VOKERA Mynute i20 User manual

40
Users Instructions
Installation &
Servicing
Instructions
THESE INSTRUCTIONS
TO BE RETAINED
BY USER
Vokèra is a licensed member of the Benchmark scheme
Vokèra is a licensed member of the Benchmark scheme
which aims to improve the standards of installation and
which aims to improve the standards of installation and
commissioning of domestic hot water systems in the UK.
commissioning of domestic hot water systems in the UK.
Mynute i
High efficiency system boiler
Mynute i20 G.C. N. 41 094 81
Mynute i30 G.C. N. 41 094 82

37
Users instructions
Things you should know Page
1.1 Gas appliances 1
1.2 Electrical supply 1
1.3 Guarantee registration card 1
1.4 Appliance Log Book (UK only) 1
1.5 How does it work? 1
1.6 Dimensions 1
1.7 Clearances required 1
1.8 Frost protection system 1
1.9 Appliance status indicators 1
Getting started Page
2.1 Before switching ON 3
2.2 Appliance controls 3
2.3 Lighting the boiler 3
2.4 Adjusting the heating temperature 3
2.5 Explanation of features 3
2.6 Automatic temperature control 3
How to... Page
3.1 How to top-up the system pressure 4
3.2 How to reset the appliance 4
3.3 How to shut down the system for short periods 4
3.4 How to shut down the system for long periods 4
3.5 How to care for the appliance 4
What if... Page
4.1 What if I suspect a gas leak 4
4.2 What if I have frequently top-up the system 4
4.3 What if the appliance is due its annual service 4
4.4 What if I need to call an engineer 4
Installation and Servicing instructions
Design principles & operating sequence Page
1.1 Principle components 7
1.2 Mode of operation (at rest) 7
1.3 Mode of operation (heating) 7
1.4 Safety devices 7
Technical data Page
2.1 Central heating 8
2.2 Gas pressures 8
2.3 Expansion vessel 8
2.4 Dimensions 8
2.5 Clearances 8
2.6 Connections 8
2.7 Electrical 8
2.8 Flue details (concentric) 8
2.8A Flue details (twin pipes) 8
2.9 Efficiency 8
2.10 Emissions 8
2.11 Pump duty 9
General requirements (UK) Page
3.1 Related documents 10
3.2 Location of appliance 10
3.3 Gas supply 10
3.4 Flue system 10
3.5 Air supply 10
3.6 Water circulation 10
3.7 Electrical supply 11
3.8 Mounting on a combustible surface 11
3.9 Timber framed buildings 11
3.10 Inhibitors 11
General requirements (EIRE) Page
3A.1 Related documents 11
3A.2 Location of appliance 11
3A.3 Gas supply 11
3A.4 Flue system 11
3A.5 Air supply 12
3A.6 Water circulation 12
3A.7 Electrical supply 12
3A.8 Mounting on a combustible surface 12
3A.9 Timber framed buildings 12
3A.10 Inhibitors 12
3A.11 Declaration of conformity 12
Installation Page
4.1 Delivery 13
4.2 Contents 13
4.3 Unpacking 13
4.4 Preparation for mounting the appliance 13
4.5 Fitting the flue 13
4.6 Connecting the gas & water 17
4.7 Electrical connections 17
Commissioning Page
5.1 Gas supply installation 18
5.2 The heating system 18
5.3 Initial filling of the system 18
5.4 Initial flushing of the system 18
5.5 Pre-operation checks 18
5.6 Initial lighting 18
5.7 Checking gas pressure & combustion analysis 18
5.8 Final flushing of the heating system 18
5.9 Setting the boiler operating temperature 18
5.10 Setting the system design pressure 18
5.11 Regulating the central heating system 19
5.12 Final checks 19
5.13 Instructing the user 19
Servicing Page
6.1 General 19
6.2 Routine annual servicing 19
6.3 Replacement of components 19
6.4 Component removal procedure 19
6.5 Pump assembly 20
6.6 Safety valve 20
6.7 Lower automatic air release valves 20
6.8 Water pressure switch 20
6.9 Flow thermistor 20
6.10 Return thermistor 20
6.11 Printed circuit board 20
6.12 Gas valve 21
6.13 Electrodes 21
6.14 Flue fan & mixer 21
6.15 Burner 21
6.16 Main heat exchanger 22
6.17 Automatic by-pass 22
6.18 Expansion vessel removal 22
6.19 Condense trap removal 22
