PLCFX5UVerified · sol.ls-electric.com
FX5U 1820H — Battery error
Warning — monitor
CAUSE
Why does it occur?
The internal backup battery is low or not installed.
REMEDY · Step by step
How to fix it?
Replace the battery per the service manual (can be done with power ON).
Do not reset repeatedly before identifying the cause. Repeated resets while ignoring a trip/alarm can cause secondary damage (IGBT failure, motor winding damage, etc.).
SOURCE
Related manual page
Summary based on the official Mitsubishi Electric manual. For accurate and complete information, always consult the official manual.
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