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Fig. 1

HOT WATER TEMPERATURE SELECTOR

 

Move the selector clockwise to increase the hot water outlet temperature, or counter-clockwise to reduce the temperature

PRESSURE GAUGE

 

Ensure the system pressure is set correctly (minimum 0.5-bar)

MODE SELECTOR SWITCH/HEATING TEMPERATURE SELECTOR

Mode selector switch: 

Hot water only 

- Select this position if you want the boiler to supply hot 

water only (no heating)

Hot water temperature selector

: move the selector clockwise to increase 

the DHW outlet temperature, or counter-clockwise to reduce the temperature 
(range: 37°C-60°C) 
The display shows the temperature values. 

Boiler at OFF/standby

 - Select this position when you want the boiler to 

be switched off for short periods (days) or if the boiler requires to be reset 

The display shows “- -”.

Heating & hot water

 - Select this position when you want the boiler to re-

spond to a heating and hot water request from the time-clock programmer

Heating temperature selector

: move the selector clockwise to increase the 

heating outlet temperature, or counter-clockwise to reduce the temperature 
(range: 40°C-80°C for standard central heating).
The automatic temperature control function (SARA) is set within the blank 
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-
ating the gauge may rise or fall slightly, this is quite normal. The minimum 
permissible level for the safe and ef

fi

 cient operation of the appliance is 0.5 

BAR. Should the pressure fall below 0.5 BAR, the boiler may lockout.

 correct pressure 

value

MODE SELECTOR SWITCH

HEATING TEMPERATURE SELECTOR 

PRESSURE GAUGE

HOT WATER

TEMPERATURE

SELECTOR

DHW pre-heat function - 

Turning the domestic hot water temperature 

adjustment knob to the symbol activates the pre-heating function. Bring the 
domestic hot water temperature adjustment knob back to the required po-
sition. The activation of this function is indicated on display with the 

icon 

ON. This function keeps the water in the domestic hot water exchanger hot, 
to reduce standby times when a request is made. The display shows the 
delivery temperature of the heating water or the domestic hot water, accor-
ding to the current request. To deactivate the pre-heat function, rotate the 
domestic hot water temperature adjustment knob back to the symbol. Bring 
the domestic hot water temperature adjustment knob back to the required 
position. This function cannot be activated when the boiler is OFF: function 
selector to OFF position.

DISPLAY

LED

Summary of Contents for Unica i28

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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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Page 42: ...41...

Page 43: ...42...

Page 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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