VOKERA Mynute 12HE User guide

Supplied By www.heating spares.co Tel. [phone]
Installation
&Servicing
Instructions
THESEINSTRUCTIONS
TOBERETAINED
BYUSER
0694
0694BR1207

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Contents
Designprinciples&operatingsequence Page
1.1 Principle components 3
1.2 Mode of operation (at rest) 3
1.3 Mode of operation 3
1.4 Safety devices 3
Technicaldata Page
2.1 Central heating 4
2.2 Gas pressures 4
2.3 Expansion vessel 4
2.4 Dimensions 4
2.5 Clearances 4
2.6 Connections 4
2.7 Electrical 4
2.8 Flue details (concentric) 4
2.8A Flue details (twin pipes) 4
2.8B Flue details (80/125) 4
2.9 Efficiency 4
2.10 Emissions 4
2.11 Pump duty 5
Generalrequirements(UK) Page
3.1 Related documents 6
3.2 Location of appliance 6
3.3 Gas supply 6
3.4 Flue system 6
3.5 Air supply 6
3.6 Water circulation 6
3.7 Electrical supply 7
3.8 Mounting on a combustible surface 7
3.9 Timber framed buildings 7
3.10 Inhibitors 7
Generalrequirements(EIRE) Page
3A.1 Related documents 8
3A.2 Location of appliance 8
3A.3 Gas supply 8
3A.4 Flue system 8
3A.5 Air supply 8
3A.6 Water circulation 8
3A.7 Electrical supply 9
3A.8 Mounting on a combustible surface 9
3A.9 Timber framed buildings 9
3A.10Inhibitors 9
3A.11Declaration of conformity 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
4.6 Connecting the gas & water 14
4.7 Electrical connections 14
Commissioning Page
5.1 Gas supply installation 16
5.2 The heating system 16
5.3 Initial filling of the system 16
5.4 Initial flushing of the system 16
5.5 Pre-operation checks 16
5.6 Initiallighting 16
5.7 Checking gas pressure & combustion analysis 16
5.8 Final flushing of the heating system 17
5.9 Setting the boiler operating temperature 17
5.10 Setting the system design pressure 17
5.11 Regulating the central heating system 17
5.12 Final checks 17
5.13 Instructing the user 17
Servicing Page
6.1 General 18
6.2 Routine annual servicing 18
6.3 Replacement of components 18
6.4 Component removal procedure 18
6.5 Pump assembly 18
6.6 Safety valve 18
6.7 Lower automatic air release valves 19
6.8 Water pressure switch 19
6.9 Primary thermistor 19
6.10 Return thermistor 19
6.11 Printed circuit board 19
6.12 Gas valve 19
6.13 Electrodes and condense sensor 20
6.14 Flue fan & mixer 20
6.15 Burner 20
6.16 Main heat exchanger 20
6.17 Automatic by-pass 21
6.18 Expansion vessel 21
6.19 Condense trap removal 21
6.20 Flue collector removal 22
Checks,adjustmentsandfaultfinding Page
7.1 Checking appliance operation 22
7.2 Appliance modes of operation 22
7.3 Appliance fan speed 23
7.4 Checking the CO2 & adjusting the valve 24
7.5 Combustion analysis test 24
7.6 Checking the expansion vessel 24
7.7 External faults 24
7.8 Electrical checks 24
7.9 Fault finding 25
7.10 Component values & characteristics 25
7.11 Boiler configuration 27
7.12 Final fault codes 26
Wiringdiagrams Page
8.1 External wiring 27
8.2 Typical control applications 27
8.3 Other devices 27
8.4 Vokera twin-channel programmer 27
Explodeddiagrams Page
9.1 Table 1 31
9.2 Table 2 32
9.3 Table 3 33
9.4 Table 4 34
9.5 Table 5 35
L.P.G.instructions Page
10.1 Related documents 36
10.2 Technical data 36
10.3 Converting the appliance gas type 36
10.4 Gas supply 36
10.5 Gas supply installation 36
10.6 Adjusting the gas valve 36
10.7 Appliance fan speed 37
Benchmark 38-39

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Generallayout(fig.1)
1 Safety valve
2 Pressure switch
3 Pump
4 Bottom auto air vent (AAV)
5 Injector
6 Condense trap
7 Return sensor
8 Flue gas analysis test point
9 Flue outlet & air intake
10 Ignition transformer
11 Top AAV
12 Flow sensor
13 High limit thermostat
14 Limit thermostat
15 Sensing Electrode
16 Spark Electrode
17 Cylindric Burner
18 Condensate level sensor
19 Main heat exchanger
20 Top AAV pipe
21 Fan assembly
22 Mixer
23 Expansion vessel
24 Hydraulic manifold
25 Gas valve
26 Condensing drain
R Heating return connection
F Heating flow connection
G Gas connection
The Mynute HE comprises a range of high-efficiency
system boilers with outputs ranging from 12 to 35kW.
These appliances – by design – incorporate electronic
ignition, circulating pump, expansion vessel, safety val-
ve,pressure gauge,and automaticby-pass.
The Mynute HE range are produced as room sealed,
category II2H3P appliances, suitable for internal wall
mounting applications only. Each appliance is provided
with a fan powered flue outlet with an annular co-axial
combustionair intakethat canberotated –horizontally –
through 360 degrees for various horizontal or vertical
applications.The Mynute HE can also be used with the
Vokera twin flue system.The Mynute HE is approved for
use with C13 & C33 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.
This booklet is an integral part of the appliance. It is
thereforenecessary toensure that thebooklet ishanded
to the person responsible for the property in which the
appliance is located/installed. A replacement copy can
be obtained fromVokera customer services.
INTRODUCTION
Fig. 1
Mynute
12-15-20-25 HE
Mynute
30-35 HE
GF
R
G
F
R

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Fig.1A
Boiler at reset/standby Select this position if/when the boiler requirestobereset
BoilerswitchedOFF Select this positionif youwantthe boilerto remainOFF (thiswill over-rideany
heating/hotwaterrequestfromthetime-clock/programmer)
BoilerswitchedON Select thisposition whenyouwantthe boilerto respondto aheating/hot water
requestfromthetime-clock/programmer
Temperatureselector Movethe temperature selectorclockwisetoincreasethe boiler outlet temperature,or
counter-clockwisetoreducetheoutletflowtemperature
2-digitLEDdisplay Displaysthe currentoutlettemperatureof theboiler. During afaultcondition,the
appropriatefaultcodewillbedisplayed(referto the usershandbookforinstructions
regardingfaultcodes)
GreenLEDlit Boilerisworking/respondingtoaheating/hotwater request
RedLEDlit Boilerhas identifieda faultand has failed-safe. Referto usershandbook for
instructionsonhowtoreset
Pressuregauge Ensurethesystempressureissetcorrectly(minimum0.5-bar)
MODESELECTOR
SWITCH
RED LED
GREENLED TEMPERATURESELECTOR
2-digitLED
display
HYDROMETRE
°C

