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Temporary lpg hookup for testing (15.0JC)


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  #1  
Old 10-01-2006, 06:40:47 PM
bkahler bkahler is offline
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Default Temporary lpg hookup for testing (15.0JC)

After reading some older posts I found mention of someone using two 20 lb bottles to test with. I'm assuming the reason for two bottles is to try and provide a longer run time before the bottles freeze. So with that in mind I've started collecting the fittings needed to try and test run the genset before I buy. What I've got so far are two bbq propane regulators with hoses, two 20 lb bottles, garretson KN regulator and fisher regulator. Along with an assortment of fittings to tie everything together. I have't got the hose that goes from the KN to the carb yet.

The way I'm thinking of hooking it up is bringing the two bbq lines/regulators from the bottles to a Tee that feeds the Fisher regulator. The Fisher regulator then feeds the KN regulator which then feeds the carb.

The section from the fisher regulator thru to the carb is pretty much how it was originally setup when I got it. I'm just teeing into the Fisher with two bottles instead of one.

Does this sound like something that will work for a quick test run to see if the genset starts and runs and at least produces some voltage?

Assuming the genset is good, and assuming full load operation (I know thats not likely to happen!) what kind of LPG consumption could I expect per hour?

Thanks,

Brad
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Old 10-01-2006, 09:03:45 PM
VaughnSimon VaughnSimon is offline
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Default Re: Temporary lpg hookup for testing (15.0JC)

First of all, there should be some factory information somewhere that tells you what the fuel consumption should be. Failing that, we could always look at the specification for other 15KW generators to get a ballpark idea. But hell, that ainít no fun, so letís figure it out to see if we can come up with a reasonable figure.

A few things that we know for sure is that:

1) A kilowatt hour is 3,413 BTUs so 15 kilowatt hours is 52,000 BTUs
2) One gallon of Propane has 95,475 BTU
3) A 20# tank has about 4.4 gallons of propane so 420,000 BTU
4) At 100% efficiency, a 20# tank would give you 8.08 hours
(420,000/52,000)

Now for the only guess: What is the efficiency of your generator?
If we assume 15%, then 8 X .15 = 1.2 hours

How did I do?

Vaughn
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Old 10-01-2006, 09:08:40 PM
Jim Davis Jim Davis is offline
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Default Re: Temporary lpg hookup for testing (15.0JC)

Brad what size is the fisher regulator? The grill regulators will freeze up fast because they will not handle the volume you need. You need a bigger regulator for a lot more flow and your propane dealer will have one. I think the KN needs about 8"WC of pressure. I bought a "pigtail" for testing. It is heavy small copper tubing about 8 inches long with a male bottle connector (POL fitting) at each end. I don't know why they sell them but they are at your local propane dealer. I cut it in two and soldered in more tubing with a pipe fitting to hook to my red regulator to hook to my Impco. I had it upside down feeding liquid.
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Old 10-01-2006, 09:22:31 PM
bkahler bkahler is offline
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Default Re: Temporary lpg hookup for testing (15.0JC)

Quote:
Originally Posted by VaughnSimon View Post
First of all, there should be some factory information somewhere that tells you what the fuel consumption should be. Failing that, we could always look at the specification for other 15KW generators to get a ballpark idea. But hell, that ainít no fun, so letís figure it out to see if we can come up with a reasonable figure.

A few things that we know for sure is that:

1) A kilowatt hour is 3,413 BTUs so 15 kilowatt hours is 52,000 BTUs
2) One gallon of Propane has 95,475 BTU
3) A 20# tank has about 4.4 gallons of propane so 420,000 BTU
4) At 100% efficiency, a 20# tank would give you 8.08 hours
(420,000/52,000)

Now for the only guess: What is the efficiency of your generator?
If we assume 15%, then 8 X .15 = 1.2 hours

How did I do?

Vaughn
Vaugh, not sure just how well you did yet!

I did find the following info on an old forum post, apparently the 15.0JC uses 110 cf/h propane under full load. Not sure how that relates to lbs/hr but I'll see what I can find for that.

I'm assuming the 1.2 hours your calculations came up with referred to 1.2 hours per lb of lpg. If so thats not to bad for emergency use especially if thats for max load. Still cheaper than a motel.

