Mitsubishi MSH-A18WV Service Manual page 12

Operation time chart
Example
OFF
Thermostat
OFF
Indoor fan
OFF
Outdoor fan
Compressor
3. Coil frost prevention
• The operation is as same as coil frost prevention during COOL mode of "I FEEL CONTROL".
• Indoor fan operates at the set speed and the compressor stops for 5 minutes, because protection(Coil frost
prevention) has the priority.
However, when coil frost prevention works while the compressor is not operating, it's speed becomes Low.
NOTE : As for outdoor fan speed control, refer to service manual for outdoor unit.
8-1-3. HEAT mode of "I FEEL CONTROL"
1. Indoor fan speed control
(1) In AUTO the fan speed is as follows.
Set temperature minus room temperature: 2 degrees or more················································· High
Set temperature minus room temperature: Between 1 and 2 degrees ····································· Med.
Set temperature minus room temperature: less than 1 degree················································· Low
(2) Cold air prevention control
The fan runs at set speed when the indoor coil thermistor RT12 temperature exceeds 22°C. The fan operates Low when
the temperature of indoor coil thermistor RT12 is below 18°C. But the fan stops when the indoor fan operates at Very
Low and the room temperature is 15°C or less.
Indoor coil thermistor
RT12 temperature
NOTE : If the temperature of RT12 reads from 18°C to 22°C at the air conditioner starting and also after defrosting, this
control works.
(3) Warm air control.
When compressor starts in heating operation or after defrosting, the fan changes the speed due to the indoor coil ther-
mistor RT12 temperature to blow out warm air.
After releasing of cold air prevention, when the indoor coil thermistor RT12 temperature is 37°C or above, the fan speed
shifts to the set speed, and when the fan speed is changed by the remote controller, the fan speed is the set speed.
When the indoor coil thermistor RT12 temperature is less than 37°C, the fan speed is controlled by time as below.
<Time condition>
less than 2 minutes ························Low
2 minutes to 4 minutes···················Med.
4 minutes or more ··························High
The upper limit of the fan speed is the set speed.
If the thermostat turns off, this operation changes to flow soft control.
(4) Flow soft control
After the thermostat turns off, the indoor fan operates at Very Low.
NOTE : When the thermostat turns on, the fan operates at the set speed. Due to the cold air prevention control, the fan
does not start at set speed until the indoor coil thermistor RT12 reads 22°C or more.
NOTE : As for outdoor fan speed control, high pressure protection, discharge temperature protection, defrost-
ing and R.V. coil control, refer to service manual for outdoor unit.
ON
ON
ON
OFF
ON
ON
OFF
8 min.
3 min.
Initial temperature difference
Released
Cold Air Prevention
<Indoor fan speed>
OFF
ON
OFF
ON
OFF
1 min.
4 min.
Fan speed
Fan speed
Set speed
Very Low or stop
18: 22:
12
ON
Difference between room
temperature and set temperature
during operation
2deg.
1deg. 1.7deg.
4deg.