Hot water causing RCD to switch off

[snowathlete]

RCD switch went last night and all the power sockets went off. Wouldnt let me turn it back on. Through a process of elimination i managed to narrow it down to the central heating/water system. Turned the boiler off via the switch on the wall and the rcd was happy.

This morning, I turned it back on and it works ok. The problem last night seemed quite permanent so im guessing the problem might be that it overheated or something like that? But i think it must be the hot water that holds the problem as when it tripped last night the main thermostat had been turned right down to 5 degrees or something. My wife just turned it up or down when she is cold or hot...so i cant see how it could have been the central heating, but rather the water which is on continuous. We have an immersion heater too, but we dont use it - always off.

Anyone able to advice me how to narrow down on the problem and identify the fault? I really need to do it myself if it is possible and doesnt involve the boiler itself, as i need to keep the cost down and if its DIYable, I'm fairly good at that sort of stuff usually.

Thanks

 

[mickg1]

have you used the hot water since ? is it still tripping

 

[mfgs]

Had this before when there is a leak dripping onto the zone valve, it makes the microswitch when either heating or hot water is called for and trips the RCD

 

[Dotty]

Assuming of course the op has zone valves......

 

[Howsie]

To be frank, if you were fairly good at this you would have found the fault by now.

Get a sparky in rather than risking it.

 

[Whn1]

Zone valve or cylinder stat.

or ghost

 

[AWheating]

its a fault to earth, so could be on any part of the heating/hot water electrics that has an earth connection/path. unless you have some basic electrical testing knowledge knowing how to safely test then i would leave to a good sparks or a good heating engineer tbh. eliminate the simple things first like water/leak, loose cables, damaged cables.

 

[mickg1]

Spill the beans then, what was the fault ?