Thanks,

Brad
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Old 10-01-2006, 09:25:28 PM
Jim Rankin Jim Rankin is offline
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Default Re: Temporary lpg hookup for testing (15.0JC)

well two bottles with regulators will be better than one, but probably best of all is to use just the pigtails to connect the bottles to one regulator that can handle the demand. Then if the bottles start to frost up, you can sink them in a water bath or set them in front of the cooling air discharge to keep them warmer.
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Old 10-01-2006, 09:31:42 PM
bkahler bkahler is offline
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Default Re: Temporary lpg hookup for testing (15.0JC)

Quote:
Originally Posted by Jim Davis View Post
Brad what size is the fisher regulator? The grill regulators will freeze up fast because they will not handle the volume you need. You need a bigger regulator for a lot more flow and your propane dealer will have one. I think the KN needs about 8"WC of pressure. I bought a "pigtail" for testing. It is heavy small copper tubing about 8 inches long with a male bottle connector (POL fitting) at each end. I don't know why they sell them but they are at your local propane dealer. I cut it in two and soldered in more tubing with a pipe fitting to hook to my red regulator to hook to my Impco. I had it upside down feeding liquid.
Jim, thanks for the reply.

I'm not sure on the fisher regulator. The only marking I can find that makes any sense on it is 722V.

I did notice on the bbq regulators that they had only about 1/16" or smaller orifice feeding the regulator. I'm hoping not to have to spend much money to test the genset. If I can show that it runs and generates my chief financial officer (aka wife!) says its ok to buy and install. If I can get a minute or two of run time that should be sufficient to see if it produces anything. Or am I wrong here? I've never dealt with lpg other than for heat before so this is all new to me.

Something else I ran across on one of the smokstak forums was mention of an accumlator on the 8"wc side. I'm guessing this might be a tank setup in the line to possibly act as a (for lack of better words) surge tank.

I do have a regulator off our our old airstream trailer. Its designed for 2 bottles into one. It was setup to feed the water heater and furnace and stove. Would this be a better choice than a bbq regulator?

Thanks for the advice (keep it coming!)

Brad
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Old 10-01-2006, 09:40:12 PM
bkahler bkahler is offline
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Default Re: Temporary lpg hookup for testing (15.0JC)

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Originally Posted by Jim Rankin View Post
well two bottles with regulators will be better than one, but probably best of all is to use just the pigtails to connect the bottles to one regulator that can handle the demand. Then if the bottles start to frost up, you can sink them in a water bath or set them in front of the cooling air discharge to keep them warmer.
Jim, in a previous post to Jim Davis I mentioned having an lpg regulator from an airstream trailer. I'm wondering if this would provide better flow than a bbq one would? With a furnace, water heater and stove all possibly drawing at the same time I would think it would have to be. I'll check it over closer tomorrow to see what info I can find on it.

Barring that I'll see if someone at work might have a bigger regulator available.

Thanks,

Brad
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Old 10-01-2006, 10:11:12 PM
Jack Hottel Jack Hottel is offline
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Default Re: Temporary lpg hookup for testing (15.0JC)

Brad,
Vaughn isn't too far off. Onan's spec on the 15.0JC is 110cf/h of 2500btu/cf propane at full load. Using his value of 95,475btu/gal we get 38.19 cf/gal which gives ~2.88gal/h. His result yields ~3.7 gal/h. Suffice it to say you can do a lot of testing if you can avoid freeze up. I agree a regulator bigger than a gas grill type is the way to go. I had borrowed one and don't remember what it was exactly(except that it was adjustable), but with it I was able to get 15 KW out of the unit for about a minute on a 20 Lb. bottle before fuel starvation set in.
Small loads could be supported for long periods. Keep the bottle in the exhausted cooling air. I was using a boiling water load and wished I could have put the bottle in that.
Have fun. The JC is a good unit.
Jack Hottel
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Old 10-01-2006, 10:12:10 PM
Jim Rankin Jim Rankin is offline
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Default Re: Temporary lpg hookup for testing (15.0JC)

The travel trailer regulator sounds promising.

