Generac Guardian 20KW

Generac, Guardian, Honeywell, Siemens, Centurion, Watchdog, Bryant, & Carrier Air Cooled Home Standby generator troubleshooting and repair questions
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Claus
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Sun Nov 10, 2019 10:45 am

I have a 20KW Generac Guardian, which I believe was installed in 2016, and has been running flawlessly and had its yearly maintenance from a Generac certified company.
We had issues with brownouts in the winter months here in WV, where the generator would start and run for a few seconds, and then shut off. Most times the transfer switch didn't go to gen. power, but sometimes it would, but only for less than a minute.
We rectified that by having the time from detecting low power increased to a couple of minutes.
So far so good...

Last week we had our scheduled service, but the maintenance guys said they couldn't get into any menu, and the display was unresponsive, so they would order a new controller board ($540), and install it and perform the maintenance when it arrived at the shop.
I checked the generator, and by the breakers on the side, the red and yellow lights are on.
The display shows fuel selection as being propane, and that it is off.
Pressing any of the buttons has no effect, except a slight flicker of the word "propane" when Manuel, Off and the Escape button is pressed.
Pressing any other button does nothing.

Per your advice in another post I disconnected the battery and disconnected the T1 harness. I also checked the battery and it shows 12.5V. I also disconnected and reconnected all connectors I could find, hoping for a bad connection, but nothing helped.

Up to our service last week, the generator worked fine and did its weekly startup with no problem, but after the service techs had been here and discovered the problem it didn't do its weekly test.

Any help or advise would be greatly appreciated!

Thank you!
Chris
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Mon Nov 11, 2019 8:37 pm

It sounds more like the ribbon cable inside the controller that connects the keypad to the board has some loose. I would remove the controller, pull the phillips head screws and check to see if it has popped out of place.
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Claus
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Tue Nov 12, 2019 7:50 am

I was inside the generator, and took the large black cover/shield off, but didn't see any ribbon cable.
Is it under the plastic "box" that has the keypad?

I'll try again to see if I can figure out how to remove the controller.


Thanks!
Claus
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Tue Nov 12, 2019 9:05 am

Update:

Got the black box with the keypad and controller off the generator.
Opened it up and found the small ribbon cable, and tried to wrestle the board off the plastic case, but no dice.
The area around the ribbon cable, as well as two other areas, had some hardened brown substance around it. I wiggled the ribbon cable, but didn't dare unplugging it. The leads on the ribbon cable above the ribbon connector were dark brown, almost black.

I suspect this brown coating is from insects that venture inside the controller housing, and I found both dead and living spiders and a couple of dead ladybugs.

Plugged all the cables back in and mounted the controller housing, but no dice. The keypad is still dead to any input.

The service techs will be here in two days to install the new board, and hopefully that will fix it.

Thanks again for your help.

Claus
Chris
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Tue Nov 12, 2019 9:34 am

I think you're probably onto the cause at least. Ants really like to get into these controllers and make a home. In the future, I would recommend using something like Ortho Home Defense Max around the perimeter of the unit to keep them away!

That's really not an awful price for a Nexus control panel... I sell them for $499.15, but list price on them (which is what most dealers use) is $638.13. So for the extra 40 bucks, not bad peace of mind to have a local dealer install it and confirm it's working well for you!
Generac tech for over 12 years. I'm here to help!
"The only source of knowledge is experience" -Albert Einstein
Looking for Generac parts? Gentek Power offers the full line of Generac replacement parts! Shop Gentek Power Generac Parts
A list of my favorite Generator & Electrical Tools! https://www.amazon.com/shop/gentek_power
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