Riello Vokera Mynute 20 VHE Release note

Installation
& Servicing
Instructions
THESE INSTRUCTIONS
TO BE RETAINED
BY USER
Mynute VHE
High efciency open vent boiler
Vokèra is a licensed member of the Benchmark scheme
which aims to improve the standards of installation and
commissioning of domestic hot water systems in the UK.
G.C. N° 41 094 70

2
Contents
Design principles & operating sequence 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
Technical data Page
2.1 Central heating 4
2.2 Gas pressures 4
2.3 Dimensions 4
2.4 Clearances 4
2.5 Connections 4
2.6 Electrical 4
2.7 Flue details (concentric) 4
2.7A Flue details (twin pipes) 4
2.7B Flue details (80/125) 4
2.8 Efciency 4
2.9 Emissions 4
General requirements (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
3.11 Appliance pipework conguration 7
General requirements (EIRE) Page
3A.1 Related documents 9
3A.2 Location of appliance 9
3A.3 Gas supply 9
3A.4 Flue system 9
3A.5 Air supply 9
3A.6 Water circulation 9
3A.7 Electrical supply 10
3A.8 Mounting on a combustible surface 10
3A.9 Timber framed buildings 10
3A.10 Inhibitors 10
3A.11 Appliance pipework conguration 10
3A.12 Declaration of conformity 10
Installation Page
4.1 Delivery 11
4.2 Contents 11
4.3 Unpacking 11
4.4 Preparation for mounting the appliance 11
4.5 Fitting the ue 11
4.6 Connecting the gas & water 15
4.7 Electrical connections 15
Commissioning Page
5.1 Gas supply installation 16
5.2 The heating system 16
5.3 Initial lling of the system 16
5.4 Initial ushing of the system 16
5.5 Pre-operation checks 17
5.6 Initial lighting 17
5.7 Checking gas pressure & combustion analysis 17
5.8 Final ushing of the heating system 17
5.9 Setting the boiler operating temperature 17
5.10 Regulating the central heating system 17
5.11 Final checks 17
5.12 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 Automatic air release valve 18
6.6 Primary thermistor 18
6.7 Return thermistor 18
6.8 Printed circuit board 18
6.9 Gas valve 19
6.10 Injectors 19
6.11 Electrodes and condense sensor 19
6.12 Flue fan & mixer 19
6.13 Burner 20
6.14 Main heat exchanger 20
6.15 Condense trap removal 20
6.16 Flue collector removal 20
Checks, adjustments and fault nding Page
7.1 Checking appliance operation 21
7.2 Appliance modes of operation 21
7.3 Appliance fan speeds 21
7.4 Checking the CO2& adjusting the valve 22
7.5 Combustion analysis test 22
7.6 External faults 22
7.7 Electrical checks 23
7.8 Fault nding 23
7.9 Component values & characteristics 23
7.10 Fault codes 23
Wiring diagrams Page
8.1 External wiring 24
8.2 Typical control applications 24
8.3 Other devices 24
L.P.G. instructions Page
9.1 Related documents 27
9.2 Technical data 27
9.3 Converting the appliance gas type 27
9.4 Gas supply 27
9.5 Gas supply installation 27
9.6 Adjusting the gas valve 27
9.7 Appliance fan speeds 28
Commissioning checklist 29
Benchmark 30-32

1
The Mynute VHE is a high-efciency boiler for open
vent system.
These appliances – by design – incorporate premix
combustion and a radial aluminium heat exchanger.
The Mynute VHE range are produced as room sealed,
category II2H3P appliances, suitable for internal wall
mounting applications only. Each appliance is provided
with a fan powered ue outlet with an annular co-axial
combustion air intake that can be rotated – horizontally
– through 360 degrees for various horizontal or vertical
applications.
The Mynute VHE can also be used with the Vokera
twin ue system.
These appliances are designed for use with an open-
vent system; consequently they are not intended for use
on sealed or pressurised systems. Please contact the
Vokera technical helpline for advice should you wish to
use the Mynute VHE on a sealed/pressurised system.
This booklet is an integral part of the appliance. It
is therefore necessary to ensure that the booklet is
handed to the person responsible for the property in
which the appliance is located/installed. A replacement
copy can be obtained from the Vokèra website - www.
vokera.co.uk.
The Mynute VHE is approved for use with C13 & C33
type ue appliacations
Mynute VHE boiler complies with basic requirements
of the following Directives:
- Regulation (EU) 2016/426;
- Yield directive: Article 7(2) and Annex III of directive
92/42/EEC;
- Electromagnetic compatibility directive 2014/30/EU;
- Low-voltage directive 2014/35/EU;
- Directive 2009/125/EC Ecodesign for energy-using
appliances;
- Regulation (EU) 2017/1369 Energy labeling;
- Delegated Regulation (EU) No. 811/2013;
- Delegated Regulation (EU) No. 813/2013.
At the end of its life, the product should be not
be disposed of as solid urban waste, but rather it
should be handed over to a differentiated waste
collection centre.
All installers are asked to follow the Benchmark
Scheme by adhering to the Code of Practise, which
can be obtained from www.centralheating.co.uk.
INTRODUCTION
Fig. 1 G FR
General layout (g. 1)
1 Gas valve
2 Condense trap
3 Vacuum detection pipe
4 Air pressure switch
5 Top AAV pipe
6 Return sensor
7 Fume thermostat
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 Sensing Electrode
15 Spark Electrode
16 Condensate level sensor
17 Cylindric Burner
18 Main heat exchanger
19 Air intake pipe
20 Fan assembly
21 Mixer
22 Condensing drain
RHeating return connection
FHeating ow connection
GGas connection

2
Fig. 1A
Boiler at reset/standby Select this position if/when the boiler requires to be reset
Boiler switched OFF Select this position if you want the boiler to remain OFF (this will over-ride
any heating/hot water request from the time-clock/programmer)
Boiler switched ON Select this position when you want the boiler to respond to a heating/hot
water request from the time-clock/programmer
Temperature selector Move the temperature selector clockwise to increase the boiler outlet
temperatu- re, or counter-clockwise to reduce the outlet ow temperature
2-digit LED display Displays the current outlet temperature of the boiler. During a fault
condition, the appropriate fault code will be displayed (refer to the users
handbook for in structions regarding fault codes)
Green LED lit Boiler is working/responding to a heating/hot water request
Red LED lit Boiler has identied a fault and has failed-safe. Refer to users handbook for
instructions on how to reset
MODE SELECTOR
SWITCH
RED LED
GREEN LED TEMPERATURE SELECTOR
2-digit LED
display


