Humidity is one of the main contaminants that are generally found in a refrigeration circuit.

The presence of humidity in a refrigeration circuit is harmful to the operation of the system and may cause further contamination due to corrosion. decomposition of the coolant, mud deposits in the oil, rust formation. All these elements can cause failures, causing a friction overheating, the appearance of copper plating and abnormal wear at the bearings level. Furthermore, the ice that forms on the expansion valve can brake or completely stop the coolant flow. The presence of moisture in a refrigeration circuit can be detected by a liquid indicator. The indicator should be mounted upstream of the thermostatic valve and of any filter drier. If the implant has been properly made and has been properly dehydrated, there should be no moisture problems.

Causes of Humidity

The cause or source of humidity in a circuit is represented by the presence of humid air that was introduced, during installation, into the refrigerant lines. Furthermore, when replacing the oil in the compressor it is necessary to strictly follow the recommended emptying and charging techniques, to avoid oil pollution in the circuit. If emptying is not carried out properly, enough water may remain in the refrigerant lines to cause corrosion and to accelerate the formation of other contaminants.

To properly vacuum a refrigerant circuit, it is usually used to proceed with a triple evacuation up to an absolute pressure of 1 mm Hg: Between a vacuum and the other the circuit is put back under pressure introducing dry nitrogen. This will reduce the time needed to perfectly dehydrate a circuit. It must be remembered that the removal of moisture from a circuit requires a very long emptying process. The only practical means of effectively dehydrating a system is the use of a vacuum pump capable of producing a pressure of less than 1 mm Hg. Most of the pumps achieve lower pressure values ??so that you will have effective dehydration.