Generators

[GMCAMARO]

We live in area that seems to lose power frequently. So we are now in the market for a generator. I had my eye on Northern Tool 15KW, Guardian. My math says I can run my whole house with AC and the garage. Anyone have any experience with Guardian generators? Home depot sells the same one. Advice would be appreciated.

 

[wakeboarder311]

they arent bad units but if you go behind home depot you will see they have a kohler unit installed for their store

 

[katmat]

I just installed a 13 kw unit from home depot. it came w/ a transfer switch/ 12 circuit sub panel. The generator will put out 55 amps @ 240 volts. I am able to run 2 frig., 2 gas furnaces, 2 smp pumps, 1 3ton a/c unit, 2 bedrooms, kitchen lights, & 1 spare circuit. I paid $2700.00 for it. If you go to home depot, go to the pro desk & tel them you want it to go thru the bid department. They send it out to the main office for special pricing. I also just ordered 2 other generators from them for 2 other homes (1- 7kw & 1- 100 kw)
Matt Murphy

 

[mikester]

I hope you mean 10KW not 100KW. I could power up every house on my street with one that big ! I have a Generac 7.5KW portable. I still havent put in a transfer switch but I just plugged it in in my garage and backfed my house. Yes the main was shut off !!!! If I had to do it again (or if I had the extra cash) I would get a diesel automatic whole house set. They run at 1800RPM and can go forever. I thought about propane but I figured if the tank ran out I wouldnt be able to get it filled.

 

[Sundowner]

I have a 7.5kw generac guardian for my house. I lose power a lot, and floor level of my basement is 4 feet below the water level of the lake in my back yard. It wasn't a hard choice for me to make. It's set up to power the fridge, the sump, the septic pump. the well pump and few circuits around the house. you don't NEED to power you whole home with itfor a ~4 hour outtage, and the generator isn't really designed to run for days on end, so don't go too crazy with oversizing it.

I called around, Home Depot had the best installed price, and the local electrican who had the contract to install them for HD was one of the best in the area. The thing has saved my **** a bunch of times. I like that it's plumbed right into thenatural gas and turns itself on whne there's an outtage. no more running home in heavy storms.

Iwant to say al lsaid and done, the whole mess was $3500-ish

 

[Dave Carney]

I have a 15kw Guardian (LPG model) that we bought new 5 years ago, it has 250 hours on it now (we once lost power for 8 days straight and it ran continuously except for an oil change). Had to put a new starter in it last fall, other than that, no problems at all. The ones made after about 2003 got a different starter that seems to be reliable.

The biggest thing is to make sure you have a big enough gas line, in most cases a new bigger gas line will have to be run to the house, or, a seperate one for the generator....it draws about 260,000 btu when running, so take that, plus all your other gas appliances, add them up, and you'll see you need a plumber.

 

[boiler7904]

I hope you mean 10KW not 100KW. I could power up every house on my street with one that big ! I have a Generac 7.5KW portable. I still havent put in a transfer switch but I just plugged it in in my garage and backfed my house. Yes the main was shut off !!!! If I had to do it again (or if I had the extra cash) I would get a diesel automatic whole house set. They run at 1800RPM and can go forever. I thought about propane but I figured if the tank ran out I wouldnt be able to get it filled.

Having the main shut off is not a guarantee that you aren't backfeeding power onto the grid and possibly injuring or killing a lineman working in your area.

The only code approved method for feeding power from a generator to a building's power system through the panel is with a transfer switch. Only other option is to use drop cords from the generator to the load itself.

Um, if you couldn't get a propane tank filled, how would you get a diesel tank filled?

 

[CraigFL]

...Um, if you couldn't get a propane tank filled, how would you get a diesel tank filled?

I think the worry may be that trying to find propane when there is a power outage would be more difficult than trying to find diesel...

 

[JohnK007]

Was looking through the Northern Tool catalog while on the throne this morning. I see Guardian offers both air cooled and liquid cooled set ups. The air cooled is naturally cheaper. Aside from price would there be an advantage to going this route? Correct me if I'm wrong but if during an extended blackout lasting say a few days, which happened to me last year, wouldn't there be less likelyhood of the liquid cooled unit from overheating? Both were LPG/NG powered.

 

[thammel]

I have an 8kw dyna-winco standby unit that I installed. It is not big enough to power an ac or heat pump, but I made that decision to save $. It covers everything else - 5 fridges, well pump, blower for propane furnace, plenty of lights, etc. So you decide on how big you want it.

Couple of comments:

1) If you have a buried propane tank as I do, then propane makes a lot of sense.
2) The automatic standby unit is a whole lot easier and practical (comes on in the middle of the night, works if you're not home, easier for the wife, etc.)
3)I prefer a separate automatic transfer switch and new subpanel. This way you're not limited by the number of circuits (6, 8, 12) that guardian provides. Bear in mind, however, that a good transfer switch will not be cheap.

