2021 on a Huawei SUN2000-L1 single-phase hybrid-ready inverter: AFCI self-check fails (Major)
Short answer
On a Huawei inverter, 2021 means: AFCI self-check fails (Major). 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: AFCI self-check fails (Major).
Part involved: AFCI circuit.
Likely causes:
- AFCI check circuit abnormal/faulty.
Is it safe?
| Does the inverter stop? | Yes |
|---|---|
| Engineer needed? | Yes |
The inverter stops until the fault clears or is reset.
Resetting itself: unknown.
Manual reset: AC and DC switches off 5 min then on; else support.
What you can check
- Read the full code and message on the inverter screen or in the FusionSolar app and note the date/time for your installer.
- Check the inverter's AC isolator next to the inverter and the solar/battery breaker in the consumer unit are ON (do not reset a breaker that trips again - call your installer).
- Huawei's troubleshooting step 'turn off the AC output switch and DC input switch, wait 5 minutes, turn on' is written for qualified personnel - ask your installer unless they have shown you this sequence.
What the engineer will check
- Power-cycle; escalate to Huawei.
Who to ask for: MCS-certified solar PV installer (DC/string work) or the original installer.
Certification: Work on DC strings and inverter enclosures: competent PV installer (MCS-certified installer for warranty/SEG continuity); electrical work notifiable under Part P (England & Wales) or equivalent.
What you might notice
Sources
- SUN2000-(2KTL-6KTL)-L1 User Manual (Copy, AU) ↗ · Issue 06 · page PDF p.87 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026