3
1.1 PRINCIPLE COMPONENTS
● A fully integrated electronic control board featuring
electronic temperature control, anti-cycle control,
pump over-run, self-diagnostic fault indicator, full
air/gas modulation
●Radial aluminium heat exchanger
●Electronic ignition with ame supervision
●Fan
●Condensate level sensor
1.2 MODE OF OPERATION (at rest)
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-protection
system protects the appliance against the risk of
frost damage. The rst stage enables activation of
the pump should the temperature of the appliance
fall to 6oC. Should the rst stage 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 for more than 24-hours.
1.3 MODE OF OPERATION
When there is a request for heat and/or hot water, via the
programmer/time clock and/or any external control, the
pump and fan are started, the fan speed will modulate
until the correct signal voltage is received at the control
PCB. At this point an ignition sequence is enabled.
Ignition is sensed by the electronic circuitry to ensure
ame stability at the burner. Once successful ignition
has been achieved, the electronic circuit 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 temperature
the burner will shut down and the boiler will perform a
5-minute anti-cycle (timer delay).
When the request for heat has been satised the pump
and fan may continue to operate to dissipate any residual
heat within the appliance.
NOTE
●The pump must be connected directly to the desig-
nated terminals within the appliance controls panel.
●When power is restored to the PCB and/or the PCB
is powered for the rst time, the appliance will enter
a 2-minute purge cycle whereby only the pump will
run for 15-seconds then off for 15-seconds.
1.4 SAFETY DEVICES
When the appliance is in use, safe operation is en-
sured by:
●Fan speed sensor and pressure differential mecha-
nism to ensure safe operation of the burner.
●A high limit thermostat that over-rides the temperature
control circuit to prevent or interrupt the operation
of the burner.
●Flame sensor that will shut down the burner when
no ame signal is detected.
●A sensor that interrupts the operation of the appli-
ance if the condense pipe becomes blocked.
SECTION 1 DESIGN PRINCIPLES AND OPERATING SEQUENCE
Fig. 2
CH
return
CH
ow
return tem-
perature
sensor
main heat
exchanger
ow temper-
ature sensor
top
AAV
drain
valve

4
SECTION 2 TECHNICAL DATA
Ref. Condition 15 °C, 1013,25 mbar, dry gas
NOTE: L.P.G. data refer to section 9
*The system should be so designed and balanced to ensure
a minimum and maximum temperatute differential of 10 °C
and 20 °C respectively, when the appliance is operating at
maximum output.
2.1 Central Heating Mynute 20 VHE
Heat input (kW) 20.00
Maximum heat output (kW) 60/80°C 19.52
Minimum heat output (kW) 60/80°C 4.83
Maximum heat output (kW) 30/50°C 20.80
Minimum heat output (kW) 30/50°C 5.35
Minimum working pressure 0.1 bar
Maximum working pressure 3.0 bar
Minimum ow rate 850 l/h*
2.2 Gas Pressures
Inlet pressure (G20) 20.0 mbar
Maximum gas rate (m3/hr) 2.12
Minimum gas rate (m3/hr) 0.53
Injector size 3.65 mm
2.3 Dimensions
Height 740 mm
Width 400 mm
Depth 342 mm
Dry weight 29 kg
2.4 Clearances
Sides 12mm
Top 150mm from casing or 25mm above ue elbow (whichever is applicable)
Bottom 150mm
Front 600mm
2.5 Connections
Flow & return 22mm
Gas 15mm
Condense 21mm
2.6 Electrical
Power consumption (Watts) 54
Supply (V/Hz) 230/50
Internal fuse 3.15A T (for PCB) - 3.15A F (for connections block)
External fuse 3A
2.7 Flue Details (concentric - 60/100)
Maximum horizontal ue length (60/100mm) 7.8m
Maximum vertical ue length (60/100mm) 8.8m
2.7A Flue Details (concentric 80/125mm)
Maximum horizontal ue length (80/125mm) 25m
2.7B Flue Details (twin pipes)
Maximum horizontal ue length (80mm/80mm) 40m/40m
Maximum vertical ue length (80mm/80mm) 40m/40m
2.8 E󰀩ciency
SEDBUK (%) 90.17 - Band ‘A’
2.9 Emissions
CO2@ maximum output (%) 9.0
CO2@ minimum output (%) 9.0
CO @ maximum output (p.p.m.) 120
CO @ minimum output (p.p.m.) 20
NOx @ maximum output (p.p.m.) 50
NOx @ minimum output (p.p.m.) 30
NOx rating class 6

5
Fig. 3
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 ashing As determined by the xed collar
of the vertical terminal
Seasonal space heating energy e󰀩ciency
class AWater heating energy e󰀩ciency class -
Parameter Symbol Value Unit Parameter Symbol Value Unit
Rated heat output Prated 20 kW Seasonal space heating energy
e󰀩ciency ηs 92 %
For boiler space heaters and boiler combination heaters:
useful heat output
For boiler space heaters and boiler combination heaters:
useful e󰀩ciency
At rated heat output and high-
temperature regime (*) P4 19,5 kW At rated heat output and high- temperature regime (*) η4 87,9 %
At 30% of rated heat output and
low-temperature regime (**) P1 6,5 kW At 30% of rated heat output and low-temperature regime (**) η1 97,3 %
Auxiliary electricity consumption Other parameters
At full load elmax 30 W Stand-by heat loss P󰀬by 34,0 W
At part load elmin 14,0 W Pilot ame energy consumption Pign - W
In Stand-by mode PSB 4,0 W Annual energy consumption QHE 38 GJ
Sound power level, indoors LWA 50 dB
Emissions of nitrogen oxides NOx 34 mg/kWh
For combination heaters:
Declared load prole -Water heating energy e󰀩ciency ηwh - %
Daily electricity consumption Qelec - kWh Daily fuel consumption Qfuel - kWh
Annual electricity consumption AEC - kWh Annual fuel consumption AFC - GJ
(*) High-temperature regime means 60 °C return temperature at heater inlet and 80 °C feed temperature at heater outlet.
(**) Low temperature means for condensing boilers 30 °C, for low-temperature boilers 37 °C and for other heaters 50 °C return
temperature (at heater inlet).

