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Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 15179
Experience:  Certified on Onan and Generac generators
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I just installed a generac 11kw generator, model no.

Customer Question

good morning Sir,
I just installed a generac 11kw generator, model no. G0064383 yesterday. on completion I turn off the main power the generator started and transferred the load, powered up the house for a few minuets. I then turned on the main power, the load transferred back to main, however the display on the generator displays error 1800; over voltage. I cleared the error by removing and replacing the 7.5 A fuse, repeat the test and the same thing happen. how can I solve this problem?
Submitted: 1 year ago.
Category: Small Engine
Expert:  Hank F. replied 1 year ago.

Hello, my name is ***** ***** I am going to assist you with this.

What is the serial number of the genset?

Customer: replied 1 year ago.
Expert:  Hank F. replied 1 year ago.

I have checked Generac's database, and this unit is not registered.

You must register the unit before setting it up.

Customer: replied 1 year ago.
I registered the set by phone at 8:56 am on Friday after trying to register on line and failed, I called *********** and activated and registered the set. That's why I am able to run it in auto.
Expert:  Hank F. replied 1 year ago.

I thought it was weird that it would run, but their database is not showing it as registered yet.

I've never actually seen a code 1800 on a Nexus controller yet, and find it odd that the manual doesn't list a single troubleshooting step.

The first thing you need to do here is to connect a voltmeter and a frequency meter, and run the unit through a couple of test cycles. What direction to go hinges on whether the unit is actually going over voltage or not, and if it is, whether it is just voltage, or if it is voltage and frequency.

Customer: replied 1 year ago.
The controller is not nexus but evulotion
Customer: replied 1 year ago.
The generator voltage and frequency are 240v 62 Hz.
However life I mentioned before the source 230v, 60Hz.
Expert:  Hank F. replied 1 year ago.

That was my mistake - I meant to say Evolution, as the Nexus controller does not give those codes.

Your source voltage had nothing to do with the Over Voltage code on the genset. The Over Voltage means the genset is putting out too much voltage.

If your genset is actually putting out 240V like it should, but you are getting an Over Voltage code, then the controller is having an issue.

The best thing to do here would be to get an authorized Generac technician out there to fix this under warranty.

The controller is not an inexpensive item.

Expert:  Hank F. replied 1 year ago.

Was this what you wanted to know?