What does Growatt error 405 mean?
"Error 405" on the screen means the relay that connects the inverter to the grid is not working properly, so the inverter won't connect. If the screen says "Warning 405", it means something else: the software (firmware) versions of two boards don't match.
Why does code 405 appear?
- The internal relay is faulty or stuck.
- Grid voltage or the neutral connection is not right.
- Warning 405: a recent software update did not finish properly.
What can you safely check for 405?
- Switch the inverter off, wait 5 minutes and switch it on again.
- Note whether the screen says "Error" or "Warning".
Safety: never reach into an electrical panel, board, gas pipe or the inside of an inverter yourself. You can get a shock or release gas. This is a mistri's job.
When should you call a mistri?
If Error 405 stays after a restart, the inverter needs repair: contact a solar mistri or service centre. For Warning 405, the installer can update the software. An inverter carries DC current from the panels and battery that can kill, even after the mains is off. Never open the inverter cover or the DC wires yourself.