Britony 80 Combi, Boiler fires up, for approx 8 secs only

[PaulScrivens]

Hi,

I own a Britony 80 Combi boiler, it's about 5 years old.

When I draw hot water or central heating the boiler fires up for about 8 seconds then the flame goes out. After resetting the boiler it will fire up for another 8 seconds.

Some mornings (after leaving boiler off) when drawing hot water it will work fine. Heating is always a problem, even after leaving the boiler off for a few hours.

A plumber has spoken to the Chaffoteaux and Maury technical support trying to diagnose the fault. He has replaced the flow switch, three way valve and pressure release valve. This has not fixed the problem.

What he has noticed is, if you pull out the plug connected to the 2/3 gas stage switch (stops boiler going into full flame) Everything works fine!

When in full flame occasionally you can hear the boiler hissing as if it's filling up (the plumber said this is something to do with the gas).

One last point, after servicing the boiler all was working fine for a few days, but then went back to acting strangely.

Anyone have any ideas? or experienced the same problem?

 

[chrishutt]

Sounds like inadequate circulation of water through heat exchanger causing overheat. Probably caused by sludge in waterways. Chemical cleaning and flushing might help. Best find an engineer who understands how combi boilers work.

 

[andsam]

Could be blocked filter in the return pipe.

 

[chrishutt]

Could be blocked filter in the return pipe.

Good point, but that wouldn't explain problem occurring in hot water mode. Nevertheless the return filter should be checked, perhaps along with DHW heat exchanger. Filter is tucked away in the plastic return manifold on the end of the copper bend above the return isolating valve (assuming it's not an SE model).

 

[DerbyLiam]

+1 on the blocked filter.