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8.5 THERMOSTAT SIGNALS
8.4 MANUA L DEFROST MODE (For H P system only)
When MANUA L DEFROS T switch in PCB is set to “1”, system will perform as
above 8.3 description.
When the switch is set to “0”, T3 ＜32° F , compressor keeps running and lasting
for 40 seconds, the system turns to the Defrost Mode. By the logic of 8.3 to
exit the Defrost Mode.
Caution: Once finishes the manual defrost, please switch the MANUA L
DEFROS T in PCB to “1”.
When JUM P switch is set to “0”:
Compressor keeps running, when T3 is < 32 °F and last for 30 minutes.
8.3 DEFROST MODE* (For H P system only)
Defrosting condition:
When JUM P 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.
* When defrosting actions, if the electrical heater kit is installed, the unit would deliver the Aux. heater
operation signal to the electrical heater kit.
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
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