Has anyone ever had code 6403 on a sunny boy 3680 inverter. The inverter has been replaced 3 times on advice from SMA as they are saying it's an internal component failure, surely not on 4 inverters though.
The original install was done by myself in February and all was fine until a few weeks ago. I have retested all the AC & DC ,had the DNO out and everything is as it should be. It's back in SMAs hands now but no one can offer a solution.
The original install was done by myself in February and all was fine until a few weeks ago. I have retested all the AC & DC ,had the DNO out and everything is as it should be. It's back in SMAs hands now but no one can offer a solution.
