Chart G Refrigerant System Check

SYSTEM DESCRIPTION

Under normal conditions, liquid refrigerant passes through the orifice tube 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. Liquid refrigerant is prevented from entering the compressor by the accumulator.

If a low charge or a partially plugged orifice tube exists, the compressor 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 A/C vents under such conditions.