An important component of a motor vehicle’s air conditioning system is the receiver dryer. A receiver dryer (which is also known as a filter drier or a receiver dehydrator) is constructed in the form of a small metal canister. The receiver dryer canister has both an inlet and outlet valve. It is employed exclusively in air conditioning systems that employ expansion valves. The receiver dryer is commonly situated within the high pressure area of the air conditioning system between the condenser and the inlet of the expansion valve. However, some are connected directly to the condenser.

The receiver dryer performs three essential functions in the operation of an air conditioning system. Firstly, it temporarily stores (or receives) oil and coolant fluid during periods of low demand when the system does not need to use it. Secondly, it contains a filter to sift out any debris that may have entered the air conditioning system. Finally, the receiver dryer canister contains a desiccant. This is a material that serves to absorb and dispel (or dry) any moisture that may have infiltrated the air conditioning system during its manufacture, assembly or fitting.

If the receiver dryer fails to work properly it will affect the operation of the air conditioning system and the system may need to be serviced and the desiccant replaced to restore normal operations.