central heating tripping RCDs

[jimj]

Strange: the heating runs fine until the timer switches on the hot water then it trips. If I overide the timer the hot water heats for 5 minutes, an hour, or 3 hours then trips. We`ve been using the emersion instead and last night when the timer/controller (Honeywell) switched OFF the heating it tripped. It trips the whole board, not just the circuit the heating runs off.
Is the timer thing faulty or is it something else?
Jim

 

[holmslaw]

..

 

[gas4you]

Somethings leaking to earth if the whole board is tripping at the rcd.

Also check any 3 port valve, or HW zone valve you may have.

A better description of your heating system and its components would help.

 

[Taylortwocities]

The pump is also a candidate for this.
Effectively, check everywhere that water and electricity come together in your system.

 

[jimj]

"Check everywhere" but what am I looking for? I suspected the motorised valve on the hot water but the wiring/connections all look good as is the junction box thing that the boiler wiring and motorised valves connect to. I`ve checked the connections at the Honeywell timer,programmer but when I say checked I mean visually and poking all the connections. There are no loose or bare wires. What else should I look for?
Thanks,
Jim

 

[holmslaw]

..

 

[gas4you]

IF the ault is only happening in relation to the HW, then this should be your area to be looking.

Unfortunately just 'looking' at wires and electrical components will not make any faults apparent. You need a multimeter to test and be competent and safe to be able to use one on live 240VAC.

I would suggest in your case the safest and fastest option for fixing is to call someone in.

 

[dingodeano]

Had this problem last year on a job i was called out to. turned out to be the hot water feed from boiler leaking whenever the hot water was 'called for' the water ran down inside boiler and on to the electric connections inside boiler. causing the rcd to trip.