6.20 Flue collector removal 23
Checks, adjustments and fault finding Page
7.1 Checking appliance operation 23
7.2 Appliance modes of operation 23
7.3 Checking the CO2& adjusting the valve 24
7.4 Combustion analysis test 24
7.5 Checking the expansion vessel 24
7.6 External faults 25
7.7 Electrical checks 25
7.8 Fault finding 25
7.9 Component values & characteristics 25
7.10 Adjustments 26
Wiring diagrams Page
8.1 External wiring 29
8.2 Typical control applications 29
8.3 Other devices 29
L.P.G. instructions Page
9.1 Related documents 31
9.2 Technical data 31
9.3 Converting the appliance gas type 31
9.4 Gas supply 31
9.5 Gas supply installation 31
9.6 Checking the CO2and adjusting the gas valve 31
Benchmark 34-35
Commissioning 36

1
USERS INSTRUCTIONS
1.1 GAS APPLIANCES
Gas Safety (Installations and Use) Regulations (UK).
In the interests of your safety and that of others it is a legal
requirement that all gas appliances are installed and correctly
maintained by a competent person and in accordance with the
latest regulations.
1.2 ELECTRICAL SUPPLY
Pleaseensurethatthisappliancehasbeenproperlyconnected
to the electrical supply by means of a double pole isolator or
un-switched socket, and that the correct size of fuse (3 AMP)
has been fitted.
Warning: this appliance must be earthed!
1.3 GUARANTEE REGISTRATION CARD
Pleasetake the timeto fill outyourguarantee registration card.
The completed warranty card should be posted within 30 days
of installation.
1.4 APPLIANCE COMMISSIONING CHECKLIST
(UK only)
A checklist section can be found at the rear of the appliance
installation booklet. This important document must be com-
pleted during the installation/commissioning of your boiler. All
GAS SAFE registered installers carry a GAS SAFE ID card,
and have a registration number. These details should be re-
corded in the Benchmark commissioning checklist section
within the installation booklet. You can check your installers
details by calling GAS SAFE direct on 08004085500. Failure
to install and commission the appliance in accordance with
the manufacturers instructions will invalidate the warranty.
This does not affect your statutory rights.
1.5 HOW DOES IT WORK?
Your Mynute i boiler supplies heated water to your radiators
and hot water to your hot water tank. The central heating is
controlledviaatimeclockandanythermostatsthatyourinstaller
may have fitted. The boiler will light when it receives a request
from the time clock via any thermostat that may be installed.
YourMynuteiboilerlightselectronicallyanddoesnothaveapilot
light. In the unlikely event of a fault developing with your boiler,
thesupplyofgasto the burner will beterminated automatically.
Dear Customer
Your Vokèra Mynute iboiler has been designed to meet and exceed the very latest standards in gas central heating technology,
and if cared for, will give years of reliable use and efficiency.
Please therefore take some time to read these instructions carefully.
Do’s and Don’t’s
- Do ensure that the system pressure is periodically checked
- Do ensure that the boiler should not be used by children or unassisted disabled people
- Do ensure that you know how to isolate the appliance in an emergency
- Do ensure that you are familiar with the appliance controls
- Do ensure that your installer has completed the appliance log book section
- Do not attempt to remove the appliance casing or gain internal access
- Do not hang clothes etc. over the appliance
- Do not forget to have the appliance serviced annually.
This booklet is an integral part of the appliance. It is therefore necessary to ensure that the booklet is handed to the person re-
sponsible for the property in which the appliance is located/installed.Areplacement copy can be obtained from Vokèra customer
services.
