# Generac 25K Voltage issues



## Pistol (Aug 16, 2012)

I recently installed a 25K Generac natural gas generator at a house. The no load voltages: 124.3V/126.3V/253.3V; Under load voltages: 127.5V/129.3V/257.2V. The amp draw is about 50A; loads are (2)- 4 ton A/C units, general lighting, general receptacles (light electronics, television, etc...).

The main problem is the voltage differences and the lights in the house flicker when both A/C units are running. I have installed hard start caps on both units and that has not alleviated the problem. My best guess is a problem in the generator... maybe stator. 

If anyone has any point of view or thoughts on this please share.


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## Service Call (Jul 9, 2011)

Your voltages seem a little high. As for the flicker it could be freq. issues or loose connections at the genny.


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## Pistol (Aug 16, 2012)

The connections seemed fine. There is a frequency adjustment in the control panel, but I am unsure exactly how to tune it. Although I believe that the regulator is automatic and frequency is directly proportional to voltage in the generator.


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## Service Call (Jul 9, 2011)

There are several meters to check freq. and the owners manual will tell you what steps to take


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## Pistol (Aug 16, 2012)

I have gone through the 'Troubleshooting Guide' and it sucks... I have explored every possible avenue that it provides with no luck. I do not have a frequency meter although I suppose I should get one. I was going to call a Generac tech out there to mess with it but they will charge me if it ends up not being warranty covered, so I was trying to exhaust ALL possible options before bleeding out any unnecessary money. The plumber I hired didn't properly hook it up so the homeowner had their own plumber come out to correct it and I'm out that money... so its just kinda frustrating at this point.


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## Service Call (Jul 9, 2011)

I understand your frustration. It can be annoying, especially when money is held up because of it. Did you provide the generator? Do the lights flicker with no A/C running? Or one running? How long was the gen running with this problem? A couple of minutes or longer? Just seeing if it might have stabilized over a longer period of time. Let's try and keep the post high on the list so that others might be able to chime in and help. Good luck.


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## TimChaput69 (Nov 14, 2011)

You can download the Generac service manual for that particular model online. There are multiple adjustments that can be made on those models. The manuals you can download are the actual service manuals the Generac Tecs get, they are flow chart oriented and very helpful I think.


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## nrp3 (Jan 24, 2009)

What comes with the generator is pretty sparse as far troubleshooting goes. The service manuals are much better. I think you would be better off getting a warranty guy out to look at it. I ended up taking the classes and becoming a warranty provider because I wanted to be able to better serve my customers, ie didn't wanted others into my installs or have to wait for parts etc. To work on the liquid cools, you'll have to take the aircooled class first and then the commercial one next. I don't do much with the bigger stuff yet so I haven't taken that class.


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## Pistol (Aug 16, 2012)

Service Call said:


> I understand your frustration. It can be annoying, especially when money is held up because of it. Did you provide the generator? Do the lights flicker with no A/C running? Or one running? How long was the gen running with this problem? A couple of minutes or longer? Just seeing if it might have stabilized over a longer period of time. Let's try and keep the post high on the list so that others might be able to chime in and help. Good luck.



Thanks for your reply. Yes, I provided the generator that I bought new locally and delivered and set it. The lights flicker with both A/C units running and is not so noticeable with only one unit running. The generator was running for maybe 20-30 minutes or so and the flickering lights occurred throughout its run when engaging both A/C units.


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## Pistol (Aug 16, 2012)

TimChaput69 said:


> You can download the Generac service manual for that particular model online. There are multiple adjustments that can be made on those models. The manuals you can download are the actual service manuals the Generac Tecs get, they are flow chart oriented and very helpful I think.



Ok, could you please provide a link. The only one I am able to find on Generac website is a pdf version of the manual I already have in print that came with the generator. Model is QTO2516ANSN.


