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Small Cabin Forum / Off-Grid Living / Help with propane setup
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MoFo2020
Member
# Posted: 21 Oct 2024 13:50 - Edited by: MoFo2020
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I have a 100lbs propane thank (might add a second one at some point) and will use it for a propane stove for now. There probably will be a tankless water heater at some point also.

My questions
What regulator should I get?
What type/size of gas line should I use from the thank to the cabin? I was thinking coper?

gcrank1
Member
# Posted: 21 Oct 2024 14:25 - Edited by: gcrank1
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Ive run a 'salvaged' 2 stage reg from a monster LP BBQ rig that was junked out. I def recommend a 2 stage! Salvage RV's are a good source for dual tank setups and small gas appliances. New regulators are not that expensive (depending upon where you buy, of course).
For delivery and your stated use, and accounting for some future growth, run a min. 1/2" line. You should verify what your local code is, some are ok with copper, some require black 'iron' pipe. Also be totally sure of the regs on tank placement regarding cabin and All The Other distances to openings in the cabin. Btw, some jurisdictions require a licensed 'pipe fitter' to hook up gas.
The old 'soapy water' test of all the fittings is absolutely necessary but better yet is to get an inexpensive 'sniffer' (got mine off Amazon, recharges on USB).

ICC
Member
# Posted: 21 Oct 2024 19:34
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Total up the BTU per hour input rate for each appliance you might want to use. Note, it is the BTU per hour input rating you would use.

Draw it out with all the distances from the regulator to each appliance.

Add up all the BTU ratings to determine the maximum required flow rate; BTU per hour. The regulator you buy will need to be rated at least that high.

Use a chart (lots available online) or calculator to determine the pipe size needed. This calculator works, although it might take a little getting used to.. It is best used on a computer rather than a small screen device, as the display can be difficult on a small screen device. After the data has been entered, it provides a size diagram. It comes with instructions.

Copper is damn expensive as the pipe sizes get bigger. I'd use the common black iron schedule 40 pipe. It used to be available cut to size and threaded at any HD or Lowes, though I have heard that some stores may have stopped that. I am not sure I believe that though as all the HD and Lowes around me still cut and thread at no extra cost when you buy the pipe from them. If using threaded pipe use pipe dope and NOT teflon tape. It's more reliable IMO.

Or look into CSST flexible stainless steel pipe. The nice thing about it is you don't need fittings to go around corners and if you need to run a long distance buy a roll and go hundreds of feet with no couplers needed. There are some restrictions on where or how to use. Same for the yellow polyethylene gas pipe. comes in rolls. Some restrictions on how and where to use.

FishHog
Member
# Posted: 21 Oct 2024 19:59
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if your just running a stove and on demand water heater, a 100lber will last you a very long time.

Brettny
Member
# Posted: 21 Oct 2024 22:59
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Forget soapy water. They sell $20 combustible gas sniffers. Typicaly with your low BTU needs you would run black copper or CST. CST is the bendable gas line. I would use that stuff over black pipe or copper if my lines where exposed on the interior.

I have nearly your same useage and a 20lb tank lasts over a year. But we only use it 1 weekend a month. I also have gas lights not too.
20241019_232105.jpg
20241019_232105.jpg


Fanman
Member
# Posted: 21 Oct 2024 23:54
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The line size will depend on the demand (measured in BTU/hr) and the line length. 3/8 is probably plenty for a stove, but might be marginal for a tankless heater depending on the size.

A two stage regulator is a must, and likely required by code. Or separate first and second stage regulators. The latter is a good idea if the tanks are far away... the first stage drops it to 10 psi, and the required pipe size is much smaller for the higher pressure. Then a second stage to drop it to the final 1/2 psi closer to the appliances.

Our cabin has two 100# tanks with a single dual stage regulator running stove, tankless heater, and clothes dryer. The heater is 130KBTU but it's very close to the tanks; the stove and dryer are back to back on opposite sides of the wall, fed by 3/8 copper line, maybe 20' away.

At the house we have two 420# tanks with a first stage regulator going into 1/2" copper to the house, where there's one second stage regulator feeding tankless heater, dryer, and stove with a mix of black pipe and copper, and another 3/8" copper line feeding to two more second stage regulators farther away for the three DV heaters that heat the house.

The "LP-Gas Serviceman's Manual" (google it) has all the charts for sizing line as well as required clearances and other useful information. I buy most of my propane components from propanewarehouse.com.

paulz
Member
# Posted: 22 Oct 2024 13:18 - Edited by: paulz
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Good discussion guys. I also use propane for cooktop and tankless water heater mainly, and a 10 gallon tank lasts a long time. I have some galvanized pipe in the supply line to the stove top, that’s bad?

gcrank1
Member
# Posted: 22 Oct 2024 13:44
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It used to be said that the galvanizing 'might' flake off and plug the appliance. The 'drip leg' at the appliance is supposed to catch moisture? and debris.
Fwiw, Ive never seen a thing in any drip leg Ive popped but I am not a pipe fitter so my experience is limited.
Imo, the higher pressure from tank 1st stage reg to the lower pressure (11" water column/under 1/2psi) would be more likely to push any contaminant than after the 2nd stage to appliance.
In your case, if the gal fittings are after the reg and just straight run to the stove the only thing that could possibly plug would be the stove oriface(s)/jets; not a big deal to pull a jet and clean it out.

paulz
Member
# Posted: 22 Oct 2024 15:08 - Edited by: paulz
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Thanks G. I also have a wall heater I seldom use (too much firewood, my exercise), we’ll see this winter. The galvanized pipe is 3/4 I think. I only use the regular one stage regulator that the small tanks use, got a double around somewhere, all screw to the tank, 20’ to inside.

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