1. Run the condensing unit until suction pressure and suction line temperature stabilize.
2. Read and record the suction pressure
3. Place a digital temperatu re probe against the suction line near the suction gauge pressure port. Read and record the temperature.
4. Reference the face of your suction gauge or use a Temperature/Pressure chart and convert the measured suction pressure to the corresponding evaporator coil saturation temperature for the refrigerant being used, Record this value.
5. Next, subtract the saturation temperature from the measured suction line temperature. The result is your actual suction vapor superheat.