Refrigerant liquid is considered subcooled when its temperature is lower than the saturation temperature corresponding to its pressure. The degree of subcooling equals the degrees of temperature decrease below the saturation temperature at the existing pressure.

Subcooling Formula = Sat. Liquid Temp. - Liquid Line Temp.

EXAMPLE:
a. Liquid Line Pressure = 417
b. Corresponding Temp. °F. = 120°
c. Thermometer on Liquid line = 109°F.
To obtain the amount of subcooling subtract 109°F from
120°F.
The difference is 11° subcooling. See the specification sheet
or technical information manual for the design subcooling
range for your unit.