Boiler keeps tripping the RCD

[JohnD]

This was lowering the resistance of one of the cables inside (say the Live Phase) more than the other (say the Neutral Phase).
This was seen by the RCD as a imbalance in the residual current and tripped my RCD.

No offence meant, but I think that explanation is codswallop.

More likely a breakdown in insulation, can be caused or accelerated by excessive heat.

 

[SFK]

John, Agreed. But it fixed it.

I too cannot see what this would make an imbalance.
Perhaps it was a simple as the cable was old and when heated leaked to earth.

This was suggested by the person I was abuot to buy a new PCB from.
He said he had seen it a few times where radiator pipes were next to cables.
SFK

 

[ianmcd]

Im pushing and pulling but it doesn’t want to come off. Is there a technique?

Ha Ha right over your head , underneath there will either be 2 x small screws that you undo or two slots that you push up with a small screwdriver then pull it forward from the bottom, but you are wasting your time, that is not tripping the RCD

 

[Kalifornia777]

Ha Ha right over your head , underneath there will either be 2 x small screws that you undo or two slots that you push up with a small screwdriver then pull it forward from the bottom, but you are wasting your time, that is not tripping the RCD

So that leave me with the Honeywell valves. Is there anyway to find out which of the 3 are causing the issue without disconnecting the wiring.

 

[John D v2.0]

So that leave me with the Honeywell valves. Is there anyway to find out which of the 3 are causing the issue without disconnecting the wiring.

You could isolate the unit and test the resistance between earth, and the live+neutral wires of each valve.
Ideally you would use an insulation resistance tester but a multimeter might be able to pick up the problem.
You would still have to disconnect the live and neutral otherwise you'd get a false reading as you'd be testing all the neutrals at the same time. And in turn, the lives.
The alternative is known as the "bang test" and you just switch it on and see if the protective device operates.
Yes another option is to remove the casing and look which one is in worst condition. I believe you can just remove the electrical head alone and leave the valve in place.

 

[Kalifornia777]

BRitishGas want to charge me £400 to rewrite the junction box with a wiring system. Is that a fair price for London?

 

[terryplumb]

Does their " wiring system" include anything other than fitting a new junction box , and connecting your existing wiring into its terminals ?

 

[ianmcd]

So that leave me with the Honeywell valves. Is there anyway to find out which of the 3 are causing the issue without disconnecting the wiring.

slacken that small screw at the top of the valve cover(with power switched off) and remove the covers , see if you can see any water ingress in any of the valves, or smell any burning smell in any

 

[John D v2.0]

BRitishGas want to charge...... Is that a fair price for London?

No,
unless in this case,it's going to take them 2 days!