Warning 405 on a Growatt MIN 2500-6000TL-X: Firmware version is not consistent
Short answer
On a Growatt inverter, Warning 405 means: Firmware version is not consistent. The inverter stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 24 September 2026 · 1 source
What it means
The manual says: Firmware version is not consistent.
Part involved: Inverter internal hardware / firmware.
Likely causes:
- Firmware mismatch.
Is it safe?
| Does the inverter stop? | Yes |
|---|---|
| Severity | Fault — needs a manual reset once the cause is fixed |
| Engineer needed? | Yes |
The inverter stops until the fault clears or is reset.
Resetting itself: sometimes clears after a restart; recurring = hardware fault.
Manual reset: restart; otherwise replacement.
What you can check
- Read and note the exact code and time from the inverter display or app (screenshot).
- Check the solar/battery AC isolator and the consumer-unit breaker/RCD are ON (do not reset a breaker that trips again immediately).
- Growatt's manual says 'restart inverter'. A homeowner can switch the inverter off and on at its AC isolator/breaker; leave DC switching to the installer unless the manual step says to switch DC off immediately (Error 202).
What the engineer will check
- Restart per manual.
- Update firmware.
- Contact manufacturer support with serial number; RMA if repeated.
Who to ask for: PV installer with manufacturer support access.
Certification: Electrician competent in grid-connected PV (BS 7671 Section 712; IET Code of Practice for Grid-connected Solar PV), ideally the original MCS-certified PV installer; brand-approved/trained installer to keep manufacturer warranty.
What you might notice
Sources
- Growatt MIN 2500-6000TL-X Installation & Operation (User) Manual, general EN 2022-06 ↗ · EN 202206 · page PDF p.23 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026