autostart generator Generac? Kohler? other?

[anwalt]

Considering a backup generator in the range of 7kw on nat gas. Interested in feedback from members with experience.

On line the only comment I saw on Kohler complained of the noise level.

Generac comments are calling for 1in gas line. Kohler says its connection is 1/2in.

My meter will be ~60 ft from genset w/ 3/4 in pipe.

thx,
tom

[blackhat]

Being a Generac tech I won't comment on the relative merits. Generac's sizing for gas sounds right but I don't have my tables at hand. I can check later. What makes you think you can run 60' of 3/4"?

[jteneyck]

17KW whole house Generac here. It's located about 60 ft from the gas meter, and is connected by a 1" (?) run of trac pipe. But I really didn't care, I hired a certified Generac contractor when I decided to get a generator. The other decision I made was to go big. The cost for a 7 KW vs a 17 KW just isn't that great. At 7 KW you will have to choose which circuits you want connected. At 14 KW (I think) and greater, you can have a whole house generator with every circuit connected. When the power goes out, life goes on as if nothing happened.

John

[R Clark]

The place we bought last year already had a 7KW generator installed. Hooked to propane.

I wish it was bigger...lots bigger. Our heat comes from a heat pump. That means if it goes out in winter, there's no heat beyond a couple of mild output gas fireplaces. In a cold weather emergency, I'm going to have to bring in my 60K BTU propane heater that runs on 110 just to make sure the pipes don't freeze.

The 7KW generator will power some lights, the water well, a refrigerator, and a microwave, and I'll still have to watch it closely.

Go bigger.

Can't talk to either brand.

[daddo]

Out of curiosity, I was wondering.
How long could one expect natural gas pressures to stay useable after a power outage?
Aren't the stations run with elect pumps?

[Robert Adams]

daddo said:

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Out of curiosity, I was wondering.
How long could one expect natural gas pressures to stay useable after a power outage?
Aren't the stations run with elect pumps?

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Nope electric pumps are way too weak. The small pump stations use big diesel engines running natural gas. The big ones use an LM1500 and the really big ones use an LM2500. They suck down nat gas at a good pace but they put out quite a bit of power via a power turbine that runs a pump. The lm1500 puts out around 20k shaft hp. Running a generator instead of a pump it's around 1mw output.
The lm1500 if s the industrial version of the j79 which was used in a ton of planes. One of the loudest engines with an afterburner.

[Estrogen Hostage]

Around here the compressors are mostly large internal combustion engines that run on the natural gas itself.

[blackhat]

Same here.

[daddo]

Are the engines self sufficient or do they rely on their being pressured natural gas to feed them from another pump station?

[blackhat]

They rely on incoming pressure. Keep on mind that those stations are actually just boosters and the system is much like the electric grid with multiple paths all interconnected and multiple feed points. Unlike the electric grid, there are merois large storage nodes connected to the network. Nat gas is an extremely reliable energy source.