We are in Portugal at the moment, and apparently the heater element has burnt out (according to local engineer who didn't even take cover off to look). What happened was we put the heater on electric and smoke started to come from the front grill along with a terrible smell. I have spoken to an engineer in the UK who will repair the heater on our return next week. Question is, as the system is now ten years old is it better to repair with new element or replace the whole heater.