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Nexus
Under Frequency
Under-frequency
Electrical · Alarm
Nexus under-frequency shuts the set down if it stays under a set frequency for more than 30 seconds. The manual's table lists 40 Hz for a 50 Hz unit, 50 Hz for a 60 Hz unit with controller 0H6680A, and 55 Hz for a 60 Hz unit with controller 0H6680B.
Seen on: Air-cooled generators with the Nexus controller covered by the Nexus diagnostic manual.
Likely causes
- The engine cannot hold the table's minimum frequency for 30 seconds, often because of load or a fuel/throttle problem.
- The threshold depends on which controller board is installed, so the code alone does not tell you which hertz number applied.
Checks an owner can do
- Remove large loads before a single restart.
- Do not assume every 60 Hz Nexus uses the same cutoff. The manual splits 0H6680A and 0H6680B.
When to call a pro
If it shuts down again with the breaker off, a technician needs to identify the controller and test speed control.
Source
Wording follows that document. Firmware can change a threshold. If this page and the manual shipped with your unit disagree, follow the manual.
What fixed mine
No approved reports for this code yet. Send one. It stays in the review queue until it is approved.
Related Generac codes
https://generatorcodes.com/brand/generac/nexus-under-frequency