Potterton Kingfisher - ignites but then turns off after 30minutes

[Richboiler]

Hi - I've had a gas fitter out twice now to repair it but its still not sorted. The boiler fires up ok but after 30mins turns itself off. The central heating pump has been replaced and the gas valve. After the fitting of the new gas valve it ran ok for 5 days but then has gone back to square one. Any ideas?... I've been in touch with Potterton/Baxi to see if II could get an engineer to come out but they don't support this model any more - the boiler is 14 years old and I'd like to repair it rather than replace it.

[Richboiler]

Hi - I've had a gas fitter out twice now to repair it but its still not sorted. The boiler fires up ok but after 30mins turns itself off. The central heating pump has been replaced and the gas valve. After the fitting of the new gas valve it ran ok for 5 days but then has gone back to square one. Any ideas?... I've been in touch with Potterton/Baxi to see if II could get an engineer to come out but they don't support this model any more - the boiler is 14 years old and I'd like to repair it rather than replace it.

[tabbypurr]

I'm wondering in what circumstances the boiler should be running continuously for over 30 minutes. Are you heating a pool with it?

NT

[Harry Bloomfield]

Richboiler used his keyboard to write :

Does it produce any fault codes?

Does it reset itself after the 30 minutes, or what do you have to do to get another 30 minutes run out of it?

What model is it?

Might it be the overheat stat operating?

[tabbypurr]

there are many things the OP does not tell us.

[John Rumm]

You need to go through the controls step by step to isolate where something is not working.

So starting with the call for heat signal to the boiler... Does that stay on when the boiler shuts off? If not work back checking the output from the zone valve, then the stat and then the programmer.

If the call for heat is still on, then check the call for heat at the gas valve itself... if that is present, then the gas valve must be faulty. If not then check the output from the internal stat. If its got a fan then look for the signal from the air pressure switch. Keep working through looking at the chain of dependencies. Is there electronic flame sensing? Is that working or is it detecting a flame failure.

[Tim+]

Other thought, could it be a low flow problem (leading to overheat)? System may be clogged up.

Tim