A/C Orifice Tube: Description

The fixed A/C orifice tube is installed in the section of the A/C liquid line closest to the A/C condenser and provides a restriction in the liquid refrigerant line between the A/C condenser and the A/C evaporator. This restriction established the pressure differential between the high and low-pressure sides of the A/C system.

The inlet end of the fixed A/C orifice tube has a nylon mesh filter screen, which filters the refrigerant and helps to reduce the potential for blockage of the metering orifice by refrigerant system contaminants. See Fig 1. The outlet end of the tube has a nylon mesh diffuser screen. The O-rings on the plastic body of the tube seal it to the inside of the liquid line and prevent the refrigerant from bypassing the fixed metering orifice.

Fig 1: Fixed A/C Orifice Tube - Typical

Courtesy of DAIMLERCHRYSLER CORP.