Hi, I hope someone can give me some advice.

My boiler cuts out after it has been on for a while. Initially it ignites perfectly, with both hot-water and also central heating. However, after a while the flame cuts out. The flame will remain out until I turn the boiler off and on again, when it usually re-ignites.

This has been going on for about a year now and it has been getting progressively worse. Now the flame cuts out sooner and it will not re-ignite unless you leave the boiler off for at least an hour.

I have had a plumber look at it, and when he first removed the front cover, and turned the boiler on, the flame ignited and stayed on for ages. Furthermore, after he did this the boiler worked perfectly for about a week. Then it returned to it's old tricks again.

I got him back and he thought that it was the air pressure switch, changing which has had no effect at all. His other idea is that the fan is faulty.

I am skeptical about his suggestion as the fan appears to be blowing out well, and starts up every time, and remains on after the flame cuts out.

Has anyone got any ideas?

Geoff, September 2008

That's what happened to mine. I'm in a rented flat so it took time for the agency to believe me, just like you, they turned it on and worked for 2 days well. Once I complained again they got the real men that know boilers out not a plumber. They found it's something to do with timer cutting out. Can't remember what they did but they replaced something within the boiler not the blue timer thing.

Paula, December 2015

It seems to be a common problem. Came across this while sorting my own problem.
www.howtomendit.com/answers.php?id=54866

Adrian, November 2008

I have exactly the same problem with my Sime not so Friendly Format. I've had an electrical engineer/plumber out twice-costing £140 - and the problem is still not solved. I suspect it's a design flaw and something to do with overheating triggering off the cut -out response. Very frustrating when the hot water cuts out in the middle of a shower!
Unless someone can come up with a definitive answer I think the best plan maybe to ditch the boiler and get a different ,more reliable make.

Maginot, October 2008

the fact it works with the cover removed does suggest aps, venturi, fan.

not familiar with your boiler im afraid but in my experience aps generally work or dont, no in betweens, fans can slow giving aps less chance but also venturis can break down, block and even warp causing aps to break circuit.

iain, September 2008