Cool Operation; Dry Operation; Heat Operation; Indoor Fan Motor Control - Mitsubishi Electric MSC-CA20VB Service Technical Manual

Table of Contents

Advertisement

3-2. 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 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 at set speed.
Coil frost prevention is as same as COOL
mode of "I FEEL CONTROL".
3-3. 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 OPERATION SELECT
button.
(3) The microprocessor reads the room tempera-
ture and determines the set temperature. Set
temperature is as shown on the right chart.
Thermostat (SET TEMP.)does not work.
The other operations are same as DRY mode of
"I FEEL CONTROL".
(4) DRY operation will not function when the room
temperature is 13°C or below.
3-4. 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 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".

3-5. INDOOR 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
feedback 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 rota-
tional frequency 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 has 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
INDICATOR Indicator lamp flashes on and off to show the fan motor abnormality.
Rotational frequency
High
Med.
High
Low
time
32

Advertisement

Table of Contents
loading

Table of Contents