Poly Run Air Conditioning&Refrigerator products

Evacuation of refrigerating system

When a refrigeration system is assembled it must be carefully evacuated (remove air from the system), before it is charged with refrigerant. This is necessary to achieve a good repair result. The main purpose of the evacuation is to reduce the amount of non-condensable gasses (NCG) in the system, and secondarily a limited drying will take place.
Moisture in the system may cause ice blocking, reaction with the refrigerant, ageing of the oil, acceleration of oxidation processes and hydrolysis with insulation materials.
Non-condensable gasses (NCG) in a refrigeration system may mean increased condensing pressure and thus greater risk of coking processes and a higher energy consumption. The content of NCG must be kept below 1 vol. percent. The evacuation may be done in different ways depending on the volume conditions on the suction and discharge side of the system. If evaporator and compressor have a large volume one-sided evacuation may be used, otherwise double-sided evacuation is recommended.
One-sided evacuation is made through the compressor process tube but this method means slightly worse vacuum and slightly higher content of NCG. From the discharge side of the refrigeration system the air must be removed through the capillary tube, which results in a substantial restriction. The result will be a higher pressure on the discharge side than on the suction side.
The main factor for the NCG content after evacuation is the equalized pressure in the system, which is determined by the distribution of volumes.
Poly Run Enterprise products including refrigeration tools, vacuum pump, Refrigerant Recovery Machine, service manifolds & gauges, charging hose, tubing tool.