-Check ventilation around the fridge. You need approximately 20mm at sides and top with 100mm at the rear. 

-The unit cannot have another ‘door’ in front of the fridge door, this is incorrect installation and voids warranty

-The unit must be 100% away from sunlight and out of the weather, this is incorrect installation and voids warranty

 -Check compressor definitely comes ON

-Check what temperature the fridge is set on.  5 is the coldest.