6
SECTION 3 GENERAL REQUIREMENTS (UK)
This appliance must be installed by a competent per-
son in accordance with the Gas Safety (Installation &
Use) Regulations.
3.1 RELATED DOCUMENTS
The installation of this boiler must be in accordance 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 undertaking, the Building Standards (Scotland)
Regulation, and Building Standards (Northern Ireland)
Regulations.
It should be in accordance also with any relevant
requirements of the local authority and the relevant
recommendations of the following British Standard
Codes of Practice.
ATTENTION
The use of PPE (Personal Protective Equipment) such
as but not limited to gloves, mask, safety glasses, etc.
is strongly recommended whenever carrying out the
installation, repair, or maintenance of this appliance –
please pay particular attention to:
• Sharp edges that may be encountered when:- han-
dling or lifting the appliance, removing parts, etc.
during installation and maintenance.
• Airborne particles that may be released and/or
disturbed when cleaning or removing components
during maintenance.
• Water treatment chemicals that could have been
added to the system water may spill from the appli-
ance and or components during maintenance.
Please refer to an appropriate Health and Safety docu-
ment such as HSE L23 (UK) or S.I. 299 (Ireland), for
more detailed advice on safe working practices and
procedures.
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 Build-
ing Regulations, with respect to the installation of the
appliance in a room or internal space containing a
bath or shower.
When an appliance is installed in a room or internal
space containing a bath or shower, the appliance or
any control pertaining to it must not be within reach
of a person using the bath or shower.
The location chosen for the appliance must permit the
provision of a safe and satisfactory ue 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 installation of the appliance will be in an
unusual location special procedures may be neces-
sary, BS 6798 gives detailed guidance on this aspect.
A compartment used to enclose the appliance must be
designed and constructed specically for this purpose.
An existing compartment/cupboard may be utilised
provided that it is modied to suit.
Details of essential features of compartment/cupboard
design including airing cupboard installations are given
in BS 6798. This appliance is not suitable for external
installation.
3.3 GAS SUPPLY
The gas meter – as supplied by the gas supplier – must
be checked to ensure that it is of adequate size to deal
with the maximum rated input of all the appliances that
it serves. Installation pipes must be tted in accord-
ance with BS 6891.
Pipe work from the meter to the appliance must be
of adequate size. Pipes of a smaller size than the ap-
pliance gas inlet connection must not be used. The
installation must be tested for soundness in accord-
ance with BS6891.
If the gas supply serves more than one appliance, it
must be ensured that an adequate supply is main-
tained to each appliance when they are in use at the
same time.
3.4 FLUE SYSTEM
The terminal should be located where the dispersal
of combustion products is not impeded and with due
regard for the damage and discoloration that may occur
to building products located nearby. The terminal must
not be located in a place where it is likely to cause a
nuisance (see g. 4).
In cold and/or humid weather, water vapour will con-
dense 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
at roofs) the terminal must be protected by a guard
of durable material. The guard must be tted centrally
over the terminal. Refer to BS 5440 Part 1, when the
terminal is 0.5 metres (or less) below plastic guttering
or 1 metre (or less) below painted eaves.
3.5 AIR SUPPLY
The following notes are intended for general guidance
only.
This appliance is a room-sealed, fan-ued boiler, con-
sequently it does not require a
Permanent air vent for combustion air supply.
When installed in a cupboard or compartment, ventila-
tion for cooling purposes is also not required.
3.6 WATER CIRCULATION
Detailed recommendations are given in BS 5449 Part
1 and BS 6798. The following notes are for general
guidance only.
3.6.1 PIPEWORK
It is recommended that copper tubing to BS 2871 Part
1 is used in conjunction with soldered capillary joints.
Where possible pipes should have a gradient to ensure
air is carried naturally to air release points and that
water ows naturally to drain cocks.
BS 5440 PART 1 FLUES
BS 5440 PART 2 FLUES & VENTILATION
BS 5449 PART 1 FORCED CIRCULATION HOT WATER SYSTEMS
BS 6798 INSTALLATION OF BOILERS OF RATED INPUT NOT EXCEEDING 60kW
BS 6891 LOW PRESSURE INSTALLATION PIPES

7
Except where providing useful heat, pipes should be
insulated to avoid heat loss and in particular to avoid
the possibility of freezing. Particular attention should
be paid to pipes passing through ventilated areas such
as under oors, loft space, and void areas.
3.6.2 AUTOMATIC BY-PASS
Vokera recommend that an automatic bypass is installed
to ensure the required minimum ow-rate is achieved at
all times. Additionally, the design of the system and its
controls should ensure that an adequate temperature
differential is met, and should be such that it prevents
boiler ‘cycling’.
3.6.3 DRAIN COCKS
These must be located in accessible positions to fa-
cilitate 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
These must be positioned at the highest points in the
system where air is likely to be trapped. They should
be used to expel trapped air and allow complete lling
of the system.
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 complete isolation
from the supply. The preferred method is by using a
double-pole switch with a contact separation of at least
3,5mm (3° high-voltage category). The switch must only
supply the appliance and its corresponding controls,
i.e. time clock, room thermostat, etc. Alternatively an
un-switched shuttered socket with a fused 3-pin plug
both complying with BS 1363 is acceptable.
3.8 MOUNTING ON A COMBUSTIBLE SURFACE
If the appliance is to be tted on a wall of combustible
material, a sheet of reproof material must protect
the wall.
3.9 TIMBER FRAMED BUILDINGS
If the appliance is to be tted in a timber framed build-
ing, it should be tted in accordance with the Institute
of Gas Engineers publication (IGE/UP/7) ‘Guide for Gas
Installations in Timber Frame Buildings’.
3.10 INHIBITORS
Vokera recommend that an 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 ad-
ministered in strict accordance with the manufacturers
instructions*.
*Water treatment of the complete heating system -
including the boiler - should be carried out in accord-
ance with BS 7593 and the Domestic Water Treatment
Association’s (DWTA) code of practice.
3.11 APPLIANCE PIPEWORK CONFIGURATION (g.4)
The appliance ‘ow’ and ‘return’ connections can be
congured to suit the following:
1. Top outlet connection
2. Bottom outlet connection
3. Top (ow), bottom (return) connection
4. Top (return) bottom (ow) connection.
3.11.1 FEED & VENT PIPEWORK
The feed and vent pipe work from the boiler to the
F&E (Feed & Expansion) tank should be congured as
shown in g. 4A using a 22 mm combined feed and
vent pipe.
NOTE
●The combined feed and vent pipe must rise continu-
ously and be unrestricted.
●The diameter of the combined feed and vent pipe
shall be 22mm.
●The minimum distance from the top of the boiler
to the bottom of the F&E tank shall be no less than
1-metre, whilst the maximum distance shall be no
greater than 30-metres.
The supply of water to the F&E tank should be taken
from the mains water supply via a suitable oat oper-
ated valve, whilst the supply from the F&E tank to the
boiler/heating circuit (via the combined feed and vent
pipe) shall be unrestricted.
Fig. 4
Fig. 4A

8
Fig. 4C
Fig. 4B
Fig. 4D
3.11.2 ALTERNATIVE CLOSE-COUPLED
ARRANGEMENT
If necessary or if preferred, a close-coupled arrangement
for the feed and expansion pipe work can be used as
an alternative to a combined feed and vent pipe. The
conguration of the close-coupled pipe work shall be
as shown in gure 4B.
NOTE
●The distance between the cold feed pipe and the
safety vent pipe shall be no more than 150mm
●The cold feed pipe must be inverted as shown in
gure 4B
●The safety vent pipe must be 22mm in diameter
●The cold feed pipe must be 15mm diameter
●The cold feed pipe and safety vent pipe must both
rise continuously and be unrestricted.
●The minimum distance from the top of the boiler
to the bottom of the F&E tank shall be no less than
1-metre, whilst the maximum distance shall be no
greater than 30-metres.
●The distance between the bottom of the F&E tank
and the highest point of the safety vent pipe must
be no less than 500mm.
The supply of water to the F&E tank should be taken
from the mains water supply via a suitable oat oper-
ated valve, whilst the supply from the F&E tank to the
boiler/heating circuit (via the cold feed pipe) shall be
unrestricted.
3.11.3 REMOTE CONNECTION
It’s permissible to connect the feed and vent pipe work
remote from the boiler, providing it’s connected to the
primary heating pipe work as shown in gures 4C/4D.
NOTE
The instructions for a combined feed and vent instal-
lation (3.11.1) or close-coupled arrangement (3.11.2)
still apply when connecting the feed and vent pipe
work remote from the appliance.

