SMA America, LLC
Troubleshooting
Installation Guide
SB50US-80US-eng-IUS112633
79
Disturbance
Vac-Bfr, Vac-Srr
The AC grid voltage is exceeding the permissible
range. The cause may be disconnection from the
power distribution grid or from an AC cable. To
prevent islanding, the Sunny Boy disconnects
itself from the power distribution grid.
If the error message "Vac-Bfr" or "Vac-Srr" is
displayed despite the grid voltage being within
the tolerable range, contact SMA.
Disturbance
VacL1-Bfr, VacL2-Bfr,
VacL1-Srr, VacL2-Srr
Voltage is too high or too low on the indicated
branch.
Disturbance
VpvMax
!PV Overvoltage!
!Disconnect DC!
The DC input voltage is exceeding the maximum
tolerable value.
Disconnect the DC line immediately.
Disturbance
Watchdog
Watchdog for operation control triggered.
Disturbance
XFMR
The transformer is connected to the wrong grid.
Check the connection of the transformer.
For grounded Delta grids: monitor whether the
grid grounding conductor is connected to
terminal L2.
In the event of unbalanced load in 200 V and
240 V grids, swapping L1 and L2 may rectify the
fault.
Disturbance
XFMR_TEMP_F
High transformer temperature. The Sunny Boy
stops and the fans run at maximum speed.
Warning
XFMR_TEMP_W
After the reduction of the high transformer
temperatures, the Sunny Boy restarts. Monitor the
function of the fans.
Fault Type
Fault Code
Description