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## nrp3 (Jan 24, 2009)

May I also suggest:

http://www.zillerelectric.com/forums/index.php

They are a Generac forum like this. They have a liquid cooled section. Some of us are over there too. You might get better suggestions. Their service department seems to be good and field questions for people.


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## TimChaput69 (Nov 14, 2011)

I'll try and find the link tomorrow....all my manuals are at home, I'm at camp right now so I'll see if I can find it with my phone.


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## TimChaput69 (Nov 14, 2011)

Ok dude that took me about 20 seconds to find it.....google Generac 25 kw service manual, its the 3rd down and its a pdf file.....115 pages of troubleshooting madness. Sorry I can't / don't know how to post a link from my phone at this time so use the info I gave ya....good luck and.doesn't sound lime its a big problem.


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## nrp3 (Jan 24, 2009)

I think he has one of the newer machines with the Nexus control panel.


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## TimChaput69 (Nov 14, 2011)

Haven't had the pleasure of working on one of those yet but like you I took the Generac course a few years ago, I remember there being a hipot adjustment for freq and voltage. Nice course that was like two or three days and they had 6-7 generators with issues that you had to fix. Anyways I'd try google and see what he can find.


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## nrp3 (Jan 24, 2009)

I think he needs this manual (0J1195):

http://www.apelectric.com/0J1195-Nexus-Liquid-Cooled-Diagnostic-Manual-p/0j1195-print.htm


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## Pistol (Aug 16, 2012)

*Update*

I appreciate all the helpful advice and comments guys, thanks. I was able to get over to check out the generator today and made sure all connections were tight and went ahead and put Noalox on the terminations on generator breaker. I did check the frequency and much to my amazement and surprise it read 120Hz... so now I don't know if there is anything much else I can do since this seems to be an internal issue perhaps and more than likely covered by warranty. I did switch the generator off and shut the breaker off as to not have it supply the house again before this issue is resolved.


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## Bbsound (Dec 16, 2011)

WHAT!?!?!

Just curious, what did you measure the freq with?


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## Pistol (Aug 16, 2012)

An Ideal meter (I don't have it here in front of me so don't have model number)... it actually measures in kHz (so it was .120 kHz or 120Hz). I did verify that the meter was working; The utility power on the house read 60Hz or .060kHz.


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## Pistol (Aug 16, 2012)

I was also advised that I could just go ahead and install a generator then pay a Generac tech/provider to do the startup so they become liable from that point on and I would be free and clear... seems like a good idea for future. Just have to figure that into the overall price.


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## Chris1971 (Dec 27, 2010)

Pistol said:


> I was also advised that I could just go ahead and install a generator then pay a Generac tech/provider to do the startup so they become liable from that point on and I would be free and clear... seems like a good idea for future. Just have to figure that into the overall price.


You sound like your not qualified to do the work. I would suggest you not do more than you can handle in the future.


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## Pistol (Aug 16, 2012)

Chris1971 said:


> You sound like your not qualified to do the work. I would suggest you not do more than you can handle in the future.



Dude, I am qualified to install conduit, wiring etc... am I a generator mechanic? No. Do I deal with generators on a regular basis? No. Do I know how to build a service, run conduit to equipment, pull wire, terminate, etc... all properly... YES. Now, when it comes down to getting technical with something I do not deal with on a daily basis then I would call in someone that DOES deal with it on a daily basis. You don't know me/or what I have done as far as electrical work. So, I would say you are not qualified to offer your opinion...


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## Chris1971 (Dec 27, 2010)

Pistol said:


> Dude, I am qualified to install conduit, wiring etc... am I a generator mechanic? No. Do I deal with generators on a regular basis? No. Do I know how to build a service, run conduit to equipment, pull wire, terminate, etc... all properly... YES. Now, when it comes down to getting technical with something I do not deal with on a daily basis then I would call in someone that DOES deal with it on a daily basis. You don't know me/or what I have done as far as electrical work. So, I would say you are not qualified to offer your opinion...


