# 100 Pound LP tank-gauge?



## eclecticcottage

Does anyone know where to find a gauge for a 100 pounder?  All I find are for littler grill tanks, 20, 40 pound max.  We finally rid ourselves of the big white elephant on the lawn (the BIG propane tank) and will be putting a 100 lb tank in it's place.  Since we will be using this for cooking and hot water, I'd like to be able to keep an eye on it-you know, no surprises mid shower or while the cookies are baking.  We'll either plumb a dual tank set up or just have a second full tank waiting in the wings so we can swap out when needed.


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## pen

I've always either grabbed it and lifted it up to feel how much is left, or else poured hot water down the side of the tank. In the right temps, after pouring the hot water your level will be apparent visually. Other times, just feel the tank after doing it as there will be a definite temp difference at the level of the liquid propane.

If you are choosing to supply your own propane, I'd suggest 2, 100 lb tanks if this is for cooking and domestic hot water. In addition, a regulator with a switch to choose from one tank or the other.

However, be careful. If cold enough outside, and especially if a tank is getting low, depending on the size and style of your hot water heater and the lines feeding your units, a 100lb cylinder may not be enough, especially if you have the oven and range top cranking at the same time.

pen


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## eclecticcottage

Looks like DH got a call back from a much more reasonable and personable person from the propane co that owned the big tank.  They will be dropping off a 250lb tank in the next few days.  The person he spoke to originally was a...erm...witch and was quoting us in the range of $400 to just have the tank set and installed, before they even put gas in it!  The person he spoke to today said she was totally off base and we'd just have to pay for the propane.  So I guess I won't need that gauge, lol.  I imagine we'll get a few years out of a tankful, the water heater is a tankless and it seems to sip the gas compared to our old 40 gallon at our Old House.  We use the stove a lot, but I don't think it really uses much.  The old tank sat at @ 15% for the past two months we've been keeping an eye on it, just recently it dipped down below that.  I think that was a 700 or so pounder.


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## Val

eclecticcottage said:


> Does anyone know where to find a gauge for a 100 pounder? All I find are for littler grill tanks, 20, 40 pound max. We finally rid ourselves of the big white elephant on the lawn (the BIG propane tank) and will be putting a 100 lb tank in it's place. Since we will be using this for cooking and hot water, I'd like to be able to keep an eye on it-you know, no surprises mid shower or while the cookies are baking. We'll either plumb a dual tank set up or just have a second full tank waiting in the wings so we can swap out when needed.


 there is a website called gasgaugedirect. they have a gauge GASLOW AD- 2G. But it looks just like ones for gas grills...the only thing is these gauges might take into account the outside temperature to help determine the fullness of the tank. It is only a start. I would like to find a gauge for 100 lb tanks as my boyfriend has wanted one as well.


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## DAKSY

http://www.raymurray.com/index.html


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## FanMan

I've never seen a weight gauge for the 100# tanks, though you can get the stick on kind that you pour hot water on... the 420# tanks I have have internal gauges.  At my cabin, I have a pair of 100# tanks with a switchable regulator.  When one goes empty, I simply switch over and replace the empty one as soon as possible.  With kitchen range, tankless hot water, and gas clothes dryer, I go through about four tanks per season.


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## eclecticcottage

Well, it appears the more reasonable person wasn't.  Still no phone call back to set up an appointment to deliver that tank.  good thing it's been cold enough to have the wood stove running so we can heat pots of water for baths on that.  But I'm now relatively annoyed with this whole process.  The guy that picked up the big tank was saying that we needed to plumb 2 100lb tanks together in sequence so they could work together because the tankless might pull too much LP.  I'm not totally sure about this, but I'm no propane expert.  The 100lb tank we had on the ventfree seemed fine even in the coldest weather, but I don't know how many BTUs either max out at.  Any thoughts on this?  We had planned on plumbing them with a switch like what was previously mentioned-one runs out, the other kicks in.


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## FanMan

Depends on how big your tankless heater is, and the outside temperature.  At 70°F, one 100# tank will handle 300,000 BTU/hr when it's full and 66,000 when it's 10% full.  At 0°F, 113KBTU when full and 28K at 10%.

