Daikin U9

High

VRV / Sky Air — Communication fault with other units in the same system.

Daikin U9: Communication fault with other units in the same system. This fault noticeably affects operation.

Possible causes

Indoor/outdoor unit in same circuit faulty/off.
Bus cable/address error in system.

Check steps

Check all units in system for power/faults.
Check bus wiring & addressing.

Affected parts

Verbindungsleitung

Safety note

230V — isolate power.

Source: Daikin SM-TS3 (Simple Self-Diagnosis by Malfunction Code, resmi) veya VRV IV+ Service Manual (ManualsLib) — SM-TS3 p.5: 'U9 Malfunction of transmission (other system) — Transmission error between other indoor and outdoor units' — exact match, VRV applicable.

Reviewed by Anıl Güzeldemir — in the refrigeration machine room since 2006, developer of Enthalio.

Look up in Enthalio →

Related fault codes

Outdoor PCB faulty.E1 Refrigerant shortage (low pressure / stop valvU0 Power supply defect / brief power failure.U2 Transmission error indoor/outdoor unit.U4 Low-pressure protection / LP sensor (suction bE4 Inverter compressor instantaneous overcurrent L5