Nitrogen is used to pressure test refrigeration equipment becasue it has an affinity for moisture and is illegal to use freon for a leak test knowing there is a potential leak in the system. Nitrogen is very environmentally friendlty. It is a dry gas that has no moisture in it. It comes pressurized in tanks around 3,000 PSI so it will allow a refrigeraton system easliy to be filled to 250PSI multipule times with the same tank.

Because of such a large pressure within the system once filled to 250PSI, it will be easy to determine if there is a leak in the system. The higher the pressure in the system, the faster the nitrogen will leak out. You will be able to determineif there is a leak by monitoring the pressure in the system for a short time. A drop in pressure indicates a leak.

Once you have determined there is a leak, you can easily find it. If you apply a soapy solution it will bubble at the source of the leak.