Do not uncap the drier or accumulator until the unit is ready for installation. Remember: the desiccant attracts moisture from the surrounding air.
Only EPA-certified technicians can purchase R-12 refrigerant, since proper recovery and recycling techniques are required to prevent damaging the environment. Improper disposal of R-12 refrigerant can result in a fine.
The receiver drier is usually located under the hood of the car. The drier should be placed where it can be kept as cool as possible. At least one independent manufacturer of aftermarket systems mounts the drier inside the evaporator case where it is always surrounded by the cool air of the evaporator.
The inlet and outlet fittings of receiver driers may be 3/8-inch SAE flare, 5/16-inch barb, O-ring, or block type. Also, receiver driers may have specially formed inlet and outlet tubing before the fitting provisions. As a rule of thumb, it is recommended to replace a receiver drier with an exact duplicate. This is particularly important to ensure refrigerant capability with the desiccant.
Manufacturers' recommendations should be followed when mounting a drier. For proper operation, the vertical-type drier must be mounted so that it does not incline more than 15°. The inlet of the drier must be connected to the condenser outlet and the outlet of the drier to the evaporator metering inlet.
The word IN is generally stamped on the inlet side of the drier. If the inlet is not stamped, an arrow indicating the direction of refrigerant flow should be visible. Remember that the refrigerant flows from the condenser bottom toward the metering device inlet. If the drier is connected in reverse, insufficient cooling will result.
As a result of improper handling or shipping, the internal parts of the drier may become dislodged and cause a partial restriction within the drier. This condition is indicated by a marked temperature change between the inlet and the outlet of the tank. If the restriction is great enough, frosting occurs at the drier outlet.
If the pickup tube is broken because of rough handling, abnormal flashing of the gas occurs in the liquid line. This is the same indication that is evident due to a low charge of refrigerant. In either case, a new drier must be installed.
Screens are located in the inlet of the metering device, the inlet of the compressor, and in the receiver drier. The screen in the thermostatic expansion valve and compressor can be cleaned or replaced. If the screen in the fixed orifice tube or drier becomes clogged, the entire component must be replaced.