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1.1 PRINCIPLECOMPONENTS
Afullyintegratedelectroniccontrolboardfeaturing
electronictemperaturecontrol,anti-cyclecontrol,
pumpover-run,self-diagnosticfaultindicator,full
air/gasmodulation.
●●
●●
●Radialaluminiumheatexchanger.
●●
●●
●Electronic ignition with flame supervision
●●
●●
●Integralhigh-headpump
●●
●●
●Fan
●●
●●
●Expansion vessel
●●
●●
●Waterpressureswitch
●●
●●
●Condensatelevelsensor
●●
●●
●Pressuregauge
●●
●●
●Safety valve
1.2 MODEOFOPERATION(atrest)
When the appliance is at rest and there are no
requests for heating or hot water, the following
functions are active:
●●
●●
●2-stage frost-protection system – the frost-
protectionsystemprotectstheapplianceagainst
therisk offrost damage. Thefirst stageenables
activation of the pump should the temperature
oftheappliancefallto6oC.Shouldthefirststage
become active, the appliance will function on
minimum +25% power until it reaches 35oC.
●●
●●
●Anti-block function – the anti-block function
enables the pump to be energised for short
periods, when the appliance has been inactive
formorethan24-hours.
1.3 MODEOFOPERATION
Whenthereisarequestforheatand/orhotwater,
viatheprogrammer/timeclockand/oranyexternal
control, the pump and fan are started, the fan
speedwillmodulateuntilthecorrectsignalvoltage
is received at the control PCB. At this point an
ignitionsequenceisenabled.
Ignition is sensed by the electronic circuitry to
ensure flame stability at the burner. Once
successful ignition has been achieved, the
electroniccircuitry increasesthegas rateto 75%
oftheMAXHeating(setbythecorrespondingHTG
trimmer) for a period of 15 minutes. Thereafter,
the boiler’s output will either be increase to
maximumormodulateto suitthe set requirement.
When the appliance reaches the desired
temperature the burner will shut down and the
boilerwillperformathree-minuteanti-cycle(timer
delay).
Whenthe requestfor heathas been satisfiedthe
appliancepumpandfanmaycontinuetooperate
todissipateanyresidualheatwithintheappliance.
1.4 SAFETY DEVICES
When the appliance is in use, safe operation is
ensuredby:
●●
●●
●a water pressure switch that monitors system
water pressure and will de-activate the pump
(when lockout condition is reached), fan and
burner should the system water pressure drop
belowthe ratedtolerance;
●●
●●
●fanspeedsensortoensuresafeoperationofthe
burner;
●●
●●
●a high limit thermostat that over-rides the tem-
peraturecontrolcircuittopreventorinterruptthe
operationoftheburner;
●●
●●
●flamesensorthatwillshutdowntheburnerwhen
no flame signal is detected;
●●
●●
●a sensor that interrupts the operation of the
applianceifthecondensepipebecomesblocked;
●●
●●
●asafety valvewhichreleases excesspressure
from the primary circuit.
Fig. 2
SECTION1 DESIGN PRINCIPLESAND OPERATINGSEQUENCE
expansion
vessel
CH
return
safety
valve
pump
return
temperature
sensor mainheat
exchanger
bottom
AAV
automatic
by-pass
pressure
switch
CH
flow
drain
valve

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Ref. Condition 15 °C, 1013,25 mbar, dry gas
NOTE: L.P.G. data refer to section 10
SECTION2 TECHNICALDATA
2.1 Central Heating 12HE 15HE 20HE 25HE 30HE 35HE
Heat input (kW) 12 15 20 25 30 34.6
Maximum heat output (kW) 60/80°C 11.84 14.81 19.68 24.53 29.31 33.67
Minimum heat output (kW) 60/80°C 3.5 3.5 5 6 7 7
Maximum heat output (kW) 30/50°C 12.74 15.90 21.16 26.30 6.84 36.54
Minimum heat output (kW) 30/50°C 3.7 3.71 5.30 6.37 7.41 7.41
Minimum working pressure 0.5 bar
Maximum working pressure 2.7 bar
Minimum flow rate 350 l/h
2.2 Gas Pressures 12HE 15HE 20HE 25HE 30HE 35HE
Inlet pressure (G20) 20.0 mbar
Maximum gas rate (m3/hr) 1.27 1.59 2.12 2.64 3.17 3.66
Minimum gas rate (m3/hr) 0.37 0.37 0.53 0.63 0.74 0.74
Injector size 4.6mm 4.6mm 4.6mm 6.7mm 7.0mm 7.0mm
2.3 Expansion Vessel 12HE 15HE 20HE 25HE 30HE 35HE
Capacity 6-litres 8-litres 10-litres
Maximum system volume 63-litres 76-litres 91-litres
Pre-charge pressure 1.0 bar
2.4 Dimensions 12HE 15HE 20HE 25HE 30HE 35HE
Height 740mm 780mm 780mm
Width 400mm 400mm 450mm
Depth 340mm 358mm 358mm
Dry weight (kg)
2.5 Clearances Mynute HE Range
Sides 12mm
Top 150mm from casing or 25mm above flue elbow (whichever is applicable)
Bottom 150mm
Front 600mm
2.6 Connections Mynute HE Range
Flow & return 22mm
Gas 15mm
Safety valve 15mm
Condense 21mm
2.7 Electrical 12HE 15HE 20HE 25HE 30HE 35HE
Power consumption (Watts) 150 150 150 150 165 165
Supply (V/Hz) 230/50
Internal fuse 3.15A T (for PCB) - 3.15A F (for connections block)
External fuse 3A
2.8 Flue Details (concentric - 60/100) 12HE 15HE 20HE 25HE 30HE 35HE
Maximum horizontal flue length (60/100mm) 7.8m 7.8m 7.8m 7.8m 7.8m 7.8m
Maximum vertical flue length (60/100mm) 8.8m 8.8m 8.8m 8.8m 8.8m 8.8m
2.8A Flue Details (concentric 80/125mm) 12HE 15HE 20HE 25HE 30HE 35HE
Maximum horizontal flue length (80/125mm) 20m 20m 20m 20m 20m 20m
Maximum vertical flue length (80/125mm) 25m 25m 25m 25m 25m 25m
2.8A Flue Details (twin pipes) 12HE 15HE 20HE 25HE 30HE 35HE
Maximum horizontal flue length (80mm/80mm) 40m/40m 40m/40m 40m/40m 40m/40m 40m/40m 40m/40m
Maximum vertical flue length (80mm/80mm) 40m/40m 40m/40m 40m/40m 40m/40m 40m/40m 40m/40m
2.9 Efficiency 12HE 15HE 20HE 25HE 30HE 35HE
SEDBUK (%) 90.7 90.7 90.5 90.4 90.2 90.0
Band‘A’ Band‘A’ Band‘A’ Band‘A’ Band‘A’ Band‘A’
2.10 Emissions 12HE 15HE 20HE 25HE 30HE 35HE
CO2@ maximum output (%) 9.0 9.0 9.0 9.0 9.0 9.0
CO2@ minimum output (%) 9.0 9.0 9.0 9.0 9.0 9.0
CO/CO2ratio @ maximum output 0.001 to 1 0.001 to 1 0.001 to 1 0.0002 to 1 0.0002 to 1 0.0002 to 1
CO/CO2ratio @ minimum output 0.0002 to 1 0.0002 to 1 0.0004 to 1 0.0003 to 1 0.0003 to 1 0.0003 to 1
CO @ maximum output (mg/kWh) 107.5 129.0 161.3 204.3 215 268.8
CO @ minimum output (mg/kWh) 21.5 21.5 43.0 32.3 32.3 32.3
NOx @ maximum output mg/kWh) 88.3 88.3 79.4 88.3 88.3 88.3
NOx @ minimum output (mg/kWh) 35.3 35.5 53.0 61.8 70.6 70.6
NOx rating class 5 class 5 class 5 class 5 class 5 class 5