I believe the pigtails are commonly used between the tank and the regulator on all stationary setups. The pigtail allows some flexibility if the regulator or piping gets jostled around or the tank shifts over time. Ridgid piping might just crack or crimp in the same situation. Your BBQ regulators should be removable from the tank tapping fitting, so you could just plumb one straight onto your larger regulator and try it if it doesn't already have it's own pigtail.

I wouldn't bother with the two tanks unless you are planning on an extended run and need the extra capacity. Instead use some method of warming the cold tank. A safe one is to set it in a container and run a garden hose through the container and let it spill over the other side. Can't get too hot if you don't use hot water (unless you have to have it), but will not allow it to freeze either.
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Old 10-01-2006, 10:38:26 PM
bkahler bkahler is offline
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Default Re: Temporary lpg hookup for testing (15.0JC)

Quote:
Originally Posted by Jack Hottel View Post
Brad,
Vaughn isn't too far off. Onan's spec on the 15.0JC is 110cf/h of 2500btu/cf propane at full load. Using his value of 95,475btu/gal we get 38.19 cf/gal which gives ~2.88gal/h. His result yields ~3.7 gal/h. Suffice it to say you can do a lot of testing if you can avoid freeze up. I agree a regulator bigger than a gas grill type is the way to go. I had borrowed one and don't remember what it was exactly(except that it was adjustable), but with it I was able to get 15 KW out of the unit for about a minute on a 20 Lb. bottle before fuel starvation set in.
Small loads could be supported for long periods. Keep the bottle in the exhausted cooling air. I was using a boiling water load and wished I could have put the bottle in that.
Have fun. The JC is a good unit.
Jack Hottel
Jack, glad to hear your efforts worked with the 20 lb bottle. Your comment about getting 15 KW out of yours during testing made me realize I hadn't considered what I would need to do for a potential load test if I can keep it running long enough

I have my trusty 225 ac lincoln welder that I suppose I could fire up and run some beads. Possibly an electric space heater or two as well. There's always something isn't there!

Thanks,

Brad
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Old 10-01-2006, 10:47:18 PM
bkahler bkahler is offline
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Default Re: Temporary lpg hookup for testing (15.0JC)

Quote:
Originally Posted by Jim Rankin View Post
The travel trailer regulator sounds promising.

I believe the pigtails are commonly used between the tank and the regulator on all stationary setups. The pigtail allows some flexibility if the regulator or piping gets jostled around or the tank shifts over time. Ridgid piping might just crack or crimp in the same situation. Your BBQ regulators should be removable from the tank tapping fitting, so you could just plumb one straight onto your larger regulator and try it if it doesn't already have it's own pigtail.

I wouldn't bother with the two tanks unless you are planning on an extended run and need the extra capacity. Instead use some method of warming the cold tank. A safe one is to set it in a container and run a garden hose through the container and let it spill over the other side. Can't get too hot if you don't use hot water (unless you have to have it), but will not allow it to freeze either.
Jim, do you remember what size the opening was on your pigtail? I have a pigtail for our motorhome that has about 1/16" (probably a little smaller) in it but it doesn't have a regulator. Its used for connecting a 20 lb or larger bottle to the motorhome for extended stays. The regulator I have for the airstream bottles is designed to connect to them directly so I shouldn't need a pigtail for that setup. (picture 2 bottle connectors going to one regulator with an outlet hose from the regulator that feeds the trailer)

It sounds like I need to try using the airstream regulator first and see if that gets me enough flow. With that regulator I can hook 2 bottles to it and use the built in valve in the regulator to select which bottle I want to use.

I like your idea on how to keep the bottle(s) from freezing. I've got some 30 gallon barrels that would work fine for that part.

Gee, this is starting to sound like fun

Thanks,

Brad
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Old 10-02-2006, 06:21:09 AM
VaughnSimon VaughnSimon is offline
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Default Re: Temporary lpg hookup for testing (15.0JC)

Quote:
I'm assuming the 1.2 hours your calculations came up with referred to 1.2 hours per lb of lpg. If so thats not to bad for emergency use especially if thats for max load. Still cheaper than a motel.
No, unfortunately I mean 1.2 hours for the whole 20# tank. Remember, a big Home Depot-type portable generater can suck a gallon of gasoline an hour, but a gallon of propane has less energy that a gallon of gas so the engine will burn more of the stuff.

