Hi. When fan starts the air pressure switch opens, gas valve opens , speaking starts then burner lit. Flame detection probe recognises flame then gas valve opens fully.
So could be flame detection probe or the temperature sensors. All fairly inexpensive and easy to fit.
hi. I don't think it could be either because the boiler locks out before there is any sparking. Meant to add the pressure switch has been changed previously but the symptom is the same
Hi . are you saying the boiler runs fine with the panel off?
If it does then it is probably the fan. Do you have a multimeter to test the ohms? You say the air pressu switch was replaced, maybe it was the fan that was going
Hi. Yes the boiler seems to fire up everytime the cover has been removed, it has also worked fine for a days and weeeks after being replaced, could the fault on the fan be intermittent.I have a multimeter and a head scratching gas safe engineer friend so would a fault show up if the boiler seems to be working fine or wait until it locks out again
Yes. They tend to start developing an intermittent fault , which is annoying , because when you turn up at a job its working again. I'll give you the general rangevthge fan should be within.most will be40 to 80 ohms. Below 20 and more than 150 , replace it . spin the blades also they must spin freely and slow down gently, if not replace. Sometimes its possible to lube the fan , but not wd40 which I'll delube it.
I feel that could be the problem.Thanks very much for your help i will get round to checking it at the weekend (if it lasts that long )