generac generators

stevie1959September 3, 2008

I recently purchased a 20kw air cooled generator from a Generac distributor. The unit initially started and ran, tested ok. The first actual power outage that occured the unit came on and operated about 45 minutes then while the motor kept running the unit quit producing power.After checking all breakers I called an electric company that warranties generac. They found copper wire from inside the generator in the bottom of the housing.They call Generac and was told this is a widespread problem with the 20kw.Now with 3 hurricanes brewing in the Atlantic and after spending 6000+ dollars for a backup generator I am witout.When calling the company they said it would be 2 or 3 weeks before they could ship a replacement,but could not give an actual timeframe.The 2 or 3 weeks is what they told the warranting company.Be aware of this issue with Generac Generators.

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Generac is NOTORIOUS for poor service.

    Bookmark   September 3, 2008 at 5:05PM
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We stopped selling Guardian a couple of years ago due to poor reliability and the kind of problems that you mentioned.
I have recently installed a couple and it seems that maybe the quality is better due to considerable redesign.
That said, I am still gun shy due to past experience.
Only time will tell.
Just as a word of warning, Guardian products are being sold these days by Carrier under their name. The only difference is the paint job and the label.

    Bookmark   September 3, 2008 at 6:28PM
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Your situation and others are the reason for "Generjunk" and other colorful terms used to describe these sets. Onan, Kohler and Cat are the names you typically see on standby sets where lives and $$$ are at risk from an outage.

At one time I thought Generac had improved some, but they are at best well behind the "big three", IMHO. There are few things more irritating than a failed standby gen-set.

    Bookmark   September 3, 2008 at 10:11PM
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When I was looking at generators I did look at a number of manufacturers and finally settled on Cummins Onan. Brand names aside the things I looked for are:

1) Weight. Seems sort of dumb, but it the generator weighs more than means there is more copper in the windings. This is good in that you have greater starting surge current capacity etc. Also you probablly have a big engine.

2) Air cooled is OK, but at 20KW, I am sort of surprised. I thought that most generators above 12KW or so tend to be water cooled. Water cooled is better in that your engine runs at a more even temperature range. Typically water cooled engines are car / truck engines and 4 cylinders. The air cooled ones are usually twin cylinders and are based off lawn mower engine sources.

3) RPM - revolutions per min. The cheaper gen sets run at 3,600 rpm. You can get away with fewer windings in the generator head, less copper, less weight. But your engines is stressed more and runs more noisly and runs faster. The better generator sets run at 1,800 rpm. Need to have 4 windings in the generator head instead of two, more copper. But are less noisy and less stressed and run more slowly.

Note however that the nicer water cooled, truck engine, 1,800 rpm, 4 winding generators are more expensive (a) to buy and (b) to install. The install cost is big because you need a concrete pad (relatively cheap) and something to lift the genset (expensive). Typically you need a small crane or back hoe for the lift. The cheaper gensets can be lifted by 4 men.

Hope you get your genset stuff sorted out OK.

Warmest regards, Mike.

    Bookmark   September 4, 2008 at 6:50AM
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Unfortunatly the differential in cost between a 15KW standby Generac and a 15kw water cooled Onan is LARGE. As in 2x or more.

For the price, if properly sized and installed, a generac home standby unit can give excellent service for its intended application. The average home standby unit will spend less than 10hrs per year under load. That is not but a few hundred hours over a design 20yr life.

We installed our 15kw air cooled Generac after Rita left us without power in 2005. Now 3 years old it has carried us through several power outages of varying length. Only repair cost so far has been a replacement battery this year. Starts and runs every Sat. Very nice to know that when the lights go out, I do not need to fumble for a flashlight. Just stay put for 30 seconds and the lights are coming back on. So is the AC. Total installed cost was less than 5k. Would have been 12 with Onan or Kohler. The 12k would not have happend.

    Bookmark   September 10, 2008 at 1:59PM
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What is your fuel source?
What did you use for a transfer switch?
What is the location of the generator relative to your service?
How much was your permit?
I am just trying to understand how you could possibly have installed it for less than 5K.

    Bookmark   September 10, 2008 at 6:30PM
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Fuel Source is natural gas. 1" fuel line over 100ft from meter on other side of house was most expensive part of the install other than the gen set itself.

UL Listed transfer switch, siemens load center, conduit, wire, connectors, hardware and pad for gen skid all came as part of the Generac kit for $2995 from Amazon. Free delivery was very well done as well, placing the package exactly where I wanted it and damage free.

No permit required by Harris County. Electrical inspection was done by service utility just prior to reconnet of service and resealing the meter. Passed inspection first time.

I did the installation and electrical work myself. Spent about $250 on misc electrical parts and ground rod.

Generac service tech for startup and initial adjustments was $200 and validated install for warranty.

    Bookmark   September 11, 2008 at 12:57PM
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Very nice.

    Bookmark   September 11, 2008 at 9:17PM
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When price is a primary consideration, you often get what you pay for. Here is another Generac/Gaurdian story.

