Freeze Prevention Control; Compressor Reverse Rotation Protection Control - Panasonic CS-C7MKP-7 Service Manual

13.5 Freeze Prevention Control

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To protect indoor heat exchanger from freezing and to prevent higher volume of refrigerant in liquid form return to
compressor.
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This control will activate when temperature of indoor heat exchanger falls below 2°C continuously for more than 4
minutes and compressor turn off.
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The current fan speed will change to freeze prevention speed after 70 seconds compressor on. The fan speed
will be increased according to the indoor pipe temperature as below figure: (Applicable for C7MKP-7, C9MKP-7
and C12MKP-7 ONLY)
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Compressor will restart again when the indoor heat exchanger temperature rises to 10°C (Recovery).
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Restart control (Time Delay Safety Control) will be applied in this control if the recovery time is too short.

13.6 Compressor Reverse Rotation Protection Control

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If the compressor is operating continuously for 5 minutes or longer and the temperature difference between
intake air and indoor heat exchanger is 2.5°C or less for continuously 2 minutes, compressor will stop and restart
automatically.
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Time Delay Safety Control is activated before the compressor restart.
Compressor starts for • 5 minutes
T ” 2.5°C for 2 minutes
T = Intake air temperature – Indoor heat exchanger temperature
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This is to prevent compressor from rotate reversely when there is an instantaneous power failure.
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If this condition happens continuously for 5 times within 50 minutes, unit will turn OFF with TIMER LED blinks.
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The 5 Times counter can be reset when either one of the following condition happen:
Unit is OFF by remote control or AUTO OFF/ON button.
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Indoor intake temperature – Indoor piping temperature > 5°C for one minute or more.
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Operation mode change.
o
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The unit could be ON by pressing OFF/ON button at remote control but the TIMER LED will continue blinking.
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TIMER LED blinking will be reset if:
Indoor intake temperature – Indoor piping temperature > 5°C for one minute or more.
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Power supply reset.
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Indoor Heat
Exchanger
Temperature
(°C)
10
4 min
2
RPM shift
(ID temp) Pipe
+0
6.0°C
+20
4.0°C
+40
2.0°C
+70
63
Recovery
Compressor OFF
7.0°C
5.0°C
3.0°C
Compressor
OFF
Compressor
restart