Chart 1C-6 Refrigerant System Check

SYSTEM DESCRIPTION:
Under normal conditions, liquid refrigerant passes through the orifice tube in the condenser outlet pipe and expands in the evaporator. Expansion occurs due to restricted flow caused by the orifice tube, which reduces pressure in the evaporator. The refrigerant absorbs large amounts of heat from the air passing through the evaporator, and gradually begins to boil as it passes through the evaporator. It is almost completely vaporized as it enters the accumulator assembly. Liquid refrigerant is prevented from entering the compressor assembly by the accumulator assembly.

If a low charge or a partially plugged orifice tube exists, the compressor assembly will cycle rapidly because the evaporator pressure is so low that the refrigerant boils almost immediately instead of gradually. Relatively warm air will come out of instrument panel outlets under such conditions.