System boiler tripping RCD at consumer unit

[Paul1978]

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]

take everything and replace, you never know

 

[king of pipes]

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]

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]

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

 

[Harvest Fields]

What boiler is it? Make and model

 

[Last Plumber]

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]

What boiler is it? Make and model

Ideal logic heat 18 system boiler

 

[Paul1978]

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]

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]

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 !