16kw Tests fine but shuts down under load...

Generac, Guardian, Honeywell, Siemens, Centurion, Watchdog, Bryant, & Carrier Air Cooled Home Standby generator troubleshooting and repair questions
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Shreveport
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Mon Jun 24, 2019 9:14 pm

Last Friday the test cycle ran fine as it does every week. Last night we had a 30 second power failure, the generator started and shut down. Then a real power failure due to the storms...

The Generator ran for about 20 seconds and shut down. Oil Low and Battery low lights were on. So I added 1/2 quart oil in the dark.

Restarted after finishing the quart of oil off and same thing with same messages...

Then I reset the circuit breakers and tried again. This time Overheating light lit up.

This is a GT990 that was installed in 2007 and maybe has 7 days Total on it. Engine runs fine and strong. It is natural gas. Serviced every February with oil change, air filter, spark plug. Engine looks brand new - no evidence of any leakage. Battery changed every other year. Current one is 16 months old.

And then of course everyone in Shreveport is not available for a service call for 2 weeks but all try to tell me I just need to scrap the thing and put in a new one. I am disabled and on disability.

One more observation. During weekly test it cranks for a bit (like a week battery) then starts. But when load is on it it fires right up with no cranking.

They tell me the computer board is bad, (one company at least with not even coming out) 250 diagnostics and 700 if board is bad and to weeks for them to come out, then two - three weeks to get a part, - then installed when they get to it.. Estimate is 6-8 weeks for repair. Then tell me like a car, once it starts going, it starts going that I really should replace it...

Questions:

Any ideas as to what might be occurring?

I replaced my HVAC 3.5 ton with the same but a higher seer and never had problems in the past. Could the higher seer be causing this?

Finally should I replace the whole thing with engine still looking new, no fluids anywhere, and never an issue before this?

Any advice is extremely appreciated... I am a real dummy when it comes to things like this. THank You.
Chris
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Wed Jun 26, 2019 10:45 am

Well, it's odd that you are getting so many different alarms during the shutdown. Is it possible that you are viewing the control panel from a slightly different angle causing the LED's to appear differently?

The controller for that generator (based on what you've said, I'm assuming a model 5243) can be had for about $267 found here: https://shop.gentekpower.com/products/g ... d-pcb-60hz

Has anyone ever adjusted the valves? Stalling issues are normally fuel related and valves that have never been done will cause fuel issues.
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Shreveport
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Wed Jun 26, 2019 12:44 pm

First of all thank you for the reply....

When viewing the lights I am always standing face first in front of it.

A few years back the unit started almost dying during testing. The repairman came out and could not find anything wrong. SO he called someone, maybe generac and they told him to bend the carburetor?????!!!! He did and it started working as it always had. Don't ask me that is what he told me... LOL

Anyways last Feb when I had the yearly maintenance done, when it tested it sounded like something was exploding in it. So I called the company that I use waited 2 weeks they came out and said it was a faulty spark plug that exploded. They changed it out and it was fine after that.

The unit other than that has been perfect until this recent debacle. Thank you for the info regarding the controller. When they try to tell me 600 I will tell them I will order it and they can come back in the usual 2 weeks to put it in.

I trust that you do not feel I should just up and replace it. As I stated the engine looks new and until this started always tested fine.

Again thank you.
Chris
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Wed Jun 26, 2019 8:49 pm

The 'exploding' you're hearing sounds like backfiring which would lead me to believe the coils are going bad, which is not uncommon for a unit of that age.

You will damage the engine if it continues to backfire. The coils could also be the reason the unit isn't starting well. It may only be running on one cylinder...

They are not an easy repair and at the cost you're talking about, they may charge you a small fortune... It's about a 2 hour job for an experienced tech.
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
Shreveport
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Wed Jun 26, 2019 9:31 pm

No everything turned out ok...That was 18 months ago right after the yearly oil change etc. It was the spark plug they put in came apart. Once they pulled the broken one out and replaced it that went away. The white ceramic(?) part was in pieces and bouncing around inside the cover as it came apart.. I am just glad I was home and got it shut off...

I wanted to ask you, is the board something I can change myself? And is there something I need to do at the transfer switch to make sure I am not fried..

Again many thanks....
Chris
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Sun Jun 30, 2019 9:13 pm

Yes, the board is just a few small phillips screws and a couple of harnesses to unplug. All power to the unit should be disconnected to prevent danger. The battery should be removed and also the N1 and N2 fuses should be pulled to shut down 240V power out to the control transformer in the generator. Once the new PCB is installed, voltage and frequency should be measured to make sure the controller is working and not set to the 50Hz mode.
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
Shreveport
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Mon Jul 01, 2019 3:52 pm

Many Thanks...
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