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7

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

  Aluminium heat exchanger

  Electronic ignition with 

fl

 ame 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-protection system – the frost-protection system protects 

the appliance against the risk of frost damage both for CH 

and DHW. For CH line, if the main temperature falls to 5°C, 

the appliance will function on minimum power until the tem-

perature on main reaches 35°C. 

  Moreover if the DHW temperature falls to 5°C, the appliance 

will function on minimum power until the temperature on main 

reaches 55°C.

  anti-block function – the anti-block function enables the pump 

and divertor valve actuator 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.

Ignition is sensed by the electronic circuit to ensure 

fl

 ame stability 

at the burner. Once successful ignition has been achieved, the 

electronic circuitry increases the gas rate to 75% for a period of 

15 minutes. Thereafter, the boiler’s output will either be increase 

to maximum or modulate to suit the set requirement.  When 

the appliance reaches the desired 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 satis

fi

 ed the appliance 

pump and fan may continue to operate to dissipate any residual 

heat within the appliance.

1.4 MODE OF OPERATION (Hot water)

When there is a request for DHW via a hot water outlet or tap, 

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 circuit to ensure 

fl

 ame stabil-

ity at the burner. Once successful ignition has been achieved, 

the electronic circuitry increases the gas rate to maximum or 

will modulate output to stabilise the temperature.

In the event of the appliance exceeding the desired temperature 

(set point) the burner will shut down until the temperature drops. 

When the request for DHW has been satis

fi

 ed the appliance 

pump and fan may continue to operate to dissipate any residual 

heat within the appliance.

Fig. 5

SECTION 1 - DESIGN  PRINCIPLES AND OPERATING SEQUENCE

1.5 SAFETY DEVICES

When the appliance is in use, safe operation is ensured by:

  a water pressure switch that monitors system water pressure 

and will 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;

  a high limit thermostat that over-rides the temperature control 

circuit to prevent or interrupt the operation of the burner;

 

fl

 ame sensor that will shut down the burner when no 

fl

 ame 

signal is detected;

 

fl

 ue sensor;

 a safety valve which releases excess pressure from the 

primary circuit.

Expansion 

vessel

Safety 

valve

Pump

Return 

temperature 

sensor

Main heat 

exchanger

Bottom 

AAV

Pressure 

switch

DHW heat 
exchanger

Diverter 

valve

Drain 

valve

DHW tem-

perature 

sensor

Flow temperature 

sensor 

Top AAV

Automatic

by-pass

DHW 

non return 

valve

Flow 

regulator

CH 

return

CH 

fl ow

DHW fl ow 

switch

DHW

inlet

DHW
outlet

Содержание Unica i28

Страница 1: ...d 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 c...

Страница 2: ...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 Showers 12 3A 12 Declaration of conformity 12 Installation...

Страница 3: ...ally Dear Customer Your Vok ra Unica 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 and effici...

Страница 4: ...nk bullet points The display shows the temperature values Pressure gauge shows the current pressure of your heating system the gauge should be set between 1 and 1 5 BAR When the appliance is oper atin...

Страница 5: ...when frost protection function is ac tive Displayed when hot water pre heat function is enabled Flashes when functioning Displayed if an alarm or fault has been detected Displayed when low system pres...

Страница 6: ...wo minutes before re setting the appliance 2 6 EXPLANATION OF FEATURES Although the Vok ra Unica has been designed for simplicity of use it utilises the latest in boiler technology enabling a host of...

Страница 7: ...ustomerServices 08443910999 UK or 056 7755057 ROI have all your details to hand including full address and postcode relevant contact numbers and your completed appliance log book ALARM CODE CAUSE ACTI...

Страница 8: ...d 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...

Страница 9: ...the boiler will perform a three minute anti cycle timer delay When the request for heat has been satisfied the appliance pump and fan may continue to operate to dissipate any residual heat within the...

Страница 10: ...a i32 Unica i36 Capacity 8 litres Maximum system volume 76 litres Pre charge pressure 1 bar 2 5 Dimensions Unica i28 Unica i32 Unica i36 Height mm 780 Width mm 400 Depth mm 358 384 Dry weight kg 40 42...

Страница 11: ...nal R To the side of a boundary 300 mm S To the side of an opening or window on a pitched roof 600 mm T Below an opening or window on a pitched roof 2000 mm V From a vertical terminal to an adjacent o...

Страница 12: ...n 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 sufficient however if the system has...

Страница 13: ...itted on a wall of combustible mate rial there is 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 b...

Страница 14: ...An alternative method of filling the system would be from an independent make up vessel or tank mounted in a position at least 1 metre above the highest point in the system and at least 5 metres above...

Страница 15: ...appliance should be mounted on a smooth vertical non combustible surface which must be capable of supporting the full weight of the appliance Care should be exercised when determining the position of...

