Fridge vents should be completely free of all obstructions to air circulation. The heat exchanger at the back of a fridge will get warm when the fridge is working. It is essential that the fridge gets rid of this heat, else the coolant will circulate back through the fridge in a warm state and try to defrost it.
The only time caravan fridge vents may be covered up is when they are put in storeage for winter.
Cledlyn
August 2008