is the air pressure switch the same as the pressure differential switch.
boiler goes through the start cycle and when it seems ready to open the main gas valve it cuts out.
pump and fan both run and I can see a flame through the inspection window
Hi ,thanks for that . from what you describe it seems that the boiler is overheating due to a faulty (primary)thermistor/ temp stat, locking out on overheat.change the the central heating stat.however vif you are changing that one , it would be best to change the hot water come too. Relatively cheap, around 20 pounds each and fairly easy to change
the boiler lies idle from 11-00 to 6.am. it cuts out at the first attempt so it does not have time to heat up .
what happens is you can go for a shower in the morning then 30 mins. later the boiler will not fire up for 2nd. shower. the ch. if you try to switch it on in the afternoon for eg. it can take 4 or 5 resets to get it going.
no fault codes, indicator light is normally green but turns to solid red when the fault happens.
Hi Does the boiler do the same for heating!? And does the hot water ever go hot , then cold,hot then cold?
yes same for heating, hot water once it goes hot it stays hot.
OK,we did go round the houses a bit but the only answer/ explanation I can give is that it is overheating, so replace the two ntc temperature sensors . as the fact it runs for a while indicates the pump etc is OK , so it must me getting too hot and cutting out on the overheat stat.
but why does it cut out first thing in the morning `when the boiler has been off all night and is cold.