How to Read a R22 Compound Gauge?

What are the typical readings on a R22 compound gauge?

A. -30 inches of mercury to 500 psi
B. 0 to 100 psi
C. -50 inches of mercury to 600 psi

Answer:

A. -30 inches of mercury to 500 psi

Reading a R22 compound gauge is an essential skill for HVAC technicians to monitor the pressure of the refrigerant in systems. A typical R22 compound gauge usually has a scale that extends from about -30 inches of mercury to 500 psi, reflecting the range of gauge pressure measured in systems using R22 refrigerant.

The scale on the R22 compound gauge allows technicians to observe both positive and negative pressure readings. The low-pressure side of the gauge shows vacuum readings in inches of mercury, with the lowest point around -30 inches. This indicates a state of vacuum or negative pressure in the system. On the high-pressure side of the gauge, pressure measurements in pounds per square inch (psi) can be observed, with the maximum point typically around 500 psi.

By interpreting the readings on the R22 compound gauge, technicians can diagnose potential issues in the HVAC system related to pressure levels. Understanding how to read and interpret the values displayed on the gauge is crucial for maintaining proper operation and efficiency of the refrigeration system.