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Fig. 4
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 25 mm
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
2.11 PUMP DUTY
Fig.3 showsthe flow-rate available– afterallow-
ing for pressure loss through the appliance – for
system requirements. When using this graph,
apply only the pressure loss of the system. The
graphisbasedona20°Ctemperaturedifferential.
Fig. 3
Flow rate (l/h)
Residual head (x 100 mbar)
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
1,6
1,8
2,0
2,2
2,4
2,6
2,8
3,0
3,2
3,4
3,6
3,8
4,0
4,2
4,4
4,6
4,8
5,0
0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500
1st speed
2ndspeed
3rd speed
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
1,6
1,8
2,0
2,2
2,4
2,6
2,8
3,0
3,2
3,4
3,6
3,8
4,0
4,2
4,4
4,6
4,8
5,0
5,2
5,4
5,6
5,8
6,0
0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500
Flow rate (l/h)
Residual head (x 100 mbar)
1st speed
2ndspeed
3rd speed
Mynute
12-15-20-25 HE Mynute 30-35 HE

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SECTION3 GENERALREQUIREMENTS(UK)
This appliance must be installed by a competent person
in accordance with the Gas Safety (Installation & Use)
Regulations.
3.1 RELATEDDOCUMENTS
The installation of this boiler must be in accord-
ance with the relevant requirements of the Gas
Safety(Installation &Use) Regulations,the local
buildingregulations,thecurrentI.E.E.wiringregu-
lations,thebylawsofthelocalwaterundertaking,
theBuildingStandards(Scotland)Regulation,and
BuildingStandards(NorthernIreland)Regulations.
Itshould bein accordancealsowith anyrelevant
requirements of the local authority and the rel-
evant recommendations of the following British
StandardCodes ofPractice.
3.2 LOCATIONOFAPPLIANCE
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.
wiringregulations, andin Scotland,the electrical
provisions of the Building Regulations, with re-
specttotheinstallationoftheapplianceinaroom
orinternal spacecontaininga bathor 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
adequateairsupplyforcombustionpurposesand
anadequatespaceforservicingandaircirculation
aroundtheappliance.Wheretheinstallationofthe
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
mustbedesignedandconstructedspecificallyfor
thispurpose.Anexistingcompartment/cupboard
maybeutilisedprovidedthatitismodifiedtosuit.
Details of essential features of compartment/
cupboarddesignincludingairingcupboardinstal-
lationsaregiveninBS6798.Thisapplianceisnot
suitablefor externalinstallation.
3.3 GAS SUPPLY
Thegasmeter–assuppliedbythegassupplier–
must be checked to ensure that it is of adequate
sizetodealwiththemaximumratedinputofallthe
appliancesthat itserves. Installation pipesmust
be fitted in accordance with BS 6891.
Pipe work from the meter to the appliance must
beof adequatesize. Pipesof asmaller size than
the appliance gas inlet connection must not be
used. The installation must be tested for sound-
ness in accordance with BS6891.
Ifthegassupply servesmore than oneappliance,
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).
In cold and/or humid weather, water vapour will
condense on leaving the terminal; the effect of
such pluming must be considered.
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.
Referto BS 5440Part1, whenthe terminalis0.5
metres(orless)belowplasticgutteringor1metre
(orless) below paintedeaves.
3.5 AIR SUPPLY
Thefollowingnotesareintendedforgeneralguid-
ance only.
Thisapplianceisaroom-sealed,fan-fluedboiler,
consequentlyit doesnot requirea permanentair
vent for combustion air supply.
When installed in a cupboard or compartment,
ventilation for cooling purposes is also not re-
quired.
3.6 WATERCIRCULATION
Detailedrecommendationsare giveninBS 5449
Part 1 and BS 6798. The following notes are for
generalguidanceonly.
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
BS 5440
BS 5449
BS 6798
BS 6891
BS 7074
PART 2
PART 1
PART 1
FLUES & VENTILATION
FORCED CIRCULATION HOT WATER SYSTEMS
INSTALLATION OF BOILERS OF RATED INPUT NOT EXCEEDING 60kW
LOW PRESSURE INSTALLATION PIPES
APPLICATION, SELECTION, AND INSTALLTION OF EXPANSION VESSELS AND ANCIL-
LARY EQUIPMENT FOR SEALED WATER SYSTEMS

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Make-up vessel
or tank
Automatic
air-vent
Non-return
valve Stopcock
5.0 metres minimum
Heating
return
ventilatedareas suchas underfloors, loftspace,
andvoidareas.
3.6.2 AUTOMATICBY-PASS
The appliance has a built-in automatic by-pass,
consequentlythereisnorequirementforanexter-
nal by-pass, however the design of the system
should be such that it prevents boiler ‘cycling’.
3.6.3 DRAINCOCKS
Thesemust belocated inaccessible positionsto
facilitate draining of the appliance and all water
pipesconnectedtotheappliance.Thedraincocks
must be manufactured in accordance with BS
2879.
3.6.4 AIR RELEASE POINTS
Thesemustbepositionedatthehighestpointsin
thesystemwhere airis likelytobetrapped. They
should be used to expel trapped air and allow
complete filling of the system.
3.6.5 EXPANSION VESSEL
Theappliancehasanintegralexpansionvesselto
accommodate the increased volume of water
when the system is heated. It can accept up to 6
litres (12-15-20HE), 8 (25HE) and 10 litres (30-
35HE)ofexpansionfromwithinthesystem, gen-
erallythis issufficient,however ifthesystem has
anunusuallyhighwatercontent,itmaybeneces-
sarytoprovideadditionalexpansioncapacity(see
6.19).
3.6.6 FILLINGPOINT
A method for initial filling of the system and re-
placingwaterlost duringservicingetc.is required
(see fig. 5). This method of filling must comply
with the current Water Supply (Water Fittings)
Regulations1999 andWater Bylaws2000 (Scot-
land).
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
andstopcockforisolationpurposes.Thefeedpipe
shouldbeconnectedtothereturnpipeascloseto
the boiler as possible.
3.6.8 FREQUENTFILLING
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
aspectsofthesystemarecapableofwithstanding
pressures up to at least 3 bar.
3.7 ELECTRICALSUPPLY
Theapplianceissuppliedforoperationon230V@
50Hzelectricalsupply;itmustbeprotectedwitha
3-amp fuse. The method of connection to the
mains electricity supply must allow for complete
isolationfromthesupply.Thepreferredmethodis
by using a double-pole switch with a contact
separation of at least 3,5mm (3° high-voltage
category).Theswitchmustonlysupplytheappli-
ance and its corresponding controls, i.e. time
clock, room thermostat, etc. Alternatively an un-
switchedshutteredsocketwithafused3-pinplug
both complying with BS 1363 is acceptable.
3.8 MOUNTINGONACOMBUSTIBLESURFACE
Iftheapplianceistobefittedonawallofcombus-
tible material, a sheet of fireproof material must
protect the wall.
3.9 TIMBERFRAMEDBUILDINGS
If the appliance is to be fitted in a timber framed
building,itshouldbefittedinaccordancewiththe
InstituteofGasEngineerspublication(IGE/UP/7)
‘Guide for Gas Installations in Timber Frame
Buildings’.
3.10 INHIBITORS
Vokerarecommend thatan inhibitor- suitable for
usewith copperand aluminium heatexchangers
- is used to protect the boiler and system from
theeffects ofcorrosion and/or electrolyticaction.
The inhibitor must be administered in strict ac-
cordancewith themanufacturers instructions*.
*Watertreatmentofthecompleteheatingsystem
- including the boiler - should be carried out in
accordancewithBS7593andtheDomesticWater
Treatment Association’s (DWTA) code of prac-
tice.
flow/return
pipe
control
valve
temporary
connection
control
valve
supply
pipe
double
check valve
Fig. 5
Fig. 5A

