Fronius Inverter Not Producing — Fix Guide

What Does This Error Mean?

Check the Fronius display for any State code — this will tell you exactly why production stopped. If no code is shown but output is zero, check that the AC isolator and DC switches are both on, and confirm it is daytime with sunlight on the panels.

Affected Models

Fronius Primo
Fronius Symo
Fronius Galvo
Fronius SnapINverter Series
Fronius GEN24 Plus

Common Causes

Active State code indicating a specific fault (see display)
AC isolator switch or DC switch turned off
Night-time or heavily overcast sky — normal, no issue
Power outage — Fronius requires grid presence to export (anti-islanding)
RCD or circuit breaker tripped on the solar circuit

How to Fix It

Read the Fronius display.

The inverter LCD shows the current status. A State code (e.g. State 102, 240, 306) explains exactly why it is not producing. Note the code and look it up — each has a specific fix.
Check both isolator switches.

Confirm the AC solar isolator (wall-mounted near the inverter) and the DC switch on the inverter itself are both fully ON. A switch that is 95% closed may appear on but not connect properly.
Check the switchboard for tripped breakers.

Open your main switchboard and look for any tripped circuit breaker or RCD. The solar circuit breaker is usually labelled Solar or PV. Reset any tripped device and wait 2–3 minutes.
Confirm the grid is live.

Fronius inverters require grid power to operate. If there is a local power outage, the inverter will not produce. Check whether other appliances in the house have power.
Power-cycle the inverter.

Turn off the AC isolator, then the DC switch. Wait 5 minutes, then turn DC back on followed by the AC isolator. The inverter will take 2–5 minutes to run through its startup sequence and begin producing.

When to Call a Professional

If all switches are on, there is daylight, the grid is live, and the inverter still shows zero output with no State code, a licensed installer should inspect the DC and AC wiring.

Frequently Asked Questions

Fronius inverter was working fine — stopped overnight. What happened?

An inverter that stops overnight and does not restart in the morning typically has a State code to explain why. Check the display first. Common causes are a tripped RCD, an AC grid fault, or (rarely) an internal hardware error.

Fronius inverter shows zero production but the green LED is on — why?

A green LED means the inverter is powered and communicating, but zero production can still occur at night or in heavy cloud. Check the display for the actual AC power output figure and the time of day.