INTRODUCTION
1.6 DIMENSIONS
1.7 CLEARANCES REQUIRED
1.8 FROST PROTECTION SYSTEM
TheMynute iisequippedwithabuilt-infrostprotectionsystem,
this enables the boiler to over-ride the time controls – even if
switched off – and operate the burner and/or pump, should
the temperature drop below 50C for the main. In particular the
burner will be in ON status until the main temperature reaches
35°C for CH appliance.
Please note that the frost protection system is designed to
protect the appliance only, should frost protection be required
for the heating system, additional controls may be required.
NOTE
The frost protection system is reliant on the appliance having a
permanentelectrical supply,andbeing in anon-fault condition.
1.9 APPLIANCE STATUS INDICATORS
Your boiler is equipped with a large LCD display that indicates
the appliance operating status.
1. THINGS YOU SHOULD KNOW
Mynute i20 Mynute i30
HEIGHT 780 mm 780 mm
WIDTH 400 mm 400 mm
DEPTH 338 mm 388 mm
ABOVE 150 mm
BELOW 150 mm
LEFT SIDE 12 mm
RIGHT SIDE 12 mm
FRONT 600 mm

2
Fig. 1
PRESSURE GAUGE
Ensure the system pressure is set correctly (minimum 0.5-bar)
MODE SELECTOR SWITCH/HEATING TEMPERATURE SELECTOR
Mode selector switch:
Boiler at OFF/standby - Select this position when you want the boiler to
be switched off for short periods (days).
Heating & hot water - Select this position when you want the boiler to re-
spondto a heatingandhot water requestfrom the time-clockprogrammer
Heating temperature selector: move the selector clockwise to increase
the heating outlet temperature, or counter-clockwise to reduce the tem-
perature (range: 40°C-80°C for standard central heating).
Theautomatic temperature control function(SARA) is setwithin the blank
bullet points.
MODE SELECTOR SWITCH
HEATING TEMPERATURE SELECTOR
PRESSURE GAUGE
Boiler reset - Select this position if the boiler requires to be reset.
Pressure gauge shows the current pressure of your heating system, the
gaugeshouldbe setbetween1 and1.5BAR. Whentheapplianceisoper-
ating the gauge may rise or fall slightly, this is quite normal. The minimum
permissible level for the safe and efficient operation of the appliance is
0.5 BAR. Should the pressure fall below 0.5 BAR, the boiler may lockout.
correct
pressure
value
DISPLAY
SARA
function

3
DIGITAL DISPLAY
Symbol/Icon Description
Displayed when heating mode is active
Displayed when frost protection function is ac-
tive
Displayed if an alarm or fault has been detected
Displayed when low system pressure has been
detected
Displayed when an external sensor is connected
to the boiler
Flame on
Displayed if an ignition fault has been detected
2.1 BEFORE SWITCHING ON
Before switching the appliance on, please familiarise yourself
with:
- howtoisolatetheappliancefromthegas,water,andelectricity
supplies;
- how to check and top-up – if necessary – the system water
pressure;
- the time clock or programmer (if fitted);
- any external thermostats and their functions;
- the appliance controls.
2.2 APPLIANCE CONTROLS (see fig. 1)
The appliance controls are situated on the lower front of the
appliance. The appliance controls include:
- pressure gauge;
- appliance mode selector;
- temperature selector
NOTE
The appliance frost protection is active in all the boiler modes.
The temperature selector can be used to vary the temperature
of the water that circulates around your radiators.
The temperature range is adjustable between 40°C and 80°C.
Refer to the main appliance status table for fault indicator and
boiler status.
2.3 LIGHTING THE BOILER
Ensure the gas and electrical supply to the boiler are
turned on.
Turn the mode selector switch to the ON position. When there
is a request for heating or hot water via the time clock or pro-
grammer, the boiler will begin an ignition sequence. When the
appliance reaches the CH set temperature, the burner will go
off for a minimum period of approximately 3 minutes.
When the programmer/time clock or external thermostats
heating request has been satisfied, the appliance will switch
off automatically.
