Heat Mode Of “I Feel Control”; Cold Air Prevention Control; Warm Air Control - Mitsubishi Electric MSZ-G09SV Service Manual

3. Coil frost prevention
The operational frequency of the compressor is controlled based on the temperature of the indoor coil thermistor (RT12).
Temperature of indoor coil thermistor:RT12
Approx. 8°C or above
Approx. 6°C to 8°C
Approx. 4°C to 6°C
Approx. 4°C or below
The indoor fan maintains the actual speed of the moment. However, when coil frost prevention works while the compressor
is not operating, it's speed becomes the set speed.
9-1-3. HEAT mode of "I FEEL CONTROL"
1. Indoor fan speed control
(1) Indoor fan operates at the set speed by FAN SPEED CONTROL button.
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

1 When the compressor is not operating,
(1) if the temperature of indoor coil thermistor RT12 is 18°C or less, the fan stops.
(2) if the temperature of indoor coil thermistor RT12 is more than 18°C, the fan operates at Very Low.
2 When the compressor is operating,
(1) if the temperature of RT12 is 22°C or more, the fan operates at set speed.
(2) if the temperature of RT12 is less than 22°C and
(1) if the temperature of room temperature thermistor RT11 is 15°C or less, the fan stops.
(2) if the temperature of room temperature thermistor RT11 is more than 15°C, the fan operates at Very Low.
Indoor coil thermistor
RT12 temperature
NOTE : If the temperature of RT12 reads from 18: to 22: at the air conditioner starting and also after defrosting, this
control works.

(3) Warm air control.

When the following any condition of 1 (a. ~ d.) and the condition of 2 are satisfied at the same time, warm air control
works.
1 a.) when the operation mode has been changed to HEAT mode
b.) when cold air prevention has been released
c.) when defrosting has been finished
d.) when the compressor starts in HEAT mode
2 When the temperature of indoor coil thermistor RT12 is less than 37°C.
When warm air control works, the fan speed changes as follows to blow out warm air gradually.
Gradation of fan speed in initial
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 indoor fan speed control.
When the temperature of RT12 has been 37°C or more, or when the set speed has been changed, this control is
released and the fan speed is the set speed.
(4) Flow soft control
When the thermostat (compressor) is off, the indoor fan operates as follows.
Compressor
OFF
ON
Initial temperature difference
Released
Cold Air Prevention
RT12 18:
<Time condition>
less than 2 minutes
2 minutes to 4 minutes
more than 4 minutes
Fan
Very Low
Set speed
Lower at the rate of 3Hz/min.
Lower at the rate of 6Hz/min.
Compressor is turned OFF for 5 minutes when temperature of
indoor coil thermistor continues approx. 4°C or below for 5 minutes
or more.
Fan speed
Set speed
Very Low or stop
22:
<Indoor fan speed>
Low
Med.
High
NOTE : When the thermostat(compressor) turns on, the fan will operate
at set speed. But until cold air prevention and warm air control
is released, the fan speed follow them.
38
Operation frequency
Normal
Fixed
Difference between room
temperature and set tem-
Fan speed
perature during operation
1 deg. 1.7 deg.
2 deg. 4 deg.