When checking pressures in an operating system, how does refrigerant oil in a hose affect the gauge reading?

When checking pressures in an operating system, the presence of refrigerant oil in the hose does not affect the gauge reading. This is because the pressure readings on gauges are primarily determined by the refrigerant gas itself, not the oil that may be present. The oil, being a liquid, does not compress in the same manner as a gas and therefore does not change the pressure measurement in the system.

Thus, when a technician reads the gauge, they can accurately assess the pressure of the refrigerant within the system without interference from any oil in the hose. This understanding is essential for properly diagnosing and servicing HVAC systems.