9
SECTION 3AGENERAL REQUIREMENTS (EIRE)
ATTENTION
The use of PPE (Personal Protective Equipment) such
as but not limited to gloves, mask, safety glasses, etc.
is strongly recommended whenever carrying out the
installation, repair, or maintenance of this appliance –
please pay particular attention to:
• Sharp edges that may be encountered when:- han-
dling or lifting the appliance, removing parts, etc.
during installation and maintenance.
• Airborne particles that may be released and/or
disturbed when cleaning or removing components
during maintenance.
• Water treatment chemicals that could have been
added to the system water may spill from the appli-
ance and or components during maintenance.
Please refer to an appropriate Health and Safety docu-
ment such as HSE L23 (UK) or S.I. 299 (Ireland), for
more detailed advice on safe working practices and
procedures.
3A.1 RELATED DOCUMENTS
The installation of this boiler must be in accordance
with the relevant requirements of the local building
regulations, the current ETCI National Rules for Elec-
trical Installations and the bylaws of the local water
undertaking.
It should be in accordance also with any relevant re-
quirements of the local and/or district authority.
3A.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 ETCI National Rules for
Electrical Installations, and I.S. 813, Annex K.
When an appliance is installed in a room or internal
space containing a bath or shower, the appliance or
any control pertaining to it must not be within reach
of a person using the bath or shower.
The location chosen for the appliance must permit the
provision of a safe and satisfactory ue 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 installation of the appliance will be in an
unusual location special procedures may be necessary,
refer to I.S. 813 for detailed guidance on this aspect.
A compartment used to enclose the appliance must be
designed and constructed specically for this purpose.
An existing compartment/cupboard may be utilised
provided that it is modied to suit.
This appliance is not suitable for external installation.
3A.3 GAS SUPPLY
The gas meter – as supplied by the gas supplier – must
be checked to ensure that it is of adequate size to deal
with the maximum rated input of all the appliances that
it serves. Installation pipes must be tted in accord-
ance with I.S. 813.
Pipe work from the meter to the appliance must be
of adequate size. Pipes of a smaller size than the ap-
pliance gas inlet connection must not be used. The
installation must be tested for soundness in accord-
ance with I.S. 813.
If the gas supply serves more than one appliance, it
must be ensured that an adequate supply is main-
tained to each appliance when they are in use at the
same time.
3A.4 FLUE SYSTEM
The terminal should be located where the dispersal
of combustion products is not impeded and with due
regard for the damage and discoloration that may occur
to building products located nearby. The terminal must
not be located in a place where it is likely to cause a
nuisance (see I.S. 813).
In cold and/or humid weather, water vapour will con-
dense 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
at roofs) the terminal must be protected by a guard
of durable material. The guard must be tted centrally
over the terminal. Refer to I.S. 813, when the terminal is
0.5 metres (or less) below plastic guttering or 1 metre
(or less) below painted eaves.
3A.5 AIR SUPPLY
The following notes are intended for general guidance
only.
This appliance is a room-sealed, fan-ued boiler, con-
sequently it does not require a permanent air vent for
combustion air supply.
When installed in a cupboard or compartment, ventila-
tion for cooling purposes is also not required.
3A.6 WATER CIRCULATION
Specic recommendations are given in I.S. 813. The
following notes are for general guidance only.
3A.6.1 PIPEWORK
It is recommended that copper tubing be used in con-
junction with soldered capillary joints.
Where possible pipes should have a gradient to ensure
air is carried naturally to air release points and that
water ows naturally to drain cocks.
Except where providing useful heat, pipes should be
insulated to avoid heat loss and in particular to avoid
the possibility of freezing. Particular attention should
be paid to pipes passing through ventilated areas such
as under oors, loft space, and void areas.
3A.6.2 AUTOMATIC BY-PASS
Vokera recommend that an automatic bypass is installed
to ensure the required minimum ow-rate is achieved at
all times. Additionally, the design of the system and its
controls should ensure that an adequate temperature
differential is met, and should be such that it prevents
boiler ‘cycling’.
3A.6.3 DRAIN COCKS
These must be located in accessible positions to fa-
cilitate draining of the appliance and all water pipes
connected to the appliance.
3A.6.4 AIR RELEASE POINTS
These must be positioned at the highest points in the
system where air is likely to be trapped. They should
be used to expel trapped air and allow complete lling
of the system.

10
3A.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 complete 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 corresponding controls, i.e. time clock, room
thermostat, etc.
3A.8 MOUNTING ON A COMBUSTIBLE SURFACE
If the appliance is to be tted on a wall of combustible
material, a sheet of reproof material must protect
the wall.
3A.9 TIMBER FRAMED BUILDINGS
If the appliance is to be tted in a timber framed build-
ing, it should be tted in accordance with I.S. 813 and
local Building Regulations.
The Institute of Gas Engineers publication (IGE/UP/7)
‘Guide for Gas Installations in Timber Frame Buildings’
gives specic advice on this type of installation.
3A.10 INHIBITORS
Vokera recommend that an 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 ad-
ministered in strict accordance with the manufacturers
instructions*.
*Water treatment of the complete heating system -
including the boiler - should be carried out in accord-
ance with I.S. 813 and the Domestic Water Treatment
Association’s (DWTA) code of practice.
3A.11 APPLIANCE PIPEWORK CONFIGURATION
(g. 5)
The appliance ‘ow’ and ‘return’ connections can be
congured to suit the following:
1. Top outlet connection
2. Bottom outlet connection
3. Top (ow), bottom (return) connection
4. Top (return) bottom (ow) connection.
3A.11.1 FEED AND VENT PIPEWORK
The feed and vent pipe work from the boiler to the
F&E (Feed & Expansion) tank should be congured
as shown in gure 4A using a 22mm combined feed
and vent pipe.
NOTE
●The combined feed and vent pipe must rise continu-
ously and be unrestricted.
●The diameter of the combined feed and vent pipe
shall be 22mm.
●The minimum distance from the top of the boiler
to the bottom of the F&E tank shall be no less than
1-metre, whilst the maximum distance shall be no
greater than 30-metres.
The supply of water to the F&E tank should be taken
from the mains water supply via a suitable oat oper-
ated valve, whilst the supply from the F&E tank to the
boiler/heating circuit (via the combined feed and vent
pipe) shall be unrestricted.
3A.11.2 ALTERNATIVE CLOSE-COUPLED
ARRANGEMENT
If necessary or if preferred, a close-coupled arrange-
ment for the feed and expansion pipe work can be
used as an alternative to a combined feed and vent
pipe. The conguration of the close-coupled pipe work
shall be as shown in gure 4B.
NOTE
●The distance between the cold feed pipe and the
safety vent pipe shall be no more than 150mm
●The cold feed pipe must be inverted as shown in g.
4B
●The safety vent pipe must be 22mm in diameter
●The cold feed pipe must be 15mm diameter
●The cold feed pipe and safety vent pipe must both
rise continuously and be unrestricted.
●The minimum distance from the top of the boiler
to the bottom of the F&E tank shall be no less than
1-metre, whilst the maximum distance shall be no
greater than 30-metres.
●The distance between the bottom of the F&E tank
and the highest point of the safety vent pipe must
be no less than 500mm.
The supply of water to the F&E tank should be taken
from the mains water supply via a suitable oat oper-
ated valve, whilst the supply from the F&E tank to the
boiler/heating circuit (via the cold feed pipe) shall be
unrestricted.
3A.11.3 REMOTE CONNECTION
It’s permissible to connect the feed and vent pipe work
remote from the appliance, providing it’s connected
to the primary heating pipe work as shown in gures
4C/4D.
NOTE
The instructions for a combined feed and vent installa-
tion (3A.11.1) or close-coupled arrangement (3A.11.2)
still apply when connecting the feed and vent pipe
work remote from the appliance.
3A.12 DECLARATION OF CONFORMITY
A Declaration of Conformity (as dened in I.S. 813)
must be provided on completion of the installation
A copy of the declaration must be given to the respon-
sible person and also to the gas supplier if required.
Fig. 5

