RCD trips everytime boiler fires up

[jbw1]

I have a Potterton Puma 80 boiler. Every time the boiler switches on from timer or fires up, the RCD trips out.
For a few weeks intermittently, only the hot water will work and CH not firing up. If I switch on the hot water, sometimes the boiler will stay fired up for the CH to come on.

My main problem now is that the boiler will not fire up at all with blowing the electrics (RCD)

Any help appreciated - could it be my pump causing this problem?
Thanks in advance
JimW

 

[BOB D.O.L.E]

I have a Potterton Puma 80 boiler. Every time the boiler switches on from timer or fires up, the RCD trips out.
For a few weeks intermittently, only the hot water will work and CH not firing up. If I switch on the hot water, sometimes the boiler will stay fired up for the CH to come on.

My main problem now is that the boiler will not fire up at all with blowing the electrics (RCD)

Any help appreciated - could it be my pump causing this problem?
Thanks in advance
JimW

pump fault or wiring on a coil somewhere fan,

 

[Aquaheat]

I'm going to guess the PCB!

Common fault on these, have a look at the PCB and in the top left corner you will probably see scorch marks and possibly melted connections.

If all that looks ok then with the power off, remove the live from the pump and put it in a terminal block. Now try turning the boiler on. If it does not trip now then it is the pump at fault.

Do not leave it on too long though! I can't remeber if this boiler has a flow switch so you may overheat the boiler if left on!

 

[jbw1]

Thanks for that advice.

Will give it a go.

Cheers

 

[jbw1]

PCB looks absolutely fine.

Not sure what I'm really doing with electrics to test the pump etc.
Have arranged for British Gas to come out in the morning - probably far safer!

Thanks for your help
Jim