Mitsubishi Electric MSZ-G09SV Service Manual page 51

(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> <Indoor fan speed>
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.
2. Outdoor fan control
Outdoor fan speed is controlled according to the temperature of ambient temperature thermistor RT63.
Outdoor fan Low operation : Until when the outside temperature decreases to 13°C or less.
Outdoor fan High operation : When the outside temperature decreases to 13°C or less.
3. High pressure protection
During heating operation, the outdoor fan and the compressor are controlled by the temperature of indoor coil thermistor
RT12 for excess rise protection of compressor discharge pressure.
• Outdoor fan
When the temperature of indoor coil thermistor RT12 goes to 55: or more, the outdoor fan is turned OFF.
When the temperature of indoor coil thermistor RT12 becomes to 52: or less, the outdoor fan is turned ON.
• Compressor
When the temperature of indoor coil thermistor RT12 goes to 75: or more, the compressor is turned OFF.
3 minutes after the compressor is turned OFF and if the temperature of indoor coil thermistor RT12 becomes 75: or less,
the compressor is turned ON.
NOTE : During the high pressure protection and for 10 seconds after high pressure protection, defrosting of outdoor heat
exchanger is not detected by the defrost thermistor RT61.
4. Discharge temperature protection
Discharge temperature protection is as same as during COOL mode of "I FEEL CONTROL".
5. Defrosting
Defrosting of outdoor heat exchanger is controlled by deicer P.C. board, with detection by the defrost thermistor RT61.
(1) Starting conditions of defrost
When all conditions of a) ~ c) are satisfied, the defrosting operation starts.
a) Under the heat operation, the compressor cumulative operation time exceeds 40 minutes without the defrosting
operation working.
b) The defrost thermistor RT61 reads - 3°C or less.
c) After releasing the high pressure protection, 10 seconds have elapsed.
(2) Releasing conditions of defrost
When the condition d) or e) is satisfied, the defrosting operation stops.
d) The defrost thermistor RT61 reads 13°C or more.
e) The defrosting time exceeds 10 minutes.
When the outside temperature goes to 18°C or more.
Until when the outside temperature goes to 18°C or more.
51
Ambient temperature
thermistor RT63 temperature
Outdoor fan speed
Low
13: 18:
High