2.4 ADJUSTING THE HEATING TEMPERATURE
Rotatethetemperatureselector–clockwisetoincrease,counter-
clockwisetodecrease–tothedesiredtemperaturesetting. The
temperaturecan be set fromaminimumof 40°C toamaximum
of 80°C (if standard CH mode is selected).
2.5 EXPLANATION OF FEATURES
Although the Vokèra Mynute ihas been designed for simplicity
of use, it utilises the latest in boiler technology, enabling a host
of functions to be carried out simultaneously.
2.6 AUTOMATIC TEMPERATURE CONTROL
Theautomatictemperaturecontrolfunction(SARA),permitsthe
boiler (when the heating temperature selector is set within the
blank bullet points) to automatically adjust (raise) the heating.
The activation and the disable of the function is visualized on
the display.
2. GETTING STARTED
65

4
3.1 HOW TO TOP-UP THE SYSTEM PRESSURE
(fig. 1-2)
Thesystempressuremustbecheckedperiodicallytoensurethe
correctoperation of the boiler.The needleonthegauge should
be reading between 1 and 1.5 BAR when the boiler is in an off
position and has cooled to room temperature. If the pressure
requires ‘topping-up’ use the following instructions as a guide.
- Locate the filling valve connections (usually beneath the
boiler, see fig. 2).
- Attach the filling loop to both connections.
- Openthe filling valveslowly until youhearwater entering the
system.
- Closethefillingvalvewhenthepressuregauge(ontheboiler)
reads between 1 and 1.5 BAR (see fig. 1).
- Remove the filling loop from the connections.
3.2 HOW TO RESET THE APPLIANCE
Whenthe redfaultLEDisilluminated,theappliancewillrequire
to be reset manually. Before resetting the boiler, check what
action is required to be taken, using the information on the
fault code table below.Allow a period of two minutes to elapse
before rotate the mode selector knob across the position
(see fig. 1).
IMPORTANT
Ifthe appliancerequirestoberesetfrequently,itmaybeindica-
tiveof a fault,please contact yourinstalleror VokèraCustomer
Services for further advice.
3.3 HOW TO SHUT DOWN THE SYSTEM FOR SHORT
PERIODS
The system and boiler can be shut down for short periods by
simply turning the time clock to the off position. It is also advis-
able to turn off the main water supply to the house.
3.4 HOW TO SHUT DOWN THE SYSTEM FOR
LONG PERIODS
If the house is to be left unoccupied for any length of time –
especially during the winter – the system should be thoroughly
drained of all water. The gas, water, and electricity supply to
the house should also be turned off. For more detailed advice
contact your installer.
3.5 HOW TO CARE FOR THE APPLIANCE
To clean the outer casing use only a clean damp cloth. Do not
use any scourers or abrasive cleaners.
3. HOW TO...
Fig. 2
control
valve temporary
connection
control
valve
supply pipe
double
check valve
flow/return
pipe
4.1 WHAT IF I SUSPECT A GAS LEAK
If you suspect a gas leak, turn off the gas supply at the gas
meter and contact your installer or local gas supplier. If you
requirefurtheradvicepleasecontactyournearestVokèraoffice.
4.2 WHAT IF I HAVE FREQUENTLY TO TOP-UP
THE SYSTEM
Ifthe system regularlyrequirestopping-up, it maybeindicative
of a leak. Please contact your installer and ask him to inspect
the system.
4.3 WHAT IF THE APPLIANCE IS DUE ITS AN-
NUAL SERVICE
Advice for tenants only
Your landlord should arrange for servicing.
Advice for homeowners
Pleasecontact VokèraCustomer Service(0844 3910999 (UK)
or 056 7755057 (ROI) if you would prefer a Vokèra service
engineer or agent to service your appliance.Alternatively your
local GAS SAFE registered engineer may be able to service
the appliance for you.
4.4 - WHAT IF I NEED TO CALL AN ENGINEER
Ifyouthinkyourboilermayhavedevelopedafault,pleasecontact
yourinstallerorVokèraCustomerServices(0844 3910999 (UK)
or 056 7755057 (ROI) have all your details to hand including
fulladdress andpostcode, relevant contactnumbers, and your
completed appliance log book.
