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? about natural gas generator

Posted by jeanie_beth (My Page) on
Mon, Jul 4, 11 at 19:37

I have a portable Generac GP7000 that is gasoline powered. I would like to have it converted to a natural gas/propane using a kit from US Carburetion as I have natural gas.

The kit would cost me $267.00.

The problem is that my "Gen In" plug, electric meter, transfer switch and breaker box are all on the NORTH end of the house on same wall.

The natural gas meter is on the SOUTH end of the house 60' away from the opposite side of the electric meter/genset inlets.

The natural gas pipe from the meter goes up the south side of the house and into the attic heading straight north.

It T's off & branches down a wall to feed a gas central heat unit, which I would NOT use in a power outage.

The pipe continues northward in attic and branches down to my gas range, which I would NOT use in a power outage.

The gas pipe continues north in attic and branches down to a 1/2" yellow hose add-on feeding an outlet to a gas grill on the west side of the house. Finally the gas pipe continues northward into the laundry room which houses my transfer switch & breaker panel and goes down a wall to my gas water heater in the same room--which I would use in a power outage.

The gas pipe in the attic that L's down to the water heater is only 10 feet from the NORTH wall by my GEN IN plug.

Most natural gas generators I see are hooked right up near the gas meter and conversion kit manufacturer says to use a 3/4" or 1" hose on ground to run to generator. This hose would be about 100" by the time I snaked it around corners of house etc...this would be very expensive too.

My gas meter does have one of those little removable plugs on my side of the meter as it elbows from meter and enters house--this is where people say to hook up a generator too with a cutoff there.

I am trying to avoid a costly hose. Plus the gas meter is right by my bedroom window--don't really want a genset running right there, plus my neighbor's room is just a few feet away. The NORTH end of the house has nobody next door to me except a busy highway, plus the north end of the house is the laundry room and noise in house from genset is no problem.

It would be much more economical for a plumber to tie into the gas pipe in the attic where it elbows down on the end of the gas pipe run and goes to water heater and exit this pipe out of the north end of the house and down to genset--less than 16' iron piping total.

The 1/2" gas grill connector coming out of exterior west wall is only 5' from my genset plug, but again, this line is only 1/2"...don't know if it would work or not by just connecting a 5 foot run of 1" hose to it & going to genset on exterior of house.

My question is do any of you have a portable natural gas generator...if so how big of a gas pipe do you need to power a converted gasoline to natural gas genset?

This may be a plumbing question. My apologies if I posted in wrong forum.


Follow-Up Postings:

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RE: ? about natural gas generator

My propane powered 80KVA generator is only feet from the propane tank and has a rather hefty size pipe running to it. I suspect you'd be best served by following their instructions even if it means running a new line all the way back to the meter/regulator.


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RE: ? about natural gas generator

Assuming 1000BTU/cu.ft. gas, your set will consume about 140-150 cu.ft. per hour at full load. Give that information to a competent gas installer and the pipe size needed can be calculated.


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RE: ? about natural gas generator

The manufacturer already mandated 3/4". That's pretty much what you need to go with. Unlike water, there's not much friction loss with natural gas.


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RE: ? about natural gas generator

Thanks guys for the replies. I guess what I was really meant to ask, is if that is a 3/4" line that is in the attic, is it OK to hook to the end of the 3/4" pipe (where it goes down to water heater) and go to the genset even though there are T's off to the furnace and stove BEFORE the gas goes to the genset or does the pipe just need to be a dedicated 3/4" line coming right out of meter and not have any branching to other devices? In other words, is gas flow more powerful coming right off the meter and straight to the 60' or so underground to the genset or is it same pressure as coming out of meter, up wall, into attic, to other gas devices and then to genset via attic?

I'm sure that the main gas line in attic is indeed 3/4" with 1/2" lines branching down to stove, furnace, gas grill.
I just need to crawl in attic and see but it is 108 degrees outside now and I'm sure it is hotter up there.


