Split-phase Quattro 48/10000

I have a Split-phase system with 2 Quattro 48/10000/120 inverter/chargers, for a hybrid domestic application. The system seem to work well with PV, the problem is that whenever it tries to use the AC input, it immediatly shuts down the grid input. How can I correct that issue?

Without details, I can think of 2 possibilities:

  1. The grid is unstable or not putting out true sine wave, leading to its being rejected. Try the accept weak AC setting.
  2. Not sure about split systems but in parallel systems, AC must be the same phase.

What do you mean by AC input and grid input?
There is AC-In-1 and AC-In-2, and AC-Out-1 and AC-Out 2 on a Quattro.

Only one input can be active at a time, with AC-In-1 preferred I believe.
Both outputs can be active.

I mean AC-In-1 in both cases

What information could be useful?

I can think of screenshots of your settings and if possible, a diagram of your installation (failing that, a listing of your components and a description of your wiring).