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Upperparadise
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# Posted: 10 Feb 2023 09:34am
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Im new to cabins I built a 10x10 off grid log cabin in Vt. Current having issues heating when I get there if temp is below freezing:
I have a small wood stove that takes a while to warm up. I have 2x buddy heaters that i want to use to warm up faster.
Issue is the propane freezes (i think) i hauled up 2x 25lb grill tanks but those seem to freeze too! I hauled up a brand new one used an adaptor to connect to buddy heater and it was shutting down after 10-20 minutes. It was 10-17f out but thats what im trying to figure out.
Anyway to heat with propane and not have it freeze? Could it be my adaptor or buddy heater? Even if I hike up 1lb camping propane it seems to freeze up after a while (30 min hike then cold cabin). Any ideas suggestions? Am I the only one that seems to have issues with propane freezing and being unreliable? Thanks!
Id put a picture if I could thanks!
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Upperparadise
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# Posted: 10 Feb 2023 09:37am
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Pictures
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Brettny
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# Posted: 10 Feb 2023 09:43am
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Theres a propane vaporization chart available, let me see if I can find it. With 2 big buddy heaters you may be pulling to many BTU off a single tank.
Tanks will frost up when cold but as long as the propane flow isnt slower it's really not a problem.
You can see by the chart that at 10*f and the tank a 20% it will only output about 10kbtu. I believe that's about what my hunting buddy (single pannel) does.
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Nate R
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# Posted: 10 Feb 2023 09:47am
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Yep, more tank surface area will help as far as frosting.
Much of the propane in the tank is liquid, and moves to vapor in the tank. That takes heat BTUs, which is pulls from the surroundings, which drops the temperature around the tank.
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Nobadays
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# Posted: 10 Feb 2023 09:56am
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Would setting the tank a few feet in front of the heater help? I've never used this sort of heater so I'm not sure this would work or be safe...?
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gcrank1
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# Posted: 10 Feb 2023 10:10am
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Definitely have the tank in the sun if possible and inside by a window and up so its getting the solar gain and the advantage of 'heat rises' would help.
Maybe you could build a little 'greenhouse' outside for the 20# tank with some windows; like a garden cold frame?
When you go there can you bring a warm 1# bottle from the vehicle and keep it wrapped up/insulated; use it first on the Buddy. Also keep the Buddy low because heat rises.
A small bat powered fan would help kick and mix the air inside for comfort. Set the fan in a cold corner blowing up and across the room so you dont feel the draft. Dont try to blow the warm air at the heater around.
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Fanman
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# Posted: 10 Feb 2023 11:54am - Edited by: Fanman
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Propane doesn't freeze (though the outside of the tank may frost up), but it does cool enough that it can't vaporize fast enough to feed the heater.
Edit, the 20# tank should be adequate, barely... for ONE 9kBTU heater.
We heat our house with propane in subzero temperatures, but we have two 420# tanks connected together.
Putting the tank on front of the heater is dangerous. Actually the tank and regulator should never be used indoors; if it leaks or vents for any reason... BOOM!
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Upperparadise
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# Posted: 10 Feb 2023 01:02pm
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That is exactly what I was wondering i knew i needed a bigger tank. Ill try the manifold for doing 2 25lb tanks but it seems like focusing on a bigger wood stove might be the best option.
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gcrank1
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# Posted: 10 Feb 2023 03:05pm
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I often see the tall 100# tanks recommended as a solution but the surface area at the top of the liquid in those isnt any bigger than in a 20# or 30#.
If you get a dual tank control (typical from rv's) and have both 20# turned on you double the vapor available. It would be the same with two 100# but they would last long, just be miserable to haul.
Btw, watch out with the rubber lines, critters like to gnaw on them. Might be you can find some old metal flex conduit to run the rubber line through or best is to hard-plumb with piping.
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FishHog
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# Posted: 10 Feb 2023 03:44pm - Edited by: FishHog
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I've run propane appliances down to -33C which is like -25F and at that point I see reduced pressures on a dual 20lb tank setup, but still works. I can't see you at 10F really being an issue. I think your more likely overloading your regulator.
Frosted up tanks is just that, frost, they should still work at an acceptable level, and aren't really freezing up.