Of course, you won't really ever be using a whole 15 KW, so you won't actually be using that much fuel. It will be more expensive that a motel, but after a disaster there are no motels. Anyhow, now you are finding out why my standby generator is only 4 KW. And even my little Onan CCK could burn nearly $1,000 worh of fuel in a month if I let it. Imagine what a 15 KW could burn!

Anyhow, that RV regulator sounds like the best bet. You don't need anything like full flow to start the thing and check it out. Most of those have a feature that switches tanks automatically. If one tank freezes up or goes empty, it just switches to the other.

Have fun
Vaughn
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Old 10-02-2006, 06:51:16 AM
Jim Davis Jim Davis is offline
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Default Re: Temporary lpg hookup for testing (15.0JC)

Brad the RV setup is the way to go. You will not be running at full load. My 30KW is rated to use 7 gallons of propane per hour but my consumption is an actual 2.65. My guess is yours will be about 1.5 max 2.0 actually running your house. If you need it there will be no motels available. I know from experience and if I need it again I will gladly pay the big bucks for the propane.
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Old 10-02-2006, 07:30:16 AM
armandh armandh is online now
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Default Re: Temporary lpg hookup for testing (15.0JC)

tom has a 15 KW home standby rated 240,000 BTU/HR full load 170,000 at half load, dicks calculator is broken, and harry thinks the estimates are in the ball park
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Old 10-02-2006, 07:46:37 AM
jerry merta jerry merta is offline
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Default Re: Temporary lpg hookup for testing (15.0JC)

the slam valve inside b/q tank will probly stop flow if you try for any large volum flow.
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Old 10-02-2006, 08:46:59 AM
K D Redd K D Redd is offline
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Default Re: Temporary lpg hookup for testing (15.0JC)

Quote:
Originally Posted by Jim Davis View Post
Brad what size is the fisher regulator? The grill regulators will freeze up fast because they will not handle the volume you need. You need a bigger regulator for a lot more flow and your propane dealer will have one. I think the KN needs about 8"WC of pressure. I bought a "pigtail" for testing. It is heavy small copper tubing about 8 inches long with a male bottle connector (POL fitting) at each end. I don't know why they sell them but they are at your local propane dealer. I cut it in two and soldered in more tubing with a pipe fitting to hook to my red regulator to hook to my Impco. I had it upside down feeding liquid.
No to be picky, but this could be a safety issue, we are getting a little mixed up on input pressure of the Garretson KN demand regulator. If you will look on the back of the regulator it is marked 6 ounces per square inch inlet pressure. Maximum inlet pressure 8 ounces per square inch. This pressure can also be stated as 11 inch water column. This pressure is what all LP fuel home appliances require for proper operation. To restate 11 inch water column = (equals) 6 to 8 oz per square inch.

Kent
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Old 10-02-2006, 01:28:10 PM
VaughnSimon VaughnSimon is offline
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Default Re: Temporary lpg hookup for testing (15.0JC)

Quote:
This pressure can also be stated as 11 inch water column. This pressure is what all LP fuel home appliances require for proper operation. To restate 11 inch water column = (equals) 6 to 8 oz per square inch.
As I learned right here about two years ago; to measure an 11" water column, all you need is a length of clear plastic tubing connected to a test port (or a tee) and formed into a "U". Add water to the tubing (no bubbles) and tape the tube to an old yardstick. Not exactly hi-tech, but it works.

Vaughn
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Old 10-02-2006, 10:41:48 PM
bkahler bkahler is offline
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Default Re: Temporary lpg hookup for testing (15.0JC)

Quote:
Originally Posted by Jim Davis View Post
Brad the RV setup is the way to go. You will not be running at full load. My 30KW is rated to use 7 gallons of propane per hour but my consumption is an actual 2.65. My guess is yours will be about 1.5 max 2.0 actually running your house. If you need it there will be no motels available. I know from experience and if I need it again I will gladly pay the big bucks for the propane.
Jim, that sounds a lot better!

In 2000 when I moved to Arkansas there were two week+ outages around christmas and new years. I was fortunate both times in that I was in Dallas so I didn't have to deal with them. I'm hoping I never have to use this genset but having it ready to go would be a nice insurance policy

Thanks,

Brad
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