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8.0 SYSTEM OPERATION
Refrigerant migration during the off cycle can result in a noisy start up. Add
a crankcase heater to minimize refrigeration migration, and to help eliminate
any start up noise or bearing “wash out”.
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 energized for at least 12 hours before the compressor is started.
(Disconnect switch on and wall thermostat off.)
The crankcase heater start-up conditions:
If the outdoor ambient temp. is
<
37.4°F and the compressor stopped for
more than three hours or the unit powered on once more, the crank heater
will be on.
Crankcase heater shut-down conditions:
If the outdoor ambient temp. is
>
44.6°F or the compressor start running ,the
crank heater will be off.
8.2 Protection
8.1 COMPRESSOR CRANKCASE HEATER(OPTIONAL)
Discharge temperature protection :
When discharge temp. is
>
275°F, the compressor will be off,
When discharge temp. is
<
194°F, the compressor will start running.
8.2.1 Protection for AC system
8.2.2
Protection for HP system
When the sensor(T3&T4) was checked open-circuit or short-circuit, the
compressor ,outdoor fan motor and 4-way valve will be off.
Discharge temperature protection:
When discharge temp. is > 275°F, the compressor will be off, When discharge
temp. is < 194°F, the compressor will start running.