How To Check Superheat And Subcooling. Take the high side pressure and convert it to temperature using chart or gauge. To check subcooling, attach a thermometer to the liquid line near the condenser.
Fully understanding superheat and subcooling is the key to a refrigeration system performing at its optimum level. While it is true that subcooling is the primary charging measurement on a txv /tev / eev system, subcooling is important to check on every system, every time you connect (whenever possible). Using table 3, you can check the range of subcooling by taking a wet bulb reading at the evaporator and a dry bulb reading from the air entering the condenser.
It is impossible in a running air conditioning system for the suction line to be 100% liquid subcooled below saturation, therefore it is.
You can determine the exact target subcooling based on the target subcooling posted on the outdoor unit rating plate or under the outdoor unit shroud. Take the head pressure and convert it to temperature on a temperature/pressure chart. A low airflow or dirty evaporator can raise subcooling. Wrap your thermocouples with insulation to obtain accurate pipe temperatures.