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Boiler keeps tripping main fuse

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I have a grant vortex combi and it keeps tripping the main fuse when the programmer calls for heating.
This has just started, it was working fine before.

Anybody got any thoughts
 
Or water inside the pump power connections be careful do it with the power isolated
 
When does it trip when the power is on or when there’s demand ?
 
Contributing as a spark in the boiler and wiring there could be many reasons for the "trip" - but as you suggest the fuse / MCB are tripping as well as the MCB then the likelyhood of a live - earth fault is possible.

Is there any water dripping from the boiler?
Valves?
When you say call for heating - are you really running the heating ATM?
Has anybody changed anything - like tried to fit a smart thermostat or programmer?
Have you done any DIY?

Tricky to give much more by the way of advice without seeing the installation first hand tbh
 
No water leaking.

Trips when demand for heating comes on from the programmer.

Nothing has changed, just started doing it today

Murdoch, what do you mean by ATM, if you mean at the moment the answer is no the heating is switched off, the domestic hot water is on and running fine, it happens when i switch the heating to on then it trips.

Thanks

Regards
 
You could do with an engineer to run some tests.
I personally would disconnect and make safe the live, neutral and earth to pump and then bring on at programmer again to rule in or out the pump.
If its not the pump then somewhere inside the control panel is the fault, providing of course you only have one heating zone and not multiple as mentioned above.
You really need an engineer to do all this for you.
 
No water leaking.

Trips when demand for heating comes on from the programmer.

Nothing has changed, just started doing it today

Murdoch, what do you mean by ATM, if you mean at the moment the answer is no the heating is switched off, the domestic hot water is on and running fine, it happens when i switch the heating to on then it trips.

Thanks

Regards

what type of controller do you have?
 
Success i think, i disconnected the pump and turned the programmer on and it didn't trip.
Will post again after i get a new one fitted.

Thanks for your help.
[automerge]1596718140[/automerge]
Problem solved, when we went to remove the pump the pump cable was jammed between the front of the flame box and flame box casing, when we took the front off the cable was fried.

Put a new cable in and it's all working now.

Thanks for all your help

Regards
 
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