Daikin U7

High

VRV / Sky Air — Communication between outdoor units / main-INV CPU fault.

Daikin U7: Communication between outdoor units / main-INV CPU fault. This fault noticeably affects operation.

Possible causes

Q1/Q2 (outdoor-outdoor) link loose/faulty.
Control/INV PCB faulty.

Check steps

Check link between outdoor units.
Power off: reseat PCB connectors.

Affected parts

Verbindungsleitung
Inverter-Platine

Safety note

High voltage! Let capacitors discharge.

Source: Daikin SM-TS3 (Simple Self-Diagnosis by Malfunction Code, resmi) veya VRV IV+ Service Manual (ManualsLib) — SM-TS3 p.5: 'U7 Malfunction of transmission between outdoor units or outdoor storage unit' — 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