had my service done and am trying to identify why restart button needs pressing maybe twice a day over a period of say 6 hours working time? engineer replaced a couple of bits on the burner but no change since. he is now suggesting replacing pump?? it seems abit of a 'stab in the dark'? as it always fires up again when pressed and works for days without a problem sometimes?? was wondering if problem could be electrical as sometimes this seems to happen once room stat temp has been reached and itcloses down and doesnt refire when temp cools again?