Expansion Block/Orifice Tube: Description and Operation

Fixed A/C Orifice Tube - Typical:

The fixed A/C orifice tube is installed in the liquid line between the outlet of the condenser and the inlet of the evaporator. The A/C orifice tube is only serviced as an part of the liquid line.

The fixed A/C orifice tube is used to meter the flow of liquid refrigerant into the evaporator coil. The high-pressure liquid refrigerant from the condenser expands into a low-pressure liquid as it passes through the metering orifice and diffuser screen of the A/C orifice tube.

The A/C orifice tube is not serviceable. The A/C orifice tube cannot be repaired and, if faulty or plugged, it must be replaced as part of the liquid line.