Faulty 3 way valve tripping electrics? CH only on when HW is

[JohnD]

It would be really nice to see some photos of the pipe layout around the boiler, pump, valve and cylinder

http://www.diynot.com/forums/viewtopic.php?t=129539

 

[MirfDiver]

Definitely only found 1 valve (in the airing cupboard), unless there's another hidden elsewhere in the house (behind cladding etc).

Switch on boiler is set to 'fully pumped' and not 'gravity'. As is the programmer.

HW/CH both been on a good while now (hours) and no RCD tripping. Could the motor have fully burned out and stopped the bad earth? does that even sound likely?

CH still only works with HW on. So still suspecting valve motor. Have ordered replacement valve motor. If it arrives before the plumber does then I'll have a go at replacing it.

 

[MirfDiver]

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• MirfDiver
• 27 Nov 2011
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• MirfDiver
• 27 Nov 2011
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• MirfDiver
• 27 Nov 2011
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• MirfDiver
• 27 Nov 2011
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• MirfDiver
• 27 Nov 2011
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pics..

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• MirfDiver
• 27 Nov 2011
• 1

 

[JohnD]

just to check, that cylinder stat does fit into a hole cut in the insulation, so it is touching the copper cylinder? it seems to be sticking out a lot.

can we have some pics of the motorised valve behind the cylinder, showing its pipes?

the pump looks extremely odd to me, perhaps I'm looking at it wrong. Where does the pipe go to, running rightwards out of the pump?

 

[ianblue]

Hi hertsboilers, I thought initially there was a second yet to be discovered V4043, but having now seen the 'photos it looks as though you are absolutely correct. It is a gravity system. The sketch you have shown is most likely spot on.
Independent control is possible but since that cannot be achieved it may be because the programmer is set to "Gravity" instead of "Fully pumped"
Maybe the OP could check that.
Oddly everything seems to be fully functional now, no RCD tripping which is baffling.
Just another possibility if the V4043 was jammed in the fully open position the Heating would not be able to run on its own.

 

[Homesafe]

could the cylinder stat being faulty cause this? just thinking aloud

 

[JohnD]

it could cause the "cylinder too hot" problem if it was faulty, incorrectly wired, or not in intimate contact with the copper cylinder (see my question above)

or it could be the valve not closing when the cyl stat is satisfied.

but not likely the RCD trip

 

[MirfDiver]

Went to bed last night and left the HW switched to on. About 3am it tripped the RCD.

This morning - reset RCD put HW and CH on and RCD tripped almost instantly.

Reset RCD, HW only on, trips RCD after about a minute.

With HW only on, boiler did fire but seemed to clicked more times before it fired. Is that relevant?

 

[ianblue]

You have a plumber coming to change an electric motor?
I'd rather have an electrician with a megger in his pocket.

 

[MirfDiver]

Plumber here.

Discovered another valve in most awkward place, hidden behind cladding next to boiler.! Its not a complete unit as in the motor is a different make to the valve.

Anyway, the valve was leaking onto the motor and that is obviously the cause of the RCD trip.

Seems the plumbing set-up isn't the finest with valves and pumps spread out weirdly.

Plumber drained the system and put a new valve on. All is well again.

Thanks for all the help guys. Should have known there was another valve hidden somewhere.

 

[ianblue]

Thanks for coming back and putting us all out of our miseries.
Great that everything is all ok now.