Auto Change Over; Outdoor Fan Motor Control; Auto Vane Operation - Mitsubishi Electric MSC-GE-VB – E Service Technical Manual

2-4. AUTO CHANGE OVER ··· AUTO MODE OPERATION (MSZ-GC/FD/GE/CGE, MLZ-KA)
Once desired temperature is set, unit operation is switched automatically between COOL and HEAT operation.
1. Mode selection
(1) Initial mode
At first, indoor unit operates only indoor fan with outdoor unit OFF for 3 minutes to detect present room temperature.
Following the conditions below, operation mode is selected.
If the room temperature thermistor reads higher than set temperature, COOL mode is selected.
If the room temperature thermistor reads set temperature or lower, HEAT mode is selected.
(2) Mode change
In case of the following conditions, the operation mode is changed.
COOL mode changes to HEAT mode when 15 minutes have passed with the room temperature 1 - 2°C below the set
temperature.
HEAT mode changes to COOL mode when 15 minutes have passed with the room temperature 1 - 2°C above the set
temperature.
In the other cases than the above conditions, the present operation mode is continued.
NOTE1: Mode selection is performed when multi standby (refer to NOTE2) is released and the unit starts operation with
ON timer.
NOTE2: If two or more indoor units are operating in multi system, there might be a case that the indoor unit, which is
operating in AUTO ( ), cannot change over the other operating mode (COOL ↔ HEAT) and becomes a state
of standby.
(3) Indoor fan control/Vane control
As the indoor fan speed and the horizontal vane position depend on the selected operation mode, when the operation
mode changes over, they change to the exclusive ones.

2-5. OUTDOOR FAN MOTOR CONTROL

Fan speed is switched according to the compressor frequency.
Fan speed
Down
High
Low
Minimum Compressor frequency

2-6. AUTO VANE OPERATION

1. Horizontal vane
(1) Cold air prevention in HEAT operation
When any of the following conditions occur in HEAT operation, the vane angle changes to horizontal position automati-
cally to prevent cold air blowing directly onto users.
Compressor is not operating.
Defrosting is performed.
Temperature of indoor coil thermistor does not exceed following temperature within about 3 minutes after compressor
starts.
• 24°C (MSZ)
• 18°C (MLZ)
NOTE: When 2 or more indoor units are operated with multi outdoor unit, even if any indoor unit turns thermostat OFF,
this control doesn't work in the indoor unit.
(2) ECONO COOL ( ) operation (ECONOmical operation)
When ECONO COOL button is pressed in COOL mode, set temperature is automatically set 2°C higher.
Also the horizontal vane swings in various cycle according to the temperature of indoor coil thermistor.
SWING operation makes you feel cooler than set temperature. So, even though the set temperature is higher, the air
conditioner can keep comfort. As a result, energy can be saved.
ECONO COOL operation is cancelled when ECONO COOL button is pressed once again or VANE CONTROL button is
pressed or change to other operation mode.
Up
MUZ-FD25/35
Maximum
MUZ-GE35/42
15 15
Compressor frequency (Hz)
Down
41
MUZ-HC/GC
33
25
MUZ-FD50
41
MUZ-GE25
33
MUZ-GE50
Up
54
43
33
54
44