SHC-410-CP (01/13)
Page 8
Final charging is done in the HEAT mode
as follows, with the charging set up described in
Figure 6:
1. Continue measuring the refrigerant charge weight as shown in Figure 6.
2. Be sure that air entering the air handler is between 70°F and 80°F. If the system is a
hydronic primary circuit, circulating water is to be held between 95°F and 105°F.
3. Close the HP valve.
Then turn the system on in the HEAT mode
.
4. Initiate final charging by opening the refrigerant container valve and the gage manifold
LP valve to allow liquid refrigerant to enter the system
SLOWLY
as shown in Figure 6.
The ACC will not allow liquid refrigerant to enter the compressor.
5. Adding liquid refrigerant will raise the liquid level in the ACC. Continue to add liquid
refrigerant to the system until the liquid level has reached the middle sight glass, as
shown in Figure 7.
6.
When the liquid level is at the middle sight glass, as shown in Figure 7, turn the
refrigerant container valve OFF.
7. When the system has run for 20 minutes (in HEAT mode), read the evaporating
temperature and condensing temperature.
The evaporating temperature can be read by attaching a thermocouple lead to the
Earth Loop Vapor Line with electrical tape, then wrapped with ½” thick insulation. The
condensing temperature can be read by attaching a thermocouple lead to the Air
Handler/CC/HWM liquid line coming into the compressor unit with electrical tape, then
wrapped with ½” thick insulation. Use an accurate temperature indicator.
In Figure 8, locate the evaporating temperature on the horizontal axis. The
corresponding condensing temperature reading should fall between the upper and
lower parallel lines in Figure 8.
The temperature profile in Figure 8 is valid for the air handler systems with an
air flow of 400CFM per Ton
. If condensing temperature is above acceptable range,
the air flow is low. If condensing temperature is below the acceptable range, air flow is
too high.
Adjust air flow as appropriate.