When you get much beyond a range in cold weather, most folks go to at least a 100 gallon (420#) tank.


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## EatenByLimestone

What you might experience (or what the propane guy was saying) is that the propane in the bottom of the tank is liquid.  Your appliance burns the gas above the liquid.  The speed that the liquid needs to change to air is related to the temperature outside and the surface area of the tank.  100lb tanks are narrow and you can burn the gas faster than the liquid will turn to the gas.

I've been able to successfully run a 22Kbtu heater in 10 degree weather with a low tank.  In fact, I ran it dry.  Come to think of it, my oven in the cabin is the same BTU, but I don't recall if I've run it during the winter.  The burners are around 9K btu each.  Either way, when I was running the propane heater I had it plumbed to its own tank.  That way I could run the stove/oven and the heater at the same without worries. You may want to do the same, and have an extra tank on hand.  One thing to consider though is the price of the propane when filling small tanks.  It cost me between 60 and 70 to fill the tank last time.  It may be cheaper if you had one of the larger tanks.  The reason I like the small tanks is I can move them in and out even if there is heavy snow on the ground.   If I remember correctly, I once calculated that I could run that 22Kbtu burner for 3 days straight on the 100lb tank before it ran dry.  

Matt


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## rkusek

I wonder if you could find a 150-200 gal upright tank that you could buy outright. I came across one when looking for salvage 500 & 1000 gal tanks for water storage on my boiler. It would have made a great homemade expansion for me but it was relatively new and still good for propane use. I think he wanted about $400. I think the 100 lb cylinders would be pretty expensive in the long run and a lot of work changing out. The wife and I lived in a 30ft camper for a year with 2 small kids while building our home in 08-09. December was extremely cold that winter here and I was filling two 30# tanks every 3 days just heating the camper (DHW was electric). Cost me about $20 a day.


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## FanMan

One thing to consider is that the 100# cylinders and the 100 gallon (420#) tanks are "DOT tanks" which means they can be installed right next to the house, unlike larger tanks (ASME tanks) which must be installed some distance away (varies depending on the size of the tank).  OTOH, the DOT tanks have a 12 year life after which they must be disposed or recertified, while the larger ASME tanks have no expiration date.

I bought a brand new 420# tank from Home Depot for something under $500, though only one HD store in my area carried it.  Later, I bought a 6 year old used tank for $250.  I'm still looking for one more if the price is right.

The gas company will typically provide the 420# tank for a nominal yearly rental or even for free (depending on how much gas you use), but then you're locked in to that one gas company.


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## eclecticcottage

I have no idea what our stove is rated at. I don't know how to figure it out-it's a 1950's (I think) era Floyd Wells, which isn't that common of a brand.  EDIT: DH checked the door tag, it's 18K for the oven, it doesn't say anything about the burners.

The tankless shows 15,000-160,000 btu range on the sticker on it. I don't think we get anywhere near the max, we have it set for 115 degrees and only use it for one thing (shower, laundry, wash dishes) at a time.

I forgot that we have a little blue flame heater on that same tank, it's 10,000 btu max. It would be a rare occurance that all three would run at once, but I suppose it's possible.

We bought most of the componants to plumb the two 100 pound tanks we have together, dh is getting the rest and working on it today.

Of course, as I typed this DH called and said one of the propane co's he called yesterday called back and might be able to drop a tank today. I never thought this one simple seeming thing would be such a project!!

EDIT: Propane co #2 still hasn't called back with a price-after they stated this AM that they would be able to drop the tank either this monring or early afternoon.  Morning ends in 10 or so minutes and they haven't even called back yet. DH has things to do this afternoon so we'll be plumbing them tomorrow.

Any way to tell if you're drawing too much and are getting into liquid vs the gas?  If we have to, we can plumb the stove seperate from the water heater and blue flame heater.


