What do manifold gauges measure?

Manifold gauges are specialized instruments used primarily in HVAC (Heating, Ventilation, and Air Conditioning) systems and refrigeration to measure the pressure of refrigerants within a system. They are designed to measure pressures compared to atmospheric pressure, providing accurate readings of both high side (usually representing the discharge pressure from the compressor) and low side (representing the suction pressure going into the compressor) pressures.

By offering these measurements, manifold gauges help technicians diagnose issues, assess performance, and ensure that a refrigerant system is operating within the correct pressure ranges. Understanding these pressures is critical for both troubleshooting and maintenance, making this measurement vital in the field.

The other options do not accurately describe the purpose and function of manifold gauges, which is specifically to gauge pressures in the context of HVAC applications rather than temperatures or pressures in isolation.