How long should a system run before you measure subcooling?

To accurately measure subcooling in an HVAC system, it is essential to wait until the temperature and pressure stabilize. When the system first starts running, it experiences changes in temperature and pressure as it reaches operational equilibrium. Subcooling is defined as the difference between the saturation temperature and the actual liquid temperature of refrigerant after it has condensed in the condenser.

If measurements are taken too soon, before stabilization occurs, the values might be inaccurate due to transient conditions. Allowing time for the system to stabilize ensures that the measurements reflect the true operating conditions, leading to more reliable subcooling readings. This provides essential insights into the efficiency and performance of the system, helping technicians diagnose issues or verify that the system is functioning properly.