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## FanMan

You won't "get into liquid vs gas"; the tank feeds from the gas at the top.  If you try to draw too much so that it cools the tank too much, the pressure will drop and your flame height will get small.  Depending on the device, the burner or even the pilot might shut down.


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## eclecticcottage

Ok, cool.

Got it all plumbed and leak checked over the weekend.  Had to let the little blue flame burn for a bit to clean out the lines and now all seems good.  Ran the oven and two burners at once on Saturday with no problems.  Now we just have to pick up another tank for the vent free and we'll be set (we used the one we had hooked to that with one we just bought to test the system out, so we'll just get a new one for that).  Proapne co #1, the one that had the big tank here to begin with hasn't even called back yet.  I imagine eventually they will, since we still have their regulator.  Propane co #2 that said they could be out Friday and never called back called this am.  Oh well, too late!  After all the fuss between all of them I'm glad we just hooked up our own, I'd rather not rely on them anyway at this point.


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## Tero35

I have a theory.  A non-contact thermometer may determine the liquid/gas level in a larger (100 lb) propane tank.  I waited well past sundown in early January.  The ambient air temperature was 20 degrees F.  The top of my 100 lb tank measured 6 degrees warmer than the bottom.  Holding the thermometer about a foot from the tank, I slowly moved the pointer up/down the tank.  As one would expect the reading changed slowly.  However, around the middle of the tank the temperature changed well over a degree, in a narrow area.  In mid-March I tried again.  This time the air temperature was 40 degrees.  Again, I found the place the reading changed abruptly.  However, it seemed an inch or two higher.  Not that I had the foresight to mark the outside of the tank.  I only use propane for cooking, and not that often.  I have not had the quantity of propane independently verified.  Nor have I tried this method on any other large tanks.

Comments would welcomed.


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## prairielife

Never tried it on a 100 lb'er but on smaller tanks a large plastic cup of very hot water tossed on the side will make the temperature point where the propane liquid level is and the gas level above stand out well, even with just your hand on the side of the tank. 

Hadn't tried it with the non-contact thermometer but seems like it would work great. 

The hot water will heat up the metal on top more than the metal in contact with propane down low since the propane will heat sink away any heat faster.  

Works better than just doing it in ambient air. 

Also try to check it when you're using some propane. Put a pot of water on to boil for tea or whatever and then head out to check. 

The evaporation happening inside the tank will make the temperature difference greater than measuring when the tank isn't having anything drawn from it. 

Of course they also make replacement valves that include a float gauge that you can have the tank valve replaced with, or if you're handy, you could dig up a way to measure the weight of the tank minus the tare weight which is usually about 18 lbs for a 100 lb tank, as I recall, but the tare weight will be stamped on the tank some where anyway, since they're usually filled by weight if they don't have a gauge. 

Hope that helps.


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## Bob101

Hello,
I came across this forum during a search of the same issue of finding an accurate way to measure propane level in larger tanks. I have three 100 GALLON (not pounds) D.O.T. tanks connected together. Right now I have no way of knowing how full they are. Considering they are connected with a manifold, and each tank weighs over 650 pounds when full...."lifting" one to check how heavy a tank may be is out of the question.

Thanks


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## EatenByLimestone

Welcome!  

Pour a pot of boiling water down the side of a tank.  You will see condensation where the propane is.


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## Bob101

EatenByLimestone said:


> Welcome!
> Pour a pot of boiling water down the side of a tank.  You will see condensation where the propane is.


Thank you Limestone, I actually have heard this, and tried it, and it did not work. But the water was not boiling, or even hot for that matter.. That may have been the issue.

Thanks again, I will give it a try. I guess this method will work no matter what the ambient temperature...


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## EatenByLimestone

It's always worked for me.   Make sure it's enough water that it stays hot all the way down the tank.  The propane will suck the heat out, causing the condensation.


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## Bob101

EatenByLimestone said:


> It's always worked for me.   Make sure it's enough water that it stays hot all the way down the tank.  The propane will suck the heat out, causing the condensation.



OK, will do. I have a BBQ grill hooked up to them fairly close (their real purpose is a 22Kw Generac).  I will use the grill.


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