Mitsubishi Electric MS-18NN Series Service Manual page 17

— COOL mode of "I FEEL CONTROL" —
OFF
Compressor and
outdoor fan motor
ON
Indoor fan motor
NOTE : Coil frost prevention during COOL mode of "I FEEL CONTROL"
There are two types of controls in coil frost prevention.
Temperature control
When the indoor coil thermistor RT12 reads -1°C or below, the coil frost prevention mode starts immediately.
However the coil frost prevention will not work for 5 minutes after the compressor starts.
The compressor stops and the indoor fan operates at the set speed for 5 minutes.
After that, if RT12 still reads below -1°C this mode prolonged until the RT12 reads over -1°C .
Time control
When the three conditions below have been satisfied for 1 hour and 45 minutes, compressor stops for 3 minutes.
a. Compressor has been continuously operating.
b. Indoor fan speed is Lo or Me.
c. Room temperature is below 26°C.
When compressor turns off half way, the accumulated time is cancelled.
When compressor turns on again, time counting starts from the beginning.
When the indoor fan speed becomes Hi or the room temperature exceeds 26°C, time counting stops temporarily.
After, when the above conditions are satisfied again, time counting restarts.
The indoor fan operates at set speed.
Indoor fan operates at the set speed by FAN CONTROL
Followings are the fan speed in AUTO.
Room temperature minus set temperature : more than 2 ~ 4 degrees (°C)··············Hi
Room temperature minus set temperature : 1 ~ 4 degrees (°C) ·····························Me
Room temperature minus set temperature : less than 1 ~1.5 degrees (°C) ·············Lo
—DRY mode of "I FEEL CONTROL"—
The system for dry operation uses the same refrigerant circuit as the cooling circuit.
The compressor and the indoor fan are controlled by the temperature and the microprocessor.
By such controls, indoor flow amounts will be reduced in order to lower humidity without much room temperature
decrease.
The operation of the compressor and indoor fan is as follows.
1. When the room temperature is 23°C or over:
Compressor operates by temperature control and time control.
Set temperature is controlled to fall 2°C as initial set temperature.
When the thermostat is ON, the compressor repeats 8 minutes ON and 3 minutes OFF.
When the thermostat is OFF, the compressor repeats 4 minutes OFF and 1 minute ON.
Indoor fan and outdoor fan operate in the same cycle as the compressor.
2. When the room temperature is under 23°C.
When the thermostat is ON, the compressor repeats 2 minutes ON and 3 minutes OFF.
When the thermostat is OFF, the compressor repeats 4 minutes OFF and 1 minute ON.
ON
OFF
Run continuously in cooling mode
ON
1 deg. 1.5 deg.
2 deg. 4 deg.
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