11
NOTE
Please refer to Section 3, Para 3.1 and use the ap-
propriate PPE when carrying out any of the actions or
procedures contained within this section.
4.1 DELIVERY
Due to the weight of the appliance it may be neces-
sary for two people to lift and attach the appliance
to its mounting. The appliance is contained within a
heavy-duty cardboard carton. Lay the carton on the
oor with the writing the correct way up.
4.2 CONTENTS
Contained within the carton is:
●The boiler
●The wall bracket
●Template
●An accessories pack containing appliance service
connections and washers
●The instruction pack containing the installation &
servicing instructions, user instructions, guarantee
registration card, and a 3-amp fuse.
4.3 UNPACKING
At the top of the carton pull both sides open – do not
use a knife – unfold the rest of the carton from around
the appliance, carefully remove all protective packag-
ing from the appliance, and lay the accessories etc. to
one side. Protective gloves should be used to lift the
appliance, the appliance back-frame should be used
for lifting points.
4.4 PREPARATION FOR MOUNTING THE APPLIANCE
The appliance should be mounted on a smooth, verti-
cal, non-combustible surface, which must be capable
of supporting the full weight of the appliance. Care
should be exercised when determining 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 g. 6) and
ue-hole (if applicable).










 
 


 






Fig. 6
SECTION 4 INSTALLATION
4.5 FITTING THE FLUE
The top ue outlet permits both horizontal and vertical
ue applications to be considered, alternatively, the
Vokera twin ue system can be utilised if longer ue
runs are required.
4.5.1 CONCENTRIC HORIZONTAL FLUE
(For concentric vertical ue, see 4.5.2).
(For twin ue applications, see 4.5.3).
The appliance can be used with either the Vokera
condensing 60/100mm concentric ue system or the
optional 80/125mm concentric ue system.
NOTE
These instructions relate only to the Vokera condens-
ing 60/100mm concentric ue system. For specic
details on the installation of the 80/125mm concentric
ue system please refer to the instructions supplied.
The appliance ue outlet elbow can be rotated through
360º on its vertical axis. In addition the ue may be
extended from the outlet elbow in the horizontal plane
(see 2.7). A reduction must also be made to the maxi-
mum length (see table below) when additional bends
are used.
Reduction for additional bends
Bend Reduction in maximum ue length for each bend
45° bend 1.0 metre
90° bend 1.0 metre
Horizontal ue terminals and accessories
Part No. Description Length
520 Horizontal ue kit 900mm
521 Telescopic ue kit 350/530mm
522 Plume management kit 1370mm
523 90-degree bend N/A
524 45-degree bends (pair) N/A
525 500mm extension 500mm
526 1000mm extension 1000mm
527 2000mm extension 2000mm
528 Telescopic extension 350/730mm
529 Wall bracket pack (5) 208mm
Using the template provided, mark and drill a 115mm
hole for the passage of the ue pipe. The hole should
be drilled to ensure any condense uid that forms, is
allowed to drain back to the appliance (see g. 7A).
The xing holes for the wall-mounting bracket should
now be drilled and plugged, an appropriate type and
quantity of xing 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.
Fig. 7 terminal or
extension
outer clam-
ps
FITTING THE HORIZONTAL FLUE KIT
Carefully measure the distance from the centre of the
appliance ue outlet to the edge of the nished outside
wall (dimension X). Add 65mm to dimension X to give
you dimension Y (see g 7A).

12
Fig. 8
Measure dimension Y from the terminal end of the
concentric ue pipe and cut off the excess ensuring
any burrs are removed. Pass the concentric ue pipe
through the previously drilled hole. Fit the ue bend to
the boiler ue outlet and insert the concentric ue pipe
into the ue bend ensuring the correct seal is made.
Using the clamp, gasket and screws supplied, secure
the ue bend to the appliance ue spigot.
NOTE
Fit the internal (white) trim to the ue assembly prior
to connecting the ue pipe to the bend.
You must ensure that the entire ue system is properly
supported and connected.
Seal the ue assembly to the wall using cement or
a suitable alternative that will provide satisfactory
weatherproong. The exterior trim can now be tted.
Fig. 7A
“X”
“Y”
30mm
1-3 degree
“X” + 65mm = “Y”
4.5.1.1EXTENDING THE FLUE
Connect the bend – supplied with the terminal kit – to
the top of the boiler using clamp (supplied) see g.
7. The additional bends & extensions have push-t
connections, care should be taken to ensure that the
correct seal is made when assembling the ue system.
Connect the required number of ue extensions or
bends (up to the maximum equivalent ue length) to
the ue terminal (see g. 7 & 8).
The ue system should have a minimum of 1º; maxi-
mum of 3º rise from the boiler to outside, to ensure any
condense uid that forms, is allowed to drain back to
the appliance.
NOTE
When cutting an extension to the required length, you
must ensure that the excess is cut from the plain end
of the extension (see g. 7 & 8). Remove any burrs, and
check that all seals are located properly.
You must ensure that the entire ue system is properly
supported and connected.
Seal the ue assembly to the wall using cement or
a suitable alternative that will provide satisfactory
weatherproong. The interior and exterior trim can
now be tted.
4.5.2 CONCENTRIC VERTICAL FLUE
The appliance can be used with either the Vokera
condensing 60/100mm concentric ue system or the
optional 80/125mm concentric ue system.
NOTE
These instructions relate only to the Vokera condens-
ing 60/100mm concentric ue system. For specic
details on the installation of the 80/125mm concentric
ue system please refer to the instructions supplied.
The vertical ue terminal can be connected directly to
the appliance ue outlet. Alternatively, an extension or
bend can be connected to the appliance ue outlet
if desired, however if additional bends are tted, a
reduction must be made to the maximum ue length
(see table below).
Reduction for bends
Bend Reduction in maximum ue length for each bend
45° bend 1.0 metre
90° bend 1.0 metre
Vertical ue terminal and accessories
Part No. Description Min-Max length
530 Vertical ue terminal 1000mm
531 Pitched roof ashing plate N/A
532 Flat roof ashing plate N/A
523 90-degree bend N/A
524 45-degree bends (pair) N/A
525 500mm extension 500mm
526 1000mm extension 1000mm
527 2000mm extension 2000mm
528 Telescopic extension 350/730mm
529 Wall bracket pack (5) 208mm

