Note the low side pressure, determine the corresponding saturation temperature, and add it to the temperature measured with a thermometer at the thermostatic expansion valve sensing bulb.

Note the low side pressure, determine the corresponding saturation temperature, and subtract it from the temperature measured with a thermometer at the thermostatic expansion valve sensing bulb.

Note the low side pressure, determine the corresponding saturation temperature, and subtract it from the temperature measured with a thermometer at the compressor suction inlet.

Subtract the temperature measured at the thermostatic expansion valve sensing bulb from the saturation temperature corresponding to the low side pressure.