R-134a RECEIVER/DRYER
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The basic design of R-12 and R-134a receiver/dryers is the same. However, while R-12 systems typically use silica gel as a desiccant, R-134a systems use Zeolite. The drying capacity (per weight) of zeolite is only about 25% that of silica gel so R-134a receiver/dryers are larger, to accommodate larger amounts of desiccant. In addition, the high-pressure cutoff switch is rated higher for an R-134a receiver/dryer, since the system operates at higher pressures.