10 Troubleshooting
Troubleshooting procedure
SMGB0136 rev.0 - 07/2021
259
10
Alarm code
81
"Momentary power interruption" or "Low voltage detected"
• This alarm is displayed to indicate a momentary power interruption or a low voltage detected during compressor
operation.
A brief power interruption (which may not cause the reset of the microcomputer), may cause, instead, the relay Y52C
or the CMC (Contactor for Compressor Motor) to release. Abnormal conditions kept for more than 60 seconds is
considered a "Critical power supply problem", since no power is detected but microprocessor is still operating. In this
case, Alarm 81 is recorded.
• A power interruption shorter than 2 seconds is considered a "Momentary Power Interruption. In this case, a Control
for recovery from "Momentary power interruption is performed.
• A power interruption longer than 3 seconds is considered a "Power failure" and the unit is stopped as a normal
stop. In this case no alarm is displayed.
• This alarm forces all operations to stop and force all digital outputs to an OFF state.
• The alarm is released when anomaly conditions are not detected for more than 10 seconds (power restored).
Alarm code
EE
Compressor protection
• This alarm code is displayed when one of the following alarms occurs three times within six hours. If the outdoor
unit operates continuously without removing the cause of the alarm, the compressor may be seriously damaged.
Alarm code Content of abnormality
02
Tripping of protection device in outdoor unit
07
Decrease in discharge gas superheat
08
Increase in discharge gas temperature
41
High pressure switch overload
42
Heating overload
47
Low pressure decrease protection activating
? NOTE
These alarms can be checked using the check mode 1. The action indicated in each alarm chart must be followed. These alarms have
to be cleared by turning OFF the main switch of the system. Pay special attention before starting. There is a possibility of causing
serious damages to the compressor.
Alarm code
b0
Incorrect setting of unit model
• This alarm code is indicated in the following condition. Check the unit model code setting (DSW4) of IU PCB after
turning OFF the power source.
Condition Action
The unit model code setting (DSW4) is not set (all pins are
“OFF”), or is set for the incorrect indoor unit type.
Set DSW4 correctly according to the dip switch setting in
“Installation and Operation Manual”.
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