13
Using the dimensions given in g. 9 as a reference,
mark and cut a 115mm hole in the ceiling and/or roof.
Fig. 9
“X”
“X”= 202mm
Fit the appropriate ashing plate to the roof and insert
the vertical ue terminal through the ashing plate from
the outside, ensuring that the collar on the ue terminal
ts over the ashing.
The xing holes for the wall-mounting bracket should
now be drilled and plugged, an appropriate type and
quantity of xing 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
The vertical ue terminal is 1.0 metre in length and
cannot be cut; therefore it may be necessary to adjust
the height of the appliance to suit or use a suitable
extension.
Connect the vertical ue assembly to the boiler ue
spigot using the 100mm clip, gasket & screws (sup-
plied), ensuring the correct seal is made. The ue
support bracket (supplied with the vertical ue kit)
can now be tted.
If the vertical ue requires extension/s or additional
bend/s, connect the required number of ue extensions
or bends (up to the maximum equivalent ue length)
between the boiler and vertical ue assembly (see g. 8).
Ensure that any horizontal sections of the ue system
have a minimum 1º; maximum 3º fall back to the boiler
(1º = 17mm per 1000mm)
NOTE
When cutting an extension to the required length, you
must ensure that the excess is cut from the plain end
of the extension (see g. 8). Remove any burrs, and
check that any seals are located properly.
You must ensure that the entire ue system is properly
supported and connected.
4.5.3 TWIN FLUE SYSTEM
The Vokera twin ue system enables greater ue
distances to be achieved (see 4.4.2) than that of a
concentric ue system. It can be used for horizontal
or vertical applications, however the twin ue system
must be converted to the dedicated concentric ue
kit for termination. It is essential that the installation of
the twin ue system be carried out in strict accordance
with these instructions.
GUIDANCE NOTES ON TWIN FLUE INSTALLATION
●The ue must have a have a minimum 1º; maximum
3º (1º = 17mm per 1000mm) fall back to the appliance
to allow any condensate that may form in the ue
system to drain via the condensate drain. Considera-
tion must also be given to the fact that there is the
possibility of a small amount of condensate dripping
from the terminal.
●Ensure that the entire ue system is adequately sup-
ported, use at least one bracket for each extension.
●The entire ue system must be adequately insulated
to maintain heat within the ue system thereby reduc-
ing the possibility of condensate production.
●As the exhaust outlet pipe can reach very high tem-
peratures it must be protected to prevent persons
touching the hot surface.
●The condensate drain pipe must be connected in
accordance with building regulations.
Reduction for bends
Bend Reduction in maximum ue length for each bend
45° bend 1.0 metre
90° bend 1.0 metre
Twin ue accessories
Part No. Description Length
0225805 Horizontal ue terminal 1.0 metre
0225810 Vertical ue terminal 1.0 metre
430 Twin adapter kit N/A
531 Pitched roof ashing plate N/A
532 Flat roof ashing 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
MOUNTING THE BOILER
The xing holes for the wall-mounting bracket should
now be drilled and plugged, an appropriate type and
quantity of xing 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.
4.5.3.1 INSTALLATION OF TWIN ADAPTOR KIT (g.
10 & 11)
•Insert the exhaust connection manifold (A) onto the
appliance ue outlet.
•Remove the blanking plate (located to the right of the
appliance ue outlet) and – using the same 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 ue spigot
and secure the exhaust manifold connection to the
ue spigot using the screw provided (C).
•Using the two holes in the air inlet plate as a guide,
drill a 3mm hole in each and secure the air inlet pipe/
bend using the screws provided.
The twin ue pipes extensions and accessories 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).

14
B
C
A
Fig. 10
Fig. 11
4.5.3.2 HORIZONTAL TERMINATION (g. 12)
The twin ue system must be converted to the dedi-
cated concentric ue 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 the
concentric terminal through the wall.
•The air inlet pipe must alwaays be level with or below,
that of the exhaust pipe.
Depending on site conditions it may be preferable to
install the terminal assembly prior to tting the twin
ue pipes.
Mark and drill a level 130mm hole for the passage of
the horizontal ue terminal. Insert the terminal assembly
into the ue hole.
Push-t the twin ue pipes onto the concentric to twin
converter box 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 ue
pipes to allow connection to the concentric to twin
converter.
NOTE
before cutting twin ue pipes ensure allowances have
been made for connection onto the previous 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 ue terminal assembly to the wall using ce-
ment or a suitable alternative that will provide satis-
factory weatherproong. The interior and exterior trim
can now be tted.
4.5.3.3 VERTICAL TERMINATION (g. 13)
The twin ue system must be converted to the dedi-
cated concentric ue kit for termination.
•The vertical terminal is supplied with a built-in con-
verter box and cannot be shortened.
•A 130mm hole is required for the passage of the
concentric terminal through the ceiling and/or roof.
Depending on site conditions it may be preferable to
install the terminal assembly prior to tting the twin
ue pipes.
Fit the appropriate ashing plate to the roof and insert
the vertical ue terminal through the ashing plate from
the outside, ensuring that the collar on the ue terminal
ts over the ashing.
Push-t the twin ue pipes onto the concentric to 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 ue
pipes to allow connection to the concentric to twin
converter.
NOTE
•Before cutting twin ue pipes ensure allowances
have been made for connection onto the previous
piece and onto the concentric to twin converter. The
last twin ue pipes must be pushed 50mm onto the
male spigots of the concentric to twin converter.
•You must ensure that the entire ue system is properly
supported and connected.
•Ensure that any horizontal sections of pipe have a
1º fall towards the appliance (17mm per 1000mm).
Fig. 12
Fig. 13