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This appliance must be installed by a competent
person in accordance with and defined by, the
Standard Specification (Domestic Gas Installa-
tions)Declaration (I.S.813).
3A.1 RELATEDDOCUMENTS
The installation of this boiler must be in accord-
ance with the relevant requirements of the local
building regulations, the current ETCI National
RulesforElectricalInstallationsandthebylawsof
thelocalwaterundertaking.
Itshould bein accordancealsowith anyrelevant
requirementsof thelocaland/or districtauthority.
3A.2 LOCATIONOFAPPLIANCE
The appliance may be installed in any room or
internal space, although particular attention is
drawn to the requirements of the current ETCI
NationalRulesfor ElectricalInstallations, andI.S.
813, Annex K.
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
adequateairsupplyforcombustionpurposesand
anadequatespaceforservicingandaircirculation
aroundtheappliance.Wheretheinstallationofthe
appliance will be in an unusual location special
proceduresmaybenecessary,refertoI.S.813for
detailed guidance on this aspect.
A compartment used to enclose the appliance
mustbedesignedandconstructedspecificallyfor
thispurpose. Anexistingcompartment/cupboard
maybeutilisedprovidedthatitismodifiedtosuit.
Thisapplianceisnotsuitableforexternalinstalla-
tion.
3A.3 GAS SUPPLY
Thegasmeter–assuppliedbythegassupplier–
must be checked to ensure that it is of adequate
sizetodealwiththemaximumratedinputofallthe
appliances that it serves. Installation pipes must
be fitted in accordance with I.S. 813.
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 I.S. 813.
Ifthegassupply servesmore than oneappliance,
it must be ensured that an adequate supply is
maintained to each appliance when they are in
use at the same time.
3A.4 FLUE SYSTEM
Theterminalshouldbelocatedwherethedisper-
sal of combustion products is not impeded and
withdueregardforthedamageanddiscoloration
thatmayoccurtobuildingproductslocatednearby.
Theterminalmustnotbelocatedinaplacewhere
it is likely to cause a nuisance (see I.S. 813).
In cold and/or humid weather, water vapour will
condense on leaving the terminal; the effect of
such pluming must be considered.
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.
RefertoI.S.813,whentheterminalis0.5 metres
(orless)belowplasticgutteringor1metre(orless)
belowpaintedeaves.
3A.5 AIR SUPPLY
Thefollowingnotesareintendedforgeneralguid-
ance only.
Thisapplianceisaroom-sealed,fan-fluedboiler,
consequentlyit doesnot requirea permanentair
vent for combustion air supply.
When installed in a cupboard or compartment,
ventilation for cooling purposes is also not re-
quired.
3A.6 WATERCIRCULATION
Specific recommendations are given in I.S. 813.
Thefollowingnotesareforgeneralguidanceonly.
3A.6.1 PIPEWORK
It is recommended that copper tubing be used in
conjunctionwith solderedcapillary 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
ventilatedareas suchas underfloors, loftspace,
andvoidareas.
3A.6.2 A UTOMATICBY-PASS
The appliance has a built-in automatic by-pass,
consequentlythereisnorequirementforanexter-
nal by-pass, however the design of the system
should be such that it prevents boiler ‘cycling’.
3A.6.3 DRAINCOCKS
Thesemust belocated inaccessible positionsto
facilitate draining of the appliance and all water
pipesconnected to the appliance.
3A.6.4 AIR RELEASE POINTS
Thesemustbepositionedatthehighestpointsin
thesystemwhere airis likelytobetrapped. They
should be used to expel trapped air and allow
complete filling of the system.
3A.6.5 EXPANSION VESSEL
Theappliancehasanintegralexpansionvesselto
accommodate the increased volume of water
when the system is heated. It can accept up to 6
litres (12-15-20HE), 8 (25HE) and 10 litres (30-
35HE)ofexpansionfromwithinthesystem, gen-
erallythis issufficient,however ifthesystem has
anunusuallyhighwatercontent,itmaybeneces-
sarytoprovideadditionalexpansioncapacity(see
6.19).
SECTION3A GENERALREQUIREMENTS(EIRE)

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Fig. 6
3A.6.6 FILLINGPOINT
Amethodforinitialfillingofthesystemandreplacing
water lost during servicing etc. is required. You
should ensure this method of filling complies with
thelocalwaterauthorityregulations.
3A.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. 5).
The cold feed from the make-up vessel or tank
must be fitted with an approved non-return valve
andstopcockforisolationpurposes.Thefeedpipe
shouldbeconnectedtothereturnpipeascloseto
the boiler as possible.
3A.6.8 FREQUENTFILLING
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
aspectsofthesystemarecapableofwithstanding
pressures up to at least 3 bar.
3A.7 ELECTRICALSUPPLY
Theapplianceissuppliedforoperationon230V@
50Hzelectricalsupply;itmustbeprotectedwitha
3-amp fuse. The method of connection to the
mains electricity supply must allow for complete
isolationfromthesupply.Thepreferredmethodis
by using a double-pole switch with a contact
separation of at least 3,5mm (3° high-voltage
category).Theswitchmustonlysupplytheappli-
ance and its corresponding controls, i.e. time
clock, room thermostat, etc.
3A.8 MOUNTINGONACOMBUSTIBLESURFACE
Iftheapplianceistobefittedonawallofcombus-
tible material, a sheet of fireproof material must
protect the wall.
3A.9 TIMBERFRAMEDBUILDINGS
If the appliance is to be fitted in a timber framed
building,itshouldbefittedinaccordancewithI.S.
813andlocalBuildingRegulations.
The Institute of Gas Engineers publication (IGE/
UP/7)‘GuideforGasInstallationsinTimberFrame
Buildings’ gives specific advice on this type of
installation.
3A.10 INHIBITORS
Vokerarecommend thatan inhibitor- suitable for
use with 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 accordance with
themanufacturers instructions*.
*Watertreatmentofthecompleteheatingsystem-
includingtheboiler-shouldbecarriedoutinaccord-
ance with I.S. 813 and the Domestic Water Treat-
ment Association’s (DWTA) code of practice.
3A.11 DECLARATION OF CONFORMITY
ADeclarationofConformity(asdefinedinI.S.813)
mustbeprovidedoncompletionoftheinstallation.
A copy of the declaration must be given to the
responsibleperson andalso tothe gas supplierif
required.
Mynute
12-15-20 HE
Mynute
25-30-35 HE

