SMA SB 2500 Installation - Manual (Page 55)

SMA Solar Technology AG Troubleshooting
Installation Manual SB25-30-IA-en-51 55
9.3 Red LED is Permanently Lit
If the red status display LED is permanently lit during operation, there is an earth fault in the PV array,
at least one of the varistors for overvoltage protection is defective or there is an insulation fault.
Procedure
1. Check for earth faults in the PV array as described in Section 9.3.1 "Checking the PV Array for
Earth Faults" (page 56).
2. If the red LED continues to be lit, check the varistors as described in Section 9.3.2 "Checking the
Function of the Varistors" (page 58).
VpvMax
Vpv-Max Overvoltage at DC input. The inverter may be damaged.
Corrective measures
Immediately disconnect the inverter from the mains.
1. Disconnect the miniature circuit-breaker.
2. If an external DC switch-disconnector is available, disconnect it.
3. If an Electronic Solar Switch is installed, remove it.
4. Remove all DC connectors.
5. Check the DC voltage:
– If the DC voltage is above the maximum input voltage, check the
plant design or contact the PV array installer.
– If the DC voltage is below the maximum input voltage,
reconnect the inverter to the PV array as described in
Section 5.4 "PV Array Connection (DC)" (page 28).
If the message occurs again, disconnect the inverter again and contact
the SMA Service Line (see Section 13 "Contact" (page 71)).
Watchdog
Watchdog Srr Internal program run fault
Corrective measures
• If this fault occurs frequently, contact the SMA Service Line.
Message Description and corrective measure