Mitsubishi Heavy Industries FDTCVA SERIES Technical Manual page 177

3) Snow protection fan control
In case the DIP switch (SW3-2) on the outdoor unit control PCB is ON, when in the stop mode or the anomalous
stop mode, the outdoor unit fan runs at 4th speed for 30 seconds every ten minutes in accordance with the ambient
air temperature (detected by Tho-A).
4) Cautions concerning outdoor unit fan start control
In case the fan turns around at 400 min
though the compressor starts in order to avoid breakdown of the fan motor.
5) If the outdoor unit fan motor is sensed to be anomalous
a) If the compressor is ON and the outdoor unit fan motor is turning at 100 min
for 30 seconds or longer, the compressor stops instantly. After the compressor is stopped for 3 minutes, if the
thermostat's ON conditions are established, the compressor starts.
b) If it is detected 5 times within 60 minutes after the fi rst detection, an anomalous stop (E48) occurs.
6) Outdoor unit fan control by power transistor cooling fan temperature
If all the following conditions are established 3 minutes after the compressor starts, the following control is imple-
mented.
a) Cooling, Dehumidifying
• Ambient air temperature Tho-A > = 33°C
• Actual compressor speed > = A rps
• Power transistor radiator fin temperature > = C°C
b) Heating
• Ambient air temperature Tho-A > = 16°C
• Actual compressor speed > = B rps
• Power transistor radiator fin temperature > = C°C
c) Control contents
i) The outdoor unit fan speed is increased by 1 speed.
ii) When sampling is done once every 60 seconds and the power transistor cooling fan temperature (Tho-P)
value is as follows.
If the power transistor radiator fin temperature (Tho-P) is > = C°C, the outdoor unit fan speed increases
by 1 speed.
If C°C > the power transistor radiator fin temperature (Tho-P) > = D°C, the current outdoor unit fan speed
is maintained.
If the power transistor radiator fin temperature (Tho-P) is < = D°C, the outdoor unit fan speed is lowered
by 1 speed.
d) End conditions
When the conditions in item
in succession.
• Compressor speed and power transistor radiator fin temperature
Item
Model
302
402
502
602
802
1002
ON
3
Ambient air temperature (˚C)
-1 or faster in reverse rotation, the fan motor doesn't try to start operation even
above and the outdoor unit fan speed determined in item (i) are sensed 2 times
A B C
60 70 80
70 70 72
85 85 72
90 90 80
70 70
80
90 90 80
176
- -
OFF
5
-1
or less or is turning in reverse
D
75
68
68
75
75
75