Checking The Dc Disconnect; Checking And Replacing The Dc Varistors - SMA SUNNY BOY 3000-US Installation Manual

11 Cleaning and Care
6. After checking the fan, return the jumpers to the original position:
• Open the inverter (see Section 9.1).
• Place the jumpers on the pin header according to the desired jumper assignment
(see Section 7.3 "Jumper Assignments for Grounding Systems", page 53).
• Close the inverter (see Section 9.2).
• Commission the inverter (see Section 8).

11.4 Checking the DC Disconnect

• Once a year, turn the rotary switch of the DC-Disconnect from the On position to the Off
position 10 times in a row. This cleans the contacts of the rotary switch and extends the service
life of the DC Disconnect.

11.5 Checking and Replacing the DC Varistors

In regions where storms or other DC overvoltages frequently occur, the DC varistors lose their
functionality if the PV plant is not equipped with additional overvoltage protection. In such cases,
SMA recommends replacing DC varistors with new ones after an operating period of 10 years in
order to ensure that the functionality of the DC varistors remains at a constant level.
Destruction of the inverter due to DC overvoltage
If DC varistors are missing, the inverter is no longer protected against DC overvoltages.
• Do not operate the inverter without DC varistors in PV plants with a high risk of DC
overvoltages.
• Replacement DC varistors should be obtained as fast as possible.
• Use the DC varistors by SMA Solar Technology AG only.
• Always replace the entire set of DC varistors.
82 SB30-40-US-IA-en-33
SMA America, LLC
Installation Manual