In HVAC terminology, what does a "manometer" measure?

A manometer is a device specifically designed to measure gas pressure. It operates by comparing the pressure of the gas in question to a known reference pressure, typically atmospheric pressure, allowing precise quantification of that pressure. This instrument is crucial in HVAC applications, as it helps technicians monitor and adjust gas pressures within systems, ensuring they operate efficiently and safely. By measuring the pressure differences, manometers can indicate whether a system is functioning within its intended parameters, which is essential for both performance and compliance with safety regulations.

The other choices relate to other aspects of HVAC system measurements: air temperature is typically measured with a thermometer or temperature sensor, fluid flow is measured with flow meters, and humidity levels are typically assessed using hygrometers. Each of these devices serves a specific function, distinguishing them from the unique role of a manometer in gas pressure measurement.