509 on a Fronius International GmbH Fronius SnapINverter: No energy fed into the grid in the past 24 hours

What it means

The manual says: No energy fed into the grid in the past 24 hours.

Part involved: feed-in monitoring.

When it shows: Class 5 status code.

Likely causes:

• Acknowledge status code; check all conditions for problem-free feed-in are met (e.g. modules covered with snow); if displayed all the time look out for further status codes.

Is it safe?

The inverter keeps running.

Resetting itself: no.

Manual reset: Acknowledge on display (Enter key).

What you can check

• Read the state code on the inverter display or in Fronius Solar.web and note date/time for your installer.
• Acknowledge the code on the display (press Enter) - Fronius says this is a user action.
• From the ground, check the panels are not covered by snow, leaves or dirt (Fronius UK support advice); never go on the roof.
• Fronius' UK homeowner support page asks you to check the inverter's DC switch is in the 'I' (on) position - only operate the switch on the inverter itself, never touch DC cables or connectors.
• Look for other state codes shown at the same time; if they persist, contact your installer.

What the engineer will check

• Check for accompanying status codes, DC isolators, string voltage, AC supply.

Who to ask for: Fronius-trained PV installer / Fronius Service Partner.

Certification: Qualified electrician (BS 7671; MCS-certified PV installer for work on the PV array/DC side).

What you might notice

• Error code shown on inverter or app
• Solar panels not generating at all

Sources

• Fronius Primo 3.0-1 - 8.2-1 Operating Instructions (HTML) ↗ · 42,0410,2165 online edition · Reviewed 24 September 2026

A code explains what the controller detected, not a confirmed root cause.

Reviewed: 24 September 2026