Fixed Orifice Tube

The fixed orifice tube 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 evaporator core. Evaporator temperature is controlled by sensing the pressure within the evaporator core with a pressure-operated electric switch. The pressure switch controls compressor operation as necessary to maintain the evaporator pressure within specified limits.

The fixed orifice tube is located in the liquid line near the condenser and has filter a screen located on the inlet ends of the tube body. The filter screens act as a strainer for the liquid refrigerant flowing through the fixed orifice opening. O-rings on the tube body prevent the high-pressure liquid refrigerant from bypassing the orifice. Adjustment or service cannot be made to the fixed orifice tube assembly which cannot be removed from the liquid line. The liquid line must be replaced, or an Orifice Tube Replacement Kit (E5VY-19D695-A) or equivalent installed if replacement of the orifice tube is necessary.

The fixed orifice tube should be replaced whenever a compressor is replaced.

If the high pressure reading is higher than normal and the suction pressure drops rapidly creating a faster than normal clutch cycle rate, the orifice tube may be restricted and should be replaced. This condition is usually indicated by the compressor having a short ON time and a long OFF time.