4. WHAT IF...

5
FAULT CODES
ALARM CODE CAUSE ALARM TYPE ACTION
_St AUTOSTOP Final Call engineer
_CL CALL FOR SERVICE Temporary then final Call engineer
A01 Ignition failure, flame not sensed,
internal fault Final Reset, check appliance operation
A02 Limit thermostat fault Final Reset, check appliance operation
A03 Fan tacho signal fault Final Reset check appliance operation, check fan
A04 Insufficient system water pressure Final Check/refill system pressure, reset, check
appliance operation
A06 Jumper tag configuration Temporary Check jumper tag configuration
A07
Primary (flow) thermistor fault Temporary Check primary thermistor, check wiring
Primary (flow) thermistor over temperature Temporary then final Reset, check appliance operation
Temperature differential Final Reset, check appliance operation, check
thermistors
A08
Return thermistor fault Temporary Check return thermistor, check wiring
Return thermistor over temperature Temporary then final Reset, check appliance operation
Temperature differential inverted Final Reset, check pump, ensure there is suf-
ficient circulation around heating circuit/s
A09
Flue thermistor or flue thermistor
counter fault Temporary Check flue thermistor counter at power on, check flue thermistor, check wiring
Flue thermistor over temperature Final Reset, check appliance operation
A11 False flame Temporary None
A77 Low temperature thermostat fault Temporary Check low temperature thermostat
Adj Calibration Na None
ACO Service operation Na None
Purge cycle mode active Na None
Flame ON Na None
Hours Stand-by Na None
- - OFF Na None

6
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.
TheMynute i arehigh-efficiencysystem boilers withoutputsof
20kW and 30kW. These appliances – by design – incorporate
electronic ignition, circulating pump, expansion vessel, safety
valve, pressure gauge and automatic by-pass.
The Mynute i range is produced as room sealed, category
II2H3P appliances, suitable for internal wall mounting applica-
tions only. Each appliance is provided with a fan powered flue
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 i can also be
used with the Vokèra twin flue system.
The Mynute i 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 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 Vokèra
customer services.
Fig. 3
General layout
1 Safety valve
2 Drain valve
3 Pressure switch
4 Pump
5 Bottom auto air vent (AAV)
6 Expansion vessel
7 Condense trap
8 Return thermistor (NTC)
9 Sensing Electrode
10 High limit thermostat
11 Flow thermistor (NTC)
12 Top AAV+De-aerator
13 Flue gas analysis test point
14 Flue outlet & air intake
15 Ignition transformer
16 Flues thermistor (NTC)
17 Spark Electrode
18 Burner
19 Main heat exchanger
20 Conveyor
21 Fan assembly
22 Mixer
23 Condense trap
24 Gas valve
25 Three way porte valve
R Heating return connection
F Heating flow connection
G Gas connection
INTRODUCTION
INSTALLATION AND SERVICING INSTRUCTIONS
R F G

7
1.1 PRINCIPLE COMPONENTS
Afullyintegratedelectroniccontrolboardfeaturingelectronic
temperature control, anti-cycle control, pump over-run, self-
diagnostic fault indicator, full air/gas modulation
Aluminium heat exchanger
Electronic ignition with flame supervision
Integral high-head pump
Fan
Expansion vessel
Water pressure switch
Flue sensor
Pressure gauge
Safety valve
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:
frost-protectionsystem–thefrost-protectionsystemprotects
theappliance againsttheriskoffrostdamage.ForCHline,if
themaintemperaturefallsto5°C,theappliancewillfunction
on minimum power until the temperature on main reaches
35°C.
anti-blockfunction–theanti-blockfunctionenablesthepump
to be energised for short periods, when the appliance has
been inactive for more than 24-hours.
1.3 MODE OF OPERATION (Heating)
When there is a request for heat via the 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.
Ignitionissensedbytheelectroniccircuittoensureflamestability
at the burner. Once successful ignition has been achieved, the
electroniccircuitryincreasesthe gas rate to 75%for aperiod of
15minutes.Thereafter,theboiler’soutputwilleitherbeincrease
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 three-minute anti-cycle
(timer delay).
