Expansion (Orifice) Tube

The plastic expansion tube, with the mesh screen, and the orifice is in the condenser outlet pipe. Refer to Expansion (Orifice) Tube Replacement or HVAC Component Views. Service and Repair

The orifice tube provides a restriction to the high-pressure liquid refrigerant in the liquid line. This meters the flow of the refrigerant to the evaporator as a low-pressure liquid. The filter screens on both the inlet and the outlet sides protect the expansion tube and the orifice from contamination. Service the tube only as a replacement assembly.

When the engine is turned OFF with the air conditioning operating, the refrigerant in the system flows from the high-pressure side of the expansion tube orifice to the low-pressure side until the pressure equalizes. This is detectable as a faint hissing sound for 30-60 seconds. The hissing is normal.

When the system diagnostics indicate a restricted expansion tube, replacement of the restricted expansion tube may not be necessary. You may remove metal chips, flakes, or slivers found on the screen with compressed air. Reuse the expansion tube under the following conditions:
- The plastic frame is not broken
- The expansion tube is not damaged or plugged
- The screen material is not torn
- The screen is not plugged with fine gritty material