Warning What does this mean?
Your system is down or running degraded, but this is not an immediate safety danger. Work through the safe steps below.
Deye Inverter Error F35 — No AC Grid Detected
F35 means your Deye inverter cannot detect the AC grid — “no AC grid” — so it has nothing to synchronize with and feed power into. In most cases the utility is simply down or a breaker has tripped. Check whether your home has power; if the grid is fine but F35 persists, your installer needs to inspect the AC wiring.
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?
Is your system producing power right now?
What this code means
Grid-tied inverters are followers, not leaders: they must see a live, stable utility grid before they produce a single watt, a behavior enforced by anti-islanding rules that protect line workers. F35 is the inverter reporting that it sees no usable AC grid at its terminals.
Deye’s manual lists the checks in order: the AC grid voltage itself, the inverter’s AC voltage detection circuit, the condition of the AC connector, and whether the grid voltage is normal. That sequence mirrors the real-world causes from most to least likely — the grid is down, a breaker or isolator is open, a connector has worked loose, or (rarely) the inverter’s own sensing has failed.
The key reassurance: F35 is usually a messenger, not the problem. Your inverter is almost certainly healthy; it is telling you the grid it depends on is missing or out of reach.
What is this downtime costing you?
Rough estimate while your system isn't producing. Adjust the numbers to match your setup.
≈ – kWh of lost production per day.
Estimate only — assumes ~80% real-world output vs. nameplate. Actual losses depend on weather, shading, panel direction, and your tariff.
Common causes
- A utility outage — the most common cause by far. No grid, no generation, and every solar system on the street is down with you.
- A tripped AC breaker or an open isolator — the solar breaker in your panel or the AC isolator by the inverter has opened, cutting the inverter off from a perfectly good grid.
- A loose or damaged AC connector — vibration, heat cycling, or corrosion can degrade the AC terminal connection until the inverter can no longer sense the grid.
- Grid voltage outside the detectable range — a severe brownout can look like “no grid” to the detection circuit.
- A failed AC voltage detection circuit inside the inverter — the least common cause, and an installer-only diagnosis.
Safe steps to try
Work top to bottom, ticking off each step as you complete it. 0 of 5 done.
Is your inverter still under warranty?
Before paying for a repair, check — your installer may fix this free.
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
Call your solar installer if F35 persists while the grid is demonstrably normal — lights on, neighbors fine. That points to the AC connector, the AC cabling, or the inverter’s detection circuit, and the manual’s own remedy sends you to the installer at that point. Call an electrician promptly if a breaker trips repeatedly, if you see scorching around the breaker or isolator, or if you smell burning: those are wiring faults, not inverter faults.
Frequently asked questions
Is F35 an inverter fault?
Usually not. F35 means the inverter cannot find the grid — and nine times out of ten, that is because the grid is down or disconnected upstream of the inverter. The code clears on its own when the grid returns, which a genuine hardware fault would not do.
How long until my system reconnects after an outage?
Once the grid is back and stable, the inverter detects it, runs its safety checks, and reconnects automatically — typically within a few minutes. There is nothing to press. If it has not reconnected after 10–15 minutes of stable grid power, do one documented restart.
Can I still get power from my panels during F35?
Not with a standard grid-tied string inverter — it is designed to shut down without the grid, and that anti-islanding behavior is a legal safety requirement. (Hybrid and battery systems are a different story; they can island intentionally.)
The grid is back but F35 is still showing. What now?
Give it 10–15 minutes of stable power first — the inverter deliberately waits for sustained stability before reconnecting. If F35 is still showing after that, do one documented restart. If the code survives the restart with the grid clearly normal, call your installer: the AC connector, the cabling, or the inverter’s detection circuit needs professional attention.
Why does F35 show up during storms even when my lights stay on?
Brief grid disturbances — a fault cleared by utility protection, a recloser operating — can drop the voltage long enough for the inverter to declare “no grid” while your lights barely flicker. The inverter then waits for sustained stability before reconnecting, which is the conservative, correct behavior.
Need a professional?
This fault may need professional diagnosis. Contact a qualified solar electrician in your area.
Sources: meaning and troubleshooting verified against the manufacturer's documentation — Deye SUN-(30-36)K-G04 User Manual Ver 2.5 (deyeinverter.com): F35 — No AC grid; remedy: check AC grid voltage, check AC voltage detection circuit, check if the AC connector is in good condition, check whether the AC grid is normal in voltage; restart inverter, and if the fault still exists, contact installer or Deye service. Also confirmed in Deye SUN-(3-10)K-G03 and SUN-(7.5-10)K-G manuals (deyeinverter.com).