Hi new to this site.Have a problem with alpha 240p combi. Hot water & Ch cycles for about 10 attemps then runs ok.Boiler calls for heat flame appears ,10 seconds later flame goes out then after a short time solenoid clicks and flame appears sometimes ,can take 10 mins to stabalise and deliver hot water. Have changed both diaphrams and associated seals, checked pressure switch to make sure pressure is ok ,fan is fine. both micro's are in the on when system calls for hw etc and maintain that position.Have a spare thermistor ,connected temporarily to eliminate temperature rise and then cut out. Have descaled primary heat exchanger . Running out of ideas problem usualy happens after not being used over night, ie frst thing in the morning, initialy thought of fan bearings tight but not so. Once the boiler is running it is fine.
Anyone have an idea please .