Question

Thetford caravan fridge N109 not cooling. Gas is lit - can hear and feel warm air thru vent outside.

Answer

If the gas is lit and the flame is strong but the fridge is not cooling it will be a cooling unit failure, this is caused by a blockage in the pipe work on the back of the fridge.

There is an old wives tail that says if you turn the fridge upside down it will fix the problem, this will sometimes make the fridge work again but it will block again so it would only be a temporary solution.

Unlike Dometic fridges you cannot replace a cooling unit on a Thetford fridge. The only real option is to replace the entire fridge.