Central heating tripping the RCD and strange noise

[charliebean]

Hi, I hope someone can help. Tonight my sockets all went off in the house and i checked the fusebox and the RCD was off. I unplugged everything and turned it back on then went round plugging things back in, turning things back on at the wall, when i got to the central heating switch it tripped the RCD again, so it seems there is some problem there.
I wonder if this could be related somehow to the loud noise we've got the last few nights when the central heating kicks in? Sounds like a big mechanical scrapping, or buildup of pressure for a couple of seconds then stops and all is fine.

At the moment at 01.22 we have no heating and im worried about my daughter who is only 2 and has been poorly this week. Got her an extra blanket, but hope it isnt too cold tonight. Not sure what else i can do. Hope someone has some advice.

thanks

 

[ukrobj]

Could be the pump/fan making the noise and also possibly tripping the system. May need to start to isolate components, so maybe tomorrow morning see if you can get a heating engineer to come over and take a look.

If the pump is separate, try switching speeds to a lower one

 

[Agile]

Fan heaters are useful!

Hot water bottle!

As stated boiler problem likely fan or pump but useful to get engineer.

Would have been better if you had called someone when you fist stared hearing these noises!

Tony

 

[charliebean]

thanks for the answers; yeah i guess it would have been better to call someone right away but i have health and money issues, so i cant respond to small problems only critical ones nowadays.

The pump in the airing cupboard is not the cause i dont think, if i have identified that part right, its sort of noisy always, a little, but the sound i heard the last few days was more of a loud noise than i think that little pump could make.

I think im going to have to call an engineer out as you say, just no heat tonight and no money to pay him with tomorrow!

 

[charliebean]

I just noticed the thermostat was right down so when it triped earlier it must have been the hot water coming on not the radiators. Does that help narrow down the fault?
Should I go for a fixed price BG thing or local guy? Did fixed price last time and saved a bit as the part they changed was a fairly major part I seem to remember...

 

[charliebean]

Ok I got up and turned the hit water to off on the Honeywell control unit. Left ch in the on/continuous position. So we now have heat - yay! I also turned the immersion heater on that we never normally use and so we have some hot water.

Just turned the hot water back on and that is working now too. Hummm. Did something get hot and now it's cooled down it works again?

Where do I go from here - can someone advice where the fault might lie and how I can diagnose it? If its something I can do myself then that would be great. Thanks

 

[mogget]

If the RCD is not tripping when set to heating only, this suggests that all of the following are OK: Boiler, pump, timer, room thermostat.

If you have two 2-port valves I would suggest the hot water motorised valve as the prime candidate.

If you have a mid position valve it could have an internal fault.

Then you've got the hot water thermostat on the tank. Least likely would be the cabling itself or a problem inside the wiring centre (junction box).

These faults however can be intermittent and therefore real so-and-so's to track down.

You may want to check you can recreate the fault first before trying to find it. If it's all working again now, it may remain a mystery

 

[Agile]

I agree that the motor valve sounds a likely problem.

This is often caused by water leaking from the shaft gland. You may be able to remove the head and see if there is any water leaking but only do that when the system has been cold for a few hours otherwise water leaking would have evaporated.

Tony