Hi . if the Fran ius running then it may the air pressure switch that has failes . this senses the fans running and fires the boiler
If not that the only other thing it can be is the flow or return thermistor/ stat.
Thank you. The air pressure switch was changed only a year ago - I find it hard to believe that it has failed again !
Is there a check I can do on the "thermistor / stat " ?
Yes the thermistors ohms reading should changevon temperature change. They range between 2000 and 40,000 . at room temp , normally around 9000-11000 .as temp rises should change.
?? No idea how to do that !
You would need a multimeter. Do you have one? Or could you get hold of one?
If not . replace the thermistors . fairly cheap and easy to fit
Hi . if happy with your answer , would you mind rating me , thanks