Try just running one of your buddy heaters first and see how its running, then light the second, if the first burns with less umph, then your overloading.
Showing up at a cold place always takes time to heat everthing up, no matter how big your woodstove is. If your current one is fine once things are warm, I wouldn't get a larger one, just realize it takes time to get the structure warm.
For that reason I never arrive late in the day in the winter anymore. One night sleeping on a rock solid mattress was enough for me to avoid that again. I make sure I arrive early enough to allow the place to get warm, even if it means a shorter trip, or a night in a motel.
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Brettny
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# Posted: 10 Feb 2023 07:14pm
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I heat a 10x14 shed with nothing for Insulation but 2in foam in the ceiling and foam tiles on the floor. Our wood stove does take time to heat it up but between my hunting buddy heater and the small wood stove it takes about 45min-1hr to heat up to 60*f from about 15-20*f. A small battery fan does help alot.
I like the style of your shelter there. I would look into air sealing things more. You do have alot of mass to heat there with those logs.
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Fanman
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# Posted: 10 Feb 2023 07:30pm
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The 20# tank should handle one heater, but not two per the chart above... not clear how you have them connected?
If there's moisture in the propane the regulator could be freezing up. Or... it's a small space, could the heater's oxygen depletion sensor be shutting it down? Easy to test, try running it with the door open or outside.
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Upperparadise
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# Posted: 10 Feb 2023 09:03pm
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Interesting idea all! Ill try those tests! For now i need a beam down the middle and I need to seal it more. Then i think a manifold for 2x25lb tanks going to 1 heater would work better. If I can run the buddy heater on high plus stove plus sealing itll warm. I like the idea bc i need to grill so combining them seems like the vapors can get out better and the room will warm making everything easier. Thanks for advice all will keep updated!
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Irrigation Guy
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# Posted: 10 Feb 2023 09:08pm
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It’s hard to tell from the pictures but it looks like you have some large gaps around the door and can’t tell if your metal roof is insulated. If you seal everything up and insulate the roof your heat load won’t be so high and you won’t need to burn so much LP which in turn will help the tank from freezing up.
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gcrank1
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# Posted: 10 Feb 2023 10:19pm - Edited by: gcrank1
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Fwiw, the std bbq tanks are 20#, there is a similar, but bit taller model used often on rv's that is 30#.
The 30# is about the limit of what I want to handle for 'ease of transport', after that they are too much.
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Fanman
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# Posted: 11 Feb 2023 08:53am
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I have to bring 100# tanks to the cabin for cooking and hot water, the last 50 yards from the truck is a PITA even with a hand truck. Fortunately I only have to do it a few times a year.
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FishHog
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# Posted: 11 Feb 2023 01:08pm
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Quoting: Fanman I have to bring 100# tanks to the cabin for cooking and hot water, the last 50 yards from the truck is a PITA even with a hand truck. Fortunately I only have to do it a few times a year.
I gave up on 100lb tanks years ago. Just not worth the struggle. Not sure why you have to use 100's, they add nothing over 20's or 30's except for longer times between changes. I switched over to 30's, all attachments are the same and would gladly handle 3x30lb over one 100lb for almost the same usage time.
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Brettny
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# Posted: 11 Feb 2023 01:20pm
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Quoting: FishHog they add nothing over 20's or 30's except for longer times between changes.
Look at the chart I posted above. You will see what they offer over 20-40lb tanks. They do sell 100lb tanks that can be filled on site via truck.
For me its 20lb tanks or 100lb tanks. 20lb tanks because there free to exchange for a new tank then I only pay $10 for a refill. 100lb tanks for bigger draw things, at this point though theres nothing drawing that much.
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FishHog
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# Posted: 11 Feb 2023 02:05pm
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Quoting: Brettny Look at the chart I posted above. You will see what they offer over 20-40lb tanks.
Clearly something I don't understand. They are filled to the same pressure, and have the same surface area since they are the same diameter and are vertical tanks.
I get how a horizontal tank can add more vapour pressure in cold temps, but how can verticals differ in anything but run time?
