Onan Generator 4000 Fault 12 - Overvoltage

[dbeeke]

I bought a used 2011 Forest River Sunseeker 3120ds last year and have been thoroughly enjoying it with my family. On the last road trip, we were using the generator at Lassen Volcanic National Park (6000+ ft elevation) and it died suddenly flashing a code 12. We looked up code 12 in the manual which means overvoltage. Makes sense as we had the AC on and the halftime oven going.

The generator will start up no problem and run fine until the 'click' occurs when the load is applied and then it dies instantly.

It is an Onan Generator 4000 with 28 hours on it. Yes, only 28.

If we shut off all the circuit breakers in the coach the generator will keep running fine. If we shut off the AC, microwave, HW tank etc and turn on the breakers it will still run. But the moment the AC is turned on, or the microwave starts, or any other load the genset dies instantly giving a code 12.

Oil is fine, filter looks clean, turned main circuit breaker on the genset off and then on again to no avail. Checked all RV plugs to makes sure nothing there is 'shorting out' something and couldn't find any problems. If the RV is plugged in to shore power everything works fine and no breakers trip or anything like that.

Any ideas how I can fix the generator problem?

Thanks in advance

[dbeeke]

Thanks for the help. To report back, it was a bad board. Installed a new one and all is well again. Thanks again.

[dbeeke]

Thanks already.

Model # is 4KYFA26100L

It is Gas, 33 amps, 120 V.

P.S. Drooled over the peak hike but didn't work with my young children. We did enjoy the Bumpass Hell Trail...even my 3 year old made it to the hot area and back.

[j-d]

If you'll post the Model Number, we may be able to send you the service manual, or do you have that? Last character in Model is "Spec Code" which indicates which revision of the basic design your genset actually is.

Visited Lassen a few years ago and loved it. I walked the trail to the peak, hope you did. Actually looked DOWN at an aircraft flying by.

Oh, an outfit called Flight Systems has some Onan information and offers parts like control boards. So does Dinosaur. But don't buy parts without some definitive troubleshooting.

[Vulcan_Rider]

You need to find an Onan service center.....a real authorized one.

Joe's RV fix-it shop might say they can fix it but who knows.

P.S. Having too much of a load on the generator will not cause an OVER voltage.

[newman_fulltime]

it sounds like a bad board you might call onan theyat one time had some revisions on them