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Using the template provided, mark and drill a
115mmhole for thepassageof theflue pipe.The
holeshould bedrilledtoensureanycondensefluid
thatforms,isallowedtodrainbacktotheappliance
(seefig. 7A).
The fixing holes for the wall-mounting bracket
shouldnowbedrilledandplugged,anappropriate
type and quantity of fixing should be used to
ensurethatthebracketismounted securely.Once
the bracket has been secured to the wall, mount
the appliance onto the bracket.
Horizontal flue terminals and accessories
Part No. Description Length
520
521
522
523
524
525
526
527
528
529
Horizontal flue kit
Telescopic flue kit
Plume management kit
90-degree bend
45-degree bends (pair)
500mm extension
1000mm extension
2000m extension
Telescopic extension
Wall bracket pack (5)
900 mm
350 /530 mm
1370 mm
N/A
N/A
500mm
1000 mm
2000 mm
350 /730 mm
208mm
Reduction for additional bends
Bend Reduction in maximum flue length for each bend
45° bend
90° bend
0.5 metre
1.0 metre
4.1 DELIVERY
Due to the weight of the appliance it may be
necessary for two people to lift and attach the
appliance to its mounting. The appliance is con-
tainedwithinaheavy-dutycardboardcarton.Laythe
cartononthefloorwiththewritingthecorrectwayup.
4.2 CONTENTS
Containedwithin the carton is:
•theboiler
•the wall bracket
•template
•anaccessoriespackcontainingapplianceserv-
iceconnectionsand washers
•theinstructionpackcontainingtheinstallation&
servicing instructions, user instructions, guar-
anteeregistration card,and a3-ampfuse.
4.3 UNPACKING
At the top of the carton pull both sides open – do
notuseaknife–unfoldtherestofthecartonfrom
aroundtheappliance,carefullyremoveallprotec-
tive 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 MOUNTINGTHE APPLI-
ANCE
The appliance should be mounted on a smooth,
vertical,non-combustiblesurface,whichmustbe
capable of supporting the full weight of the appli-
ance.Careshouldbeexercisedwhendetermining
thepositionoftheappliancewithrespecttohidden
obstructions such as pipes, cables, etc.
When the position of the appliance has been
decided–usingthetemplatesupplied–carefully
mark the position of the wall- mounting bracket
(seefig. 6)and flue-hole(if applicable).
4.5 FITTING THE FLUE
The top flue outlet permits both horizontal and
verticalflueapplicationstobeconsidered,alterna-
tively,theVokeratwinfluesystemcanbeutilised
iflongerfluerunsarerequired.
4.5.1 CONCENTRICHORIZONTAL FLUE
(For concentric vertical flue,see 4.5.2)
(For twinflue applications,see 4.5.3)
TheappliancecanbeusedwitheithertheVokera
condensing60/100mmconcentricfluesystemor
the optional 80/125mm concentric flue system.
NOTE
These instructions relate only to the Vokera
condensing 60/100mm concentric flue system.
For specific details on the installation of the 80/
125mmconcentricfluesystempleaserefertothe
instructionssupplied.
The appliance flue outlet elbow can be rotated
through 360º on its vertical axis. In addition the
fluemaybeextendedfromtheoutletelbowinthe
horizontalplane (see2.8). Areduction mustalso
bemadetothemaximumlength(seetablebelow)
whenadditionalbendsareused.
SECTION4 INSTALLATION
Fig. 7

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11
FITTINGTHE HORIZONTAL FLUE KIT
Carefullymeasurethe distancefromthecentre of
theapplianceflueoutletto theedgeof thefinished
outside wall (dimension X). Add 65mm to
dimensionXto giveyouDimensionY (seefig 7A).
Measure dimension Y from the terminal end of
the concentric flue pipe and cut off the excess
ensuring any burrs are removed. Pass the
concentricflue pipethroughthe previouslydrilled
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.
Using the clamp, gasket, and screws supplied,
secure the flue bend to the appliance flue spigot.
NOTE
Fit the internal (white) trim to the flue assembly
prior to connecting the flue pipe to the bend.
You must ensure that the entire flue system is
properly supportedandconnected.
Seal the flue assembly to the wall using cement
or a suitable alternative that will provide
satisfactoryweatherproofing.Theexteriortrim can
now be fitted.
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.Theadditional bends& extensionshave
push-fit connections, care should be taken to
ensure that the correct seal is made when
assemblingtheflue system. Connectthe required
number of flue extensions or bends (up to the
maximumequivalentfluelength)totheflueterminal
(see fig. 7 & 8).
The flue system should have a minimum of 1º;
maximum of 3° rise from the boiler to outside, to
ensure any condense fluid that forms, is allowed
to drain back to the appliance.
NOTE
Whencutting anextension totherequired length,
you must ensure that the excess is cut from the
plainendoftheextension(see fig. 7&8). Remove
any burrs, and check that all seals are located
properly.
You must ensure that the entire flue system is
properly supportedandconnected.
Fig. 7A
Fig. 8
Seal the flue assembly to the wall using cement
or a suitable alternative that will provide
satisfactory weatherproofing. The interior and
exterior trim can now be fitted.
4.5.2 CONCENTRICVERTICALFLUE
Theappliance can beusedwith eithertheVokera
condensing60/100mm concentricfluesystem or
the optional 80/125mm concentric flue system.
NOTE
These instructions relate only to the Vokera
condensing 60/100mm concentric flue system.
For specific details on the installation of the 80/
125mmconcentricflue systemplease refertothe
instructionssupplied.
Theverticalflueterminalcanbeconnecteddirectly
to the appliance flue outlet. Alternatively, an
extension or bend can be connected to the
applianceflueoutletifdesired(see4.4.2),however
ifadditional bendsare fitted,areduction mustbe
made to the maximum flue length (see table in
thenext page).
“X”
“Y”
30mm
1-3 degree
“X” + 65mm = “Y”

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Reductioninmaximumfluelengthforeachbend
Reductionforbends
Bend
45°bend
90°bend 1.0metre
1.0metre
Reductionforbends
Bend Reductioninmaximumfluelengthforeachbend
45°bend
90°bend 0.5metre
1.0metre
Vertical flue terminaland accessories
Part No. Description Min-Max length
530
531
532
523
524
525
526
527
528
529
Verticalflueterminal
Pitchedroof flashing plate
Flatroof flashing plate
90-degreebend
45-degreebends(pair)
500mmextension
1000mmextension
2000mmextension
Telescopic extension
Wall bracketpack(5)
1000mm
N/A
N/A
N/A
N/A
500mm
1000mm
2000mm
350/730mm
208mm
Usingthedimensionsgiveninfig.9asareference,
mark and cut a 115mm hole in the ceiling and/or
roof.
Fit the appropriate flashing plate to the roof and
insertthe verticalflueterminalthroughtheflashing
platefrom theoutside,ensuring thatthecollar on
the flue terminal fits over the flashing.
The fixing holes for the wall-mounting bracket
shouldnowbedrilledandplugged,anappropriate
type and quantity of fixing should be used to
ensurethatthebracketismounted securely.Once
the bracket has been secured to the wall, mount
the appliance onto the bracket.
IMPORTANT
The vertical flue terminal is 1.0 metre in length
andcannot becut;therefore itmaybe necessary
toadjust theheightof theappliance to suitor use
a suitable extension.
Fig. 9
Connect the vertical flue assembly to the boiler
fluespigotusingthe100mmclip,gasket,&screws
(supplied),ensuring thecorrect sealismade.The
flue support bracket (supplied with the vertical
flue kit) can now be fitted.
If the vertical flue requires extension/s or
additional 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
systemhaveaminimum 1º;maximum 3ºfall back
to the boiler (1º = 17mm per 1000mm)
NOTE
Whencutting an extensiontothe required length,
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 supportedandconnected.
4.5.3 TWIN FLUE SYSTEM
TheVokeratwin fluesystem enables greaterflue
distances to be achieved (see 4.4.2) than that of
a concentric flue system. It can be used for
horizontalorverticalapplications,howeverthetwin
flue system must be converted to the dedicated
concentric flue kit for termination. It is essential
that the installation of the twin flue system be
carried out in strict accordance with these
instructions.
GUIDANCE NOTES ON TWIN FLUE
INSTALLATION
•Theflue must haveaminimum 1º;maximum 3º
(1º = 17mm per 1000mm) fall back to the
appliancetoallowanycondensatethatmayform
in the flue system to drain via the condensate
drain. Consideration must also be given to the
fact that there is the possibility of a small
amountofcondensatedrippingfromtheterminal.
•Ensurethatthe entire fluesystem isadequately
supported, use at least one bracket for each
extension.
•The entire flue system must be adequately
insulatedtomaintainheatwithin the fluesystem
thereby reducing the possibility of condensate
production.
•As the exhaust outlet pipe can reach very high
temperatures it must be protected to prevent
persons touching the hot surface.
•Thecondensate drainpipe mustbeconnected
inaccordance withbuilding regulations
“X”
12/15/20HE = 202mm
25/30/35HE = 218mm
“X”