15
4.6 CONNECTING THE GAS AND WATER
The appliance is supplied with a 15mm service valve for
the gas connection and 22mm copper to brass adapters
for the ow and return connections. The service valve
is of the compression type. The accessories pack also
contains sealing washers etc, for use with the service
valve and copper connections.
When connecting pipe work to the valves, tighten the
compression end rst 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 (g. 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 (g. 6)
The appliance is supplied with 22mm copper to brass
adapters for the ow and return service connections.
NOTE
The ow and return pipe work can be routed verti-
cally through the rear of the appliance via the 2-holes
located in the appliance back frame.
Depending on system requirements, it may necessary
to increase the size of the ow & return pipe work after
the service connections.
4.6.3 CONDENSE PIPE
During normal operation the boiler produces condense
which is collected in a trap located in the lower part
of the boiler. A exible pipe (condense outlet pipe) is
connected to the outlet of the trap. The exible 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.
CONNECTING THE CONDENSATE OUTLET
Gently pull the condense outlet pipe down from its
location inside the boiler until approximately 100mm
protrudes from the underside of the boiler. Connect a
suitable plastic (not copper) pipe (no less than 20mm
diameter) to the outlet pipe and ensure it discharges
in accordance with building regulations or other rules
in force.
4.7 ELECTRICAL CONNECTIONS
The electrical supply must be as specied in section
3/3A. A qualied electrician should connect the elec-
trical supply to the appliance. If controls – external
to the appliance – are required, a competent person
must undertake the design of any external electrical
circuits, please refer to section 8 for detailed instruc-
tions. ANY EXTERNAL CONTROL OR WIRING MUST
BE SERVED FROM THE SAME ISOLATOR AS THAT OF
THE APPLIANCE. The supply cable from the isolator to
the appliance must be 3-core exible 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 (g. 14)
To gain internal access to the appliance you must rst
remove the casing, proceed as outlined below:
•Locate and remove the 2-screws on the front under-
side of the casing (C)
•Remove the 2 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 safely until required.
Re-t in the reverse order.
Fig. 14
C
BB
C
Fig. 15
Mains (230V)
terminal block
4.7.2 APPLIANCE TERMINAL 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 forwards and down.
Locate the terminal block cover (see g. 15).
NOTE
The appliance comes with a factory tted link (‘TA’) to
allow basic operation of the boiler once the circulating
pump has been connected. If it is anticipated that ex-
ternal controls will be required please refer to the wiring
diagrams in section 8 for more detailed information.
4.7.3 CONNECTING THE MAINS (230V) INPUT (g. 16)
Locate and remove the screws securing the terminal
block cover (230V). Pass the supply cable through the
cable anchorage point.
Connect the supply cable wires (LIVE, NEUTRAL, &
EARTH) to their corresponding terminals (L, N, & E)
on the appliance terminal block. When connecting the
EARTH wire, ensure that it’s left slightly longer that
the others, this will prevent strain on the EARTH wire
should the cable become taut.

16
NOTE
Please refer to Section 3, Para 3.1 and use the ap-
propriate PPE when carrying out any of the actions or
procedures contained within this section.
5.1 GAS SUPPLY INSTALLATION
Inspect the entire installation including the gas meter,
test for soundness and purge. Refer to BS 6891 (I.S.
813 in ROI) for specic instruction.
5.2 THE HEATING SYSTEM
The appliance contains components that may become
damaged or rendered inoperable by oils and/or debris
that are residual from the installation of the system,
consequently it is essential that the system be ushed
in accordance with BS 7593 Code of Practice and the
following instructions.
5.3 FILLING THE CONDENSE TRAP
The rst time you turn the boiler on and in case of
maintenance work, before using the appliance you
must ll the siphon with water and make sure that
the condensation is evacuated correctly. Fill the
condensation collection siphon pouring 1 litre of water
into the boiler combustion-analysis outlet with the
boiler off, and check that:
- the safety cut-off device is oating
- water is owing correctly from the discharge pipe
out of the boiler
- the condensate outlet connection line is watertight.
If the condensate outlet circuit (siphon and pipes)
is working correctly, the condensation level will not
exceed the maximum.
Filling the siphon before using the appliance, and
the use of a safety cut-off device inside the siphon,
prevent exhaust gases from being released into the
environment.
Repeat during standard and non-standard maintenance
work.
MAX
~
15mm
g. 17
5.3A INITIAL FILLING OF THE SYSTEM
Remove appliance casing as described in 4.7.1, iden-
tify 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 the
heating system are closed. Proceed to ll the system
via the feed and expansion tank and begin venting all
manual air release valves, starting at the lowest rst.
Once the system has been lled. Inspect the system
for water soundness, rectifying any leaks.
5.3.1 MANUAL AIR RELEASE (g. 17)
When the boiler has been lled for the rst time or the
system has been drained and relled, it will be neces-
sary to release any air that may have become trapped
within the appliance heat exchanger. Slacken the bleed
screw until water is released and then close.
IMPORTANT, THERE ARE NO OTHER MANUAL AIR
RELEASE VALVES LOCATED ON THE APPLIANCE.
5.4 INITIAL FLUSHING OF THE SYSTEM
The whole of the heating system must be ushed both
cold and hot as detailed in 5.8. Open all radiator and/
or heating zone 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. Rell the boiler and heating system as
described in 5.3.
Fig. 17a
SECTION 5 COMMISSIONING
4.7.4 CONNECTING THE PUMP (230V) OUTPUT (g. 16)
Pass the pump cable through the cable anchorage
point. Connect the pump cable wires (LIVE, NEUTRAL,
& EARTH) to their corresponding terminals (L, N, & E)
on the appliance terminal block. When connecting the
EARTH wire, ensure that it’s left slightly longer that
the others, this will prevent strain on the EARTH wire
should the cable become taut.
Do not remove the link wire unless additional external
controls are to be tted (see section 8). The securing
screw on the cable anchorage should now be tightened.
This must be done before the control fascia is re-tted
in the upright position. The appliance casing, screws,
and lower cover can now be re-tted.
Fig. 16

