Why is a compound gauge named so?

A compound gauge is named for its ability to indicate both pressure and vacuum within a system. This functionality is important in many applications, such as refrigeration, heating, and system diagnostics, where both positive pressure and negative pressure (vacuum) conditions can occur. The gauge typically has a scale that allows it to read pressures in both the positive and negative ranges, thus providing a comprehensive view of the pressure conditions within a system.

Understanding this dual capability is critical when monitoring systems that can operate under varying pressure conditions. It allows technicians and maintenance personnel to ensure that systems are functioning correctly, which is crucial for system efficiency and safety. The ability of a compound gauge to deliver this dual information is what sets it apart from other types of gauges that might only measure one state (either pressure or vacuum) at a time.