Fault Code U9

Fault: Malfunction of transmission (other system)
Transmission error between other indoor and outdoor units Defective electronic expansion valve of other indoor unit Defective indoor unit PCB of other indoor unit
Improper connection of transmission wiring between indoor and outdoor unit
 

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.