System boiler tripping RCD at consumer unit

Paul1978 · Nov 13, 2018

Hi, I am looking for advice on a system boiler on S plan that keeps tripping the RCD for heating system. Friend called me, she had no power to boiler and called an electrician as the RCD wouldn’t reset. The electrician checked programmer and said it had power to connections and thermostat, but no power to the boiler. The programmer display was flickering and the red leds weren’t illuminated when selecting CH & HW on selector. I’m going to have a look tomorrow and she asked me to pick up new programmer, is it likely to be this with power to the connections on programmer or could it be pump or MV. Sorry but I don’t do much fault finding and repairs although I’m industry, was just so I can pick a pump and MV up while at merchants, any advice welcomed, thanks !

dancinplumba · Nov 13, 2018

take everything and replace, you never know

king of pipes · Nov 14, 2018

A siezed pump can cause this that would be my first thing to check , had it on a 3port also post your findings please . Kop

Ric2013 · Nov 14, 2018

I've had the accellerator on the thermostat short out against a metal bit: had to bend the resister away from the metal bit (it was almost new too!). Drayton Combistat.

Murdoch · Nov 14, 2018

extremely unlikely to be the programmer ..... leaking MV would be the best place to start IME

Harvest Fields · Nov 14, 2018

What boiler is it? Make and model

Last Plumber · Nov 14, 2018

You need to test, don’t guess, it could cost fortunes.
If you don’t know how to test for faults like this, get a Heating Engineer in to do it.

Paul1978 · Nov 14, 2018

Harvest Fields said:
What boiler is it? Make and model

Ideal logic heat 18 system boiler

Paul1978 · Nov 14, 2018

Last Plumber said:
You need to test, don’t guess, it could cost fortunes.
If you don’t know how to test for faults like this, get a Heating Engineer in to do it.

I know how to check for resistance of pump and motorised valves, I’m going over in a bit to have a look in afternoon. Just don’t do a lot of fault finding, I’m thinking it’s gona be the pump or MV!

Paul1978 · Nov 14, 2018

king of pipes said:
A siezed pump can cause this that would be my first thing to check , had it on a 3port also post your findings please . Kop

Thanks, that’s what I’m thinking, I will check the pump first I think, I’ll keep updated

Paul1978 · Nov 15, 2018

Hi, thanks for all the advice, it was the pump that failed. Disconnected the pump from wiring centre and replaced 3amp fuse in spur, reset the trip and it was fine. Measured the ohms across the live/neutral and was 110 ohms, changed pump and got power at boiler cheers for the advice !

System boiler tripping RCD at consumer unit

Paul1978

dancinplumba

king of pipes

Ric2013

Plumbers Arms member

Murdoch

Harvest Fields

Last Plumber

Paul1978

Paul1978

Paul1978

Paul1978

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