Humidity in a refrigeration system (sealed unit), represents the major source of defects, causing from freezing to corrosion, damaging and blocking valves, filters and pipes. Humidity in the form of vapor (relative humidity) is found everywhere, both in solids as in liquids and gaseous.
In order to evaluate what kind of problem is the humidity, it is convenient to examine the effect caused within the system. Moisture, usually located on the low pressure side, will result in obstruction of the capillary tube or expansion valve. If we heat the freezing point, the ice crystals will return to the vapor state and the refrigerant will flow normally again, but after some time, it will again block the passage of the refrigerant.
The humidity can also be moved through the system by the drag of the coolant.
This refrigerant combines with moisture decomposing into the formation of acids, accelerated by the high temperature, also inducing oxidation. The non-grease oil used in sealed compressors has great affinity for water. This, transformed into acid, combines with the oil, traversing the parts subject to lubrication, corroding them.
