BAXI 51/5 PCB ??

[FLYFIFER]

Hi guys new to all this and looking for help, i have a baxi 51/5 back boiler all electrics tested and ok but it will not fire up, had a electrical problem which blew a fuse in my fuse box prior could the pcb be blown if so where will i get a cheap pcb and is there any fuses in the boiler which may have blown, many thanks.

 

[cross thread]

pcb will most likley have a fuse built in for protection, but have you decided what took out the main fuse,often get wiring that has gone brittle on bbu systems as they have not used heat proof flex

 

[geoff@cetltd]

It's fairly rare or a PCB to cause a fuse to blowe

It's much more likely that something attached to it is the culprit

Look at the solder side of the pcb, if there is no evidence of a track having blown, the odds are that the pcb has survived

 

[Robmcdade]

Hi Guys,

i also have a problem with my Baxi 51/5 back boiler, ive got an amber light on the PCB, when I switch the boiler stat to zero and then on it wont fire up. Ive had a guy at work check out the PCB which looks fine, all the controls are calling for heat and the pump is running fine. We have had the heating on constant for the last few days, any help would be great. Ive check the board for 240v and its getting that, it seems to only get 50v to the gas valve and 24v to the ignition. I dont know if this is correct, would changing the PCB sort my problem.

Cheers,

Rob.

 

[popeye2755]

Hi Guys,
it seems to only get 50v to the gas valve

Where EXACTLY are you measuring that? Across the valve itself?

 

[Robmcdade]

Im metering on the live and neutral from the terminal block on the board going to the gas valve. To be honest im not sure if im doing it right

 

[popeye2755]

Is the Meter set to AC or DC?

 

[Robmcdade]

AC voltage

 

[Gas1976]

Meter across orange and brown on the lead going to gas valve and also red and blue.this will confirm if you have the correct voltage at the gas valve.i'm not sure which is which,one set is the pilot solenoid and the other is the main burner solenoid.you should have 230vac at one only,if you have this it will be powering the pilot solenoid.the other solenoid will get power when the pilot is established.hope this makes sense?if you're getting 230vac at the pilot solenoid you're going to need to replace the gas valve-a job for a gas safe registered engineer

 

[Robmcdade]

Cheers for that, I dont seem to be getting any voltage across orange and brown or red and blue, only 50v when i meter across blue and brown etc

 

[gazthepottertonengineer]

Does the light on the pcb turn red after a while?

 

[Robmcdade]

No its just got a constant amber light standby mode right?

 

[gazthepottertonengineer]

If you have power to the pcb and switched live to the pcb and light is still amber ie standby mode as you say then it's almost certainly a pcb fault as if it were anything else to do with the boiler pcb would be red light!

 

[Agile]

Sounds to me as if its best diagnosed by a registered boiler engineer to avoid replacing parts which may not be the fault.

Tonby