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Twinflue accessories
Part No. Description Length
0225805 Horizontal flue terminal 1.0 metre
0225810 Vertical flue terminal 1.0 metre
430 Twin adapter kit N/A
531 Pitched roof flashing plate N/A
532 Flat roof flashing plate N/A
0225815 Condensate drain kit N/A
0225820 0.25m extension (pair) 250mm
0225825 0.5m extension (pair) 500mm
0225830 1.0m extension (pair) 1000mm
0225835 2.0m extension (pair) 2000mm
0225840 45º bend (pair) N/A
0225845 90º bend (pair) N/A
0225850 Twin bracket (5) N/A
0225855 Single bracket (5) N/A
MOUNTINGTHE BOILER
The fixing holes for the wall-mounting bracket
shouldnowbedrilledandplugged,anappropriate
type and quantity of fixing should be used to
ensurethatthebracketismountedsecurely. Once
the bracket has been secured to the wall, mount
the appliance onto the bracket.
4.5.3.1 INSTALLATION OFTWIN ADAPTORKIT(fig.10
&11)
•Inserttheexhaustconnection manifold (A) onto
the appliance flue outlet.
•Removethe blankingplate (located tothe right
oftheapplianceflueoutlet)and–usingthesame
screws – install the air inlet plate (B).
•Using the hole in the exhaust connection
manifold as a guide, drill a 3mm hole in the
appliance flue spigot and secure the exhaust
manifoldconnection tothe fluespigotusing the
screwprovided(C).
•Using the two holes in the air inlet plate as a
guide, drill a 3mm hole in each and secure the
airinlet pipe/bendusing thescrewsprovided.
Thetwinflue pipesextensions andaccessories
can now be installed by pushing together (the
plain end of each extension or bend should be
pushed approximately 50mm into the female
socket of the previous piece).
B
C
A
Fig. 10
4.5.3.2 HORIZONTALTERMINATION (fig.12)
The twin flue system must be converted to the
dedicated concentric flue kit for termination.
•The horizontal terminal is supplied with a built-
in converter box and cannot be shortened.
•A 130mm hole is required for the passage of
theconcentric terminalthrough thewall.
•The air inlet pipe must always be level with or
below, that of the exhaust pipe.
Dependingonsite conditions itmay bepreferable
to install the terminal assembly prior to fitting the
twinflue pipes.
Markanddrill a level130mm holefor thepassage
of the horizontal flue terminal.Insert the terminal
assembly into the flue hole.
Push-fitthe twin flue pipes onto the concentricto
twinconverterboxensuringthatthe exhaust pipe
connects to the exhaust connection on the
concentric to twin converter.
If necessary cut the plain ends (male) of the twin
fluepipes toallow connectiontothe concentricto
twinconverter.
NOTE
Before cutting twin flue pipes ensure allowances
havebeenmade for connectiononto theprevious
piece and onto the concentric to twin converter.
The last twin Flue pipes must be pushed 50mm
onto the male spigots of the concentric to twin
converter.
NOTE
Seal the flue terminal assembly to the wall using
cement or a suitable alternative that will provide
satisfactory weatherproofing. The interior and
exterior trim can now be fitted.
4.5.3.3 VERTICALTERMINATION (fig.13)
The twin flue system must be converted to the
dedicated concentric flue kit for termination.
●●
●●
●The vertical terminal is supplied with a built-in
converter boxand cannotbe shortened.
●●
●●
●A 130mm hole is required for the passage of
theconcentric terminalthroughthe ceilingand/
orroof.
Dependingonsite conditions itmay bepreferable
to install the terminal assembly prior to fitting the
twin flue pipes.
Fit the appropriate flashing plate to the roof and
insertthe verticalflueterminalthroughtheflashing
platefrom theoutside,ensuring thatthe collar on
the flue terminal fits over the flashing.
Push-fitthe twin flue pipes onto the concentricto
twin converter ensuring that the exhaust pipe
connects to the exhaust connection on the
concentric to twin converter.
If necessary cut the plain ends (male) of the twin
fluepipes toallow connectiontothe concentricto
twinconverter.
NOTE
●●
●●
●Beforecuttingtwinfluepipesensureallowances
havebeenmadeforconnectionontotheprevious
pieceand onto theconcentric totwinconverter.
The last twin flue pipes must be pushed 50mm
onto the male spigots of the concentric to twin
converter.
Fig. 11

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4.6 CONNECTINGTHE GASANDWATER
Theapplianceissupplied withservicevalves.The
service valves are of the compression type.The
accessories pack contains sealing washers etc,
for use with the service valves.
Whenconnecting pipe worktothe valves,tighten
the compression end first then insert the sealing
washers before tightening the valve to the
appliance.
●●
●●
●You must ensure that the entire flue system is
properly supportedandconnected.
●●
●●
●Ensurethatanyhorizontalsectionsof pipe have
a 1º fall towards the appliance (17mm per
1000mm).
Fig. 13
NOTE
It will be necessary to hold the valve with one
spannerwhilst tighteningwith another.
4.6.1 GAS (fig. 6)
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)
The appliance is supplied with 22mm service
valvesfortheflowandreturnconnections,connect
a22mmpipe tothe inletofeachvalve andtighten
both nuts.
NOTE
Depending on system requirements, it may
necessarytoincrease the sizeof theflow &return
pipe work after the service valve connections.
4.6.3 SAFETYVALVE (fig. 6)
Connect the safety valve connection pipe to the
safety valve outlet. Connect a discharge pipe to
theother endof thesafety valveconnection pipe
and tighten. The discharge pipe must have a
continuousfallawayfromthe appliance tooutside
and allow any water to drain away thereby
eliminating the possibility of freezing. The
dischargepipemustterminate ina position where
any water – possibly boiling – discharges safely
without causing damage or injury, but is still
visible.
4.6.4 CONDENSE PIPE
During normal operation the boiler produces
condense which is collected in a trap located in
the lower part of the boiler. A flexible pipe
(condense outlet pipe) is connected to the outlet
of the trap.The flexible pipe must be connected
to a plastic waste pipe only. The plastic waste
pipe must have a minimum of a 3º fall towards
the drain. Any external run of pipe should be
insulated to prevent the risk of freezing.
CONNECTINGTHE CONDENSATE OUTLET
Gently pull the condense outlet pipe down from
its location inside the boiler until approximately
100mmprotrudesfrom the underside oftheboiler.
Connect a suitable plastic (not copper) pipe (no
less than 20mm diameter) to the outlet pipe and
ensure it discharges in accordance with building
regulationsor otherrules inforce.
4.7 ELECTRICALCONNECTIONS
The electrical supply must be as specified in
section 3/3A. A qualified electrician should
connect the electrical supply to the appliance. If
controls–externaltotheappliance–are required,
a competent person must undertake the design
of any external electrical circuits, please refer to
section 8 for detailed instructions. ANY
EXTERNAL CONTROL OR WIRING MUST BE
SERVEDFROMTHESAMEISOLATORASTHAT
OFTHE APPLIANCE.The supply cable from the
Fig. 12

