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Small Cabin Forum / Off-Grid Living / Propane Plumbing
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paulz
Member
# Posted: 25 Nov 2020 01:03pm
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Is my cooktop that is running off this single stage regulator going to run off the two stage that my heater requires?
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20201125_095122_resi.jpg


ICC
Member
# Posted: 25 Nov 2020 02:44pm
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Any household propane appliance can run off a dual stage regulator as long as the regulator, piping, etc. has the BTU capacity. Not necessarily the reverse though.

paulz
Member
# Posted: 25 Nov 2020 03:17pm
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Thanks ICC. Got my under cabin plumbing in, need some fittings inside next.

gcrank1
Member
# Posted: 25 Nov 2020 07:06pm
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The 1st stage reduces the very high tank pressure to something not far above the 2nd regulator (typically reg's to about 11" water column), this makes the system much more stable and Safer. Not terrible expensive, same thing found on RVs if you are using 'portable' DOT tanks.
The line sizing, dia. and length, are your calc after that, plenty of info online.

ICC
Member
# Posted: 25 Nov 2020 08:17pm - Edited by: ICC
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To expand on the pressure differential between first and second stage.

The pressure inside the tank runs between 100 and 200 PSI, depending on volume of propane in the tank and the temperature. Let's call that extreme pressure.

The first stage reduces the tank pressure to 8 to 12 PSI. Let's call that high pressure. The second stage regulator reduces that to the 11 inches of water column. That is low pressure. Those numbers are for propane; natural gas pressures run even lower.

NOTE: 10 PSI = 276 INCHES of water column. 11 inches W.C. = 0.4 PSI. So first stage pressure is still way higher than second stage, not just a little bit above.

My installation has the propane tank about 120 feet from the home and shop. We have a separate first stage regulator (painted red) on the tank. Then 120 feet of buried pipe to the second stage regulator (painted green) on the shop and a
continuation of high-pressure line to another second stage regulator on the house.

The higher pressure line from first stage to second stage reduced the size of the pipe needed to deliver the volume required for all the appliances, furnaces, etc at the shop and home.

paulz
Member
# Posted: 26 Nov 2020 04:42am
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Hmm, so can I still use the two stage regulator I have now at the tank, feeding into 20' of 1/2" pipe to the heater (30k btu) and cook top?

ICC
Member
# Posted: 26 Nov 2020 09:11am
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As long as the regulator specs and piping charts indicate that is good for the BTU's, all is fine. It is the pressure and volume that is delivered to whatever appliance is connected at point of use that matters.

Single stage regulators are cheaper and some things like BBQ's and cheap stove tops operate okay when supplied by a single stage regulator, so that is what they can use.

paulz
Member
# Posted: 26 Nov 2020 11:38am
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Thanks ICC. I checked the link you posted awhile back, 1/2" pipe was more than suited to my needs, and the two stage regulator I have runs my heater fine so it should be OK, unless running the cook top at the same time chokes it. Easier to change than the plumbing!

Brettny
Member
# Posted: 26 Nov 2020 02:40pm
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This may help if you need to calculate propane tank size.
A 30kbtu heater you will need a 100lb tank to support removing 30kbtu at 30* but it would also work at 10* unlike the 40lb tanks.

How big is your tank paul?
Propanevaporizationa.jpg
Propanevaporizationa.jpg


paulz
Member
# Posted: 26 Nov 2020 04:17pm
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Thanks Brett. Interesting. I have it on a 40lb., it does fine but only about 6' of hose running out side the cabin to the tank, and the cook top is on a separate 20lb. tank. We only get a few days in the low 30s a year. Been wanting to get this done right for awhile..

A few years ago I made this rolling rack for the four 100lb. tanks down at the firehouse for the emergency generator. They are talking about getting a permanent tank, in which case I will get the rack and the tanks.
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Brettny
Member
# Posted: 26 Nov 2020 05:02pm
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That chart is for the tank being 25% full. Do you find in the cold weather the tank has some left or freezes up when the heater slows down?

paulz
Member
# Posted: 26 Nov 2020 05:29pm
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Y'know, I'm not really sure. I have only one 40 pounder, two 30s and a bunch of 20s, and I have been switching them around trying to get them all empty for refills. The heater usually only runs for maybe 1/2 to 1 hour when I get to the cabin, then maybe that amount each morning if the wood stove has petered out. So I don't through a lot. Haven't hit any 30s yet this year, heater seems to be working fine in the 40s.

