Mitsubishi Electric MSC-GE-VB Service Manual page 6

2. Indoor fan speed control
(1) In AUTO the fan speed
(MSC-GE20/25/35VB)
Indoor fan speed at set speed by FAN SPEED CONTROL button.
Set temperature minus room temperature: 1.7°C or more ················································· High
Set temperature minus room temperature: between 1 and 1.7°C ································· Med.
Set temperature minus room temperature: less than 1°C ············································· Low
(MSH-GD80VB, MSH-GE50VB)
Set temperature minus room temperature: 2°C or more ····················································· High
Set temperature minus room temperature: between 1 and 2°C········································· Med.
Set temperature minus room temperature: less than 1°C ····················································Low
(2) Cold air prevention control
When the compressor is not operating (MSC-GE20/25/35VB):
( ) If the temperature of indoor coil thermistor RT12 is 0°C or less, the fan stops.
( ) If the temperature of indoor coil thermistor RT12 is more than 0°C, the fan operates at Very Low.
When the compressor is operating:
( ) If the temperature of RT12 is 22°C or more, the fan operates at set speed.
( ) If the temperature of RT12 is less than 22°C and
( ) if the temperature of room temperature thermistor RT11 is 15°C or less, the fan stops.
( ) if the temperature of room temperature thermistor RT11 is more than 15°C, the fan operates at Very Low.
NOTE : If the temperature of RT12 reads from 18°C to 22°C at the air conditioner stating 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 temperature to blow out warm air.
After releasing of cold air prevention, when the indoor coil thermistor 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 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 in MANUAL is the set speed.
The upper limit of the fan speed in AUTO is the speed decided by the indoor fan speed control. (Refer to 1-3.2.(1).)
If the thermostat turns OFF, this operation changes to flow soft control. (MSH-GD80VB, MSH-GE50VB)
(4) Flow soft control (MSH-GD80VB, MSH-GE50VB)
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 reads 22°C or more.
3. Outdoor fan speed control (MUH-GD80VB)
Outdoor fan speed control is as follows.
Temperature of
ambient temperature
thermistor
13°C 18°C
Initial temperature difference
Initial temperature difference
Released
Cold Air Prevention
18°C 22°C
<Indoor fan speed>
Outdoor
fan speed
High
Low
Fan speed
Fan speed
Fan speed
Set speed
Very Low or stop
6
Difference between room
temperature and set tem-
perature during operation
3°C
1°C 1.7°C
Difference between room
temperature and set tem-
perature during operation
2°C
4°C
1°C 1.7°C