U7

Daikin Indoor Unit Capacity / Model Mismatch or Addressing Error

Multi-split Daikin system shows U7; one or more indoor units do not operate correctly

Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Incorrect indoor unit model connected to outdoor unit, Duplicate or incorrect indoor unit address setting, Incorrect wiring order between indoor units and outdoor unit ports, Faulty indoor PCB identification circuit

How to Fix / Troubleshooting

Safety first: Turn off power to the entire multi-split system before changing any wiring or DIP switch settings.

What to check:

Confirm that all indoor units are Daikin models compatible with the specific outdoor unit (check model numbers against the installation manual).
Check that each indoor unit is wired to the correct port on the outdoor unit as per the piping/wiring schedule.
On models with address switches or automatic addressing, follow the Daikin procedure to re-run auto-addressing or set unique addresses manually.

Technician actions:

Verify indoor unit capacity codes via service mode and compare with outdoor unit configuration.
Correct any wiring crossovers between indoor units.
If a single indoor unit consistently causes U7, test by swapping its connection with another port; replace its PCB if the fault follows the unit.

Repair Difficulty

Hard 4/5

Required Part

Indoor Unit Main PCB

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