You said it, your not qualified. Find someone who is.:thumbup:


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## Pistol (Aug 16, 2012)

Chris1971 said:


> You said it, your not qualified. Find someone who is.:thumbup:


Generators are a small part of what I deal with, so I was seeking information.


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## Dawizman (Mar 10, 2012)

I came across a generator once before that was putting out 120hz. I can't recall exactly what the fix was, but i do remember that something was not bonded, or grounded properly.

Just thought I'd put that out there...


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## dronai (Apr 11, 2011)

Pistol said:


> I was also advised that I could just go ahead and install a generator then pay a Generac tech/provider to do the startup so they become liable from that point on and I would be free and clear... seems like a good idea for future. Just have to figure that into the overall price.


Doesn't the manual have the full start up procedure ? 

Warrenty should cover anything else. 120hz = double the voltage ! Can you locate where to adjust the frequency ?

Or since your voltage is all over the place, maybe the voltage regulator is bad ?


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## frenchelectrican (Mar 15, 2007)

dronai said:


> Doesn't the manual have the full start up procedure ?
> 
> Warrenty should cover anything else. 120hz = double the voltage ! Can you locate where to adjust the frequency ?
> 
> Or since your voltage is all over the place, maybe the voltage regulator is bad ?


Did the OP hear the prime mover speed ? if it was running at either 1800 T/min ( for 4 pole type ) or 3600 T/min ( For two pole type ) if used 1800 engine speed and ran at 3600 T/min there will be serious issue will arise if not watch out.

I have see couple larger generator got damaged by overspeed.

But if reading 120 HZ while the engine is running correct speed then you have other issue with the system.

Merci,
Marc


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## Southeast Power (Jan 18, 2009)

Pistol said:


> I appreciate all the helpful advice and comments guys, thanks. I was able to get over to check out the generator today and made sure all connections were tight and went ahead and put Noalox on the terminations on generator breaker. I did check the frequency and much to my amazement and surprise it read 120Hz... so now I don't know if there is anything much else I can do since this seems to be an internal issue perhaps and more than likely covered by warranty. I did switch the generator off and shut the breaker off as to not have it supply the house again before this issue is resolved.


I don't think 120Hz would be possible with those voltages.
I think you might have a warranty issue.
Invest in the service call and let us know what you found please.


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## nrp3 (Jan 24, 2009)

The first standby I did, Cummins 30kw, I had the generator guys do the terminations and testing. Don't really feel guilty about it. The customer was a long time and very important one. All I wanted was it to be a success and it was. Since then I have taken some classes and gained some experience, though far from expert. Taking care of the customer is the first priority. Nothing wrong with getting some help. Customer won't care so long as what he paid for works.


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## sparky1423 (Sep 18, 2010)

I have always used a generator service company to do the start ups. They have a prepackaged deal....basically, I purchase the generator from them at their price and it includes site prep, delivery, placement and start up. Basically, all I am responsible for is the initial termination and plumber. Once they do the start up, all responsibilities go to the generator company. It's more expensive, but worth it to me.


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## nrp3 (Jan 24, 2009)

The guys I worked with did a good job. Delivered, set up and tested it. They do the annual service too. I do all this for the Generac stuff now. The other was cummins and I haven't had the training for that yet.


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## Pistol (Aug 16, 2012)

So, the 120Hz I was reading was supposedly a glitch in the meter... it was picking up harmonics/noise created from the generator. Proper reading should be under load. Frequency reads 60Hz. 

Still having issue with the lights (incandescent) in the house blinking. I hadn't had the chance to isolate the second A/C unit to see if its just that unit causing the problem. Getting Generac rep to come out Tuesday or earliest avail to verify everything is ok. Problem may be within premises wiring or grounding. As far as I can see there's nothing wrong with my installation. Will have them check fuel pressure pre start and under load when both A/C units kick on.... should not drop more than 1" W.C.


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