Service manual

ESIE03–01 Error Codes: System Malfunctions

Part 3 – Troubleshooting 3–63

4.3 Reverse Phase (U1)

Error code U1

This error code is only for 3-phase equipment.

Error generation The error is generated when the difference between phase L1 and L3 is not 240°. The illustration below

shows the 3-phase network.

Causes The possible causes are:

P Malfunctioning power supply wiring connection

P Broken or disconnected power supply wiring

P Malfunctioning outdoor unit PCB

12090 180

L1 L2 L3

240

240˚

270 360

L3 L

240˚

120˚