15
FIELD INSTALLED ACCESSORIES
COMPRESSOR CRANKCASE HEAT (CCH)
While scroll compressors usually do not require crankcase heaters, there are
instances when a heater should be added. Refrigerant migration during the off cycle
can result in a noisy start up. Add a crankcase heater to minimize refrigerate migra-
tion, and to help eliminate any start up noise or bearing “wash out.”
NOTE: The installation of a crankcase heater is recommended if the system charge
exceeds the values listed in Table 7.
All heaters are located on the lower half of the compressor shell. Its purpose is to
drive refrigerant from the compressor shell during long off cycles, thus preventing
damage to the compressor during start-up.
At initial start-up or after extended shutdown periods, make sure the heater is ener-
gized for at least 12 hours before the compressor is started. (Disconnect switch on
and wall thermostat off.)
TIME DELAY CONTROL (TDC)
The time delay (TDC) is in the low voltage control circuit. When the compressor
shuts off due to a power failure or thermostat operation, this control keeps it off at
least 5 minutes which allows the system pressure to equalize, thus not damaging
the compressor or blowing fuses on start-up.
TABLE 7
MAXIMUM SYSTEM CHARGE VALUES
FIGURE 3
CONTROL WIRING FOR GAS OR ELECTRIC HEAT
FOR TYPICAL ELECTRIC HEAT
FOR TYPICAL GAS OR OIL HEAT
Charge Limit
Model Compressor
Without
Size Model Number
Crankcase Heat
18 H21J14BABCA 7 lbs.
24 H21J19BABCA 7 lbs.
30 H21J24BABCA 7 lbs.
36 H21J30BABCA 9 lbs.
42 H23C383ABCA 8 lbs.
48 H23C423ABCA 8 lbs.
60 H23R543ABCA 12 lbs.
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