17
5.5 PRE-OPERATION CHECKS
Before attempting the initial lighting of the appliance,
the following checks must be carried out:
• Ensure all gas service valves from the meter to the
appliance are open and the supply pipe has been
properly purged;
• Ensure the proper electrical checks have been car-
ried out, (see 7.8) particularly continuity, polarity, and
resistance to earth;
• Ensure the 3 AMP fuse – supplied with the appliance
– has been tted.
• Ensure the system has been properly lled and
vented.
• Ensure the ue system has been tted properly and
in accordance with the instructions.
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 ap-
pliance will now operate as described in 1.2. Should
the appliance fail to ignite, refer to 5.6 and/or section
7 (mode of operation & fault nding).
NOTE
When power is restored to the PCB and/or the PCB
is powered for the rst time, the appliance will enter a
2-minute purge cycle whereby only the pump will run
for 15-seconds then off for 15-seconds and will not
“re” until this period has elapsed.
5.7 CHECKING GAS PRESSURE AND COMBUSTION
ANALYSIS
The appliance is factory set so should require no ad-
ditional adjustment once installed. However to satisfy
the requirements of GSIUR 26/9 (I.S. 813 ROI), it will
be necessary to gas rate the appliance using the gas
meter that serves the appliance and carry out a com-
bustion analysis check in accordance with BS 7967
(UK) to ensure that correct combustion is occurring,
see ow chart on the dedicated section.
Additionally, if the gas valve has been adjusted, re-
placed, 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 carry out a combustion
analysis check, then it will not be possible to comple-
te the commissioning procedure.
Details on how to carry out the combustion analysis
can be found in section 7.
IMPORTANT
It’s imperative that a sufcient dynamic – gas – pres-
sure is maintained at all times. Should the dynamic
gas pressure fall below an acceptable level, the ap-
pliance may malfunction or sustain damage.
5.8 FINAL FLUSHING OF THE HEATING SYSTEM
The system shall be ushed in accordance with BS
7593 Code of Practice (I.S. 813 ROI). Cleansers or
chemicals used, must be suitable for Aluminium heat
exchangers and shall be from a reputable manufacturer
and shall be administered in strict accordance with the
manufacturers’ instructions.
NOTE
Chemicals used to cleanse the system and/or inhibit
corrosion must be pH neutral, i.e. they should ensure
that the level of the pH in the system water remains
neutral.
Premature failure of certain components can occur if
the level of pH in the system water is out-with normal
levels.
5.8.1 INHIBITORS
See Section 3 “General Requirements”.
5.9 SETTING THE BOILER OPERATING TEMPERA-
TURE
The ow outlet temperature can be adjusted between
20 °C - 78 °C via the Heating thermostat knob (see
g.1).
5.10 REGULATING THE CENTRAL HEATING SYSTEM
Fully open all radiator and circuit valves and run the
appliance for both heating and hot water until heated
water is circulating. If conditions are warm remove
any thermostatic heads. Adjust radiator return valves
and any branch circuit return valves until the individual
return temperatures are correct and are approximately
equal.
5.11 FINAL CHECKS
• ENSURE ALL TEST NIPPLES ON THE APPLIANCE
GAS VALVE ARE TIGHT AND CHECKED FOR TIGHT-
NESS.
• ENSURE THE APPLIANCE FLUE SYSTEM IS FITTED
CORRECTLY AND IS PROPERLY SECURED.
• ENSURE ALL PIPE WORK IS RE-CHECKED FOR
TIGHTNESS.
• RE-FIT APPLIANCE CASING.
• COMPLETE BENCHMARK CHECKLIST.
FOR UK ONLY
Complete details of the boiler, controls, installation and
commissioning in the Benchmark checklist at the back
of this book. It is important that the Benchmark chec-
klist is correctly completed and handed to the user.
Failure to install and commission the appliance to the
manufacturers instructions will invalidate the warranty.
5.12 INSTRUCTING THE USER
Hand over all documentation supplied with this appli-
ance – 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 loca-
tions of all drain points. Show the user how to operate
the appliance and any associated controls correctly.
Show the user the location of any isolating valves and
the location of all manual air release points.
Explain to the user how to turn off the appliance for
both long and short periods and advise on the neces-
sary precautions to prevent frost damage.
Explain to the user that for continued safe and efcient
operation, the appliance must be serviced annually by
a competent person.
IMPORTANT
To validate the appliance warranty, it’s necessary to
register the appliance details with us. The warranty
can be registered in several ways:
• By completing the warranty registration card and
posting to us using the pre-paid envelope supplied
• Online at: vokera.co.uk
• For UK residents by calling: 0870 607 0281
• For ROI residents by calling: 1850 221121.

18
SECTION 6 SERVICING INSTRUCTIONS
NOTE
Please refer to Section 3, Para 3.1 and use the ap-
propriate PPE when carrying out any of the actions or
procedures contained within this section.
6.1 GENERAL
Once the appliance has been serviced, the benchmark
Service Record must be completed.
For UK only: It is important that the Benchmark Service
Record is correctly completed and handed to the user.
Failure to install and commission the appliance to the
manufacturers instructions will invalidate the warranty.
To ensure the continued safe and efficient efficient
operation 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 Vokera spare part. It should be remembered that
although certain generic components may look similar,
they will be specic to an individual appliance or product
range. Use of non-genuine Vokera spare parts could
invalidate your warranty and may pose a potential safety
hazard. The frequency of servicing will depend upon the
particular installation conditions, but in general, once per
year should be sufcient. It is the law that any servicing
work is carried out by competent person such as a Vokera
engineer, an approved service agent, British Gas, CORGI
registered personnel or other suitably qualied 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
•Check the operation of the appliance and ensure it
functions as described in section 7.
•Compare the performance of the appliance with its
design specication. The cause of any noticeable de-
terioration should be identied and rectied without
delay.
•Thoroughly inspect the appliance for signs of damage
or deterioration especially the ue system and the
electrical apparatus.
•Check and adjust – if necessary – all burner pressure
settings (see 7.4).
•Carry out an analysis of the ue gases (see 7.5) and
visually check the condition of the entire ue assembly.
•Compare the results with the appliance design specica-
tion. Any deterioration in performance must be identied
and rectied without delay.
•Check that the burner and main heat exchanger are
clean and free from any debris or obstruction.
•Check and clean – if necessary – the condense trap to
ensure correct operation.
6.3 REPLACEMENT OF COMPONENTS
Although it is anticipated that this appliance will give years
of reliable, trouble free service, the life span of compo-
nents will be determined by factors such as operating
conditions and usage. Should the appliance develop a
fault, the fault nding section will assist in determining
which component is malfunctioning.
6.4 COMPONENT REMOVAL PROCEDURE
To remove a component, access to the interior of the
appliance is essential and it’s therefore necessary to
remove the appliance casing (4.7). Isolate the appliance
from the electrical supply and remove the fuse. And, when
necessary, drain the appliance and heating system. En-
sure some water absorbent cloths are available to catch
any residual water that may drip from the appliance or
removed component. Undertake a complete commis-
sioning check as detailed in section 5, after replacing
any component.
ALWAYS TEST FOR GAS SOUNDNESS IF ANY GAS
CARRYING COMPONENTS HAVE BEEN REMOVED OR
DISTURBED.
6.4.1 AIR BOX FRONT COVER REMOVAL (g. 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.
clips
Fig. 18
6.5 AUTOMATIC AIR RELEASE VALVE (g. 19)
Carry out component removal procedure as described in
6.4. Remove the drain pipe (A). Unscrew the top AAV (B).
Replace in the reverse order. Loctite or similar should be
used as a thread sealant for the AAV.
A
B
Fig. 19
6.6 PRIMARY THERMISTOR (g. 1)
Carry out component removal procedure as described
in 6.4. Unclip and remove the air chamber front cover.
Unclip the primary thermistor from the ow outlet pipe.
Disconnect thermistor electrical plug. Replace in the
reverse order.
6.7 RETURN THERMISTOR (g. 1)
Carry out component removal procedure as described in
6.4. Unclip and remove the air chamber front cover. Unclip
the return thermistor from the return inlet pipe. Disconnect
thermistor electrical plug. Replace in the reverse order.
6.8 PRINTED CIRCUIT BOARD (g. 20)
Carry out component removal procedure as described in
6.4. Pull the control fascia forward and lower it. Locate
and remove the screws (A) which secure the PCB cover,
push the clips (B) and remove cover, after carefully taking
note of all wiring connections and jumper tag congu-
ration, disconnect all wiring from the PCB, locate and
remove the PCB securing screws, remove the required
PCB. Replace in the reverse order ensuring that the posi-
tion of the 3 control knobs are correctly aligned with the
respective potentiometers on the PCB.
Fig. 20 A
B