance
onthisproduct,pleasecontact‘HeatingServices’
on08702641220orHeatingServices,POBOX
167,BRADFORD,BD194WL.
9-litre (Orange) 10-litre (Blue) 11-litre (Beige)
Spare Fitted Spare
100 HE
8-litre (White) 9-litre (Orange) 10-litre (Blue)
Fitted Spare Spare
85 HE

Supplied By www.heating spares.co Tel. [phone]
16
SECTION 6 SERVICING INSTRUCTIONS
6.1 GENERAL
Toensurethecontinuedsafeandefficientopera-
tion of the appliance, it is recommended that it is
checked and serviced at regular intervals.
To ensure correct and safe operation of the
appliance, it is essential that any worn or failed
component be replaced only with a genuine
spare part.
The frequency of servicing will depend upon the
particular installation conditions, but in general,
once per year should be adequate.
It is the law that any servicing work is carried out by
competentpersonsuchasanengineer,anapproved
service agent, British Gas, CORGI registered per-
sonnel or other suitably qualified personnel.
The following instructions apply to the appliance
and its controls, but it should be remembered
that the central heating and the domestic hot
water systems would also require attention from
time to time.
6.2 ROUTINE ANNUAL SERVICING
Checktheoperation of the applianceandensure
it functions as described in section 7. Compare
the performance of the appliance with its design
specification. The cause of any noticeable dete-
riorationshouldbeidentifiedandrectifiedwithout
delay.
Thoroughly inspect the appliance for signs of
damage or deterioration especially the flue sys-
tem and the electrical apparatus.
Check and adjust - if necessary - all burner
pressure settings (see section 7.3).
Check and adjust - if necessary - the system
design pressure (see section 5.10).
Carry out an analysis of the flue gases (see 7.4)
and visually check the condition of the entire flue
assembly. Compare the results with the appli-
ance design specification. Any deterioration in
performancemustbeidentifiedandrectifiedwith-
out delay.
Ensureboth flueventurisarecleanandfreefrom
any debris or obstruction.
Ensure the burner, main heat exchanger and
latent heat collector are clean and free from any
debris or obstruction.
6.3 REPLACEMENT OF COMPONENTS
Although it is anticipated that this appliance will
giveyearsofreliable,troublefreeservice,thelife
spanofcomponentswillbedeterminedbyfactors
such as operating conditions and usage. Should
the appliance develop a fault, the fault finding
section will assist in determining which compo-
nent is malfunctioning.
6.4 COMPONENT REMOVAL PROCEDURE
Toremoveacomponent,accesstotheinteriorof
the appliance is essential. Isolate the appliance
from the electrical supply and remove the fuse.
And when necessary, close all service valves on
the appliance, remove the appliance casing as
described in section 4.7.1 and drain the water
content from the appliance via the drain valve
located at the front of the hydraulic section using
thetubeprovided.Ensuresomewaterabsorbent
cloths are available to catch any residual water
that may drip from the appliance or removed
component. Undertake a complete commission-
ingcheck as detailed insection 5, afterreplacing
any component. ALWAYS TEST FOR GAS
SOUNDNESS IF ANY GAS CARRYING COM-
PONENTS HAVE BEEN REMOVED OR DIS-
TURBED.
6.5 PUMP ASSEMBLY fig. 15
Carry out component removal procedure as de-
scribed in 6.4.
Thepumpheadcanbereplacedbydisconnecting
theelectricalconnectionatthepumpandremoving
the 4-Allen screws that secure the head to the
pump base. Alternatively, the complete pump
assembly can be removed as follows:
●disconnect the electrical connection from the
pumpcontrol box
•locateandremovethepressuregaugesecuring
pinanddisconnectthepressuregaugefromthe
pumpassembly
•Refer to fig. 15 and remove items A & B
•Locate and remove the pump locking pin ‘G’ (it
maybenecessarytoremovethevalveactuator
F to facilitate this) and lift the pump assembly
clear of the hydraulic manifold.
