Hi drained down the system to repair a couple of weeping radiators, refilled the system to 1.5 bar vented all the rads everything seemed normal this morning the shower ran warm and the hot water from the taps never got really red hot,the boiler is firing up for 10-20secs then going out then fires again and goes through the same sequence over and over again
the same sequence of events takes place when the central heating is switced on, before the burner goes out there is a click from a relay or something,eternally grateful if someone out ther could diagnose the possible cause.
Thanks Craig

craig, September 2008

Hi I read an article on a different site where someone had an identical problem to the one I was experiencing however unlike me he had'nt drained down his radiators he fitted a new PCB which solved the problem,I bit the bullet fitted one myself £120 and it cured the problem also .

craig, October 2008

pretty sure the auto air vent is inside the combustion area on the side of the heat exchanger on a 24i which presents a problem as you should be a RGI to go in there as you need to prove all is well before allowing the boiler to run again.

I think its probably not allowing the air out keeping a nice blanket of air through your exchanger which is why its overheating.

dont think you'll get the old fella running until thats ruled out.

iain, September 2008

Thanks for the replys tried bleeding the rads and the pump the problem persists Ian mentioned the auto air vent but I don't know how to check this,I did however try freeing the air as suggested but again no joy.
Thanks Craig

craig, September 2008

id say air in heat exchanger, is auto air vent working on boiler??? if its letting air out you could try turning ch on for few seconds to set pump away and hopefully free some air then knock off and wait a few then repeat.

iain, September 2008

Craig now thet you have had the system things have moved roundit, ie the water. I would go through and bleed the whole system again. As it worked fine before you drained it down, sounds like an air lock to me.

Harry B, September 2008