Fronius Symo Hybrid Inverter Code 474 — RCMU sensor faulty

What does 474 mean?

The Residual Current Monitoring Unit (RCMU) sensor within the inverter has been detected as faulty. This prevents the inverter from feeding any energy into the grid.

• RCMU sensor hardware failure
• Internal wiring fault to RCMU sensor
• Component aging

Click steps to track your progress.

1. 1

   Perform a full AC and DC power cycle of the inverter: Disconnect both AC and DC power, wait 5 minutes, then reconnect.

2. 2

   Observe the inverter to see if the error clears and energy feeding resumes.

3. 3

   If this status code keeps recurring, contact your system engineer for diagnosis of the RCMU sensor.