The thermostatic expansion valve is designed to moderate the amount of refrigerant sent into the evaporator. The expansion valve has an adjustment needle on the side of the valve that allows you to set the amount of coolant used. Turning the adustment needle a quarter turn is equal to one degree. The adjustment needle is very sensitive, so you must allow at least 20 minutes between each adjustment.
Determine whether you need to increase or decrease the temperature reading on the thermostatic expansion valve.
Locate the adjustment needle on the thermostatic expansion valve.
Turn the adjustment needle one quarter turn counterclockwise to decrease the temperature. Each quarter turn is equal to one degree.
Turn the adjustment needle a quarter turn clockwise for each degree needed, to increase the temperature.