Mitsubishi Heavy Industries SRK100VNXPZSX Technical Manual page 187

(h) Power transistor temperature protection
(i) Protective control (single phase model only)
If the power transistor temperature (detected with TIP) exceeds the setting value, the compressor speed (frequency)
is controlled to suppress the rise of power transistor temperature.
Reset
Power transistor temp. (°C)
(i) Anomalous power transistor current
(i) Prevents over-current on the inverter. If the current value in the power transistor exceeds the setting value, the
compressor stops.
(ii) If the current value in the power transistor exceeds the specified value and the compressor stops 4 times within 30
minutes, E42 is displayed on the remote control and it enters the anomalous stop mode.
(j) Anomalous inverter PCB
If the power transistor detects any anomaly for 15 minutes, including the stop of compressor, E51 is displayed on the
remote control and it enters the anomalous stop mode.
(k) Anti-frost control by the compressor frequency control
(i) If the indoor unit heat exchanger temperature (detected with Th2) exceeds the setting value at 4 minutes after the
start of compressor, the compressor speed (frequency) is controlled to initiate the anti-frost control of indoor unit
heat exchanger.
(ii) When there are 2 indoor unit heat exchanger temperatures (Th2), the lowest temperature is detected.
Reduces compressor frequency
at each minute.
(iii) Regarding the anti-frost control by the operation stop, refer to the operation control function by the indoor unit
control and the cooling, dehumidifying frost prevention of page 72.
(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.
➀ Cooling electronic expansion valve aperture (EEVC) is 500 pulses.
➁ Suction overheat is 10°C or higher.
③ Compressor speed (frequency) is 60 rps or higher.
[Contents of control]
➀ When the suction overheat is 10°C or higher, the compressor speed (frequency) is reduced at each 1 minute.
➁ Compressor speed (frequency) does not rise till the cooling expansion valve becomes 460 pulses.
③ This control takes 60 rps as its lower limit so that compressor speed is not controlled when it is less than 60 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 unit heat exchanger temperature (Th2) and the indoor unit return air temperature (Th1).
[Control condition]
When the state that the indoor unit heat exchanger temperature (Th2) does not become lower than the indoor unit
return air temperature (Th1) by 4°C or more continues for 1 minute.
[Contents of control]
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.
Reduces compressor frequency
at each minute.
Retention
77 80
Retention
1.5 3.5
Indoor unit heat exchanger temp. (°C)
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Note (1) Value in ( ) are for the single phase model 100~140.
Reset
186
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'17 • PAC-T-257