Daikin error code U0
What it means
Refrigerant shortage or undercharge detected.
Possible causes
Refrigerant leak in the system Incorrect refrigerant charge at commissioning Expansion device or distribution issues causing low effective charge
Suggested fix
A technician should confirm low charge with gauges and temperature measurements, perform leak detection and repair, then recharge the system by weight according to Daikin specifications.
Safety first. Isolate the power supply before inspecting any unit. Refrigerant-circuit
and electrical repairs must be carried out by a qualified, registered technician.
Other Daikin codes
- A1 — Indoor PCB defect or internal failure.
- A5 — Freeze-up protection activated for the indoor heat exchanger.
- A6 — Indoor fan motor fault.
- C4 — Faulty indoor heat exchanger temperature sensor.
- C9 — Faulty indoor suction air (room) temperature sensor.
- E1 — Outdoor circuit board fault.
- E7 — Outdoor DC fan motor fault.
- F6 — High pressure control activated in cooling mode.
- U2 — Power supply voltage drop or main circuit overvoltage.
- U4 — Transmission failure between indoor and outdoor units.