Expansion Block/Orifice Tube: Description and Operation

NOTE: The A/C evaporator core orifice should be replaced whenever an A/C compressor is replaced.

DESCRIPTION
The A/C evaporator core orifice, located in the liquid line near the A/C condenser core assembly, is the restriction creating the dividing point between the high and low-pressure liquid refrigerant, and meters the flow of liquid refrigerant into the A/C evaporator core.

OPERATION
The filter screen acts as a strainer for the liquid refrigerant flowing through the A/C evaporator core orifice opening. O-ring seals, on the A/C evaporator core orifice housing prevent the high-pressure liquid refrigerant from bypassing the A/C evaporator core orifice. If the high pressure reading is higher than normal and the suction pressure drops rapidly creating a faster than normal A/C clutch cycle rate, the A/C evaporator core orifice may be restricted and should be replaced. This condition is usually indicated by the A/C compressor having a short ON time and a long OFF time. Adjustment or service cannot be made to the A/C evaporator core orifice assembly. The liquid line must be replaced, or an Orifice Tube Replacement Kit (E5VY-19D695) installed, if replacement of the A/C evaporator core orifice is necessary.