Determining the target requires indoor wet and outdoor dry bulb temperatures. Take indoor wet bulb measurement just outside the return air duct.
Indoor Wet Bulb means the bulb of the thermometer is kept wet with pure water and a cloth covering the bulb to keep it wet.
Outdoor dry bulb is the outdoor ambient temperature of the air entering the compressor coils. Thermometer placement is important, keep out of the sun.
"Automatic" or "Manual" Target
Using manufacturer's Subcooling target:
Follow the directions and find the appropriate Subcooling target given your current environmental conditions.
Once a value is determined use the [Menu] Tab, [Settings] option and disable the [Calculate] switch under the Subcooling target section to enable entering a target Subcooling value. This tells HVAC Buddy® to override any automatic calculations for target Subcooling and use your manual entry. Verify manual Subcooling target by looking under the Subcooling target number in the app calculator output display. It will read "manual".
Using Automatic target:
HVAC Buddy® can calculate targets when wet bulb temperatures range from 57°F to 73°F and outdoor ambient temperatures range from 75°F to 115°F. Values outside these ranges cause an error condition cancelling further calculations. Target Subcooling can vary depending on conditions.
Verify the value is automatically being calculated by looking for the word "auto" under the Subcooling target number in the app calculator output display. If it displays "manual" the switch can be changed in the [Menu] tab, [Settings] menu option and enabling the [Calculate] switch. When you do this the manual target number will be removed.