gaswatch inline propane tank gauge loose

Does a Propane Tank Gauge Work?

Often we are asked: Does a propane tank gauge work? This is a very common question for those who are sick of running out of gas halfway through a cook. The short answer to this is: Yes, if you know how to use it. On this page will go in-depth how to properly install it onto your grills propane tank and how to read and use the propane gauge properly.

To begin we will explain how to install the propane tank gauge on your grill:

Pictured below is an inline propane tank pressure gauge. As you can see it has two different ends. The side with the large black collar will be screwed directly onto your 20 lb propane tank and the hose from your grill will screw onto the brass end.

propane gauge fittings

First remove the tank from under your grill and turn the gas flow off using the knob on the top. Then disconnect the gas line going to your grill by unscrewing the black collar and then gently pulling the hose.

Pro Tip: 

Because your propane tank and hoses use flared fittings: Pipe dope and/or teflon tape is not needed for a good seal. If fact the use of teflon tape may cause the pipe fittings to become loose over time.

To install the gas gauge onto the tank:

Simply slide the end with the black collar into place, while being sure to hold it straight. Then tighten the collar onto the tank. Holding the gauge straight is important here. All modern propane tanks have a safety built into the valve to prevent gas leaks, typically you will hear a click when the gauge is properly tightened down. Sometimes the tank connection here can be quite touchy so slow and steady is the best way to go.

Then take the gas line and while holding the hose end tighten the black collar from the hose onto the other end of the gauge. Once started threading you can hold the gauge to keep it from spinning. Hand tight will be fine do not use a wrench or any other tool you will ruin the plastic sleeve.

Does a propane tank gauge work

Make sure your burners are in the off position and open the gas valve on the top of the tank. Listen for leaks, if you have one it will typically it will be a loud hissing noise but any sound is not good. Once your valve has been opened your gauge should be giving you a reading it won’t be completely accurate but if gas is flowing through it the needle should have moved.

Now turn on all your burners for about 5 seconds and quickly turn them off. This is to eliminate any air that may have gotten into the system. Now the gauge will be giving you an accurate reading. Green is good, yellow means time to change the tank and if its red chances are your tank doesn’t have enough gas to light the grill.

Finally: turn the gas from the propane tank off and watch the needle on the gauge. If the needle starts to drop you have a gas leak. If this happens disconnect the propane tank and do not use your grill until the issue is fixed.

Now does a propane tank gauge work?

Now that the gauge is installed and everything is working properly. Notice that the needle does not move like the gas gauge on your car. You can use your grill over and over. The needle will not seem to move at all. This is because it is measuring the gas pressure. Your propane tank is designed to deliver a steady amount of pressure consistently.

When the propane is down to about a quarter of a tank or 5 lbs of propane or so the pressure begins to fall and this is when the gauge will move into yellow.

When the needle on the gauge is in the red the tank is no longer usable. This is not to say that it is empty it still probably has a few pounds of gas in it. There is just not enough propane to provide pressure to deliver it through the hoses.

When your tank is at the 5 pound mark along with the yellow needle you may notice your grill not getting as hot as fast as it used to. Making for longer grilling times. If the gauge just hit the yellow you may still be able to get a few short grilling sessions out of it, just don’t attempt a long cook.

Problems:

Most inline gauges also have a safety regulator built-in. This senses any strange variation of the gas flow and will automatically lower the flow of gas down to next to nothing. This safety regulator can cause you some grief, if you turn your burners up and down to quickly. It can be reset but the regulator must be removed from both the tank and hose for it to reset.

Another problem with this type of gauge is the fact that it will read higher when it is warmer outside and lower when below freezing. This is one reason why it just has zones. A semi full tank will read at the top end of the green zone in the summer and in the winter it will be at the bottom end of the same zone. Both are still green and mean the same thing.

When it is warm out you may get more grilling time out of your tank when it hits the yellow. Yellow means it’s time to fill the tank it really doesn’t matter what the weather.

While some people and websites may say these gauges don’t work they actually do. The problems stem from a gauge that is well into the green can go into the yellow quickly and because they sit under your grill it goes unnoticed.

So the bottom line on does a propane tank gauge work or not.

An inline pressure gauge is inexpensive, easy to install and does exactly what it is supposed to do when used properly.

Propane Exchange Review

See what we think about using the propane exchange to fill our tanks.

Propane Exchange Review cover

There is a more accurate option now available and that is a propane tank scale.

I should probably note here that we stopped stocking this item a few years back. This is because you can find them on Amazon for a lower price then we can get them.

We know a lot of people have had experience with this so we would like to know if you think. Does a propane tank gauge really work or not? Answer in the comments section

Mike

aka Sultan of Sizzle


I have been blogging about and selling grilling tool for over 12 years. A Certified Food Safety Professional, KCBS member, award winning writer and have over 10 years experience in the food service industry.

“I have experienced some of the best food this country has to offer and nothing is better than the food that comes off my own grill!”

This article contains links to 4thegrill’s products and ads from Amazon. 4theGrill is not responsible for the content of the off site links we provide.

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Inline Propane tank pressure gauge
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15 comments

  1. Robert Peloquin

    These in-line gauges are snake oil. They only read pressure, not liquid level. Anyone still selling these things is, in my opinion, a scam artist and those that buy them are uninformed rubes. Pressure does not tell you how much LP you have left. It tells you pressure. And as your article says, pressure does not change much till the tank is down to an unusable level. The gauge never moves out of the green till there’s no more liquid left in the tank to vaporize. (empty).