Guess I'll go googling
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Bruces
Member
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# Posted: 11 Feb 2023 03:09pm
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Got tired of lugging 100# tanks to an island camp ,went to 60# tanks and they are the perfect size to handle .
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ICC
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# Posted: 11 Feb 2023 04:38pm - Edited by: ICC
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That table is correct. It was posted here quite a long time ago.
Propane cylinders are filled by the volume (weight) of propane. When the temperature drops the volume contracts. The contraction reduces the propane pressure in the cylinder. The contraction is more noticeable with a 20# cylinder compared to a 100# cylinder.
Combined with the pressure reduction that the colder temperatures cause, the liquid propane evaporates into a gaseous state more slowly. That results in a lesser amount of gaseous propane being available with the smaller-sized containers and lower temperatures. It becomes more pronounced as the volume in the cylinder falls.
Not that is makes a lot of difference a 100# cylinder is about 2 inches greater in diameter than a 20# cylinder. That increases the surface area inside the 100# cylinder by approx a third. That helps too.
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Tim_Ohio
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# Posted: 11 Feb 2023 05:43pm
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If you want to get a little more life out of the lower volume in a 20lb cylinder, put it in a water bath, such as a galvanized tub. I did this for years, when I used it combined with oxygen for brazing torches and 96k btu glass working torches. The cylinders would start to ice up and I’d loose pressure as the volume was reduced. It might be a trick for someone running low and needs to get by through a weekend or something like that. Just a tip I learned.
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Fanman
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# Posted: 11 Feb 2023 06:41pm
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Quoting: Brettny Look at the chart I posted above. You will see what they offer over 20-40lb tanks. They do sell 100lb tanks that can be filled on site via truck.
100# tanks are what's available. Most of my neighbors' tanks are filled on site, but the truck's hose won't reach my cabin and a few others, so they leave a dozen or so tanks at a spot they can reach and we swap them out as necessary.
Even in the summer, anything smaller isn't adequate for a stove, tankless water heater, and gas clothes dryer.
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gcrank1
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# Posted: 11 Feb 2023 07:48pm
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Well, Ive learned some stuff from this 
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Upperparadise
Member
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# Posted: 11 Feb 2023 11:09pm
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Me too someone on another forum said get a diesel heater im strongly considering that too seems like a very reliable simple clean way to go. The propane for me doesnt seem that reliable as I hoped i think the 2 thank to 1 manifold may help will try that out and report back. Keeping my eyes peeled for a diesel heater too.
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darz5150
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# Posted: 12 Feb 2023 12:00am
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Quoting: Upperparadise get a diesel heater im strongly considering that too seems like a very reliable simple clean way to go. The propane for me doesnt seem that reliable
Diesel will go bad, propane doesn't. I've only had problems with the regulators. I have 2 100# tanks for my shop. It seems I have problems with the regs frosting up when it gets around 20 F. I wrapped a little string of christmas lites around the regulator, and it keeps it from freezing up, like heat tape, till I can fire up the wood fire furnace. I have tried multiple regulators.
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Upperparadise
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# Posted: 12 Feb 2023 12:52am
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Yea thats what im thinking about the regulator find a way to keep it warm even hot hands heat packs. Looking at the diesel it looks good but i agree hard to deal with gas going bad
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darz5150
Member
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# Posted: 12 Feb 2023 01:01am
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Quoting: Upperparadise even hot hands heat packs.
That's a great idea. ðŸ‘
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Brettny
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# Posted: 12 Feb 2023 07:05am
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Quoting: FishHog They are filled to the same pressure, and have the same surface area since they are the same diameter and are vertical tanks.
100lb tanks are bigger around than 20-40lb. Since the 20-40lb vaporization is different I suspect that the vertical surface area also matters. Also propane isnt filled to a pressure, its filled to a weight or volume.
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Brettny
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# Posted: 12 Feb 2023 07:08am
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Quoting: Fanman Even in the summer, anything smaller isn't adequate for a stove, tankless water heater, and gas clothes dryer
It depends on the btu input of those appliances but no a gas dryer is never going to work with a tank smaller than a 100lb tank. My on demand water heater and stove both work find off there own 20lb tank and have been for years, even at 10*f..granted on not rosting a Turkey at 10*.
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