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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.
8.1 COMPRESSOR CRANKCASE HEATER(Optional)
8.3 DEFROST MODE* (For HP system only)
When the sensor T3
(Condenser pipe temperature)
&T4
(Outdoor ambient
temperature
) was checked open-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.
High pressure protection
When high pressure is
＞
638PSIG, the compressor and the outdoor fan motor
will stop running.
When high pressure is
＜
464PSIG, the compressor and the outdoor fan motor
will start running(3 minutes delay necessary ).
Low pressure protection
When low pressure is
＜
21PSIG, the compressor and the outdoor fan motor
will stop running.
When low pressure is
＞
44PSIG, the compressor and the outdoor fan motor
will start running(3 minutes delay necessary ).
In stand-by status, if low pressure protection was checked out, the compressor
would not start running.
If protection cycles occur four times within 30 mins, the system must power on
once more.
T4 function:
When T4 is < 5 °F, the compressor will stop. If the electrical heater kit is
installed
in the indoor unit, the outdoor unit will send the operation signal to the indoor
unit.
When T4 is > 10.4 °F, the compressor will restart
.
Defrosting condition:
When JUMP switch is set to “1”, the defrost mode will start if one of following
conditions is satisfied:
1. Compressor keeps running, when T4 is > 28.4 °F and T3 is < 32 °F and last
for 40 minutes;
2. Compressor keeps running, when T4 is < 28.4 °F and T3 is < 32 °F and last
for 50 minutes.
8.2 Protection (For HP system only)
* When defrosting Actions, if the electrical heater kit is installed in the indoor unit, the outdoor unit
would deliver the Aux. heater operation signal to the indoor unit.
