SMA SB 4200TL HC Multi-String - Manual (Page 47)

SMA Technologie AG Replacing the Varistors
Installation Guide SBTLHCMS-IEN080411 Page47
10 Replacing the Varistors
The Sunny Boy is a complex high-technology device. As a result, the possibilities for fix-
ing faults on site are limited to just a few items. Do not attempt to carry out repairs other
than those described here. Use the
SMA Technologie AG 24-hour exchange service
and repair service instead.
If the red LED on the status display glows continuously during operation, you should first
of all make sure that there is no ground fault in the PV generator. Only skip points 3 to
5 if the green LED is permanently lit at the same time.
1. Disconnect the Sunny Boy from the low-voltage
grid (switch the line circuit breaker to its "off" po-
sition). Make sure the grid cannot be inadvert-
ently reconnected and test to make sure no
voltage is present at the AC output.
2. Remove the Electronic Solar Switch.
3. Immediately remove the DC cables from the Sun-
ny Boy in order to completely disconnect the PV-
generator from the Sunny Boy.
Make sure you note the order of the individual
inverter inputs so you can put them back in the
right place later!
4. Taking one DC plug connector at a time, mea-
sure the voltages between one DC plug connec-
tor of a string and earth potential. Pay attention
to the safety instructions!
Warning!
Dangerous high voltages may be present. Danger of death!
Off!