My van (Swift Sandymere - Charisma)has a Thetford N112 which after 2 years has stopped cooling on 240v (gas OK) Warm air comes from the top Ventilator which would seem to indicate some sort of life but it doesn't cool at all. Last week on site I paid £40 to have a man come out, take out the fly screens then tell me the element was working! It still didn't cool at all. Can anyone suggest further things to try?