Thermo Pride Air Handlers ECM Blower 13/14 SEER (AH2) - Manual (Page 20)

18
HOW TO MEASURE LIQUID SUB-COOLING
(NOTE: A good electronic thermometer and accurate liquid pressure gauge with a check valve in the
Schraeder fitting are necessary).
: Failure to use a liquid side hose fitting with a built in check valve may result in personal
injury and significant refrigerant loss.
Sub-cooling is measured by taking a temperature and pressure reading. See Figure L. The pressure reading
is gauged at the pressure port located on the liquid service valve. The temperature reading is taken at the
liquid line at the 3:00 o'clock or 9:00 o'clock position with the liquid line as the center of the clock.
Figure L.
Make sure the tube where the temperature is measured is not in direct sunlight.
Read the temperature at the liquid line.
Read the liquid pressure.
Then convert pressure into temperature.
Next, subtract the measured tube temperature from the converted suction temperature.
The end result is the liquid sub-cooling.
EXAMPLE:
Measured Temp = 95oF
Measured Pressure = 211PSI which equates to a 105oF saturation temperature.
(Listed temperature for measured pressure according to R-22 temperature scale on manifold gauge or R-
22 section of pressure temperature chart)
The difference equals the degrees superheat = 10oF