Today, we are going to look at issues related to a partially restricted filter/drier. For this purpose I have included a service checklist (Table 1) as well as a number of illustrations.
The filter drier (Figure 1) is located in the refrigeration system’s liquid line. The liquid line is located between the receiver and metering device (Figure 2). Filter driers can become restricted from moisture, sludge, dirt, or oil. However, any restriction or damage to the liquid line from the receiver outlet to the metering device inlet will have similar symptoms as a restricted filter drier. Because the filter drier is located in the liquid line, a restricted filter drier can now be referred to as a liquid-line restriction. Assume, for sake of discussion, that the refrigeration system is a TXV/receiver system employing a filter drier and sight-glass. The system has R-134a as the working refrigerant.