Auto A/C Terms - Glossary
External Equalizer

Some conventional type expansion valves which use a capillary tube sensing device, also include an external equalizer tube. The external equalizer is actually a thin capillary tube that is attached to the expansion valve and also threads into the suction line of the A/C system.

The external equalizer senses the suction line pressure returning to the compressor. In doing that, it provides a shock absorber type action for the expansion valve so that the expansion valve is not moving too quickly from fully opened to fully closed. In short, the equalizer moderates the expansion valves opening and closing.

Understand that external equalizer type expansion valves include two capillary tubes and are not interchangeable with other expansion valve designs that only incorporate one capillary tube.