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Propane Tank Gauge

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  • mliew Jul 23, 2009 06:44 PM
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Anyone have a recommendation for a propane tank gauge? Amazon sells one that looks pretty nice (http://www.amazon.com/GasWatch-TVL212...) but reviews on it are mixed. Thanks.

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  1. A scale. Propane tanks are filled and measured by weight. There's an empty weight stamped on the side of the collar that protects the valve. It'll say TW 17.8, or something close to 18 lbs, for a 20 lb tank, the standard grill size. Empty, it weighs 17.8 lbs (or whatever is stamped there.); full, it weighs 20 lbs more. Of course, if you take your tank to an exchange place, you're only getting 15 lbs these days.

    There's no reliable way to convert from the pressure in the tank to the volume of propane left. Propane is a liquid under pressure, so what you've got in the tank is a liquid, with a high pressure gas layer above that. As you use gas, some of the liquid vaporizes to keep the pressure reasonably constant. The equilibrium pressure varies with temperature, and at low temperatures, and high draw rates, the gas pressure can fall well below that, even with plenty of gas left in the tnak. To get an accurate measure of the gas available, you need a scale (or a finely calibrated arm; I used to fill propane tanks, and could tell with in a pound or so how much was in them just by lifting them) or a float in the tank, which isn't an option on standard propane tanks.

    1 Reply
    1. re: dscheidt

      Interesting. I never thought about how it would work from a physics aspect. I guess that would explain why those gauges aren't very accurate.

      I guess I could always stick to the "pour hot water down the side" method or invest in a scale.

    2. I have a gadget with a magnet to hold it low on the tank. It plays a tune when the gas level reaches the sensor. It works OK as a warning that I'm getting low on gas. But I find the only real solution is to have a second tank available when the first tank runs out of fuel. Most places I buy propane in fact asume that the tank is empty when you take it in for a refill. You can tell because the don't reset the scale.

      3 Replies
      1. re: mexivilla

        There's no reason to reset the scale. The pump turns off (or the operator turns it off) when the scale trips. A 20 lb tank of propane holds (surprise, surprise...) 20 lbs of propane, weighs about 18 lbs empty, and the hose and valve weigh a couple pounds. Set the scale for 40 lbs, and it trips when the combination weighs 40 lbs. Doesn't matter if it starts out weighing 20 lbs (what an empty tank and hose do) or 39 lbs. the tank filler doesn't care how much propane it takes, since they're usually charging a flat rate. (If they're honest, they should tell you you're tank is more than about 1/2 full.)

        1. re: dscheidt

          It really doesn't matter what you're weighing a scale should always be reset to the tare weight to obtain an accurate measurement. And surprise, surprise a 20lb. propane tank can hold more than 20lb of propane. The 20lb is the legal limit set at about 80% of real capacity.
          It's strange that we are so accepting of the method of propane tank refill which we would never accept in a butcher shop.

          1. re: mexivilla

            NO. NO. NO. NO. It's idiotic statements like "a 20lb tank can hold more than 20lbs" that have saddled us with the overfill protection device valves. Propane tanks filled to 80 or 85% of liquid capacity to allow for the change of vapor pressure and the expansion of the liquid propane with increased temperature. It's safety, not a conspiracy to make you fill your tank more often.

      2. I have one and it seems to work well enough. I agree about weighing it for an accurate measurement but I don't have a scale I wanna leave out on the deck.

        DT

        1. Our current Gas Grill (which hardly ever gets used, 'cause charcoal is so much better... but I digress) has a built in scale, calibrated to let you know by % how much gas is left.
          And yes it seems that a couple of the local re-fill stations are shorting on the fill-up. When questioned one owner said "didn't think any-one would know".

          G.

          1. We had one and it worked for a while, but then it seemed like it was interfering with the gas output to the grill. Plus, we learned through trial and error that you have to push down on the gauge to get a reading (much like tire pressure gauges).

            In the end, we just bought a second small tank. If the first one runs out, we switch it out for the full one and then go exchange the empty one. This way, we also know that the one we're exchanging is completely empty, instead of guessing.

            1. I have a similar one. It seems to work OK. I still keep a backup tank on-hand, but the gauge at least helps me guess whether the current tank will run out before I'm finished.

              1. There are some inexpensive tape on gauges that are actually pretty accurate -- and cheap.

                5 Replies
                1. re: RGC1982

                  Not that I've found

                  DT

                  1. re: Davwud

                    Not accurate, not cheap, or not both? I haven't shopped for one in a couple of years since I got a grill with a built-in scale. Just curious.

                    1. re: RGC1982

                      I had one, don't remember what I paid for it that was absolutely useless. I seemed more like it was influenced by the outside temperature than the tank temperature.

                      DT

                      1. re: Davwud

                        I used to live in New Jersey, and it worked well enough. Not as accurate as good gauge, but you could defintely see where the line was. I can't say that I used in in January, but I know I used it quite a bit for at least eight or nine months of the year in that climate. Maybe there are different tapes, who knows. BUT -- the best remedy for this is a spare tank. That is what I do.

                        1. re: RGC1982

                          Mine was a magnetic thing that looked similar to those tapes you put on an aquarium.

                          DT

                2. I thought that everyone with a gas grill would have a second tank always full and at the ready.

                  G.

                  1 Reply
                  1. re: legourmettv

                    Or if you live in a hurricane prone area, two spares.

                  2. Hank Hill down at Strickland Propane would know. Me, I always keep a full spare on hand, problem solved. Even with weighing, you can't judge how much longer it's going to last. Do you want to take a chance of running out before that nice steak is done?

                    1. The GasWatch TVL 212 priopane tank gauge is definitely an excellent gauge. I have one myself and don't know how I lived without it. I got mine at http://www.gaswatch.com .

                      1. An alternative to buying a second 20-pound tank is to buy a "steak saver" fitting that will let you hook up a 1-pound tank (the kind used by campers for lanterns, space heaters and camp stoves.)

                        http://www.northerntool.com/images/pr...

                        A pound of propane is good for 22,000 BTU's, which should give you at least 20-30 minutes to wrap things up (or have someone run out and get the 20-pound tank refilled/exchanged).

                        A similar fitting is available that will allow you to re-fill the 1-pound tanks from the 20-pound tanks.

                        1. I take it by all the posts that I shouldn't be nervous about keeping an extra propane tank hanging around. Is there any special way that I should store it? I mostly use charcoal but I use the gas grill for quick things during the week so the spare would be stored for quite a long time. Is that a problem? Can I keep it under my deck? I don't have a lot of space anywhere.

                          1 Reply
                          1. re: sparkareno

                            sure. Propane doesn't exactly go bad in storage. Assuming you've got a normal, well-ventilated under deck, that's a good place to store it.