Combi Boiler Tripping Out Mains Circuit

[Frosty75]

Hi there,

This is my first post... any help much appreciated!

I have a Potterton Combi 80 Boiler that trips out the house electrics.

The flat has 2 mains circuits, one for the lights and one for the plug sockets including the switch the boiler is attached to.

About a month ago, the plug socket circuit trip switch flicked to off. The electricity switch box has no fuses, just trip switches. To isolate the problem device I tuyrned everything off at the sockets, TVs, kettle, dishwasher, washing machine etc. including the boiler.

I then set about turning everything back on one by one. This isolated the problem to the switch attached to the boiler. Whenever this is turned back on the trip switch goes again.

I had an engineer come out to look at this after spending a couple of days at my girlfriends flat but when he came out, it just worked again. He visually checked the PCB and saw no problems so we just left it at that.

Since then, it has happened a couple more times. The first time, just leaving the boiler powered off at the switch for a couple of hours then turning it back on seemed to work. The second time (yesterday) it won't turn back on without tripping the mains circuit.

To my understanding, this would most likely be one of the electrical components (PCB, pump, fan) but can anyone advise how I can check which it may be before ordering a part?

Any other advice gratefully recieved!


Thanks,

Frosty

 

[alan m 1974]

Check and see if disconnecting pump worksd,then try fan,gas valve.I am sure these have a transformer in as well,but just taking the pump connection out the pcb will see if it blows,but if its only happening now and then,maybe the transformer is going

 

[alan m 1974]

also check pcb,top left,neutrul is it burning out

 

[Gasguru]

Check the flow thermistor seal is not leaking water onto the pump wiring box (sometimes the wiring box comes away from the pump body allowing water ingress).

Check the auto air vent and heat exchanger pipes on the left are not leaking water into the gas valve mains connector.

Check the water flow switch (brass lump behind pcbs) is not leaking water onto connector strips.

You could wire the pump directly to mains via a 2 or 3 Amp fuse (with the boiler off) and see if it trips.

Testing the fan/gas valve reserved for corgi.

 

[alan m 1974]

Yes,i forget that you shouldnt be touching most parts on the boiler,

 

[Frosty75]

Thanks for the replies. Sounds like it could be one of a few things then.

Guess I'll have to get an engineer round again. Do they usually carry all parts with them, if I tell them the make model in advance?

Not had much experience with this before as I've previously rented houses.

 

[Gasguru]

If they've any sense they will ask make/model...some boilers aren't worth looking at.

Some will carry parts if they specialist in a particular make..all depends, if
merchants are close and you work on anything there's a limit on the van stock.

 

[bengasman]

if it is the old model gasvalve, it is prone to condensation dripping from the coldwaterfeed into the solenoid connection if the boiler is in kitchen or bathroom. Where is yours?