What reading indicates a low stage compressor discharge pressure under normal conditions?

A reading of 31 PSIG indicates a low stage compressor discharge pressure under normal conditions. In refrigeration systems, particularly in multi-stage setups, the low stage compressors are typically designed to operate at lower pressure ranges compared to higher stage compressors. Discharge pressures for low stage compressors commonly range anywhere from about 25 to 35 PSIG, depending on the specific design and application of the system.

In the context of the choices provided, 31 PSIG falls well within this typical operating range for a low stage compressor. It suggests that the compressor is functioning properly under normal conditions, without undue stress or significant deviation from expected performance levels. Higher pressure readings, like 154 PSIG and 167 PSIG, would typically indicate a high stage compressor's discharge pressure, rather than one operating in the low stage. Therefore, 31 PSIG is identified as the appropriate reading for confirming standard operational levels for low stage compressors in an industrial refrigeration context.