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20

6.14 FLUE FAN & MIXER (fig. 28-29)

Carry out component removal procedure as described in 6.4. 

Remove the air chamber front cover. Locate and remove the 

gas pipe locking pin (

A1

) and swing/rotate the gas pipe away 

from the fan assembly (

B1

), (if necessary unscrew the gas 

pipe from the gas valve 

G1

). Locate and slacken the silencer 

(

H1

). Locate and remove the sense electrode. To remove the 

fan (

E1

), disconnect the electrical connections attached to 

the fan, locate and remove the four screws (

F1

). Gently ease 

the fan from its location. To remove the mixer (

C1

) locate and 

remove the three screws (

D1

), the mixer can be removed after 

the fan removal. Replace in the reverse order. Ensure all seals 

are in good condition, taking care to ensure they are replaced 

correctly.

6.15 BURNER (fig. 28)

Carry out component removal procedure as described in 6.4. 

Remove the air chamber front cover. Locate and remove the 

gas pipe locking pin (

A1

) and swing/rotate the gas pipe away 

from the fan assembly (

B1

), (if necessary unscrew the gas 

pipe from the gas valve 

G1

). Locate and slacken the silencer 

(

H1

), disconnect the electrical connections attached to the 

fan. Disconnect the electrode leads and ancillary wiring from 

their respective connectors. Locate and remove the screws 

(

I1

) which secure the burner assembly in position to the heat 

exchanger (

J1

). Gently ease the fan assembly out of its location. 

Once the assembly has been removed, the burner (

K1

) can 

be withdrawn from the heat engine. Ensure the seals (

L1

) is in 

good condition, taking care to ensure it is replaced correctly. 

Replace in the reverse order.

Fig. 27

6.13  ELECTRODES (fig. 27)

Carry out component removal procedure as described in 6.4. 

Remove the air chamber front cover. Disconnect the electrode 

leads and ancillary wiring from their respective connectors. Re

-

move the retaining screws (

V

) for electrode. Remove the spark 

ignition electrode (

W

). Remove the flame sensor electrod (

Y

).

6.12 GAS VALVE (fig. 26)

Carry out component removal procedure as described in 6.4. 

The gas valve must be changed as complete unit. Disconnect 

the electrical plug and leads from the gas valve, slacken and 

unscrew gas valve inlet

 

and outlet connections. 

Please note, 

the sealing washers (

Q

) must be discarded and replaced with 

new sealing washers. Disconnect the compensation pipe (

R

). 

Unscrew gas pipe connections (

S-T

), the gas valve can now 

be removed. Replace in the reverse order. Check and adjust 

burner pressure settings.

WARNING, A GAS TIGHTNESS CHECK MUST BE CAR-

RIED OUT.

6.12.1 INJECTOR (fig. 26)

Carry out component removal procedure as described in 6.4. 

Unscrew and remove gas pipe connections (

S-T

). Locate and 

remove the injector (

U

) inside the valve. Replace in the reverse 

order. Check and adjust burner pressure settings.

WARNING, A GAS TIGHTNESS CHECK MUST BE CAR-

RIED OUT.

Q

Q

U

S

T

C1

D1

E1

F1

V

Y

W

H1

I1

J1

K1

L1

L1

Fig. 26

V

W

Y

Fig. 28

which secure  the PCB cover, remove cover, after carefully tak-

ing note of all wiring connections and jumper tag configuration. 

Unhook and remove connection block (

P

). Disconnect all wiring 

from the PCB, locate and remove the PCB securing screws, 

remove the required PCB. Replace in the reverse order ensur

-

ing that the position of the 2 control knobs are correctly aligned 

with the respective potentiometers on the PCB.

Ensure  that  the  correct  jumper  tag  configuration  has  been 

respected. It will be necessary to check the functioning of the 

PCB is set for the correct boiler type/application.

Содержание Excel 25

Страница 1: ...S TO BE RETAINED BY USER Vok ra is a licensed member of the Benchmark scheme which aims to improve the standards of installation and commissioning of domestic hot water systems in the UK Excel High ef...

Страница 2: ...3A 5 Air supply 11 3A 6 Water circulation 11 3A 7 Electrical supply 11 3A 8 Mounting on a combustible surface 11 3A 9 Timber framed buildings 11 3A 10 Inhibitors 11 3A 11 Showers 11 3A 12 Declaration...

Страница 3: ...el 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 efficiency Please therefore take some ti...

Страница 4: ...et temperature or counter clockwise to reduce the temperature range 37 C 60 C Boiler at OFF standby Select this position when you want the boiler to be switched off for short periods days or if the bo...

Страница 5: ...may be necessary to reduce the flow of water at the hot water outlet tap NOTE If the appliance fails to ignite during the ignition sequence it will enter a lockout condition Should this occur please a...

Страница 6: ...switch in the bottom position To select OFF mode move the selector switch in the upper position APPLIANCE STATUS LED AND FAULT CODES Fig 3 4 WHAT IF 5 SETTING THE VOK RA Advice for homeowners Please c...

