A/C Pressure Switch

Refrigerant Containment Switch - R-134a System

A refrigerant containment switch is used on all models with air conditioning to interrupt A/C compressor operation in the event of high system discharge pressures which could result in loss of refrigerant charge. The switch is located in the discharge line between the A/C compressor and the A/C condenser core. The switch is sensitive to the discharge pressure and functions to interrupt the A/C compressor operation if the discharge pressure exceeds a setting of 2751.1-3068.2 kPa (399-445 psi). The switch is a single function switch which only controls the circuit to the A/C cycling switch.

To introduce the subject of refrigerant flow, a simplified diagram follows which illustrates the pressure changes which take place in a typical refrigerant circuit. The diagram also calls out the physical state of the refrigerant as it passes through the circuit.