Mitsubishi Electric CITY MULTI PUHY-400YMF-B Service Handbook page 70

(13) Operation Mode
1) Operating modes of the indoor unit
The following five modes can be set by the remote control.
1 Cooling mode
2 Heating mode
3 Dry mode
4
Fan mode
5
Stop mode
2) Operating modes of the outdoor unit
The following are the 3 modes for the outdoor unit.
1 Cooling mode
2 Heating mode
3 Stop mode
Note : If the outdoor unit has been in the cooling mode and the other indoor units (in stop, fan, thermostat off) are set
to the heating mode, those indoor units will not be operated and the heating indicator will be flashed on the
remote controller. The reverse also applies when the outdoor unit is operated in the heating mode and the
cooling indicator will be flashed on the remote controller.
(14) Emergency response operating mode
The emergency operation mode is a mode in which the unit is run in an emergency to respond to the trouble when the
compressors (No. 1, No. 2) break down, making it possible to carry out a trouble reset using the remote control.
1) Starting the Emergency Operation Mode
1 Trouble occurs (Display the trouble code root and trouble code on the remote control).
2 Carry out trouble reset with the remote control.
3 If the trouble indicted in 1 above is of the kind that permits emergency operation (see the table below), initiate a
retry operation.
If the trouble indicated in 1 above is of the kind where emergency operation is impossible (see the table below),
restart operation after carrying out the previous trouble reset (without entering the emergency operation mode).
4 If the same trouble is detected again during the retry operation in 3 above, carry out trouble reset once more
with the remote control, then try emergency operation starting corresponding to the contents of the trouble.
Table Emergency Operation Mode Patterns and Trouble Codes for which Emergency Operation is Possible or Impossible
Emergency Mode
Codes for which emergency operation is
Pattern
possible.
When a No. 1
Serial transmission trouble
Compressor Failure
VDC sensor/circuit trouble
Occurs
Breaking of overcurrent
Bus voltage trouble
Radiator panel overheat
protection
Overcurrent protection
Cooling fan trouble
Thermal sensor trouble
(Radiator panel)
IDC sensor/circuit trouble
When No. 2
Overcurrent protection
Compressor Failure
Occurs
Caution
During emergency operation, only X marked percentage of indoor units can be operated during emergency operation.
In case, more than X marked percentage of indoor units are operated, over than the percentage of indoor units
would be on the stand-by mode.
No. 1 Compressor Failure
No. 2 Compressor Failure
All indoor units are operated in cooling mode
All indoor units are operated in heating mode
All indoor units are in fan or stop mode
0403
4200
4210
4220
4230
4240
4260
5110
5301
400 500
× ×
48 % 65 %
× ×
65 % 65 %
Trouble Codes for which
Emergency Operation is
Impossible
Trouble codes other than
those at left.
–67–
Action
Emergency Operation only with the
No. 2 Compressor
* After the retry operation, even if
there is a different trouble code
detected within <Inverter
Trouble> at left, press the button
and after resetting, start the unit
by emergency operation.
[Example]
4250 → Reset → Retry → 4240
→ Reset → Emergency
operation
Emergency Operation only with the
No. 1 Compressor