SMA SB 2800i Installation - Manual (Page 22)

Installation Installation Guide
20 SMA Regelsysteme GmbH SB2800i-11:SE0504
If the lower yellow LED repeatedly blinks once
a second for four times, immediately disconnect
the grid voltage and the PV generator from the
Sunny Boy 2800i. The input voltage is too high.
The inverter might be damaged!
Check whether string voltages comply with limiting values stated
in chapter 4.2 "Requirements: PV-Modules" (p. 12). If the values
are too high, the planner / installer of the PV generator must
modify the strings.
If the LED blinks again when the PV plant is reconnected to the
inverter although string voltages have been checked to be ok,
disconnect the PV panel again and contact SMA Regelsysteme
GmbH (see chapter 9 "Contact" (p. 35)).