When the request for heat has been satisfied the appliance
pumpandfanmaycontinuetooperatetodissipateanyresidual
heat within the appliance.
1.4 SAFETY DEVICES
When the appliance is in use, safe operation is ensured by:
awaterpressureswitchthatmonitorssystemwaterpressure
and will de-activate the pump, fan, and burner should the
system water pressure drop below the rated tolerance;
fan speed sensor to ensure safe operation of the burner;
ahighlimitthermostatthatover-ridesthetemperaturecontrol
circuit to prevent or interrupt the operation of the burner;
flame sensor that will shut down the burner when no flame
signal is detected;
flue sensor;
a safety valve which releases excess pressure from the
primary circuit.
Fig. 4
Safety
valve
Pump
Main heat
exchanger
Bottom
AAV
Drain
valve
Flow temperature
sensor Top AAV
Automatic
by-pass
CH
return CH flow
SECTION 1 - DESIGN PRINCIPLES AND OPERATING SEQUENCE
Pressure
switch
Return
temperature
sensor

8
SECTION 2 - TECHNICAL DATA
2.1 Central Heating Mynute i20 Mynute i30
Heat input (kW) 20.00 30.00
Maximum heat output (kW) 60/80°C 19.62 29.25
G20 G31 G20 G31
Minimum heat output (kW) 60/80°C 2.76 3.95 3.50 4.87
Maximum heat output (kW) 30/50°C 21.44 31.77
Minimum heat output (kW) 30/50°C 3.00 4.20 3.80 5.29
Minimum working pressure 0.25-0.45 bar
Maximum working pressure 2.5 bar
Minimum flow rate 300 l/h
2.3 Gas Pressures Mynute i20 Mynute i30
Inlet pressure (G20) 20.0 mbar
Heating maximum gas rate (m3/hr) 2.12 3.17
Minimum gas rate (m3/hr) 0.30 0.38
Injector size (mm) 4.70 flap side - 4.20 free side 5.10 flap side - 4.70 free side
2.4 Expansion Vessel Mynute i20 Mynute i30
Capacity 8 litres
Maximum system volume 76 litres
Pre-charge pressure 1 bar
2.5 Dimensions Mynute i20 Mynute i30
Height (mm) 780
Width (mm) 400
Depth (mm) 338 388
Dry weight (kg) 40 38
2.6 Clearances Mynute i20 Mynute i30
Sides 12mm
Top 150mm from casing or 25mm above flue elbow (whichever is applicable)
Bottom 150mm
Front 600mm
2.7 Connections Mynute i20 Mynute i30
Flow & return 22mm
Gas 15mm
Safety valve 15mm
Condense 21mm
2.8 Electrical Mynute i20 Mynute i30
Power consumption (Watts) 102 118
Voltage (V/Hz) 230/50
Internal fuse 3.15AT (for PCB) - 3.15AF (for connections block)
External fuse 3A
2.9 Flue Details (concentric 60-100) Mynute i20 Mynute i30
Maximum horizontal flue length (60/100mm) 7.80m 7.85m
Maximum vertical flue length (60/100mm) 8.80m 8.85m
2.9A Flue Details (concentric 80-125) Mynute i20 Mynute i30
Maximum horizontal flue length (80/125mm) 20m 14.85m
Maximum vertical flue length (80/125mm) 21m 15.85m
2.9B Flue Details (twin pipes) Mynute i20 Mynute i30
Maximum horizontal flue length (80mm/80mm) 50m/50m 38m/38m
Maximum vertical flue length (80mm/80mm) 50m/50m 38m/38m
2.10 Efficiency Mynute i20 Mynute i30
UK (%) 2005 90.30 90.03
2.11 Emissions Mynute i20 Mynute i30
CO2 @ maximum output (%) 9.0
CO2 @ minimum output (%) 9.0
CO @ maximum output (ppm) 150
CO @ minimum output (ppm) 10 5
Nox rating class 5