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the terminal must be protected by a guard of durable material. 
The guard must be fi 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-fl ued boiler, consequently it 
does not require a permanent air vent for combustion air supply.
When installed in a cupboard or compartment, ventilation for 
cooling purposes is also not required.

3A.6 WATER CIRCULATION

Specifi 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 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 fl 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 fl oors, loft space and 
void areas.

3A.6.2 AUTOMATIC BY-PASS

The appliance has a built-in automatic by-pass, consequently 
there is no requirement for an external by-pass, however the 
design of the system should be such that it prevents boiler 
‘cycling’.

3A.6.3 DRAIN COCKS

These must be located in accessible positions to facilitate 
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 fi lling of the system.

3A.6.5 EXPANSION VESSEL

The appliance has an integral expansion vessel to accom-
modate the increased volume of water when the system is 
heated. It can accept up to 8 litres of expansion from within 
the system, generally this is suffi cient, however if the system 
has an unusually high water content, it may be necessary to 
provide additional expansion capacity (see 6.18).

3A.6.6 FILLING POINT

A method for initial fi lling of the system and replacing water lost 
during servicing etc. is provided (see fi g. 7). You should ensure 
this method of fi lling complies with the local water authority 
regulations. 

3A.6.7 LOW PRESSURE SEALED SYSTEM

An alternative method of fi lling 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 fi g. 8). The cold feed from 
the make-up vessel or tank must be fi tted with an approved 
non-return valve and stopcock for isolation purposes. The feed 
pipe should be connected to the return pipe as close to the 
boiler as possible.

3A.6.8 FREQUENT FILLING

Frequent  fi lling or venting of the system may be indicative 
of a leak. Care should be taken during the installation of the 
appliance to ensure all aspects of the system are capable of 
withstanding pressures up to at least 3 bar.

3A.7 ELECTRICAL SUPPLY

The appliance is supplied for operation on 230V @ 50Hz electri-
cal 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 fuse spur with a contact separation 
of at least 3,5 mm (3° high-voltage category). 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 fi tted on a wall of combustible mate-
rial, there is no requirement for a sheet of fi reproof material to 
protect the wall.

3A.9 TIMBER FRAMED BUILDINGS

If the appliance is to be fi tted in a timber framed building, it 
should be fi 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 specifi c 
advice on this type of installation.
 

3A.10 INHIBITORS

Vokèra 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 administered in strict accordance with 
the manufacturers instructions*.
*Water treatment of the complete heating system - including 
the boiler - should be carried out in accordance with I.S. 813 
and the Domestic Water Treatment Association’s (DWTA) code 
of practice.

3A.11 DECLARATION OF CONFORMITY

A Declaration of Conformity (as defi ned in I.S. 813) must be 
provided on completion of the installation. 
A copy of the declaration must be given to the responsible 
person and also to the gas supplier if required.

Summary of Contents for Mynute i20

Page 1: ...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 system...

Page 2: ...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 Prep...

Page 3: ...tomatically Dear Customer Your Vok ra Mynute i boiler 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...

Page 4: ...unter clockwise to reduce the tem perature range 40 C 80 C for standard central heating The automatic temperature control function SARA is set within the blank bullet points MODE SELECTOR SWITCH HEATI...

Page 5: ...ance 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 t...

Page 6: ...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 electricit...

Page 7: ...rary then final Reset check appliance operation Temperature differential Final Reset check appliance operation check thermistors A08 Return thermistor fault Temporary Check return thermistor check wir...

Page 8: ...ons 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...

Page 9: ...nissensedbytheelectroniccircuittoensureflamestability at the burner Once successful ignition has been achieved the electronic circuitry increases the gas rate to 75 for a period of 15minutes Thereafte...

Page 10: ...e 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 Conde...

Page 11: ...300 mm Q From the top of the vertical terminal to the roof flashing As determined by the fixed collar of the vertical terminal R To the side of a boundary 300 mm S To the side of an opening or window...

Page 12: ...high water content it may be necessary to provide additional expansion capacity see 6 18 3 6 6 FILLING POINT A method for initial filling of the system and replacing water lost during servicing etc di...

Page 13: ...s no requirement for a sheet of fireproof material to protect the wall 3 9 TIMBER FRAMED BUILDINGS If the appliance is to be fitted in a timber framed building it shouldbefittedinaccordancewiththeInst...

Page 14: ...es with the local water authority regulations 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...

Page 15: ...on its vertical axis In addition the flue may be extended from the outlet elbow in the horizontal plane see2 9 Areductionmustalsobemadetothemaximumlength see table below when additional bends are use...

Page 16: ...d be drilled LEVEL to ensure any condense fluid that forms is allowed to drain back to the appliance The fixing holes for the wall mounting bracket should now be drilled and plugged an appropriate typ...

Page 17: ...ect the required number of flue extensions or bends up to the maximum equivalent flue length between the boiler and vertical flue assembly Ensure that any horizontal sections of the flue system have a...