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RE: ? about natural gas generator

I wonder why the gas appliances and furnace would not be used in a power outage? If Winter, how to heat the house? The purpose of the generator is to supply the relatively small power requirements of the furnace so that it is usable.


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RE: ? about natural gas generator

Our winters are mild--we hardly even turn on the gas central heat in the winter because it dries my skin out and causes severe nose bleeds on myself. As for cooking with the gas range, if the power outage were in the winter, I would only briefly cook with it. If the power outage were in the summer, I wouldn't cook on it at all due to adding more heat to the home. I never use the oven on it from May-October even with power on..if I use the stove at all in summer, it is briefly stove top--we grill outside just about everyday on the patio.

If the winter is cold and power is out for a long time, we have a 12' x 22' insulated metal building with a 8000 BTU window unit and natural gas heater and a trundle bed in it and PC & TV--all of which has its own separate transfer switch and genset if worse comes to worse and I need heat in winter.


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RE: ? about natural gas generator

Hi,

I have a generator which is hooked up to a propane tank, 20,000 Watts Cummins Onan RS 20,000. This has a 4 cylinder Ranger engine made by Ford.

The gas line is 3/4 inch and runs from the propane tank. The gas line by code is limited to 100 feet (New York state). And you cannot have an underground join in the gas line.

The gas line does not have to be very big because the propane is under presure and when under pressue it is actually a liquid. Right by your generator the gas line will connect to a Regulator. This regulator "converts" or more accurately will allow the propane to expand. The propane then becomes a gas and be at a lower pressue. This gas is then passed into the "propane carbaretor" which you will mount on your genset.

So a relatively thin line can feed quite alot of propane because of the liquid to gas transformation.

Things to watch out for a Carbon Monoxide poisoning. I would not site the genset near any windwows near a house. Also having a high pressue gas line snaking all over your house could be a fire risk and may not be allowable by code.

Note if you bury the propane line, you only have 100 feet to play with and you have to bury it deep. This means expensive. Think a back hoe or some mechanical digger.

If you are going to all the troule with the gas line etc., maybe it would be worth it to consider a new genset as well.

warmest regards, Mike.


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RE: ? about natural gas generator

"The manufacturer already mandated 3/4". That's pretty much what you need to go with. Unlike water, there's not much friction loss with natural gas."

Inlet size does NOT determine needed pipe size to deliver gas.
There IS enough pressure drop in longer runs (or lots of turns) to require pipe size adjustments.

The tables are in the back of the plumbing code usually.


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RE: ? about natural gas generator

You can run 3/4 pipe from the regulator for 25 feet maximum, deduct 3 feet for each elbow. If you use 1" pipe the run can be up to 100 feet, also deduct 3 feet per elbow.
I would recommend running the line outside the house, it is much easier. To see if your home's internal lines can provide the correct flow, you can measure the sizes and distances or ask a professional.


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RE: ? about natural gas generator

Consider scrapping the idea of modifying a gasoline generator to use natural gas. Use what you have since it is more efficient than natural gas. Look at the efficiency of gasoline versus propane and natural gas and the cost of each. Many believe that a propane or natural gas burning engine will be trouble free. It's still an engine that requires maintenance. Don't be misled by the salesmen! Furthermore, you will pay dear for service work on the natural gas unit versus a simple 4 cycle gasoline engine. Consider who you must have perform maintenance on each.


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RE: ? about natural gas generator

The maintenance on my Natural Gas generator takes me a couple of hours per year. It's just an oil, filter, and coolant change. The longest part is running the spent coolant over to the county seat where the closest recycling facility is.


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RE: ? about natural gas generator

"Consider scrapping the idea of modifying a gasoline generator to use natural gas. Use what you have since it is more efficient than natural gas. Look at the efficiency of gasoline versus propane and natural gas and the cost of each. "

The big advantage of natural gas is if you lose power for an extended amount of time. If you are running a gas generator you will need to keep several gas cans handy and if the power is out in the area you will not be able to get more since the pumps will not be working. With natural gas unless there is a problem with the supply lines you can run for days and not have to worry about running out of fuel.


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