ASHRAE Standard 153 provides a means for measuring the mass flow capacity of reversing valves used on heat pumps and other refrigerating systems. The standard was created because accurate capacity data are needed to facilitate the proper application of four-way valves in a varietyof refrigerating systems that employ a variety of refrigerants.

The test method is intended to be within the capabilities of most users and producers employing conventional laboratory apparatus. This standard allows the use of a wide variety of test fluids, including the refrigerant intended for the end application.