The LPA pump is used to pressurise the liquid line with no temperature rise, which subcooles the liquid, ensuring vapour-free liquid delivery to the expansion valve. Thermostatic expansion valves will maintain capacity and meter properly with as little as 25 psi pressure drop across the valve if vapour-free liquid is present at the valve inlet, provided that the liquid temperature is also low.

The benefits are:

Proper operation of a refrigeration or air conditioning system when minimum head pressure controls are set to reduce head pressures, thereby saving energy and increasing capacity at mild to cold outdoor temperatures. The LPA pump eliminates the usual problems of capacity loss and poor oil return due to operating with low head pressures.

Improved performance and efficiency of a system that has flash vapour in the liquid line. This is especially apparent if flash vapour is a serious problem, as in systems with excessive liquid line pressure drop, elevation gain in the liquid line, or if the air surrounding the line is warmer than the outdoor temperature.

Reduced scaling problems on water cooled systems when a small amount of high pressure liquid from the pump outlet is injected into the discharge line, reducing the vapour temperature.

Lower condensing temperature to condensing media temperature differential due to increased heat transfer when more of the available condenser surface is used for condensing rather than de-superheating, due to liquid injection into the discharge line.