I've never really gotten a handle on how to tell if a tank is empty. I have a scale there and compare that to the TW on the tank, that's about the best I can do. Never really using propane in my life until I built the cabin it's still somewhat of a mystery to me.

Fanman
Member
# Posted: 26 Nov 2020 09:50pm
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Quoting: ICC
The pressure inside the tank runs between 100 and 200 PSI, depending on volume of propane in the tank and the temperature. Let's call that extreme pressure.


Actually the volume of propane in the tank doesn't affect pressure at all, unless there's no liquid left and only residual gas pressure is left. The pressure in the tank depends solely on the vapor pressure of the propane, which is dependent on temperature, from zero at -44°F, 130psi at 80°F, to 230 psi at 120°F.

Quoting: paulz
I've never really gotten a handle on how to tell if a tank is empty. I have a scale there and compare that to the TW on the tank, that's about the best I can do.


Weighing the tank is the only good way to tell, unless you have a forklift tank with an actual level gauge inside. You can pick up and shake the smaller tanks to judge the approximate amount of liquid left. Pressure gauges tell you nothing other than "your tank is empty now." There are temperature sensitive sticker gauges you can buy, they change color according to temperature...you stick them to the side of the tank and then pour hot water on the gauge, you can see the color change of the sticker at the liquid level (if you don't have hot water you're out).

Fanman
Member
# Posted: 26 Nov 2020 09:52pm - Edited by: Fanman
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duplicate post

gcrank1
Member
# Posted: 26 Nov 2020 10:51pm
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I can tell when one is empty when whatever it is hooked up to stops running, lol. When I acquire another with unknown use I weigh and subtract the tare weight, what is left is the liquid propane weight.
Our real refill places charge for the quantity to fill, not a flat rate for the jug. But that 12yr expiration on a DOT tank has bit me more than once and the recert. with a 5yr thereafter bites too. So I bought a used 50gal (200+#) tank this year with the 'multi-valve'. Im hoping I can get the gas man to fill it on one of his many trips by. Worst case is I have to haul it in but it sure is a lot of surface area inside so it should work to lower temps well.

ICC
Member
# Posted: 26 Nov 2020 11:24pm
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Quoting: gcrank1
So I bought a used 50gal (200+#) tank this year with the 'multi-valve


An ASME tank?

Brettny
Member
# Posted: 27 Nov 2020 06:13am
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Gcrank if your paying for a recert on a 20lb tank your doing it wrong. Exchange it for a new one and carry on. The place I go dosnt check them and refills 20lb tanks for $10. This is also the reason why if I need a bigger tank than 20lb I go right to a 100lb. 30-40lb tanks just dont offer a whole lot more BTU and I cant exchange them.

gcrank1
Member
# Posted: 27 Nov 2020 10:45am
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Sorry to say that my 50gal. is a DOT tank, I may end up having to hoist it onto the trailer and take it in for this next fill. What Im hoping for is what happened last time at the prev owner's, the pane-man just refilled it when in neighborhood. Lots of cabins and cottages in this area.
Our one local supplier will re-cert for free if you refill there, a bit more per gal. than the cheapest refiller who doesnt re-cert so it kinda balances out. All the exchange tanks around here are only 15ish# in a 20#er at about $20. Too bad for us that they lie about the '80% fill' thing; ie, a 20# in a '20#er is already 80% of its capacity.

ICC
Member
# Posted: 27 Nov 2020 11:34am
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Quoting: gcrank1
I may end up having to hoist it onto the trailer and take it in for this next fill.


I asked because here in NM a propane dealer who is following all the state regs will not refill a DOT tank that was not designed/meant to be a portable unit if it is brought into their refill station. Only those 100# and smaller cylinders, designed to be portable are allowed to be transported for refill.

Strangely, because of the way the law is written it is okay for a dealer to do the initial fill on a new DOT tank and have that transported to the ground site where it will be used. But not a refill.

I have an ASME salvaged from an old class A RV that is mounted on a trailer frame. I use it at a remote cabin. I tow it into town for a refill as the propane trucks will not deliver to that location. It beats using portables. A side benefit is that it is equipped to enable liquid transfer so I can refill portable cylinders though that may not be actually legal for me to do.

gcrank1
Member
# Posted: 27 Nov 2020 06:33pm
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Oh, a big tank on its own trailer frame, I Like It!
I have been under the impression that here in WI a 50gal/200# DOT is still considered 'portable'. Based on your timely comments I will certainly do some checking before I go to any heavy work; Thanx.

