Vaillant VCW GB 221H no DHW boiler fires but goes out after

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morrispd

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• 19 Aug 2009

• #1

Apologies if this is already covered, i've searched but no joy.

The boiler is Vaillant combi-compact VCW GB 221H and G.C# is 47 044 14

CH works fine
Diverter switches when the hot tap is switched on
Boiler fires for 10 seconds then flames go out but ignition stays lit.

Can anyone shed any light on this and if they have a manual please send me a link or a file, thanks, paul

[email protected]

 

Agile

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• 20 Aug 2009

• #2

Thats sounds odd and might indicate a PCB fault.

Thats unusual on your model though!

Tony

 

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morrispd

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• 20 Aug 2009

• #3

Ive read there is some kind of timed shut off. I would have thought it was waiting for a fan to start and then it would kick in full but there doesn't seem to be a fan, I don't have any documents so can't look in there. Do you know if it could be some kind of pressure switch?

It doesn't seem to fire up really powerfully for either CH or DHW but the tails for the CH do get hot.

 

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morrispd

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• 20 Aug 2009

• #4

UPDATE : the burner is going out because the overheat switch is tripping, if I leave the water running the burner re-lights once the cold water flow has cooled the boiler a little, it then runs for maybe 10 seconds and then trips again. I was told it could be a blocked heat exchanger, the one at the top. I took it off and it seemed blocked but I flushed it through with de-scaler and it now seems clear. The boiler works a bit better now, I get hot water if I make the flow slow but the boiler still trips every 10-20 seconds. Any ideas?

 

H

holty

• 20 Aug 2009

• #5

plate heat ex

 

H

holty

• 20 Aug 2009

• #6

sorry not exactly a plate heat ex, but on the same lines.