Supplied By www.heating spares.co Tel. [phone]
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Fig. 14
isolator to the appliance must be 3-core flexible
sized 0.75mm to BS 6500 or equivalent. Wiring
to the appliance must be rated for operation in
contact with surfaces up to 90ºC.
4.7.1 CASING REMOVAL (fig. 14)
To gain internal access to the appliance you must
firstremovethecasing,proceedasoutlinedbelow:
●●
●●
●remove the 4 screws (B) located at the Left &
Right of the underside of the casing
●●
●●
●lift the casing upward to disengage it from the
top locating hooks and then remove
●●
●●
●store the casing and screws (B) safely until
required.Re-fitin thereverse order.
4.7.3 CONNECTINGTHE MAINS (230V) INPUT (see
fig. 16).
Unhook and remove the terminal block cover
(230V). Pass the cable through the cable
anchoragepoint.
Connectthesupply cable wires(LIVE, NEUTRAL
& EARTH) to their corresponding terminals (L, N
& E) on the appliance - 230V - terminal block.
When connecting the EARTH wire, ensure that
it’sleft slightly longer(about 2cm)that theothers,
thiswill preventstrain on theEARTH wireshould
the cable become taut.
Do not remove the link wire unless additional
external controls are to be fitted (see section 8).
Thesecuringscrewonthecableanchorageshould
now be tightened.This must be done before the
control fascia is re-fitted in the upright position.
Theappliance casing, screws andlowercovercan
nowbe re-fitted.
Fig. 15
Optional devices
(24V) terminal block
Mains (230V)
terminal block
4.7.2 APPLIANCETERMINAL BLOCK
The appliance terminal block is located on the
rear of the control fascia. Remove the casing as
described in 4.7.1. Gently pull the control panel
forwardsanddown.Locatetheterminalblockcover
(seefig. 15).
NOTE
Theappliancecomeswithafactoryfittedlink(‘TA’)
toallowbasic operationofthe boiler viathemode
selector switch. If it is anticipated that external
controlswill berequiredplease refertothe wiring
diagramsinsection8formoredetailedinformation.
Fig. 16
B
BB
B

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5.1 GAS SUPPLY INSTALLATION
Inspect the entire installation including the gas
meter,test for soundnessandpurge.RefertoBS
6891 (I.S. 813 in ROI) for specific instruction.
5.2 THE HEATING SYSTEM
The appliance contains components that may
becomedamaged orrenderedinoperable byoils
and/ordebristhatareresidualfromtheinstallation
of the system, consequently it is essential that
the system be flushed in accordance with the
followinginstructions.
5.3 INITIAL FILLING OFTHE SYSTEM
Ensure both flow and return service valves are
open, remove appliance casing as described in
4.7.1, identify the automatic air release valves
(AAV) and loosen the dust cap/s by turning the
cap anti-clockwise one full turn.
Ensure all manual air release valves located on
theheating system areclosed.Connect thefilling
loop as shown in fig. 5, slowly proceed to fill the
systembyfirstlyopeningtheinletvalveconnected
tothe flowpipe, andthen turning thelever onthe
fill valve, to the open position. As water enters
the system the pressure gauge will begin to rise.
Once the gauge has reached 1 BAR close both
valves and begin venting all manual air release
valves, starting at the lowest first. It may be
necessary to go back and top-up the pressure
until the entire system has been filled. Inspect
the system for water soundness, rectifying any
leaks.
5.3.1 MANUAL AIR RELEASE (fig.17)
Whentheboiler hasbeen filledforthe first timeor
the system has been drained and refilled, it will
be necessary to release any air that may have
become trapped within the appliance heat
exchanger.Slacken the bleedscrewuntilwater is
releasedand thenclose.
IMPORTANT,THERE ARENO OTHERMANUAL
AIR RELEASE VALVES LOCATED ON THE
APPLIANCE.
5.4 INITIAL FLUSHING OFTHE SYSTEM
Thewhole ofthe heatingsystem must beflushed
both cold and hot as detailed in 5.8. Open all
radiatoror heatingvalves andthe applianceflow
&returnservicevalve.Draintheboilerandsystem
from the lowest points. Open the drain valve full
bore to remove any installation debris from the
boilerpriorto lighting.Refill theboilerand heating
system as described in 5.3.
5.5 PRE-OPERATION CHECKS
Beforeattemptingtheinitiallightingoftheappliance,
the following checks must be carried out:
●●
●●
●Ensureall gasservicevalves fromthe meterto
theapplianceare openandthesupply pipehas
beenproperlypurged;
●●
●●
●Ensurethe properelectrical checkshavebeen
carried out, (see 7.8) particularly continuity,
polarity, and resistance to earth;
●●
●●
●Ensure the 3 AMP fuse – supplied with the
appliance – has been fitted;
●●
●●
●Ensurethe systemhasbeen filled,vented, and
the pressure set to 1 BAR;
●●
●●
●Ensurethe flue systemhasbeen fittedproperly
and in accordance with the instructions;
●●
●●
●Ensure all appliance service valves are open.
5.6 INITIAL LIGHTING
Ensure the electrical supply to the appliance is
switched on. Ensure any external controls are
switched to an ‘ON’ position and are calling for
heat.
Move the selector switch to the ON position, the
appliance will now operate as described in 1.2.
Shouldtheappliancefailto ignite, referto 5.6 and/
or section 7.
5.7 CHECKING GAS PRESSURE AND
COMBUSTIONANALYSIS
The appliance is factory set and requires no
additionaladjustment onceinstalled.However to
satisfythe requirementsof GSIUR26/9 (I.S. 813
ROI),itwillbenecessary to gasratethe appliance
using the gas meter that serves the appliance.
If the installation does not include a gas meter
(for example LPG) and there are no means by
whichtocalculatethegas rate, thenacombustion
analysis test must be carried out in accordance
with BS 7967 (UK) to ensure the appliance is left
working safely and correctly.
Additionally, if the gas valve has been adjusted,
replaced, or the appliance has been converted
for use with another gas type, then it becomes
necessary to carry out a combustion analysis/
check to ensure that correct combustion is
occurring.
If there are no means to gas rate the appliance
and/or carry out a combustion analysis check,
then it will not be possible to complete the
commissioningprocedure.
Details on how to carry out the combustion
analysis can be found in section 7.
SECTION 5 COMMISSIONING
Fig. 17

