Replacing The Varistors - SMA Sunny Boy SB 2500 Installation Manual

SMA
Technologie AG

9 Replacing the Varistors

The Sunny Boy is a complex high-technology device. As a result, the possibilities for
fixing 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 replacement
service and repair service instead.
If the red LED on the status display shines continuously during operation, you should first
of all make sure that there is no ground fault in the PV generator.
1. Disconnect the Sunny Boy from the low
voltage grid (switch the line circuit breaker to
its "off" position or pull out the AC plug).
Make sure the grid cannot be inadvertently
reconnected.
You must make sure that no voltage is present
at the AC output before opening the Sunny
Boy.
2. Disconnect the DC plug connectors for all
strings.
3. Disconnect the PV generators from the Sunny
Boy.
4. Taking one DC plug connector at a time,
measure the voltages between one DC plug
connector of a string and ground potential.
Pay attention to the safety instructions!
5. Measure the voltage between DC plug
connectors and ground potential.
Caution! Dangerously high voltages may be present. Danger of death!
Installation Guide
Replacing the Varistors
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SB25_30-11:SE0307 Page 51