Relating to another posting

http://www.howtomendit.com/answers.php?id=38227

I have a 23MFFI, and intermittantly the boiler tries to relight itself (even though it is burning fine) as though it thinks it has gone out and sometimes (if it thinks this for 7 seconds) it locks down and needs resetting. The boiler always fires up first time.

I have had the detection electrode replaced, but has made no difference.

Would this be a similar thing to the attached link (i.e. need a PCB change or could be due to something else (e.g. dodgy earth?), due to its intermittant nature.

If so, which PCB would it be?, as the flame detection circuit is on the power PCB, but the logic for the shutdowns must be on the Electronics PCB. I don't want to have to get both of them changed if possible.

Dave, November 2006

My mffi 31 was doing the same when warm. AO1 lock out. Was still under guarantee, Ariston sent out an engineer the day after phoning them, pcb replaced and now ok.

j., October 2007

Nope, on both HW and CH. I have noticed by applying slight pressure (with my hands) to the transformer on the power PCB, when it is trying to relight itself (unnecessarily), it stops it from occuring, so my money is on the power PCB at the moment

Also noticed it only does it when the boiler and components are warm. It never causes any problems during a startup from cold or for the first hour or so

Dave, November 2006

Only on hot water? Kev

kev, November 2006