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( m) Pump down control
If the pump down switch SW9 is turned on for 2 seconds during an operation stop and abnormal stop (not including when the
thermostat is OFF), pump down operation starts. (It is disabled during indoor unit operation. It is enabled during an abnormal
stop of the indoor unit and during power OFF.)
( i ) Control contents
1) Close the liquid side service valve. (Leave the gas side fully open.)
2) In the cooling mode, set the target speed at 62 rps and start the compressor.
3) The red and green indicators (LED) on the outdoor unit’s control PCB keeps flashing.
4) Except for low pressure control, each protective and abnormal sensing control is enabled.
5) The outdoor fan is controlled the same as normal.
6) The electronic expansion valve (cooling, heating) is fully opened.
7) The solenoid valve (SV1) goes on for 2 minutes after the pump down operation starts and after that, it goes OFF.
(ii) Control end conditions
Stop control is executed according to any of the following conditions.
1) A low pressure of 0.087 MPa or lower is detected continuously for 5 seconds.
a
Red LED: On, Green LED: flashing, Remote controller: displays stopped.
b
Restarting is possible when low pressure exceeds 0.087 MPa.
c
The electronic expansion valves (cooling, heating) remain fully open.
2) Stop according to error detection control
a
Red LED: On, Green LED: flashing is displayed.
b
Restarting is not possible. ordinary operation is restored by resetting the power supply.
c
The electronic expansion valves (cooling, heating) remain fully open.
3) When the cumulative compressor operating time by pump down control is 5 minutes.
a
Red LED: Off, Green LED: flashing, Remote controller: Stop.
b
Pump down repeat is possible.
c
The electronic expansion valves (cooling, heating) remain fully open.
Note (1) Close the gas side operating valve after the compressor stops.
Caution:
If the pump down switch is pressed, communications with the indoor units is cancelled, so the message
“communications error – E5” is displayed on the indoor unit and the remote controller, but there is no error.
