Mitsubishi Electric PUHY-HP120TNU-A, Service Handbook

Page: 107 / 324

[5-2 Outdoor Unit Control ]
20
- chapter 5 HWE18240_GB
5 Control
(2) Ending the emergency operation
1) End conditions
When one of the following conditions is met, emergency operation stops, and the unit makes an error stop.
Œ
When the integrated operation time of compressor in cooling mode has reached four hours.
Œ
When the integrated operation time of compressor in heating mode has reached two hours.
Œ
When an error is detected that does not permit the unit to perform an emergency operation.
2) Control at or after the completion of emergency operation
Œ
At or after the completion of emergency operation, the compressor stops, and the error code reappears on the remote con-
troller.
Œ
If another error reset is performed at the completion of an emergency mode, the unit repeats the procedures in section (1)
above.
Œ
To stop the emergency mode and perform a current-carrying operation after correcting the error, perform a power reset.
2. Communication circuit failure or when some of the outdoor units are turned off
This is a temporary operation mode in which the outdoor unit that is not in trouble operates when communication circuit failure
occurs or when some of the outdoor units are turned off.
(1) Starting the emergency operation (When the OC is in trouble)
1) When an error occurs, the error source and the error code appear on the display on the remote controller.
2) Reset the error via the remote controller to start an emergency operation.
Precautions before servicing the unit
Œ
When the OC is in trouble, the OS temporarily takes over the OC's function and performs an emergency operation. When this
happens, the indoor unit connection information are changed.
Œ
In a system that has a billing function, a message indicating that the billing system information has an error may appear on
the TG-2000A. Even if this message appears, do not change (or set) the refrigerant system information on the TG-2000A.
After the completion of an emergency operation, the correct connection information will be restored.
(2) Starting the emergency operation (When the OS is in trouble)
1) A communication error occurs.
ĺ
An emergency operation starts in approximately six minutes.
Error codes that permit an emergency operation (Applicable to both OC and OS)
Emergency operation pattern (2 outdoor units)
(3) Ending the emergency operation
When communication is restored, the emergency mode is cancelled, and the units go into the normal operation mode.
Trouble source
Circuit board failure or the power
to the outdoor units is off 6607
6608 No acknowledgement error
No response error
Error codes that permit an
emergency operation
Error code description
OC
Cooling
Heating
OC failure
pattern
Trouble
Normal
Permitted Permitted
Permitted Permitted
Normal
Trouble
OS failure
pattern
OS
Emergency
operation
Maximum total capacity
of indoor units (Note 1)
Capacity that matches
the total capacity of the
operable 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.