306 on a Fronius International GmbH Fronius SnapINverter: LOW PV OUTPUT - intermediate circuit voltage too low for feeding energy into the grid
Short answer
On a Fronius International GmbH inverter, 306 means: LOW PV OUTPUT - intermediate circuit voltage too low for feeding energy into the grid. The inverter keeps running with some functions stopped. An engineer is needed to fix the cause.
Reviewed 24 September 2026 · 1 source
What it means
The manual says: LOW PV OUTPUT - intermediate circuit voltage too low for feeding energy into the grid.
Part involved: DC input.
When it shows: Class 3 status code.
Likely causes:
- Rectified automatically; routinely shown early morning and evening (not a fault); if it occurs with sufficient insolation contact your system engineer.
Is it safe?
| Does the inverter stop? | Partly |
|---|---|
| Severity | Information only |
| Engineer needed? | Yes |
The inverter keeps running with some functions stopped.
Resetting itself: yes.
Manual reset: Automatic when condition clears.
What you can check
- Read the state code on the inverter display or in Fronius Solar.web and note date/time for your installer.
- 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.
- Normal at dawn/dusk and in very dull weather.
What the engineer will check
- If shown in good sunlight: measure string open-circuit voltage, check DC connectors/isolators, module defects.
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
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