What is PSIG in the context of refrigeration pressure measurements?

In refrigeration pressure measurements, PSIG refers specifically to gauge pressure, which is measured relative to the ambient atmospheric pressure. This means that PSIG indicates the pressure that is higher than the surrounding atmospheric pressure. For example, if a gauge reads 10 PSIG, that means the pressure within the system is 10 psi greater than the atmospheric pressure outside it.

This concept is essential for technicians working with refrigeration systems because it allows them to monitor system pressures effectively and ensure that the system is operating safely and efficiently. By evaluating PSIG, technicians can determine if the refrigeration cycle is performing as expected and can troubleshoot potential issues based on pressure readings.

Understanding PSIG is crucial for diagnosing problems or optimizing the performance of a refrigeration system since many of the operating parameters rely on having an accurate sense of pressure relative to the atmospheric condition, rather than absolute pressure, which would include the weight of the atmosphere at that location.