Checking The Function Of The Varistors - SMA SUNNY TRIPOWER 8000TL Installation Manual

SMA Solar Technology AG
11.3 Checking the Function of the Varistors
If the inverter displays the event number "74", then one of the varistors is probably defective.
Varistors are wear parts. Their 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.
Check the varistors as described below:
1. Disconnect the inverter as described in section 8 "Disconnecting the Inverter" (page 70).
DANGER!
Danger to life due to high voltages in the inverter Death due to electric shock.
There is residual voltage in the inverter. The inverter needs 10 minutes to electrically
discharge.
• Wait 10 minutes before you open the upper enclosure lid or the DC lid.
CAUTION!
Danger of burn injury due to hot components inside the inverter!
• Wait until the components inside the inverter have cooled down.
2. Unscrew the captive screws of the DC lid on the left-
hand side of the connection area.
3. Lift the DC lid upwards and remove it.
Installation Manual
Troubleshooting
STP8-17TL-IA-IEN112030 93