Dry Operation; Fan Motor Control; Rotational Frequency Feedback Control; Fan Motor Lock-Up Protection - Mitsubishi Electric MSZ-G09SV Service Manual

9-2. COOL ( ) OPERATION
(1) Press OPERATE/STOP(ON/OFF) button. OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select COOL mode with the OPERATION SELECT button.
(3) Press TEMPERATURE buttons (TOO WARM or TOO COOL button)to select the desired temperature.
The setting range is 16 ~ 31°C
Indoor fan continues to operate regardless of thermostat's OFF-ON
Coil frost prevention is same as COOL mode of "I FEEL CONTROL"
9-3. DRY ( ) OPERATION
(1) Press OPERATE/STOP(ON/OFF) button.
OPERATION INDICATOR lamp of the indoor unit turns on with a
beep tone.
(2) Select DRY mode with the OPERATION SELECT button.
(3) The microprocessor reads the room temperature and determines
the set temperature. Set temperature is as shown on the right
chart.
(4) DRY operation will not function when the room temperature is
13°C or below.
9-4. HEAT ( ) OPERATION
(1) Press OPERATE/STOP(ON/OFF) button.
OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select HEAT mode with the OPERATION SELECT button.
(3) Press TEMPERATURE buttons (TOO WARM or TOO COOL button) to select the desired temperature.
The setting range is 16 ~ 31°C.
(4) Indoor fan speed control, high pressure protection, defrosting, R.V. coil control are the same as HEAT mode of "I FEEL
CONTROL"

9-5. FAN MOTOR CONTROL

1. Rotational frequency feedback control

The indoor fan motor is equipped with a rotational frequency sensor, and outputs signal to the microprocessor to feed-
back the rotational frequency. Comparing the current rotational frequency with the target rotational frequency (High,
Med.,Low) the microprocessor controls SR141 and adjusts fan motor electric current to make the current rotational fre-
quency close to the target rotational frequency. With this control, when the fan speed is switched, the rotational frequency
changes smoothly.

2. Fan motor lock-up protection

When the rotational frequency feedback signal is not output for 12 seconds, (or when the microprocessor cannot detect
the signal for 12 seconds) the fan motor is regarded locked-up. Then the electric current to the fan motor is shut off. 3
minutes later, the electric current is applied to the fan motor again. During the fan motor lock-up, the OPERATION INDI-
CATOR lamp flashes on and off to show the fan motor abnormality. (See page 69.)
9-6. AUTO VANE OPERATION
(1) Vane motor drive
These models are equipped with a stepping motor for the horizontal vane. The rotating direction, speed, and angle of
the motor are controlled by pulse signals (approx. 12V) transmitted from indoor microprocessor.
(2) The horizontal vane angle and mode changes as follows by pressing the VANE CONTROL button.
Rotational frequency
High
Med.
Set temperature and
:
initial room temperature in dry mode
35
30
25
20
15
10
10
High
Low
time
40
15 20 25 30
Initial room temperature
35 :