Onan 4.0 KY (gas) generator not putting out 4 kw
I have a 2010 Onan 4KW KY gas generator that seems to be running okay except that I can't seem to get a full 4000 watts out of it before tripping the main breaker (near the start switch).
During these cold winter months (Rochester, NY) I have been starting up the generator every 2 weeks and after letting it warm up, I run it under load ( 3 ceramic heaters ) for 1 hour.
I measured each of the heaters using a Kill-O-Watt meter to measure their actual load. But when I set the combination of the 3 heaters for a total of anything over ~3400 watts, the main breaker trips after about 10 seconds. Below 3400 watts the generator will run with no problems.
Not much else is running while I am running this test. The only thing might be the charger for the 12v starter battery, I can't see that taking 400 watts to charge.
Is this behavior normal? - Or is the 4.0KW rating a surge rating (the manual doesn't indicate this). I am at ~1000 ft. elevation. Is the elevation derating causing the drop. I thought this was associated with the engine power itself which doesn't seem to have a problem delivering 4kw of power until about 10 seconds later when the breaker trips.
Thanks,
FBN.
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