Onan underfrequency error

Mark Pitt


   My Onan MDKAV shutdown with a code 15 “underfrequency” shutdown code.  It had been running for one hour making water and topping up the batteries.  Nothing else running. It was producing about 20 amps at the time.  No previous hint of trouble except for one small thing.  My Bluesea in-line digital multimeter has shown 49.8 hz for the past few months, down from the 49.9hz it showed for the prior few years, which is down from the 50.0 it showed for the first few years. The boat is 15 years old. I thought nothing of this small change in frequency since the generator has run perfectly for years.

i have lots of clean fuel in the tank and the fuel filter is relatively new. There is no apparent issue with the fuel line.  Any ideas?

  Mark Pitt
Sabbatical III, SM 419, Bequia, West Indies

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