•Locateandremovetheexpansionpipelocking
pin,anddisconnecttheexpansionpipefromthe
pumpassembly
Replaceinthereverseorder.
6.6 AUTOMATICAIRRELEASEVALVEfig.15(AAV)
Carry out component removal procedure as de-
scribed in 6.4.
Locate and remove the pressure gauge pipe
securing pin and disconnect the pipe from the
pump assembly. Locate and remove the AAV
securing pin (G) and lift the AAV free from the
pumpassembly.
Replaceinthereverseorder.
Fig. 15
AAV
A
B
G
F

Supplied By www.heating spares.co Tel. [phone]
17
6.7 SAFETY VALVE fig. 16
Carry out component removal procedure as de-
scribed in 6.4.
Disconnect and remove the safety valve outlet
pipe.Locateandremovethesafetyvalvesecuring
pin (B). The safety valve can now be removed.
Replaceinthereverseorder.
Checkandclean(ifnecessary)thecondensetrap
(see6.29).
6.8 WATER PRESSURE SWITCH fig. 1
Carry out component removal procedure as de-
scribed in 6.4.
Disconnect the 2-wires from the water pressure
switch, taking note of their locations. Locate and
remove the pin that secures the water pressure
switch to the hydraulic assembly. Remove the
waterpressureswitchfromthehydraulicassembly.
Replaceinthereverseorder.
6.9 PRESSURE/TEMPERATUREGAUGEfig.1
Carry out component removal procedure as de-
scribed in 6.4.
Locateandremovethepressuregaugesecuring
pin and disconnect the pressure gauge from the
pump assembly. Locate the spring tabs on the
pressure gauge body, push and hold tabs in, to
enableextractionofthegaugefromitslocationon
thecontrol panel.
Replaceinthereverseorder.
6.10 PRIMARYTHERMISTOR fig. 17
Carry out component removal procedure as de-
scribed in 6.4.
Unclip and remove the air chamber cover and
remove the right side air baffle.
Disconnectthermistor electrical plug.
Using a 13mm spanner slacken and remove the
thermistorandsealingwasher(1,2)fromthemain
heatexchanger.
NB,itmay be necessary todisconnectorremove
theflowpipe from the heatexchangerto facilitate
this.
Replaceinthereverseorder.
6.11 HIGH LIMIT THERMOSTAT fig. 18
Carry out component removal procedure as de-
scribed in 6.4.
Unclipand remove the air chamber cover.
Pull off electrical connections from the high limit
thermostat (2), slacken and remove retaining
screws(3).
Replaceinreverseorder.
6.12 PRINTEDCIRCUITBOARDfig.19
Carry out component removal procedure as de-
scribed in 6.4.
Locate and remove the screws that secure the
PCB cover, then remove cover. After carefully
taking note of all wiring connections, disconnect
all wiring from the PCB, locate and remove the
PCBsecuringscrews(2,3,),removetherequired
PCB (Main or ignition control). Replace in the
reverseorder.
NOTE
EnsurethatanyreplacementPCBhasthecorrect
jumpertagconfiguration,andthattherelevantgas
pressuresare correctlyset/adjusted (see 7.8.1).
6.13 GAS VALVE fig. 20
Carry out component removal procedure as de-
scribedin6.4.Thegasvalvemustbechangedas
completeunit.Disconnecttheelectricalplug and
leads from the gas valve.
Slacken and unscrew gas valve inlet and outlet
connections (3). Please note, the sealing wash-
ers(2) must be discardedand replaced with new
sealingwashers(2).Locateandremovegasvalve
retaining screws on the underside of the boiler if
required. The gas valve can now be removed.
Replace in the reverse order. Check and adjust
burner pressure settings. WARNING, A GAS
SOUNDNESSCHECKMUSTBECARRIEDOUT.
Fig. 18
Fig. 17
Fig. 16 E
B

Supplied By www.heating spares.co Tel. [phone]
18
6.14 INTEGRALTIMESWITCH(iffitted)
Carry out component removal procedure as de-
scribed in 6.4.
