SMA SB 2500TL-21 Installation - Manual (Page 22)

Product Description SMA Solar Technology AG
22 SB25-30TLST-21-IA-en-13 Installation Manual
4.11 Varistors
Varistors are voltage-dependent resistors to protect the inverter against overvoltage. The inverter is
equipped with two thermally-monitored varistors.
The function of the varistors can diminish with age or repeated strain as a result of overvoltage. This
can cause varistors to wear. The inverter detects if one of the varistors is defective and indicates a
disturbance.
The varistors are specially manufactured for use in the inverter and are not commercially available.
You must order new varistors directly from SMA Solar Technology AG.