10KW Air cooled Propane, runs in the Auto Setting

[dbajaer]

Hi from Baja Cal, we have a 3 year old Generac Guardian 10 KW, it runs on propane. We had a little problem with it earlier this year. Our power went out and so our faithfull Generac came on automaticly, the outage lasted several days, we decided to shut off the generator to give it a rest and save on propane, little did we realize that the utility lines had about 40 volts! Since we shut down the gen, the auto transfer swtich could not switch back with so low a voltage, it melted down one of the solonid coils. I bought a new transfer switch and replaced the melted coils. We have had the whole unit in the off position for two months, I tried to turn it back to "Auto" today and the unit starts the motor running! Since the utility voltage is normal, the switch ramains in the "utility" position and the gen just runs and runs...I shut off the utility breaker at the meter, the Auto Transfer switch changed over normally to gen, that was great, so I then switched the City Utility back on and the transfer switch shifted back to City power but the generator kept on running.

I took digital photos of the wires in the transfer switch and they are exactly correct as it was wired before changing the solonoids. We can still use the Generator but the automatic feature is not available unless we want to have it run 24/7. Help! My guess is the control board failed.

[cosmicvoid]

My guess is the control board failed.Or the transformer that steps the utility voltage down to 16 v for the controller board. If you're handy with a voltmeter, you might could check the voltages on the transformer terminals. Check the schematic in the manual.

[Kelly Myers]

Hi.

This is a pretty easy situation to figure out. Let me explain to you what SHOULD be happening, and we can go from there.


Utility sense is derived from the transfer switch. The generator monitors N1/N2. On newer generators, it is looking for >83% nominal voltage.

You can easily tell if your generator is seeing proper voltage by the green "System Set" light on the dummy light panel on the generator.

When the generator is in OFF, you shouldn't have any lights on. When you turn it to auto you should have a solid green light. This means its sensing proper voltage, and the utility company is making proper voltage, and it is reaching the transfer switch, and ultimately reaching the generator.

If you turn the generator to auto, and you have a flashing green light, that means the generator is not seeing nominal voltage. This is because of a brownout/power outage, or the power is not reaching the generator from the transfer switch.

You have to find out where the power loss is happening. Here is how I would trouble shoot it with an electrical meter. And I of course recommend having a licensed electrician do this :D

1. Turn your VOM to AC Voltage.
2. Test power on the line side of the N1/N2 fuses. This can be achieved by removing the plastic cover protecting the fuses. Voltage between N1/N2 should show >230
3. If voltage is proper, move to the load side of the fuses, or the bottom of the fuses. Again, we should have >230V between N1/N2.
4. If voltage is not proper in step 3, remove the fuses and check them. This is the most common problem.
5. If voltage is proper in test 3, open up the j-box on the outside of the house. This should have the plastic plug in adapter. Unplug the adapter and check for voltage between N1/N2. It should be >230V.
6. If voltage is proper in the J-Box, open up the right side of the generator. This is the cover that goes over the 2 pole breaker. Test voltage at the terminal strip inside the generator. If you have >230V between N1/N2, then we know the wires good :)

But that means we have a bad transformer, or a bad PCB.

Keep me updated!


(Copy/pasted from the transfer switch forum)

[dbajaer]

First I want to thank you both because without your very valuable information, I could never have solved the problem. I left out one tiny item of information, here in Baja we have very unreliable current from CFE. We have brown outs and service losses as a regular event. Probably almost everyone that lives here has a back up generator for both this and for the long outage times after hurricanes. Lots of us went to the Generac unit as it is an enexpensive and reliable way to use propane as a fuel to keep things working like freezers and telephones.
Our first problem after installing the Generac's was at times the city voltage would rapidly bounce up and down for an extended period of time, this would overheat the transfer switch and cause it to fail. We found that by using a 'single phase line monitor' we could set the turn-on turn-off time to 15 minutes and this stopped the needless melting down of the transfer switches.
I changed out my ICM 491 monitor when I first noted the problem of my Gen running in the auto position, now with your info, it took only a few minutes to realize that the new line monitor was also not putting voltage into the n-2 wire going into the generator. The problem is of course back to Mexico, CFE has raised our incomming voltage, I am reading almost 260 volts, well the line monitor wants the cut out voltage to be somewhere close to 12% of the voltage from CFE. I just had to raise the setting on the monitor! The monitor was doing its job and cutting off the control wire to the gen not from low voltage but because of high voltage! All is well and now we can sit back and relax drink a few Coronas and know our trusty Generac is watching.......:)

Without your great information, I would have never resolved the problem, thanks tons and tons...Don Schenk

[Kelly Myers]

Glad you figured it out!

If you ever burn up more coils down the road, give us a call. I had a special voltage monitor made up that drops out the n1 line to the generator if there is ever less then 210 volts at the residence.

We have brown out issues around SE Michigan, as well as a lot of places in Nevada.

The power company should NEVER allow a brown out to happen. It damages everything that has power ran to it. After having a ton of burned up coils, I decided to design something to fix the issue. This issue was resolved in the new lineup of generators. Generac finally realized that power companies don't always do their job of killing power during a brown out.

My voltage monitor tricks the generator into thinking a brownout is really a power outage, and you will never burn a utility coil up again.

I've sold over 300 of them, and I've never had an issue with one of them failing.

And on a side note, I'd much rather be south of the border right now. Its raining and 55F here in Michigan :( Coronna's with the furnace on don't go hand in hand. lol