The short answer
Check the app's configured string status matches the real wiring, then check connections and any Y-connectors.
Plain explanation
From the Huawei manual for the SUN2000 inverter: In the app check the configured string status matches the real wiring. Installer checks cable connections at inverter and string terminals. The rest of the checklist is below; work through it in order. Installer only: DC and AC work on a live PV system is dangerous, so owners should note the code and call their installer.
Steps from the source
- In the app check the configured string status matches the real wiring
- Installer checks cable connections at inverter and string terminals
- Installer checks any 2-in-1 (Y) connectors
- Fix the loose/broken connection
Source
Huawei Inverter Alarm Reference, Issue 09 (2024-11-01), EDOC1100345192, Alarm 2015, §16, p20files.keno-energy.com ↗
Where installers ask this
- brand new Huawei inverter not working (r/solar)
- reddit.com/r/solar/comments/14htozc/
- reddit.com/r/solar/comments/lmbg08/
General guidance based on the manufacturer's manual or the named source. Always follow the current manual for your exact model and your national code. DC and AC electrical work is for qualified installers only. Not affiliated with or endorsed by any brand named; trademarks belong to their owners.