Receiver Dryer: Description and Operation

CAUTION:
^ When you are working on the A/C system it is important to plug all connections which have been opened in order to prevent the receiver from sucking in moisture from the air. If the A/C system has been open for more than 15 minutes altogether, install a new receiver. It will then have absorbed so much moisture that it cannot operate any longer.

^ A new receiver should also be fitted if there has been a break in a hose or a major leakage. If minor leakage has occurred, such as in a hose connection, it will not be necessary to install a new receiver.

Technical Description
Its purpose is to store and dehumidify the refrigerant. A three-stage pressure monitor is fitted on the desiccant container. It has the following functions:
- It allows the compressor to work at temperatures down to ± 0 °C. The pressure in the system at this temperature is about 2 bar.

- It starts the engine's cooling fan at a pressure of about 16.5 bar. When the pressure has dropped to about 12.5 bar, the fan is switched off.

- It breaks the electric circuit to the compressor if the pressure rises above 30 bar. When the pressure has fallen to about 24 bar, the compressor is reconnected.

An additional pressure monitor is fitted on cars for hot-climate countries. It starts the second stage of the ventilation fan when the pressure in the A/C system exceeds 22 bar.

The service connection for the high-pressure side is also fitted on the receiver.

Mode Of Operation
The refrigerant is stored and dehumidified in the receiver.

The refrigerant enters the receiver as a liquid under high pressure and at high temperature. It passes through the filter, where it is dehumidified and any particles removed. The refrigerant is then transported, as a liquid, to the expansion valve.

The system's pressure monitor is located on the receiver (two pressure monitors are used in hot climate countries).