When switched on, it takes too long (about 10min or more) to fire while pump and fan working straight away. Cuts off OK but refire about 10-15min while heated water curculating get cooler so are the radiators.
Some of the netaheat range had a mercury flame failure device fitted similar to the ones on cookers.If it has one of these then it could be on the verge of packing in.Hope not as you may struggle getting the part now.