I did the entire installation myself except for the propane hookup. Everything was flawless and has worked great!

Tom

 

[Ira]

Was looking through the Northern Tool catalog while on the throne this morning. I see Guardian offers both air cooled and liquid cooled set ups. The air cooled is naturally cheaper. Aside from price would there be an advantage to going this route? Correct me if I'm wrong but if during an extended blackout lasting say a few days, which happened to me last year, wouldn't there be less likelyhood of the liquid cooled unit from overheating? Both were LPG/NG powered.

With the standby (i.e., permanently mounted) generators, there are two big issues to consider with any residential brand/size...air cooled (A-C) vs. liquid cooled (L-C), and 3600 RPM engine speed vs. 1800 RPM engine speed.

L-C is better. 1800 RPM engine speed is better. Both increase generator lifespan significantly. I think I've seen where the life expectancy of a 3600 RPM A-C generator is 3000 running hours. I can't remember how much L-C and/or 1800 RPM adds to the lifespan, but it is significant. In many cases, the 3600 RPM A-C generators use engines that are similar in design to large mower engines. L-C 1800 RPM models use engines that are more like automotive/truck gasoline engines. Some are actually modified engines from GM, Ford, etc. I've only seen a few 1800 RPM L-C that are under 20kW. There are a few 3600 RPM L-C models around 20-25kW. I've never seen an 1800 RPM A-C model. 1800 RPM L-C models are significantly more expensive than an equivalent output 3600 RPM A-C models, but they don't overlap very often. Under 22kW? Most are 3600 RPM A-C. 22kW or more? Usually 1800 RPM and L-C.

Lastly, the cost of the automatic transfer switch (if it isn't included in the "package") and professional installation/startup/checkout can exceed the cost of the generator.

Regards,
Ira

 

[JohnK007]

Thanks Ira, good info to remember when I go shopping for a stand-by. Is it common to find an 1800 rpm genset that's LPG/NG powered? Or are most of those diesel?

 

[Dave Carney]

Anybody that uses up a 3000 hour air cooled engine in their lifetime....should probably consider moving! Most folks won't get to one third to one half that amount.

 

[Ira]

Thanks Ira, good info to remember when I go shopping for a stand-by. Is it common to find an 1800 rpm genset that's LPG/NG powered? Or are most of those diesel?

Most 1800 RPM liquid cooled residential standby generators I've come across in my research are LPG/NG powered.

Here's a couple of websites that have quite a few models from different manufacturers...

http://www.nooutage.com/autogen.htm

http://www.generatorjoe.net/subcat.asp?0=247

Neither site sells Guardian. Their website is here...

http://www.guardiangenerators.com/Default.aspx

I do not work for or represent any of the companies above. Also, another potential benefit of 1800 RPM over 3600 RPM is that the lower engine speed usually means a quieter generator. Since most people place them very close to their house, this could be an issue. You can find the sound rating for most models in their spec's. In my case, when I get one it will be 200 feet from my house on the other side of my man cave, so noise is not a big thing.

One of the things I've struggled with while trying to decide what to get is buying online and having an "independent" installer do the installation versus buying from a dealer that supplies the gen and does the installation. You can certainly save a lot on most brands of gens by buying online and having an independent do the installation (or do it yourself). Note that most manufacturers require someone that is certified to do the initial startup or else they may void the warranty. The dealers I checked with in Houston usually give little if any discount on the generator. I've been told that not buying from a dealer puts you at the bottom of their list when problems occur, and that is understandable. However, a generator is not something you want to have to wait on service for if something goes wrong when you need it to work. The good thing about standby generators with an auto transfer switch is that the weekly exercise cycle they go thru should help cause problems to crop up during non-emergency times.

Regards,
Ira

 

[Ira]

Anybody that uses up a 3000 hour air cooled engine in their lifetime....should probably consider moving! Most folks won't get to one third to one half that amount.

You're right. 3000 hours is 125 days of continuous operation. I don't recall what the estimated life of an 1800 RPM liquid cooled unit was, but I think it was significantly longer, maybe twice as long. I equate (maybe incorrectly) increased lifespan with somewhat increased dependability. If these things don't work at the moment you need them to, they're pretty much worthless.

1800 RPM liquid cooled generators (instead of the same size 3600 RPM air cooled) may be overkill for most people, but then again, most of the people on this site would probably plead guilty to a little overkill on things like this (e.g., their garage).
Regards,
Ira

 

[Dave Carney]

With regard to noise, I have an air cooled 15kw sitting the minimum allowable distance from my house (18") We have 6" R19 exterior walls, but the only way to hear the generator running while inside, is to be in the room immediately adjacent to the generator, and even then it's not much noise at all. Less than a microwave, small fan, electric coffee pot, etc.

