This normally comes with the ingress of air in the system. Moisture may freeze at the expansion valve, giving some of the indication of under charging. It will contribute to the corrosion in the system. It may cause lubrication problems and breakdown of the lubricating oil in the refrigerant compressor.
Action moisture in the refrigeration system :
- Renew silica gel in case of minor moisture.
- collect refrigenant and remove all air and moisture by vacuum pump if the amount is huge.