underfrequency fault error message

[AirCapitalDuo]

We have successfully used our factory-installed Onan 5.5 generator many times, but now it will only run for about 30 seconds and then shut off... another 30 seconds later the error message "Underfrequency fault." appears on the inCommand screen.

Anyone familiar with what causes that?

[rohrmann]

Probably the engine is not running up to the proper speed to get the frequency up to 60hz, which is the standard frequency in the US. The engine controls should adjust the speed of the engine automatically.

[AirCapitalDuo]

thanks @rohrmann - unfortunately, that's well beyond my skillset... so, we made an appointment with our local Cummins service center to take a look.

I did make a minor adjustment to what may have been the governor, and now it stays running unless we try to turn on more than one A/C unit. That should be good enough to get us by if the power goes out before we take it in.