Locate and remove the PCB cover and securing
screws(fig. 19/19A), locate and remove the time
clock retaining screws, remove time clock. Dis-
connect wiring after carefully taking note of all
electrical connections. Replace in the reverse
order.
6.15 ELECTRODE,BURNER&INJECTORSfig.21
Carry out component removal procedure as de-
scribed in 6.4.
Unclip and remove the air chamber cover (2).
Locate and remove the 6 screws securing the
frontcombustioncover(3),pullthecovertowards
you before lifting and disengaging. Disconnect
the electrode lead. Ease the electrode sealing
grommet from its seating (4).
FIG.22:locateandremovethefourscrewswhich
secure the burner in position (1), gently ease the
burner out of its location. Once the burner has
beenremoved,theelectroderetainingscrewcan
be removed. Locate the burner injectors (2) and
remove (if necessary). Replace in the reverse
order. Please note, the injector sealing washers
(3) must be replaced if the injectors have been
removed, ensure all seals are in good condition,
takingcaretoensuretheyarereplacedcorrectly.
Replaceinthereverseorder.
6.16 FLUE FAN fig. 23
Carry out component removal procedure as de-
scribed in 6.4.
Unclipandremovethe air chamber cover,gently
Fig. 19a
M
M
CLK-1
CLK-4
Fig. 20
Fig. 21 Fig. 22

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19
pull the cover towards you before lifting and
disengaging. Locate and remove the six screws
that secure the front combustion cover, then
remove the cover. Disconnect the electrical con-
nections and silicone tubes attached to the fan,
noting their positions. Locate and remove the
screws (6) that secure the air pressure switch
assembly(4 &5).Locateandremovethescrews
thatsecurethefluehoodandairbaffle,disconnect
theflueclip(1)fromthefan-flueelbow,andgently
easethefan(3)&fluehoodassembly(2)fromits
location.Locateand removethefourscrewsthat
securethefantothefluehood.Removethefanto
flueelbow.Replaceinthereverseorder.Ensureall
sealsareingoodcondition,takingcaretoensure
theyare replaced correctly.
6.17 MAINHEATEXCHANGERfig.23/24
Carry out component removal procedure as de-
scribed in 6.4.
Unclipandremovethe air chamber cover,gently
pull the cover towards you before lifting and
disengaging. Locate and remove the six screws
that secure the front combustion cover, then
remove the cover. Remove the air chamber side
panels if necessary by unscrewing the securing
screws. Disconnect the flow and return connec-
tions (4,5, fig. 24) and the primary thermistor on
theheatexchanger.Theheatexchangercannow
be withdrawn from the appliance. Replace in the
reverseorder.Ensureallsealsareingoodcondition,
takingcaretoensuretheyarereplacedcorrectly.
6.18 AIR PRESSURE SWITCH fig. 23
Carry out component removal procedure as de-
scribed in 6.4.
Unclipandremovethe air chamber cover,gently
pull the cover towards you before lifting and
disengaging.Locate and remove the two screws
(6) holding the air pressure switch to the air
chamber. Disconnect the electrical connections
andsiliconetubes(10)attachedtotheairpressure
switch,notingtheirconnections/positions.Replace
in the reverse order. Ensure all seals are in good
condition,takingcaretoensuretheyarereplaced
correctly.
6.19 FLOWRESTRICTORfig.25
Carry out the component removal procedure as
describedin 6.4.
Slackenthecoldwateroutletpipe(A)attheDHW
flowswitchanddisconnect.Easetheflowrestrictor
(B)fromitsseating.Replaceinthereverseorder.
Ensureallsealsareingoodcondition,takingcare
to ensure they are replaced correctly.
6.20 DHWFLOWSWITCHfig. 25
Carry out component removal procedure as de-
scribed in 6.4.
Disconnect the cold water inlet/outlet pipes (A)
fromtheDHW flow switch. Disconnectthewiring
tothe DHW flowswitch. Lift theDHW flow switch
from its location. Replace in the reverse order.
Ensureallsealsareingoodcondition,takingcare
to ensure they are replaced correctly.
