boiler problem Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[bazza]

hi everyone my mums combi boiler a vokera will not fire up in any mode hw or ch wen you switch it on it just doesnt do anything and a red light comes on she hasnt got the manuel so cant check for trouble shooting hope someone can help as she cant afford repair bills so hoping its something i will be able to help her with thanx 4 any advise bazza

[ALDA]

MIGHT HAVE LOCKEDOUT, TRY RESET BUTTON.

[bazza]

thanx alda 4 advse tried resetting but no joy cheers

[ALDA]

BAZZA,

"IF YOU ARE NOT CONFIDENT WITH OPERATING THE BOILER GET SOMEONE IN".

WHAT IS THE SYSTEM PRESSURE?

IF THIS HAS DROPPED THE BOILERS INBUILT SAFTEY WILL NOT ALLOW IT TO FIRE UP!!!

SWITCH OFF BOILER, INCREASE THE PRESSURE(1-1.5 bar)TO ALLOW BOILER TO CONTINUE INTO ITS START UP SEQUENCE WHEN SWITCHED BACK ON.

IF THE BOILER DOES FIRE UP, THEN THE REASON FOR THE DROP IN SYSTEM PRESSURE SHOULD BE INVESTIGATED AND RECTIFIED.

ALDA

[htg engineer]

Low system pressure light ?

[bazza]

hi mate had a look at my mums boiler 2 day as it wont fire in either ch or hw mode checked the water pressure and it was at 1.5 bar so ok so set boiler to hw and turned tap on i cud ere the fan running but not the pump so i disconnted wires in pump and connected a test lead with a 3amp plug and retested and the pump started cud ere it running but boiler still wudnt fire up i wud appreciate your advise on possible faults as i am a qualified plumber and av had acs training i am confident on working on them but obviosly if it is a gas fault i wiill call someone in just wud like to know wat cud be wrong 4 experience sake cheers bazza

[ALDA]

MUST'NT BE SPARKING!

SPARK ELECTRODE FAULT OR COULD NEED CLEANING (LIKELY).

FAN NOT RUNNING AT CORRECT SPEED (MAYBE).

[htg engineer]

Possibly a fault with the air pressure switch, when the fan runs can you hear a connection being made in the air pressure switch ?

When the fan starts try removing the silicone tube from the fan and use your mouth to apply pressure to the air pressure switch - You have to be extremely careful as the boiler may fire up now, make sure the burner and combustion area are clear. If it does fire up it's probably the fan isn't reaching max speed.

If it doesn't fire up - you're back to square one unfortunately, but I'm guessing its a air pressure switch that requires changing rather than the fan.

Hope this helps solve the problem

[bazza]

hi htg enineer i waz mistaken about the fan running i thought i heard it but it was the wind blowing in from the flu (it was end of a long day wen i first looked ah ah ) so ive checked 4 voltage at the fan terminals and at the circiut board and all i got was a zero reading checked the pump at terminals at pump and circuit board again got zero reading its as if theres no power coming from pc board it that the most likely fault or is it more likely to be a wiring fault cheers bazza

[htg engineer]

Check to see if you have power going into the boiler/pcb - from the fused spur ? if you have - but no power coming from the PCb - then the PCB needs replacing.

[bazza]

thanx htg engineer 4 all your help i got a freind of mine whos an electrition to check the wiring and he got the same as me that 230 v was going in to the circuit board but nothing coming out but the circuit board looks like new no scortch marks or anything dont know if u av worked on a vokera b4 but there is a water pressure switch an the manuel says if it senses low primary flow rate it deactivates the pump and stops ignition sequence im asking cause wen i removed the casing there was a tube which connected to the primary flow pipe and the other end of the hose was just hanging in the boiler unattached i was wondering if it shud be attached to the flow switch or is that not a possible fault thanx again 4 all your help much appreciated bazza

[htg engineer]

Best bet - would be to get hold of the boiler manual - this should tell you how to change components and will show where sensing tubes should be connected.

Havent had much to do with Vokera's only worked on a few. Have you checked boiler manual for any safety device's that could be keeping the boiler off.

Overheat stat, with manual reset
Flue overheat stat
etc etc ...

There's normally 2x 2amp fuses on the PCB, are these ok ?

What's the model of the boiler ?

[bazza]

hi htg engineer cheers 4 all the advise the boiler is a vokera compact 24 but seeing as there was no power going to the fan from the pcb boared ive decided to go with a new pcb and fingers crossed it works cause they not cheap ah ah i will be picking the part up either wednesday or thursday so will let u know how i get on thanx 4 the help bazza

[bazza]

hi mate its me again ah ah changed the pcb board 2day and still nothing its just the same wen i switch it on the green light flashes twice an then goes to red and stays on that my mum as just decided to inform me that wen the boiler first went out the system pressure was low so she topped it up so im wondering if it cud be the water pressure switch that sent the boiler to lockout and is now preventing it from firing up could that be a reason or is it not a likely fault for example wud the fan still run if water pressure switch was at fault (cause fan is still not running) thanx 4 the help bazza

[htg engineer]

'Have you checked boiler manual for any safety device's that could be keeping the boiler off.

Overheat stat, with manual reset
Flue overheat stat
etc etc ... ' ??

It seems there's something keeping the boiler off, either a overheat stat or a low pressure switch

Have you followed the Fault Finding Diagram in the instruction manual ? if you haven't got one - go to Vokera.co.uk you'll find the manual there. It seems to point to PCB though.


Does the selector have a winter position ?