Info What does this mean?

A status message, not a fault. It usually clears on its own and needs no action from you.

Fronius Inverter STATE 306 Error: Meaning, Causes & Safe Fix

STATE 306 (LOW PV POWER) means there is not enough sunlight for the inverter to feed the grid — it appears every morning and evening and is not a fault. It clears by itself.

What should I do first?

Two quick questions — we'll point you to the right starting point.

Is this code still showing on your inverter's display?

What this code means

The intermediate circuit voltage has dropped below the threshold needed for grid feed operation because the solar panels are not producing enough power — typically at dawn, dusk, or in very low light. The manual states explicitly that status codes 306 (LOW PV POWER) and 307 (LOW PV VOLTAGE) appear naturally every morning and evening due to low solar irradiance and are not the result of a fault. Grid feed pauses briefly and resumes automatically; the inverter returns to the startup phase.

Common causes

Low sunlight at sunrise or sunset — normal operation (most common)
Heavy cloud cover, shading, or dirt sharply reducing panel output
If it appears repeatedly in strong midday sun: a possible panel or string issue needing an installer check

Safe steps to try

Work top to bottom, ticking off each step as you complete it. 0 of 3 done.

Check the time of day — morning or evening appearances are normal; do nothing.
Watch the display: the status clears on its own as light levels change.
If STATE 306 appears repeatedly in bright midday sun, note the times and contact your system installer.

Is your inverter still under warranty?

Before paying for a repair, check — your installer may fix this free.

Brand Year installed

Based on typical standard warranty terms — always confirm with your warranty card or installer paperwork, as terms vary by model, region, and purchase date.

When to call an electrician

Only if the code keeps recurring with sufficient solar irradiance (bright daylight) — then contact your system installer, per the manual. Morning and evening appearances need no action at all.

Frequently asked questions

Is STATE 306 an error?

No — the manual says it appears naturally every morning and evening due to low sunlight and is not the result of a fault.

Why does it show up every day?

Your panels cannot make enough power at dawn and dusk for grid feed, so the inverter pauses briefly. It resumes automatically as light increases.

When should I worry about 306?

Only if it shows up repeatedly in strong sunlight. That could indicate a panel or string problem — contact your installer.

Sources: meaning and troubleshooting verified against the manufacturer's documentation — Fronius Primo 208-240 Operating Instructions, 42,0410,2116 (EN-US) — Status Codes, Class 3