Supplied By www.heating spares.co Tel. [phone]
17
IMPORTANT
It’simperativethatasufficientdynamic–gas–pressure
is maintained at all times. Should the dynamic gas
pressurefallbelowanacceptablelevel,theappliance
maymalfunction or sustaindamage.
5.8 FINAL FLUSHING OFTHE HEATING SYSTEM
The system shall be flushed in accordance with
BS 7593 (I.S. 813 ROI). A cleanser - suitable for
aluminium heat exchangers - should be used. It
shallbe froma reputablemanufacturer andshall
be administered in strict accordance with the
manufacturers’ instructions and the DWTA code
of practice.
5.8.1 INHIBITORS
SeeSection 3 “GeneralRequirements”.
5.9 SETTING THE BOILER OPERATING TEMPE-
RATURE
Theflowoutlettemperaturecanbeadjustedbetween
40°C-80°CforstandardCHsystemsandbetween
20 °C - 45°C for under-floor CH systems (see par.
7.11)via theHeatingthermostat knob(seefig.1).
5.10 SETTINGTHE SYSTEM DESIGN PRESSURE
Thedesign pressureshouldbe aminimumof 0.5
BAR and a maximum of 1.5 BAR. The actual
reading should ideally be 1 BAR plus the
equivalent height in metres (0.1 BAR = 1 metre)
tothe highestpointin thesystemabove thebase
of the appliance (up to the maximum of 1.5 BAR
total).N.B.The safety valveis setto liftat 3BAR/
30 metres/45 psig.To lower the system pressure
to the required value, drain off some water from
theappliance drainvalveuntil therequired figure
registerson thepressure gauge(seefig. 1).
5.11 REGULATING THE CENTRAL HEATING
SYSTEM
Fully open all radiator and circuit valves and run
theappliance forboth heating andhot wateruntil
heatedwateris circulating.If conditionsare warm
remove any thermostatic heads. Adjust radiator
returnvalves and anybranchcircuit returnvalves
untiltheindividualreturntemperatures are correct
andare approximately equal.
5.12 FINALCHECKS
●●
●●
●ENSURE ALL TEST NIPPLES ON THE
APPLIANCE GAS VALVE ARE TIGHT AND
CHECKEDFORSOUNDNESS.
●●
●●
●ENSURETHE APPLIANCEFLUE SYSTEMIS
FITTED CORRECTLY AND IS PROPERLY
SECURED.
●●
●●
●ENSURE ALL PIPE WORK IS RE-CHECKED
FORSOUNDNESS.
●●
●●
●RE-FITAPPLIANCE CASING.
●●
●●
●COMPLETEBENCHMARKCHECKLIST.
FORUK ONLY
Completedetailsoftheboiler,controls,installation
and commissioning in the Benchmark checklist
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 INSTRUCTINGTHE USER
Hand over all documentation supplied with this
appliance – including these instructions – and
explain the 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
howto operate theapplianceand anyassociated
controls correctly.
Showthe userthe location ofthe fillingvalveand
how to top-up the system pressure correctly and
showthe location ofallmanual airrelease points.
Explain to the user how to turn off the appliance
for bothlongand shortperiodsand advise onthe
necessaryprecautions toprevent frostdamage.
Explain to the user that for continued safe and
efficientoperation,theappliancemustbeserviced
annuallyby acompetent person.
IMPORTANT
Tovalidatethe appliance warranty, it’s necessary
to register the appliance details with us. The
warrantycan beregistered inseveral ways:
●●
●●
●bycompletingthewarrantyregistrationcardand
posting to us using the pre-paid envelope
supplied
●●
●●
●online at:vokera.co.uk
●●
●●
●for UK residents by calling: 0870 607 0281
●●
●●
●forROI residentsby calling:1850221121.

Supplied By www.heating spares.co Tel. [phone]
18
SECTION 6 SERVICING INSTRUCTIONS
6.1 GENERAL
To ensure the continued safe and efficient
operationoftheappliance,itisrecommended that
it is checked and serviced at regular intervals.To
ensurecorrectandsafeoperationoftheappliance,
it is essential that any worn or failed component
be replaced only with a genuine Vokera spare
part. It should be remembered that although
certaingeneric componentsmaylooksimilar,they
willbespecifictoanindividualapplianceorproduct
range. Use of non-genuine Vokera spare parts
could invalidate your warranty and may pose a
potentialsafetyhazard.The frequency ofservicing
will depend upon the particular installation
conditions, but in general, once per year should
be sufficient. It is the law that any servicing work
is carried out by competent person such as a
Vokera engineer, an approved service agent,
BritishGas,CORGI registered personnelorother
suitably qualified personnel. The following
instructionsapplytotheapplianceanditscontrols,
but it should be remembered that the central
heatingandthedomestichotwatersystemswould
also require attention from time to time.
6.2 ROUTINE ANNUAL SERVICING
●●
●●
●Checktheoperationoftheapplianceandensure
it functions as described in section 7.
●●
●●
●Comparetheperformanceof the appliancewith
its design specification. The cause of any
noticeabledeteriorationshouldbeidentifiedand
rectified without delay.
●●
●●
●Thoroughly inspect the appliance for signs of
damage or deterioration especially the flue
system and the electrical apparatus.
●●
●●
●Check and adjust – if necessary – all burner
pressuresettings (see 7.4).
●●
●●
●Check and adjust – if necessary – the system
designpressure (see5.10).
●●
●●
●Carry out an analysis of the flue gases (see
7.5),andvisuallychecktheconditionoftheentire
flue assembly.
●●
●●
●Compare the results with the appliance design
specification.Any deteriorationinperformance
must be identified and rectified without delay.
●●
●●
●Checkthattheburnerand mainheatexchanger
arecleanandfreefromanydebrisorobstruction.
●●
●●
●Checkandclean –ifnecessary– thecondense
trapto ensurecorrectoperation.
6.3 REPLACEMENTOF COMPONENTS
Although it is anticipated that this appliance will
giveyears ofreliable,trouble freeservice,the life
spanofcomponents will bedetermined byfactors
such as operating conditions and usage. Should
the appliance develop a fault, the fault finding
section will assist in determining which
componentis malfunctioning.
6.4 COMPONENTREMOVAL PROCEDURE
Toremovea component,access tothe interiorof
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.
Ensuresomewaterabsorbentclothsareavailable
tocatch any residualwaterthat maydrip fromthe
appliance or removed component. Undertake a
complete commissioning check as detailed in
section 5, after replacing any component.
ALWAYSTEST FOR GAS SOUNDNESS IFANY
GAS CARRYING COMPONENTS HAVE BEEN
REMOVED OR DISTURBED.
6.4.1 AIR BOX FRONT COVER REMOVAL (fig.18)
Locate the two clips and remove air box front
cover.If it’s necessary to remove the air box side
cover, locate and remove the 4 securing screws.
6.5 PUMP ASSEMBLY (fig. 19)
Carry out component removal procedure as
describedin6.4.Locateandremovethe2securing
screws (A) at the rear of the pump assembly.
Disconnect the flow pipe (B, only for 30-35HE)
fromthecombustionchamberconnection,slacken
the pipe at the hydraulic assembly and swing/ro-
tate clear of the pump assembly.
Disconnectand removethe pumpoutletpipe (C)
from the pump assembly/combustion chamber
connection. Remove the expansion pipe locking
pin from the top of the pump assembly and
withdrawtheflexible pipe (D).Locateandremove
the pressure gauge securing pin (D) and
disconnect the pressure gauge from the pump
assembly.
Disconnect the electrical wiring from the pump’s
electrical connection point (E). Remove locking
pin (F) from pump base and lift pump assembly
clear of the hydraulic manifold. The pump
assembly can now be removed from the
appliance.Replace carefullyinthe reverse order.
6.6 SAFETYVALVE (fig.19)
Carry out component removal procedure as
described in 6.4. Disconnect the outlet pipe from
the safety valve, remove safety valve locking
screwfromthe hydraulicmanifold. Replaceinthe
reverseorder.
clips
Fig. 18