Mitsubishi Heavy Industries V Multi FDC71VNX Technical Manual page 132

(l) Dewing prevention control
[Control condition]
During cooling and dehumidifying operation, if all the following conditions are established, the compressor speed
(frequency) is reduced to prevent dewing and water splash.
(i) Cooling electronic expansion valve aperture (EEVC) is 500 pulses.
(ii) Suction overheat is 10°C or higher.
(iii) Compressor speed (frequency) is A rps or higher.
[Control contents]
(i) When the suction overheat is 10°C or higher, the compressor speed (frequency)
is reduced at each 1 minute.
(ii) Compressor speed (frequency) does not rise till the cooling expansion valve
becomes 460 pulses.
(iii) This control takes A rps as its lower limit so that compressor speed is not controlled when it is less than A rps.
(m) Refrigerant quantity shortage protection
Under the compressor protection start III control during cooling and dehumidifying operations, the following control is
performed by detecting the indoor heat exchanger temperature (Thi-R) and the indoor return air temperature (Thi-A).
[Control condition]
When the state that the indoor heat exchanger temperature (Thi-R) does not become lower than the indoor return air
temperature (Thi-A) by 4°C or more continues for 1 minute.
[Control contents]
It judges that the flowing of refrigerant in to the indoor unit is insufficient so that the compressor is stopped and E57
is displayed on the remote control.
(n) Broken wire detection on temperature thermistor and low pressure sensor
(i) Outdoor heat exchanger thermistor, outdoor air temperature thermistor and low pressure sensor
If the following is detected for 5 second continuously within 2 minutes to 2 minutes and 20 seconds after the
compressor ON, the compressor stops. After a delay of 3 minutes, it restarts but, if the same is detected repeatedly 3
times within 40 minutes, the compressor stops with the anomalous stop.
Note (1) During defrosting and for 3 minutes after the end of defrosting, it is not detected.
• Outdoor heat exchanger thermistor: -50°C or lower
• Outdoor air temperature thermistor: -45°C or lower
• Low pressure sensor: 0V or under or 4.0V or over
(ii) Discharge pipe temperature thermistor, suction pipe temperature thermistor
If the following is detected for 5 seconds continuously within 10 minutes to 10 minutes and 20 seconds after the
compressor ON, the compressor stops. After a delay of 3 minutes, it restarts but, if the same is detected repeatedly 3
times within 40 minutes, the compressor stops with the anomalous stop.
Note (1) During defrosting and for 3 minutes after the end of defrosting, it is not detected.
• Discharge pipe temperature thermistor: -10°C or lower
• Suction pipe temperature thermistor: -50°C or lower
(o) Fan motor error
(i) If the fan speed of 100min
operation command of fan tap at ① speed or higher), the compressor stops.
(ii) When the fan motor speed drops to 100min
the anomalous stop mode with E48 displayed on the remote control.
(p) Anomalous stop by the compressor start stop
(i) When it fails to shift to the compressor DC motor's rotor position defection operation at 5 seconds after establishing
the compressor start condition, the compressor stops temporarily and restarts 3 minutes later.
(ii) If it fails to shift to the position detection operation again at second time, it judges the anomalous compressor start
and stops the compressor by the anomalous stop (E59).
or under is detected for 30 seconds continuously under the outdoor fan control (with the
-1
or under 5 times within 60 minutes and the compressor stops, it enters
-1
131
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'19 • PAC-T-327
Model A rps
FDC71 42
FDC100-140 60