At Perth mobile car air conditioning service we have found how important it is to include a pressure test on you car aircon as part of our service when you call us out ,if the air conditioner gas is below what it needs to be then we has a problem with the car aircon system which needs to be fixed so what we do is connect in to the air conditioner system and pressure test the system with nitrogen at a pressure that is higher that the normal gas pressure and this allows us to see if you have any leakage from your air conditioner hoses or fittings