Mitsubishi Electric MS-A18WV Service Manual page 11

8-1-1. COOL mode of "I FEEL CONTROL"
1. Indoor fan speed control
Indoor fan operates at the set speed by FAN SPEED CONTROL button.
In AUTO the fan speed is as follows.
Room temperature minus set temperature : 1.7 degrees or more··························High
Room temperature minus set temperature : Between 1 and 1.7 degrees················Med.
Room temperature minus set temperature : less than 1 degree······························Low
2. Coil frost prevention
Temperature control
When the indoor coil thermistor RT12 reads 0°C or below(MS-A18WV) /3°C or below(MS-A24WV)/ RT12 or RT13
reads -1°C or below (MS-A30WV), the coil frost prevention mode starts immediately.
However, the coil frost prevention doesn't work for 5 minutes since the compressor has started.
The indoor fan operates at the set speed and the compressor stops for 5 minutes.
After that, if RT12 still reads below 0°C(MS-A18WV)/ 3°C(MS-A24WV)/ RT12 or RT13 still reads below-1°C (MS-
A30WV) this mode prolonged until the RT12 reads over 0°C(MS-A18WV)/ 3°C(MS-A24WV) / RT12 or RT13 still reads-
over-1°C(MS-A30WV).
Time control
When the three conditions as follows 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 Low or Med.
c. Room temperature is below 26°C.
When compressor stops, the accumulated time is cancelled and when compressor restarts, time counting starts from the
beginning.
Time counting also stops temporarily when the indoor fan speed becomes High or the room temperature exceeds
26°C. However, when two of the above conditions (b.and c.) are satisfied again. Time accumulation is resumed.
Operation chart
Example
OFF
Compressor
Outdoor fan
ON
Indoor fan
NOTE : As for outdoor fan speed control and discharge temperature protection, refer to service manual for outdoor
unit.
8-1-2. 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 room temperature.
By such controls, indoor flow amounts will be reduced in order to lower humidity without much room temperature decrease.
1. Indoor fan speed control
Indoor fan operates at the set speed by FAN SPEED CONTROL button.
However, in AUTO fan operation, fan speed becomes Low.
2. The operation of the compressor and indoor/ outdoor fan
Compressor operates by room temperature control and time control.
Set temperature is controlled to fall 2°C from initial room temperature.
Indoor fan and outdoor fan operate in the same cycle as the compressor.
•When the room temperature is 23°C or over:
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.
•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.
Initial temperature difference
ON
(continuously at set speed)
Fan Speed
ON
OFF
11
Difference between room
temperature and set temperature
during operation
3deg.
1deg. 1.7deg.