Fanman
Member
# Posted: 28 Nov 2020 08:55am
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If I understand the regs correctly, the 12 year limit on DOT tanks applies to transporting them full, once in place they may be legally filled even if beyond the 12 year limit. I know some of the camps near our cabin have 420# tanks that are a lot older than 12 years (at our cabin we exchange 100# tanks that are owned by the gas company). I guess I'll just have to see what happens when one of the 420# tanks at our house expires in the next year or so, I doubt the guy driving the gas truck even looks at it.

As an aside, we cooked our Thanksgiving turkey in a NG oven temporarily converted to propane running off a 20# tank with a BBQ regulator and rubber hose in our daughter's garage. The oven was sitting in her garage awaiting a kitchen remodel, with the tank outside the garage door. Definitely not to code but safe enough for a one time use.

gcrank1
Member
# Posted: 28 Nov 2020 09:13am
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Does that 420# really have DOT stamped on it?
One other thing here that can bite is the 'minimum fill' upcharge if you dont take x # of gal. Aint like that truck that drives by about every other day has to make a special trip to my place.

ICC
Member
# Posted: 28 Nov 2020 12:21pm
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Quoting: Fanman
I guess I'll just have to see what happens when one of the 420# tanks at our house expires in the next year or so, I doubt the guy driving the gas truck even looks at it.


There are some sloppy propane dealers and drivers. Some rules on propane vary from state to state adding to confusion. Many home permanent style tanks are owned by the propane dealer. The driver does not have to check the date because that is on record. If the tank is not owned by the supplier the driver is supposed to check the date before filling, just as he is supposed to check that any permanently installed tank still has some propane in it before re-filling. Not every driver does. Just like any industry or service, there can be workers who get sloppy in their work habits.

The dealer I have used for decades does watch dates on privately owned tanks and will do an inspection and recertify the tank. Mainly they are looking for rust, dents and obvious faults with piping, etc. $50 minimum and that goes up with the size of the tank.

And my OCD makes me to note that a tank and a cylinder are different. Many times the incorrect name is used. 20 pounders are not tanks; they are cylinders. Tanks are those things that are permanently mounted. They can be DOT or ASME. Cylinders refer to the portable containers and those are all DOT.

Fanman
Member
# Posted: 28 Nov 2020 09:58pm
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Quoting: gcrank1
Does that 420# really have DOT stamped on it?
One other thing here that can bite is the 'minimum fill' upcharge if you dont take x # of gal. Aint like that truck that drives by about every other day has to make a special trip to my place.


Yes, the 420# (100 gallon) vertical tanks (excuse me, "cylinder") is a DOT size.

In our case we have automatic delivery every three weeks.

Quoting: ICC
...Many home permanent style tanks are owned by the propane dealer. The driver does not have to check the date because that is on record. If the tank is not owned by the supplier the driver is supposed to check the date..


We own ours, which gives us the ability to switch suppliers; propane dealers aren't allowed to fill tanks owned by other suppliers. They much prefer company owned tanks.

Brettny
Member
# Posted: 29 Nov 2020 06:41am
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You get a propane delivery every 3 weeks? How much are they putting in the tank?

Fanman
Member
# Posted: 29 Nov 2020 08:04pm
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Quoting: Brettny
You get a propane delivery every 3 weeks? How much are they putting in the tank?


I'd have to check, but it's a reasonable number for a 2000 sf house (heat + clothes dryer, adding stove + water heater soon). Of course it varies, and they probably don't actually come every 3 weeks in the summer.

Brettny
Member
# Posted: 30 Nov 2020 06:57am
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O I understand now. I have a co worker with almost all the same uses and they dropped 3 of those tanks in his back yard.

paulz
Member
# Posted: 10 Dec 2020 10:44am
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Hey guys, got my propane plumbing done yesterday, so I thought.. Now instead of separate tanks for wall heater, cook top and water heater, I have one tank feeding all three.

I have the two stage regulator that was feeding the wall heater at the tank. That's working fine, but the cook top burners are much weaker. That may be OK, takes longer to boil water but maybe my pans won't be so sooty. But the L5 water heater is now weak, lukewarm on highest setting.

So, can I put the single stage at the tank and the two stage feeding off it at the wall heater? See first post for photos.

Brettny
Member
# Posted: 10 Dec 2020 01:35pm
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What pressure do each appliance take?

paulz
Member
# Posted: 10 Dec 2020 01:57pm
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Both the L5 and the cook top came with single stage regulators and work great with them. The wall heater required the two stage. I don't see why I can't use a single stage at the tank and run it through the two stage at the heater. Going to try it.

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