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COMMISSIONING: CO AND COMBUSTION RATIO CHECK

 

 

 

 

 

 

 

 

 

 

SET BOILER TO MAXIMUM RATE 

In accordance with, section 7.3, set boiler to operate at maximum rate (full load condition). Allow sufficient time for combustion to 
stabilise. , insert analyser probe into air inlet sampling point. 

Is O2 

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20.6% 

and CO2 < 0.2%? 

Verify flue integrity 

Analyser readings indicate 
that combustion products 
and inlet air are mixing. 
Further investigation of the 
flue is therefore required. 
Check that flue components 
are correctly assembled, 
fixed and supported as per 
boiler/flue instructions. 
Check that flue and flue 
terminal are not obstructed. 

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and CO2 < 0.2%? 

CHECK CO AND 
COMBUSTION RATIO 
AT MAXIMUM RATE

With boiler still set at 
maximum rate, insert 
analyser probe into flue 
gas sampling point. 
Allow readings to 
stabilise before 

di

Is CO less than 
350ppm AND 
CO/CO

ratio less 

than 0.004? 

YES 

N

YES 

NO 

Check all seals 
around the appliance 
burner, internal flue 
seals, door and case 
seals. Rectify where 
necessary. 

Is CO less 
than 350ppm 
AND 
CO/CO

ratio 

less than 
0.004? 

CHECK CO AND COMBUSTION 
RATIO AT MINIMUM RATE 

With boiler set at minimum rate, 
insert analyser probe into flue 
gas sampling point. Allow 
readings  to stabilise before 
recording. 

NO 

Turn off appliance and 
call Vokera’s technical 
helpline for advice. 
The appliance must not 
be commissioned until 
problems are identified 
and resolved. 

Turn off appliance and call 
Vokera’s technical helpline 
for advice. 
The appliance must not be 
commissioned until 
problems are identified and 
resolved. If commissioning 
cannot be fully completed, 
the appliance must be 
disconnected from the gas 
supply in accordance with 
the GSIUR. 

NOTE: 

Check and record CO and 

combustion ratio at both 
maximum AND minimum rate 
before contacting the Vokera 

SET BOILER 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/CO

2

ratio 

lless

 

tthan 0.004 ?

 

NO 

Boiler is operating satisfactorily
No further actions required.

Ensure test points are capped, boiler case is correctly replaced and all other commissioning procedures are completed. 
Complete Benchmark Checklist, recording CO and combustion ratio readings as required. 

NOTE 

The air/gas ratio valve is factory-set and must not be 
adjusted during commissioning unless this action is 
recommended, following contact with the Vokera 
technical help line. If any such adjustment is 
recommended and further checking of the boiler is 
required, the engineer must be competent to carry out 
this work and to use the flue gas analyser accordingly. 
If the boiler requires conversion to operate with a 
different gas family (e.g., conversion from natural gas 
to LPG) separate guidance will be provided by the 
Vokera technical help line and must be followed. 

NO 

BEFORE CO AND COMBUSTION RATIO CHECK

The installation instructions should have been followed, gas 
type verified and gas supply pressure/rate checked as required 
prior to commissioning. 
As part of the installation process, 

ESPECIALLY WHERE A 

FLUE HAS BEEN FITTED BY PERSONS OTHER THAN THE 
BOILER INSTALLER

, visually check the integrity of the whole 

flue system to confirm that all components are correctly 
assembled, fixed and supported. Check that the maximum flue 
lengths have not been exceeded and all guidance has been 
followed (e.g. Technical Bulletin 008).

 

The flue gas analyser should be of the correct type, as specified 
by BS 7967. 
Before use, the flue gas analyser should have been maintained 
and calibrated as specified by the manufacturer. The installer 
must have the relevant competence for use of the analyser. 
Check and zero the analyser 

IN FRESH AIR

, as per analyser 

manufacturer’s instructions. 

YES 

YES 

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 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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