SMA SMC 4600A Installation - Manual (Page 66)

Troubleshooting SMA Solar Technology AG
66 SMC46-60A11-IA-en-81 Installation Manual
9.3.2 Checking the Function of the Varistors
Varistors are wear parts, whose functional efficiency diminishes with age or following repeated
responses as a result of overvoltages. It is therefore possible that one of the thermally monitored
varistors has lost its protective function, and thus the red LED is glowing.
Check the function of the varistors as described below:
1. Open the inverter as described in Section 7.2 "Opening the Inverter" (page 48).
2. With the aid of a multimeter, determine for both
varistors in the installed state whether a conductive
connection exists between connectors B and C.
Position of the varistors
You can determine the position of the varistors using the illustration below.
Note the following assignment of the
terminals:
• Terminal A: outer terminal
(varistor connection with loop)
• Terminal B: middle terminal
• Terminal C: outer terminal
(varistor connection without loop)
Result Measure
☑ There is a conductive connection: Presumably there is a different error in the inverter.
• Contact the SMA Service Line
(see Section 13 "Contact" (page 80)).