Cool Mode Of “I Feel Control”; Indoor Fan Speed Control; Coil Frost Prevention; Temperature Control - Mitsubishi Electric Mr.Slim MSZ09UN Service Manual

(5) TEMPERATURE buttons
In "I FEEL CONTROL" mode, set temperature is decided by the microprocessor based on the room temperature.
In addition, set temperature can be controlled by TOO WARM or TOO COOL buttons when you feel too cool or too
warm.
Each time the TOO WARM or TOO COOL button is pressed, the indoor unit receives the signal and emits a beep tone.
Fuzzy control
When the TOO COOL or TOO WARM button is pressed, the microprocessor changes the set temperature, consider-
ing the room temperature, the frequency of pressing TOO COOL or TOO WARM button and the user's preference to
heat or cool. So this is called "Fuzzy control", and works only in "I FEEL CONTROL" mode.
In DRY mode of "I FEEL CONTROL", the set temperature doesn't change.
TOO
COOL
... To raise the set temperature 2~4 degrees(°F)
TOO
WARM
... To lower the set temperature 2~4 degrees(°F)
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.
MSZ09UN
Room temperature minus set temperature : 3 degrees or more·······································High
Room temperature minus set temperature : Between 2 and 3degrees·····························Med.
Room temperature minus set temperature : less than 2 degrees······································Low
MSZ12UN
Room temperature minus set temperature : 4 degrees or more·······································High
Room temperature minus set temperature : Between 2 and 4 degrees····························Med.
Room temperature minus set temperature : less than 2 degree·······································Low

2. Coil frost prevention

1 Temperature control

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. 46°F or above
approx. 43°F to 46°F
approx. 39°F to 43°F
approx. 39°F or below
The indoor fan maintains the actual speed of the moment.
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 79˚F.
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
79°F. However, when two of the above conditions (b.and c.) are satisfied again. Time accumulation is resumed.
Initial temperature difference
Initial temperature difference
lowering at the rate of 6Hz/min.
Compressor is turned off for 5 minutes when temperature of indoor
coil thermistor continues approx. 39°F or below for 5 minutes or
more.
25
Difference between room
temperature and set temperature
Fan speed
during operation
2 deg.
Fan speed
Operation frequency
normal
fixed
lowering at the rate of 3Hz/min.
4 deg.
3 deg.
Difference between room
temperature and set
temperature during
operation
4 deg. 7 deg.
2 deg. 3 deg.