Superheat Calculator

Calculate and verify superheat for fixed orifice (piston/capillary) systems.

Refrigerant

Measurements

Suction Pressure (psig)

Suction Line Temp (°F)

Target Superheat (for charging)

Indoor Wet Bulb (°F)

Outdoor Dry Bulb (°F)

Superheat Formula

Superheat = Suction Line Temp − Saturation Temp

Saturation temperature is determined from suction pressure using the PT chart for the specific refrigerant.

Target Superheat Guidelines

Fixed orifice: Use superheat chart (5-20°F typical)
TXV: 10-15°F (use subcooling for charging)
Low SH: Possible liquid floodback (undercharge or restriction)
High SH: Low refrigerant, airflow issue, or restriction