R e s i d e n t i a l Tr a n q u i l i t y
®
2 7 S p l i t ( T T S ) - 6 0 H z H F C - 4 1 0 A
R e v. : 8 M a y, 2 0 1 4 C
20
G e o t h e r m a l H e a t i n g a n d C o o l i n g
Refrigeration Installation
Checking Superheat and Subcooling
Determining Superheat:
1. Measure the temperature of the suction line at a point
near the expansion valve bulb.
2. Determine the suction pressure by attaching refrigeration
gauges to the suction schrader connection at the
compressor.
3. Convert the pressure obtained in step 2 to saturation
temperature (boiling point) by using the pressure/
temperature conversion table on the gauge set.
4. Subtract the temperature obtained in step 3 from step
1. The di
ff
erence will be the superheat of the unit or the
total number of degrees above saturation temperature.
Refer to Tables 14d for superheat ranges at speci
fi
c
entering water conditions.
Example:
The temperature of the suction line at the sensing bulb is
50°F. The suction pressure at the compressor is 110 psig
which is equivalent to 36°F saturation temperature from the
HFC-410A press/temp conversion table on the gauge set.
36°F subtracted from 50°F = 14°F Superheat.
Determining Sub-Cooling:
1. Measure the temperature of the liquid line on the smaller
refrigerant line (liquid line) just outside of the cabinet.
This location will be adequate for measurement in both
modes unless a signi
fi
cant temperature drop in the liquid
line is anticipated.
2. Determine the condensor pressure (high side) by
attaching refrigerant gauges to the schrader connection
on the liquid line service valve. If the hot gas discharge
line of the compressor is used, refer to the appropriate
column in Tables 14d.
3. Convert the pressure obtained in step 2 to the
saturation temperature by using the press/temp
conversion table on the gauge set.
4. Subtract the temperature of Step 3 from the temperature of
Step 1. The di
ff
erence will be the sub-cooling value for that
unit (total degrees below the saturation temperature). Refer
to Tables 14a to 14d for sub-cooling values at speci
fi
c
entering water temperatures.
Example:
The condenser pressure at the service port is 335 psig,
which is equivalent to 104°F saturation temperature.
Discharge pressure is 365 psig at the compressor (109°F
saturation temperature). Measured liquid line temperature is
100°F. 100°F subtracted from 104°F = 4 degrees sub-cooling
(9 degrees if using the compressor discharge pressure).
