The efficient operation of a refrigeration system depends, to a great extent, on the internal cleanliness of the unit. Only clean, dry refrigerant and clean, dry oil should circulate in the system.
Many troubles in refrigeration systems can be traced to the presence of moisture. As moisture circulates through the system and encounters oil and refrigerant, it can cause many complex actions. In some cases, moisture may cause a chemical breakdown of the oil, the refrigerant and the motor winding insulation of the compressor. Acids are then created, which ruin the motor windings.
A common method of removing or eliminating moisture is a liquid line drier. If enough drying material is used for both high- and low-moisture ranges, and if it is fully activated, it can keep the refrigerant both clean and dry.
The conventional straight-through drier is a brass, copper or steel cylinder filled with a chemical (desiccant), such as activated alumina or silica gel. These materials remove moisture by adsorption. A drier is like a sponge; both ends of the drier usually contain filter elements. The end caps are fitted with either flare or soldered connections.
Filter driers should be installed on every refrigeration system, and you should change your filters every time the system is open to the atmosphere for servicing.