The Receiver Dryer is a canister shaped component containing a dessicant pack which serves to filter and remove moisture from refrigerant. The Receiver dryer has inlet and outlet ports and is located on the High pressure side of the air conditioning system. Refrigerant recovery is required before attempting to change the receiver dryer.
Refrigerant may leak out of the receiver dryer if the metal cannister becomes corroded or rubber seals fail, which will cause loss of operation of the air conditioning system.
If the dessicant pack inside the receiver dryer cannister fails then dessicant beads may be released in to the air conditioning system pipework which will then often accumulate in restricted areas such as orifice tubes and thermal expansion valves causing system blockage. A refrigerant system blockage will cause excessively high system pressure usually detected by high pressure switch operation which may prevent air conditioning system operation. In some cases compressor damage may occur.
A wide range of receiver dryers is available to the vehicle aftermarket from both original equipment and aftermarket parts suppliers.
The air conditioning system should be empty of refrigerant before component removal.
Legislation requires that certain refrigerants are only recovered by qualified personnel. Refrigerant recovery means that the cooling fluid of the refrigeration system which may be in either gas or liquid form be safely removed from the refrigeration system and contained in approved storage cylinders. Records are kept of refrigerant removal and recharge quantities to provide traceability and compliance with environmental legislation.
Following safe refrigerant recovery, the depressurised system may be dismantled to change the receiver dryer and reassembled. An Oxyfgen Free Nitrogen Pressure test is carried out to check for any system leakage which must be rectified before any recharge of refrigerant. Following satisfactory pressure test, the refrigeration system must be put in to vacuum, then vac hold tested, before regas.
On many automotive applications, refrigerant system lubricant is added during the regas process. Domestic and commercial air conditioning refrigeration systems may differ because the compressor has a seperate refrigerant oil reservoir.
Following vehicle air conditioning regas, system pressures and vent temperatures should be checked for correct operation.
Many manufacturers recommend receiver dryers are changed every 24 months but this may vary according to manufacturers recommended service interval.
Renewal of the receiver dryer is always recommended if the air conditioning system has been disassembled during component removal and replacement or following leak repairs due to moisture absorbance from atmosphere.