I have worked for several cellular companies over the years and at one of them we threw out Generac. The National sales manager came to the company and asked why we no longer bought their generators. I asked him if I could go to the local auto parts store and buy a fan belt, radiator hose, fuel pump, starter motor or an oil filter. he said no, but the company had several warehouses around the country that were stocked and could ship the next day. Told him that doesn't do me any good when I have a major storm going on and the roads were basically shut down from the outside world.
Told the sales manager to come back when his company used off the shelf parts and not all special order. It cost him about 40 to 80 generators a year that we were putting out at new cell sites. He left sputtering to himself and never heard from him again.
The cellular companies I worked for seemed to like Katolight and Kohler generators. I ordered them with John Deer diesel engines and could get parts for them at just about any auto store I went to.
The reason we landed on using diesel was like others have said, you can get it almost any place. It is easy to transport. The only headache you have is to make sure you keep the fuel conditioner in the fuel tank for both hot and cold climates. That way you don't get fungus growing in the hot climates and the fuel doesn't gel in the cold climates.
I don't recommend placing any generator on a bed of paving blocks. Your much better off pouring a slab for the generator. This way you can bolt it down. That way the small units stay there and don't walk off in the middle of the night with someone that wants it better than you. The larger units use the slab to help kill the vibrations and it keeps them in one place.
If you do look at a diesel generator, the cost will be more up front. But you will be glad in the long run if you have to go hunting for fuel. It will transport nice in almost any liquid container. However I point out that you should be transporting the fuel only in an approved container for it.
Fuel is always an issue with any generator you plan on using. Figure out how much fuel it will use at full load over a 24 hour time span. Then multiply that by what ever number you need to fit your location. Don't forget that if the power is out, the local gas station probably won't have power to run his pumps either.
As for looking at running an air conditioner, look at the name plate where the power use is listed. There will be a locked rotor amp rating. This is what you need to get the compressor started. Generally it takes 3 times the normal running current to crank over the air conditioner from a cold start. Many have an option to add what is called a "Soft Start Kit" to it. Make sure you get that installed so the unit will start easier. Plus it helps to keep your power bill down some. It actually helps reduce the dead load starting current. Also ask about a time delay relay to be installed. This keeps the unit from starting up the moment the power comes back on.
If you have a well pump, don't forget to add this to the items that has to be powered by the generator. You can't live very long without running water in the house. You can deal with no hot water, but when the wife says there is no water to flush the toilet, your going to catch it big time.
There are a number of auto transfer switches on the market. If your looking to put in a full time backup generator for the house, I would look at adding a second breaker panel. Put all your emergency powered devices on it and have it on the load side of the auto transfer switch. This way you don't have to run around and shut off the breakers to locations and devices that you can do without to shed the total load from the generator.
You will have no problems finding an 1800 RPM generator in the larger sizes. It's the units below the 30 KW point that it's a roll of the dice. The reason you find the 3600 RPM units is that they are cheaper to make when they run at the higher RPM.
Here is one word of caution about the larger units and the engine speed. Generac likes to use a smaller engine on many of their units and run them through a gearbox. This allows the generator to spin at the 1800 RPM, but causes the engine to spin at 3600 RPM or more. I got suckered into this one time with a 100 KW Generac unit. Didn't see the specs on it until it was installed. It keeps the engine cost down, but it runs up the maintenance costs. You need to change the oil more often.
The other reason I shy away from Generac, is they use a real cheap voltage regulator. If it gets wet, you loose you regulation. Found this out on several high wind and heavy rain conditions. Had a generator running during a storm and suddenly the lights went out. Generator was still purring away, but nothing came out for power. Took a hot air gun and about half an hour of blowing hot air on the circuit board before it would work again. Had both a Kohler and a Katolight running beside the Generac and they both worked flawlessly.
Here is another heads up on an asperated engine running on either natural gas or propane (LP). The gas regulator inside the generator uses the normal atmospheric pressure to function. If you have high gusty winds or a tornado go by, the gas regulator looses it's mind and can't regulate the flow of the fuel correctly during these gusts. You either get too much fuel or too little. Either way, the engine will probable come to a stop. You crank it up again and your good to go till the next time.
Had the gas regulator blow my mind at a couple of cellular sites that would keep loosing power during a heavy gusty storm. It took a number of phone calls and talking with some people that knew the generators real good. You can't just bag the entire cabinet up like a shipping package. What we ended up was to block off the side vents nearest the regulators and relied on the end vents to provide enough cooling.
Then we had to deal with the mud wasps in the south. They seem to love the smell of the propane and natural gas at the regulators. They would build their nests in the vent holes of the regulators. The solution was to go to the auto store and buy some of the bronze fuel filters ans screw them into the vent holes. This provided the needed filtering to keep the wasps out and allow venting.
Never a dull moment in the generator field. Lets hear from others with their problems and solutions.
Jim
Size-wise I am pretty well set on 20Kw LP but brand???? and Installer???
