Low fan supply voltage

On string inverters, a cooling fan problem shows up as an ExtFanErr alarm. The fan runs at variable speed according to load and temperature. The listed causes are a blocked fan, a fan past the end of its service life, and poor contact at the fan socket connector. Poor contact at the connector is the cause most closely tied to the fan getting too little supply voltage. Before replacing parts, the manual says to watch the inverter for 5 minutes to see whether the alarm clears by itself. A fan that is not working is one known reason for inverter overheating, where the inverter reduces its output because of temperature. During service, the internal fan and power supply connectors on the circuit board tray are separate plug connections. Check that they are seated properly when looking into a fan supply problem.

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• sentence 2: support check: partial - The three causes are listed, but nothing links poor connector contact to the fan getting too little supply voltage; that is unsupported inference.
• sentence 5: support check: partial - Passage shows fan and power supply connectors are disconnected separately on the PCBA tray, but says nothing about checking seating when investigating a fan supply problem. -->