Страница 7: ...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...

Страница 8: ...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 9: ...ume 74 litres Pre charge pressure 1 bar 2 5 Dimensions Excel 25 Excel 29 Height mm 715 Width mm 405 Depth mm 250 Dry weight kg 28 29 2 6 Clearances Excel 25 Excel 29 Sides 12mm Top 150mm from casing o...

Страница 10: ...ain pipe etc 25 mm E Below eaves 25 mm F Below balcony car port roof etc 25 mm G To the side of a soil drain pipe etc 25 mm 60mm for 80 125 5 flue H From internal external corner 25 mm 60mm for 80 125...

Страница 11: ...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 12: ...is to be fitted on a wall of combustible material There is no requirement to protect the wall 3 9 TIMBER FRAMED BUILDINGS If the appliance is to be fitted in a timber framed building it shouldbefitte...

Страница 13: ...W 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 least 1 metre above the highest point in the system an...

Страница 14: ...plane see2 9 Areductionmustalsobemadetothemaximumlength see table below when additional bends are used Reduction for additional bends Bend Reduction in maximum flue length for each bend 45 bend 1 0 me...

Страница 15: ...e installation of the 80 125mm concentric flue system please refer to the instructions supplied The vertical flue terminal can be connected directly to the ap pliance flue outlet Alternatively an exte...

Страница 16: ...ir 2000mm 0225840 45 bend pair N A 0225845 90 bend pair N A 0225850 Twin bracket 5 N A 0225855 Single bracket 5 N A MOUNTING THE BOILER The fixing holes for the wall mounting bracket should now be dri...

Страница 17: ...wards the appliance 17mm per 1000mm Fig 13c Fig 14 4 6 CONNECTING THE GAS AND WATER The appliance is supplied with an accessory pack that includes service valves Theservicevalvesareforwelding Theacces...

Страница 18: ...circuits please refer to section 8 for detailed instructions ANYEXTERNALCONTROLOR WIRING MUST BE SERVED FROM THE SAME ISOLATOR AS THAT OF THE APPLIANCE The supply cable from the isolator to the appli...

Страница 19: ...d properly and in ac cordance with the instructions ensure all appliance service valves are open 5 6 INITIAL LIGHTING Ensure the electrical supply to the appliance is switched on Ensure any external c...

Страница 20: ...tres flow restrictor 5 12 FINAL CHECKS ENSURE ALL TEST NIPPLES ON THE APPLIANCE GAS VALVE ARE TIGHT AND CHECKED FOR TIGHTNESS ENSURE THE APPLIANCE FLUE SYSTEM IS FITTED CORRECTLY AND IS PROPERLY SECUR...

Страница 21: ...ved from the appliance Replace carefully in the reverse order 6 6 SAFETY VALVE fig 22 Carry out component removal procedure as described in 6 4 Disconnect the outlet pipe G from the safety valve remov...

Страница 22: ...omponent removal procedure as described in 6 4 Remove the air chamber front cover Disconnect the electrode leads and ancillary wiring from their respective connectors Re move the retaining screws V fo...

Страница 23: ...ibed in 6 4 Remove the locking pin Q1 that secures the cover R1 to the hydraulic manifold Using a hooked piece of wire carefully withdraw the by pass cartridge S1 and or DHW non return cartridge T1 En...

Страница 24: ...onnectthewiringtotheDHWflowswitch Slacken and unscrew the inlet connection Unscrew the nut E2 Lift the DHW flow switch housing from its seating If necessary remove the locking pin F2 from the DHW flow...

Страница 25: ...sed for more that 20 minutes 7 2 3 HEATING MODE With the selector switch in the heating hot water position and any additional controls time clock programmer room thermostat etc calling for heat the ap...

Страница 26: ...ut the component removal procedure as described in 6 4 You must ensure that the boiler is completely drained of water Using a suitable pressure gauge remove dust cap on expansion vessel and check the...

Страница 27: ...letion 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 any faultfinding the electr...

Страница 28: ...c information on the suitability of a particular control Further guidance on the recom mended practice for the installation of external controls can be found in CHeSS HC5 HC6 www energyefficiency gov...

Страница 29: ...oiler lock out CN1 CN15 Connectors CN5 Room thermostat 24 Vdc 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...

Страница 30: ...yellow led blinking gas valve maximun setting press twice burner running at maximum DHW yellow led blinking red led fixed gas valve minimum setting press three time burner running at minimum yellow l...

Страница 31: ...3 However if the CO2 reading is incorrect the minimum gas pressure must be adjusted as follows locate the minimum adjustment screw fig 37 using a suit able screwdriver remove the protection plug using...

Страница 32: ......

Страница 33: ......

Страница 34: ...to stabilise YES Is CO less than 350ppm AND CO CO2 ratio less than 0 004 NO Boiler is operating satisfactorily No further actions required Ensure test points are capped boiler case is correctly repla...

Страница 35: ......

Страница 36: ...s 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 the...

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