Fig. 25
6
7
8
1
3
2
9
4
5
10
A
B
C
Fig. 23
Fig. 24

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20
6.21 DHWHEATEXCHANGERfig.16/16A
Carry out component removal procedure as
describedin 6.4.
Before removing the DHW heat exchanger, it will
benecessarytoremovethegas valve (see 6.13).
Locateand remove the DHWoutlet pipe (A)from
theLH(left hand) DHW manifold andDHWoutlet
connection.
Locateandremovethelockingpins(1)thatsecure
the flexible pipe (B) that connects both hydraulic
manifoldsand then remove the pipe.
Locate and remove the 2-screws (C) that secure
theDHWheatexchangerto the LH and RHDHW
manifolds and gently ease the DHW heat
exchanger from its location.
Locateandremovethelockingpin(2)thatsecures
theLH DHWmanifoldtotheLHhydraulicmanifold
andthen remove themanifold.
GentlyeasetheLHDHW manifold away from the
LH hydraulic manifold and disconnect the wiring
tothesecondary(DHW)thermistor.
Replace in the reverse order ensuring all seals
arecorrectly positioned andin good condition.
Replace the gas valve in accordance with the
instructionsdetailed in 6.13.
6.22 VALVEACTUATORfig.26
Carry out component removal procedure as de-
scribed in 6.4.
Remove the locking pin (A) that secures the
actuator(B)tothehydraulicmanifold.Disconnect
the electrical plug from the actuator. Replace in
thereverseorder.
6.23 DIVERTOR VALVECARTRIDGE fig.26
Carry out component removal procedure as de-
scribed in 6.4.
Remove the valve actuator as described in 6.22.
Removethecartridgelockingpin(C)and-usinga
suitable pair of pliers - withdraw the cartridge
assembly. The cartridge assembly is a non-
serviceable item and therefore needs to be re-
placedifit’ssuspectedasbeingdamagedorworn.
Fig. 26
Fig. 26a
Replace in the reverse order ensuring that the
seating cam inserts into the locating groove
correctly (see fig. 26a). Ensure all seals are in
good condition, taking care to ensure they are
replacedcorrectly.
6.24 DHWTHERMISTORfig. 27
Carry out component removal procedure as de-
scribed in 6.4.
Disconnect the electrical plug. Using a suitable
pairofpliers,removethethermistorlockingpin(E)
and ease the thermistor (F) from its seating.
Replaceinthereverseorderensuringthesealing
ring is in good condition.
6.25 AUTO BY-PASS VALVE fig. 27
Carry out component removal procedure as de-
scribed in 6.4.
Locateandremovethehydrauliccoverlockingpin
(A)andremovethecover.Usingasuitablehooked
wireorscrewdriver,gentlyeasethe valve(C)from
itsseating.Ensureallsealsareingoodcondition,
takingcaretoensuretheyarereplacedcorrectly.
Replaceinthereverseorderensuringthecartridge
is facing the correct way.
6.26 DHWNON-RETURNVALVEfig.27
Carry out component removal procedure as de-
scribed in 6.4.
Locateandremovethehydrauliccoverlockingpin
(A)andremovethecover.Usingasuitablehooked
wire or screwdriver, gently ease the non-return
valve (D) from its seating. Ensure all seals are in
good condition, taking care to ensure they are
replaced correctly. Replace in the reverse order
ensuring the cartridge is facing the correct way.
6.27 EXPANSION VESSEL fig. 1
Shouldtheremovalandreplacementoftheexpan-
sion vessel be deemed impractical, an external
expansionvessel may be fitted to the return pipe
as close to the appliance as possible.
6.27.1 EXPANSION VESSEL REMOVAL (with suffi-
cientclearanceabove)
Carry out component removal procedure as de-
scribed in 6.4.
Disconnect the flue from the appliance.
Disconnect the flexible expansion pipe from the
vessel. Locate and remove the four screws (A)
that secure the vessel top holding plate (B),
remove the plate (fig. 28). The expansion vessel
E
E
D
C