 

[Stuart in MN]

1800 RPM liquid cooled generators (instead of the same size 3600 RPM air cooled) may be overkill for most people, but then again, most of the people on this site would probably plead guilty to a little overkill on things like this

One thing to remember is that for best results the generator shouldn't be too oversized either. Otherwise you can end up in a situation where the engine is basically idling all the time, and just like letting your car idle excessively it's not good for it. The generator should be under load when it's running or otherwise you periodically need to 'blow out the carbon' to keep it happy.

 

[Ira]

One thing to remember is that for best results the generator shouldn't be too oversized either. Otherwise you can end up in a situation where the engine is basically idling all the time, and just like letting your car idle excessively it's not good for it. The generator should be under load when it's running or otherwise you periodically need to 'blow out the carbon' to keep it happy.

Is that really applicable for a generator? Depending on the generator model, it's either going to run at 1800 RPM all the time or 3600 RPM all the time. Although I think some of the Guardian 3600 RPM models actually run at a lower RPM during their weekly self-test, thus the "Whisper quiet test" feature.

To me, it sounds more like the difference between a truck's engine turning 1800 RPM (or 3600) going down the road empty versus the engine turning at 1800 RPM (or 3600) going down the road with a heavy load. Neither quite the same as idling.

For many people (like me), a standby residential generator that is 15kW or larger will be running at a low percentage of capacity unless the A/C or some other power hungry appliance is running, which may happen only intermittently. Depending on the time of the year, or when my wife wants to bake something in the electric oven (the rest of our appliances are LPG), it may run at 25% or less for the length of an outage.

Regards,
Ira

 

[Stuart in MN]

Residential generators do tend to have to run under varying loads, as people turn on and off stoves, the furnace runs, etc. as compared to industrial or commercial applications that are usually more constant.

I don't think you'd have any problems with a 15kw or so gas generator. It does have to be big enough to run essential loads, even though much of the time it may just be powering a few light bulbs.

On the other hand, Diesel generators are sensitive to running at light load - they can suffer from wet stacking or 'slobbering'. Unburned fuel collects in the exhaust system, and eventually gums things up - in extreme cases, you'll get a black goo oozing out of the exhaust pipe. Here's a couple explanations.

http://en.wikipedia.org/wiki/Wet_stacking
http://www.gmag.org/forum/forum_posts.asp?TID=402&PN=1&mbDate=8/1/2005 10:16:01 AM

I was mainly thinking about how some guys figure if big is good, too big is even better...for instance, I saw someone selling a 60kw generator on Craigslist the other night for a low price. While it may be tempting, something like that wouldn't be a good choice for home use.

 

[Blown71X]

Having the main shut off is not a guarantee that you aren't backfeeding power onto the grid and possibly injuring or killing a lineman working in your area.

Oh I would just love to hear the explaination for this.....


And believe me i`m not condoning backfeeding by any stretch.


Rick

 

[JohnZ]

Detroit Edison (now called DTE) is our mickey-mouse electric utility, with failures for no apparent reason that may last five minutes or five hours or more. We tired of the hassle - had a 7.5KW portable generator and small transfer switch wired in, but we had to be home to drag it out, plug it in, and keep feeding it gasoline. After losing two freezers full of food twice in three months when failures occurred when we were gone over a weekend, I had an 18-KW Generac/Guardian fully-automatic natural gas-powered system installed in June, 2003.

Eight weeks later we had the famous 3-day northern grid failure, and all we had to do was reset the digital clocks - it paid for itself right then as far as I'm concerned. It runs 10 minutes a week for its self-test (about 8 hours a year - hardly worth worrying about in terms of engine wear), and has probably run about 120 hours of actual full-load time during failures since 2003. It needed a starter last year, otherwise has been trouble-free.

The gas company installed the high-flow meter and secondary regulator free, and 120' of 2" iron pipe through the basement from there to the generator at the other end of the house was part of the generator installation, along with wiring the transfer switch to the circuits I designated. More details and photos at:

http://www.villagephotos.com/pubbrowse.asp?folder_id=359956

 

[mikester]

Having the main shut off is not a guarantee that you aren't backfeeding power onto the grid and possibly injuring or killing a lineman working in your area.


I just came back to this post. Sorry I didnt get here sooner. So boiler7904, are you saying that shutting my main off isnt going to stop my generator from backfeeding the lines going to the poles ?? WTF ???? What happens when Im working in the panel and I shut the main off ? Are you telling me that I can still get fried even with the main disconnected ? Common sense tells me somethings wrong with that. As far as a manual transfer switch, I know thats the best way of doing it. I planned on having one put in right after I bought the generator but I just never got around to it. I looked at the GenTran 10 circuit switch but things like that some how always wind up on the back burner.