Expansion Block/Orifice Tube: Description and Operation

Expansion (Orifice) Tube Description:

The plastic expansion tube, is located between the condenser outlet and the evaporator inlet. The expansion tube includes a mesh screen and an orifice. The tube restricts the high pressure liquid refrigerant in the liquid line. The system meters the flow of refrigerant to the evaporator as a low-pressure liquid. The filter screens on both the inlet (1) and the outlet (3) sides protect the expansion tube and the orifice form contamination. When the system diagnostics indicate a restricted expansion tube, it may not be necessary to replace the tube. Metal chips, flakes or slivers found on the screen may be removed with compressed air. The expansion tube is reusable if the none following conditions are present:
^ A broken plastic frame
^ A damaged or plugged brass expansion tube
^ Any torn screen material
^ A plugged screen (gritty material in screen)