Here is a link that might be useful: Another Generac failure

    Bookmark   September 13, 2008 at 7:10PM
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Ike has left us without power since the early am hours Sat. Generac has been running for 5 days straight now. Have never run it this long but its doing fine so far. Consumes about a pint of synthetic oil in 24hrs run time which is less than the Onan on our RV. My gas bill is going to be high, but its nice not to be without power for this long.

Houston is a mess with 2 million households without power.

    Bookmark   September 17, 2008 at 4:34PM
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Glad to hear you and the Generac are doing OK. What is the oil change interval on your set, maybe 150-200 hours? You will probably be doing one before long.

    Bookmark   September 17, 2008 at 5:00PM
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Good to hear that icthorne but if your using synthetic oil
in your gen you can kiss that motor good by in about 1 year and i'm giving you a big margin.(maybe 6 months ?)
Synthetic oil has no zink in it and unless your gen motor
has a roller cam in it( i dought it ) your cam will look like a 3/4 inch water pipe in a year or less. Why is your motor using so much oil ? Never mind. I forgot you are using synthetic oil. I have a 18 H.P. Onan rider mower that the original owner gave to me. Couldn't keep oil in it. He was using 10w30. WRONG. the lable says 30 weight only. I use half a quart of oil in a season and this mower is to small for my lawn and is over worked. I might be wrong but check your manual for your gen. Your probably using the wrong oil. I hope your motor is still O.K.

    Bookmark   September 17, 2008 at 6:38PM
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Recomended oil change frequency is 150hrs or annually. Its had 2 changes already as its 3 years old. I will change it this weekend if the power does not come back.

The recomended oil is Full Synthetic 5W30. I called Generac and asked about using Shell Rotella Synthetic 5W40 as we already use it in most everything else and they agreed it was a very good fit in the Houston climate. So that's what it runs. I overstated the engine's oil usage. In a week of run time I have used less than 1/2 gal topping off every day so its not a pint a day, more like 8oz. Still far less than my Onan 6.5KW Emerald on the RV uses.

You are also mistaken about the zinc (ZDDP) additive content of synthetic oils. The formulations are different for various blends, has nothing to do with synthetic or conventional. And FYI, Shell Rotella Synthetic has 1200PPM of ZDDP in its formulation. The Onan gen set has well over 2000 hrs on it running this oil so its not a problem for air cooled engines, quite the opposite, its a recomended application. Also, its very hard to compare oil consumption for natural gas engines to gasoline ones due to the very different types of contamination and lack of oil dilution in NG applications.

I also went and read the article posted above on the other generac problem. I don't doubt the guy in the article had a blown generator stator winding, but it was not a result of insufficient air flow through or around the generator. I have the same 15kw air cooled model he has and was VERY concerned after reading the article. Went home last night and spent some time really looking over the cooling flow design. First, the generator does not share a compartment with either the muffler or the exhaust pipe. Second all the air that the intake fan on the engine end draws into the enclosure and across the cylinder heads is forced THROUGH the generator housing and out a cooling air port just behind the stator bearing carrier. There is also a discharge air fan in that compartment that helps to draw air through the generator housing, all the air from the engine fan plus additional air from the front air intake vents near the battery compartment. Then the exhaust is blown into the hot air just before it is blown out of the enclosure. Pretty slick design resulting in LOTS of air flow for both engine and generator and a engine oil cooler.

Lastly, several articles speaking on the air cooled gen sets report that the generators used incorporate sleeve type bearings. This is not true. The generator only has one bearing and its a true roller bearing. The engine bearings are pressurized oil sleeve bearings like in automotive engine applications.

Thanks to this conversation sparking a bit of research on just what I have sitting next to my house, I feel much better about the unit's design.

    Bookmark   September 18, 2008 at 10:44AM
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Follow up to original post,finally received installed generator on Nov. 25th after being in three weeks guaranteed shipment since Sept. 3rd only ran for test so far so not sure or confident of reliability.Must say ladies at generac call center were nice enough even though they seem to have no input to actual replacement logistics or info. Keep your incident number when calling as this will save the aggrevation of hearing "contact your local dealer". Dealer delivered in 3 days of having received new generator.Was told warranty would start over as it broke the first time it was suppose to work. We will see,Hope it performs from here on out.

    Bookmark   December 9, 2008 at 3:01PM
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I have a 15KW Generac Generator that is not sensing the utility, therefor it will not start when the power goes out, the unit does work but I've got to turn off my main feed breaker and manually start the generator. Can this sensor be changed out easly and where is it in the transfer switch box.

    Bookmark   July 20, 2010 at 12:58PM
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Have you tried calling Generac? That is where I'd start.

    Bookmark   July 20, 2010 at 2:50PM
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Without knowing the model number of your generator I won't warranty these answers, but they are good for 90 percent of small Generacs.

(A)"Can this sensor be changed out easly..." If you mean by the average homeowner, probably not.

(B)"...where is it in the transfer switch box"...utility voltage sensing is not done in the transfer switch for most air cooled models. Your failure to realize this is a factor in answer A.

Also, it is advisable to be in a sitting position well away from breakable objects when inquiring about pricing of replacement parts.

    Bookmark   July 20, 2010 at 9:57PM
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