Checking The Function Of The Varistors - SMA Sunny Boy 1100 Installation Manual

Troubleshooting
9.1.2 Checking the Function of the Varistors
Varistors are wearing parts. Their functioning becomes restricted through aging or due to repeated
responses as a result of overvoltages. It is therefore possible that one of the thermallly monitored
varistors has lost its protective functioning, and thus the red LED is lit.
Position of Varistors
The position of the varistors can be seen in section 5.1.2 „View from Inside" (15).
Observe the following allocation of the terminals:
• Terminal A: outer terminal (varistor connection with crimp)
• Terminal B: middle terminal
• Terminal C: outer terminal (varistor connection without crimp)
You can check the functioning of the varistors in the following manner:
1. Open the Sunny Boy as described in section 7.1 „Opening the Sunny Boy" (31).
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.
Result
There is a conducting connection.
There is no conducting connection.
36 SB11_17-IEN084820
Measure
There is probably another fault in the Sunny Boy.
• Close the Sunny Boy as described in section
7.2 „Closing the Sunny Boy" (32).
• Contact the SMA Service Line
(see section 13 „Contact" (44)).
The respective varistor is not working and must be
replaced.
The varistors are specially manufactured for use in the
Sunny Boy and are not commercially available. They must
be ordered directly from SMA Solar Technology (see
section 12 „Accessories" (43)).
• For the replacement of the varistors, continue with
step 3.
SMA Solar Technology AG
Installation Guide