Страница 16: ...m 29450127 2000m extension 2000 mm 29450128 Telescopic extension 372 519 mm 529 Wall bracket pack 5 208mm Using the template provided mark and drill a 125mm hole for thepassageofthefluepipe Theholesho...

Страница 17: ...ld be drilled LEVEL to ensure any condense fluid that forms is al lowed to drain back to the appliance The fixing holes for the wall mounting bracket should now be drilled and plugged an appropriate t...

Страница 18: ...he required number of flue extensions or bends up to the maximum equivalent flue length between the boiler and vertical flue assembly see fig 17 Ensure that any horizontal sections of the flue system...

Страница 19: ...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...

Страница 20: ...The boiler is supplied with a 2 metre fly lead This lead can be used for connection to the electrical supply Connect the fly lead to a fused plug or fused isolator in the following way brown wire to L...

Страница 21: ...liance and carry out a combustion analysis check in accor dance with BS 7967 UK to ensure that correct combustion is occurring see flow chart on page 38 Additionally if the gas valve has been adjusted...

Страница 22: ...RE CHECKED FORTIGHTNESS RE FIT APPLIANCE CASING COMPLETE BENCHMARK CHECKLIST FOR UK ONLY Complete details of the boiler controls installation and com missioning in the Benchmark checklist at the back...

Страница 23: ...the expansion pipe Locate and remove the AAV locking pin G from the pump assembly and remove the AAV assembly H Replace in the reverse order 6 7 1 TOP AUTOMATIC AIR RELEASE VALVE fig 32 Carry out comp...

Страница 24: ...g from their respective connectors Remove the retaining screws W for electrode and remove 6 12 GAS VALVE fig 35 Carry out component removal procedure as described in 6 4 The gas valve must be changed...

Страница 25: ...sion vessel be deemed impractical an external expansion vessel may be fitted to the return pipe as close to the appliance as possible 6 18 1 EXPANSION VESSEL REMOVAL with suf ficient clearance above f...

Страница 26: ...Slacken and unscrew the inlet connection E2 Unscrew the nut H2 Lift the DHW flow switch housing from its seating If necessaryremovethelockingpin I2 fromtheDHWflowswitch Replace in the reverse order e...

Страница 27: ...d 55 C respectively the boiler will fire on minimum 25 power until the primary thermistor exceeds 55 C Thereafter the pump will over run for a period of 30 seconds 7 2 3 HEATING MODE With the selector...

Страница 28: ...of greater than 0 008 1 can be deemed as immediately dangerous 7 5 CHECKING THE EXPANSION VESSEL Carry out the component removal procedure as described in 6 4 You must ensure that the boiler is compl...

Страница 29: ...res on the appliance On completion of any task that required the disconnection and re connection of any electrical wiring or component these checks must be repeated 7 8 FAULT FINDING Before attempting...

Страница 30: ...mary thermistor check wiring Primary flow thermistor over temperature Temporary then Final Reset check appliance operation Temperature differential Final Reset check appliance operation check thermist...

Страница 31: ...e number of rotations corresponding to the maxi mum domestic hot water output table 1 Check the CO2 value table 4 if the value does not match the value given in the table use the gas valve maximum adj...

Страница 32: ...e system temperature required the default temperature for calculating the curve is 20 C The graph below can be used to determine the correct curve setting REFERENCE TEMPERATURE 15 C REFERENCE TEMPERAT...

Страница 33: ...nctioning of the display can be personalised by program ming three parameters When button P1 on the display is held down for at least 10 sec the programming procedure is activated The three parameters...

Страница 34: ...l strip M6 must be moved over to the room thermo stat socket position Vokera external sensor fig 50 Fig 50 M2 External alarm M6 E S external sensor OT opentherm connection OPTIONAL DEVICE 24V TERMINAL...

Страница 35: ...e white white EXTERNAL ALARM M2 white 4 1 1 3 orange red black red black orange CN8 J1 J1 VIS MEDIUM AKL Main PCB P1 Selector switch and heating potentiometer P2 DHW potentiometer P3 Potentiometer to...

Страница 36: ...he appliance to another gas type it is necessary to change the injector and adjust the gas valve CO2 To change the injector see 6 12 1 To adjust CO2 values see 10 6 9 4 GAS SUPPLY The gas supply must...

Страница 37: ...However if the CO2 reading is incorrect the minimum gas pressure must be adjusted as follows locate the minimum adjustment screw fig 44 using a suit able screwdriver remove the protection plug using...

Страница 38: ...MUM 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 2 ratio l less t t...

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Страница 40: ...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...

Страница 41: ...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...

Страница 42: ...41...

Страница 43: ...42...

Страница 44: ...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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