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GoodWe Fac Failure

Updated June 2026 · Reviewed for technical accuracy · ~2 min read

Fac Failure (error 03) means your GoodWe measured the grid frequency outside the window it is allowed to operate in, so it disconnected to stay compliant. Like Utility Loss and Vac Failure, this is almost always the grid's doing, not your inverter, and it reconnects on its own once the supply is steady again.

What usually causes it

  • A weak or unstable grid. Rural lines and busy networks can let the frequency drift in and out of range.
  • Running off a generator. A genset whose speed wanders pushes the frequency outside the limits.
  • Passing grid events. Switching, faults or heavy local demand can nudge the frequency briefly.
  • A wrong grid-code or country setting chosen at install, if it never reconnects on a clearly healthy grid.

How to handle it safely

  1. Wait and watch. In most cases the GoodWe reconnects by itself within minutes once the frequency settles.
  2. Check if it is the grid. Notice if lights flicker or neighbours have supply issues. A noticeably unstable grid explains a recurring Fac Failure.
  3. If you are on a generator, the genset frequency may be the cause. A more stable generator or a different setup is the fix.
  4. If it never reconnects on a normal grid, have your installer confirm the grid-code or country profile was set correctly for your region.

Quick decision flowchart

Fac Failure appears
↓ wait a few minutes
✅ Reconnects on its own → a passing grid event. Nothing to fix.
❌ Stays disconnected on a healthy grid → check the grid-code setting or the generator.
↓
If it persists with a stable grid, contact your installer or GoodWe.

Related GoodWe codes

Vac Failure, Grid voltage Utility Loss, No grid Relay Check Failure

FAQ

Fac Failure keeps coming and going through the day.

That is normal on a weak or busy grid. The inverter is doing its job, dropping off when the frequency drifts out of range and reconnecting when it settles. If it happens constantly, ask your utility about supply quality in your area.

Do I need to do anything about Fac Failure?

Usually no. It clears itself once the grid frequency is back in range. Only act if it never reconnects in a normal grid, which points to a wrong grid-code setting, or if you are running off a generator whose frequency is unstable.

Helpful guides

Error codes explained How to safely restart your inverter

Sources

  • GoodWe inverter user manual and error-message list (Fac Failure / error 03 = grid frequency out of permitted range; inverter reconnects automatically when the grid recovers).
  • GoodWe installer documentation on grid-code and country settings.
⚠️ Safety disclaimer. Solar inverters carry lethal DC and AC voltage even when "off". This guide covers reading the code and waiting for an automatic reconnect only. Grid-code changes and any wiring work must be done by a licensed installer or electrician.