Mitsubishi Electric City Multi PUHY-P500YSHM-A Service Handbook page 87

[ VIII Control ]
-13- Emergency Operation Mode
1. Problems with the outdoor unit
Emergency operation mode is a temporary operation mode in which the outdoor unit that is not in trouble operates when one
of the outdoor units is in trouble.
This mode can be started by performing an error reset via the remote controller.
(1) Starting the emergency operation
1) When an error occurs, the error source and the error code will be displayed on the display on the remote controller.
2) The error is reset using the remote controller.
3) If an error code appears that permits an emergency operation in step 1) above, (See the table below.), the retry operation
starts.
4) If the same error is detected during the retry operation (step 3 above), an emergency operation can be started by resetting
the error via the remote controller.
Error codes that permit an emergency operation (Applicable to both OC and OS)
Trouble source
Compressor
Fan motor
Inverter
Thermistor
* Capacity is reduced during emergency operation. (Capacity varies depending on the number of outdoor units that
have failed.)
Emergency operation pattern (2 outdoor units)
(Note 1) If an attempt is made to put into operation a group of indoor units whose total capacity exceeds the maximum
allowable capacity, some of the indoor units will go into the same condition as Thermo-OFF.
HWE07150
Error codes that permit an
emergency operation
0403
4220, 4225
4230
4240
4250, 4255
5110
5301
TH2
5102
TH3 5103
TH4 5104
5105
TH5
5106
TH6
5107
TH7
OC
OS
Emergency
operation
Maximum total capacity
of indoor units (Note 1)
Error code description
Serial communication error
Bus voltage drop
Heatsink overheat protection
Overload protection
Overcurrent relay trip
Heatsink temperature sensor failure (THHS)
Current sensor/circuit failure
Subcool heat exchanger bypass outlet temperature sensor failure
Pipe temperature sensor failure
Discharge temperature sensor failure
Accumulator inlet temperature sensor failure
Subcool heat exchanger liquid outlet sensor failure
Outside air temperature sensor failure
OC failure OS failure
pattern pattern
Trouble Normal
Normal Trouble
Cooling
Permitted Permitted
Heating
Permitted Permitted
100%
- 78 -
GB