- Solar and energy
- Solar inverter
311
Fronius inverter event 311
Risk level
Critical
Stop using the equipment and contact a professional.
Urgency
Immediate
Quick answer
Fronius defines event 311 as: The polarity of one or more DC strings is reversed. The useful next discriminator is the named DC input, recent string work and recorded polarity state. Preserve the event before any reset.
Safety first
What to do now
- Preserve the exact event context
Save event 311, timestamp, inverter model/serial, firmware, red-LED state, affected phase/string, power and weather before clearing anything.
- Collect one safe discriminator
Leave feed-in stopped. Record the named input and recent string, connector or module work; do not unplug or reverse any DC connector. Record the named DC input, recent string work and recorded polarity state; do not change multiple parameters or circuits at once.
- Respect the electrical stop point
Do not reconnect until a PV installer has measured polarity and voltage on every affected string against the approved design.
What you must never do
- Do not attempt this professional task: Measured handoff for Fronius 311
What a technician must be able to justify
A technician is coming
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Measured handoff for Fronius 311
What they doSafely isolate each affected string, measure polarity and open-circuit voltage at the correct test point, compare with the string schedule and correct the DC termination before reconnecting.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Solar and energy
- Brand
- Fronius
- Product type
- Solar inverter
Known code variants
- événement Fronius 311
- evento Fronius 311
- Fronius Ereignis 311
- Fronius event 311
- Fronius inverter 311
- Fronius Symo / Eco 311
- Fronius Wechselrichter 311
- inversor Fronius 311
- inverter Fronius 311
- onduleur Fronius 311
What it means
Official meaning: The polarity of one or more DC strings is reversed. Decision boundary: capture the named DC input, recent string work and recorded polarity state. Safely isolate each affected string, measure polarity and open-circuit voltage at the correct test point, compare with the string schedule and correct the DC termination before reconnecting.
Warnings and stop conditions
- Criticalsource verified
Reversed PV polarity and live DC connectors can cause arc, fire and lethal shock. Do not unplug, probe or reverse a string yourself.
Evidence: Fronius Symo / Eco status diagnostics
Sources and technical references
- 1
Fronius Symo / Eco status diagnostics
Fronius International GmbH · 2025 · official_doc
Was this entry useful?