Page 18: ...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 the concentric terminal through the wall...

Page 19: ...reen yellow to EARTH connection Insertthesupplied3 AMPfuseintothefusedisolatororfusedplug Should the fly lead be unsuitable refer to 4 7 3 for details on how to connect the electrical supply directly...

Page 20: ...UK to ensure that correct combustion is occurring see flow chart on page 36 Additionally if the gas valve has been adjusted replaced or the appliance has been converted for use with another gas type...

Page 21: ...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 specification The cause of any noticeable dete...

Page 22: ...and remove the air chamber front cover Remove the AAV locking pin M from the deaerator assembly and remove the AAV assembly N Replace in the reverse order 6 8 WATER PRESSURE SWITCH fig 29 Carry out co...

Page 23: ...electrode leads and ancillary wiring from their respective connectors Remove the retaining screws W for electrode and remove 6 12 GAS VALVE fig 31 Carry out component removal procedure as described in...

Page 24: ...cal an external expansion vessel may be fitted to the return pipe as close to the appliance as possible 6 18 1 EXPANSION VESSELREMOVAL with sufficient clearance above fig 37 Carry out component remova...

Page 25: ...Locate and remove the screw A2 that secures the flue gas analysis test point cover B2 Remove the clip and the fumes thermostat C2 Locate and remove the screws D2 that se cure the flue collector to th...

Page 26: ...sition and any additional controls time clock programmer room thermostat etc calling for heat the appliance will operate in the heating mode The pump and fan will be activated via the flow temperature...

Page 27: ...PLETION On completion of the combustion analysis check and or any gas valve adjustment refit the plug fig 40 L2 and move the mode selector through position Remove the test probe from the test point an...

Page 28: ...at the fuse has failed but no fault is in dicated a detailed continuity check will be required to trace the fault A visual inspection of components may also assist in locating the fault 7 7 3 POLARITY...

Page 29: ...pm GAS VALVE CALIBRATION Connect the boiler to the power supply Open the gas tap Set the function selector to OFF RESET monitor off Remove the screws E remove the casing remove the re taining screw be...

Page 30: ...0 15 20 25 30 ROOM TEMPERATURE CURVE OFFSET DELIVERY TEMPERATURE C EXTERNAL TEMPERATURE C Fig 42 The boiler is supplied with the adjustments shown in the table Depending on plant engineering requireme...

Page 31: ...FLOW OUTLET TEMPERATURE C T80 Maximum set point for standard T range JP7 removed T45 Maximum set point for low T range JP7 inserted Fig 43 CN8 CN7 CN6 CN5 CN12 1 JP1 JP2 JP3 JP4 JP5 JP6 JP7 JP8 CN15...

Page 32: ...appliance can be used with the following controls twin channel programmers The appliance can be used in conjunction with typical S Plan systems and Y Plan systems Please contact Vokera technical shou...

Page 33: ...CN2 NO NC C black black BE11 FUNCTIONAL DIAGRAM Fig 45 S W CO2 function button F S 1 Flame sensor F1 Fuse 3 15A T F External fuse 3 15A F M3 Terminal strip for electrical connection hight power P Pum...

Page 34: ...10 0 CO2 minimum output 10 0 10 0 CO maximum output ppm 190 160 CO minimum output ppm 20 15 CO2 FUNCTIONS ACTION ON THE BUTTON DISPLAY combustion analysis mode press once burner running at maximum hea...

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Page 36: ...OHU LQWHUORFN 3URYLGHG ALL SYSTEMS 7KH V VWHP KDV EHHQ XVKHG DQG FOHDQHG LQ DFFRUGDQFH ZLWK 6 DQG ERLOHU PDQXIDFWXUHU V LQVWUXFWLRQV Yes KDW V VWHP FOHDQHU ZDV XVHG KDW LQKLELWRU ZDV XVHG 4XDQWLW OLWU...

Page 37: ...HSKRQH 1R DV VDIH UHJLVWHU 1R 5HFRUG W PD UDWH 2 SSP AND 2 W PLQ UDWH KHUH 3RVVLEOH 2 SSP AND 2 RPPHQWV 6LJQDWXUH SERVICE 04 DWH QJLQHHU QDPH RPSDQ QDPH 7HOHSKRQH 1R DV VDIH UHJLVWHU 1R 5HFRUG W PD UD...

Page 38: ...R TO MINIMUM RATE In accordance with section 7 3 set boiler to operate at minimum rate to minimum load condition Allow sufficient time for combustion to stabilise YES Is CO 350ppm and CO CO2 ratio les...

Page 39: ...39...

Page 40: ...ies vokera co uk www vokera co uk www vokera ie Sales General Enquires T 0844 391 0999 F 0844 391 0998 Vok ra Ireland West Court Callan Co Kilkenny T 056 7755057 F 056 7755060 Vok ra Limited reserve t...

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