Emergency Operation Mode - Mitsubishi Electric PUHY-HP72 Service Handbook

[5-2 Outdoor Unit Control ]
5-2-16

Emergency Operation Mode

1. Problems with the outdoor unit
Emergency operation mode is a mode in which outdoor units that are operating normally take over the operation of the out-
door units that are experiencing problems. (HP144-HP240T(Y)SNU models go into an emergency operation mode when one
outdoor unit 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
0403
4220,4225,4226
4230,4235
4240,4245
Compressor
Fan motor 4250,4255,4256
Inverter
5110
5120
5301
5305,5306
Thermistor TH2 5102
TH3 5103
TH4 5104
TH5 5105
TH6 5106
TH7 5107
TH15 5115
Power 4102
4115
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.
HWE18240_GB
Error codes that permit an
emergency operation
Serial communication error
Bus voltage drop
Heatsink overheat protection
Overload protection
Overcurrent relay trip
Heatsink temperature sensor failure (THHS)
DCL temperature sensor circuit fault
Current sensor/circuit failure
Position error
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
Compressor shell bottom temperature sensor fault
Open phase
Power supply sync signal abnormality
OC
OS
Cooling
Emergency
operation
Heating
Maximum total capacity
of indoor units (Note 1)
Error code description
OC failure OS failure
pattern pattern
Trouble Normal
Normal Trouble
Permitted Permitted
Permitted Permitted
60%
19
chapter 5 -