Fault Code U3

Fault: Check operation not executed or transmission error
Check operation is not executed.
 

For Daikin split and multi-split air conditioning systems included wall-mounted, duct-connected, floor-standing, multi-flow, stylish, european, ururu sarara & cassette-type units.
If molded case circuit breakers or earth leakage circuit breakers have tripped, do not reset the breaker immediately without first checking for any problems with insulation of equipment.
Resetting breakers without a check of insulation may cause damage to equipment.