Mitsubishi Electric MSH-18NV Service Manual page 13

— HEAT mode of "I FEEL CONTROL" —
1. Indoor fan speed control
(1) In AUTO the fan speed is as follows.
Set temperature minus room temperature: 2 degrees or more················································· Hi
Set temperature minus room temperature: Between 1 and 2 degrees ····································· Me
Set temperature minus room temperature: less than 1 degree················································· Lo
(2) Cold air prevention control
The fan runs at set speed when the indoor coil thermistor RT12 temperature exceeds 22°C. The fan operates at VLo
when the temperature of indoor coil thermistor RT12 is below 18°C. But the fan stops when the indoor fan operates at
VLo and the room temperature is 15°C or less.
NOTE : At initial in hysteresis this control works.
(3) Warm air control.
When compressor starts in heating operation or after defrosting, the fan changes the speed due to the indoor coil
thermistor RT12 temperature to blow out warm air.
After releasing of cold air prevention, when the indoor coil 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 temperature is less than 37°C, the fan speed is controlled by time as below.
<Time condition>
less than 2 minutes ························Lo
2 minutes to 4 minutes···················Me
4 minutes or more ··························Hi
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 VLo.
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. High pressure protection
During heating operation, the outdoor fan motor is controlled by the temperature of indoor coil thermistor RT12 for excess
rise protection of compressor discharge pressure.
Outdoor fan OFF : 60°C
Outdoor fan ON : 56°C
High pressure protection chart
Example
Indoor coil thermistor
RT12 temperature
60˚C
56˚C
Outdoor fan motor
NOTE 1 During high pressure protection and for 4 minutes and 15 seconds after high pressure protection, defrosting of
outdoor heat exchanger is not detected by the defrost thermistor RT61.
NOTE 2 When connected to MXZ-32NV-
for the temperature to the outdoor unit according to the indoor coil temperature.
For the further information, refer to the service manual No.OB185 REVISED EDITION C(Outdoor unit: MXZ-32NV-
or MXZ-32NV-
E2
Initial temperature difference
Released
Cold Air Prevention
<Indoor fan speed>
High pressure protection
Released
ON
OFF
or MXZ-32NV-
E1
) or the service manual No.OB227 REVISED EDITION-B(Outdoor unit: MXZ-32RV-
Fan speed
Fan speed
Set speed
VLo or stop
18: 22:
Outdoor fan
OFF
ON
56: 60:
ON
OFF
or MXZ-32RV- outdoor unit, the indoor unit send the data
E2 E1
13
Difference between room
temperature and set temperature
during operation.
2deg. 4deg.
1deg. 1.7deg.
Outdoor fan motor
turn OFF
Outdoor fan motor
turn ON
).
E1
E1