    1. John Collins

      Oh. For heaven’s sake, Robert. The item works as advertised. Use if for what it was made for not for what you want it to do. Otherwise, you will be dissatisfied.

  2. I have attached the same gauge to my 30 lb propane tanks then the other end to my generator. The generator would not start! I have removed the gauge and the generator starts! I wanted a gauge to tell me when to replace the tank! The tanks were just filled and new tanks.

    1. Bruce Fergusson

      Had the same experience and h=this article told me why…
      “ This senses any strange variation of the gas flow and will automatically lower the flow of gas down to next to nothing…”
      The generator suddenly starting is the “strange variation” and then… My 7.5Kw generator starts, then quickly stops just as you described.

  3. Since propane is not like a air tank because propane is liquid until it leaves the tank to the regulator. The only proper way to measure how much you have left in grilling is with a proper scale. Otherwise the inline gauges are more a go or no go measurement which is largely based on a tank that has liquid will produce enough gas for cooking, but that’s not saying much. It won’t tell you if you have half a tank of liquid,or a quarter tank or less. It simply tells you if its in the Green it currently has gas pressure to cook. Somewhat useful I guess but not very accurate.

  4. Ok, here’s the truth about these gauges. YES they work, and they work well. You just have to understand the concept and use them correctly. Propane tanks are not like the fuel tank in your vehicle. On a gas tank you have a continuous amount of fuel pressure all the way down until your tank goes dry. On a propane tank, you are using the vapor off the top of the tank and as the vapor level drops, the liquid boils and replaces the vapor used. NEVER read these gauges if an appliance has not been running on the system. In general you want to read them after the appliance has been running for at least 15 minutes. In the case of a gas grill, you read the gauge just before you turn off the grill. This gives an accurate reading for the next time you are going to grill. The larger the tank, the higher the vaporization rate, so on a tank larger than a #20 or you are using a low btu appliance, you may not be pulling the gas off at a high enough rate to get a good reading until you get down to around 20% of the tanks liquid volume. Also, the black plastic connector on these gauges has a flow limiter. Usually they are limited to about a 60,000 btu max load, which is why you usually only see them used for grills, which have a typical max load of around 30,000 – 45,000 btu’s. If the appliance you are using it on has a max load greater than 60,000 btu’s, the safety check is going to think there is a major gas leak in the hose and it’s going to shut down. One more note. Say you have a #20 tank and you use it on a 30,000 btu grill. Then you switch to a different appliance that is 60,000 btu’s. You are going to get 2 different readings because the draw rate is higher on the 2nd appliance. This is why you have to size the tank for the load you are going to use. The gauge is telling you if you have enough vaporization rate for THAT particular appliance that you have hooked up at that time, with what ever level of liquid you have in the tank at that time. Hope this explains how they work. If you have any further questions, email me. I have been working in the propane business for the last 35 years, so I can probably answer your questions.

    1. Steve Wekar

      I purchased a gauge for my generator. The gauge does not register when just attached to the tank.
      Should I attach one end to the generator and the other end to the tank to ensure it’s working?

    2. Hi Rob. I am going to be using an 11 lb Flame King propane tank. I want to use a splitter with a gauge so I can use my Camp Chef Summit 2 burner which is 20,000 BTU’s per burner. I also want to attach my Mr. Heater Buddy Portable. A few questions.
      1. Can these be used at the same time?
      2. Can I use just one appliance at a time and keep them both attached? I assume yes on this one.
      3. If I only have one appliance attached and the other end of the splitter is not attached to an appliance, will it leak? It should seal I would think.
      I am also thinking about getting a scale so I can weigh the tank for a more accurate method of assessing tank percentage but hoping that a Y splitter with a gauge would give me some info on tank percentage.
      4. Will the tank gauge needle gradually go down or just quickly drop when the amount of gas no longer pressurizes the tank adequately? I did read your post and understand I think the difference between a liquid gas vs petrol and how this relates to a gauge working, but still a little confused if the needle gradually goes down or just goes from full on green to yellow when propane level is low.
      Really appreciate any answers and advice. Thanks.

  5. Anthony P Lenning

    Thanks Rob for the information as a retired fireman I completely understand what you’re talking about and if you think about liquids and gases and know how they work you can understand how the gauges work.
    P.s. I see the negative response calmed down.

    1. Indeed.People tend to comment on what they want vs what they need and won’t bother to learn the difference. Kind of like paint with primer as if mixing the two actually accomplishes anything. It defeats the entire purpose of primer in the first place, but don’t try telling that to someone too lazy to paint two coats on a wall they can paint one coat on.. With gauges they don’t bother to learn and think there should be a float valve inside a propane tank except there would be no way to hook up to it for a complete numb skull.. We mass manufacture professional grade numb skulls these days..

  6. Ehem… These gauges are made to detect leaks in the system, more specifically major leaks and have nothing to do with volume of gas in the system, just pressure in the line..
    Just watch the magic of an actual demonstration of how they work..and they work exactly the same way in the US as they do in the UK.. https://youtu.be/ImVhMcjSrsQ
    Now, ain’t that magical sports fans?

    1. Just think how handy something like that would be in the event you managed to run over your gas line with your lawn mower.. I’m pretty sure that’s happened a few times out in the real world..

  7. Jeffrey Utter

    Correction: The first commenter, Robert Peloquin, is correct. The pressure of a gas over a liquid in a closed container is dependent on the temperature, not by how much liquid is below it. So these gauges are next to worthless. Why do you think Weber went to weight scales on their grills? The only really accurate way to know how full your tank is, is to weigh it empty, weigh it full, and then anywhere in between you can weigh it and figure out using simple arithmetix. Notice the author gave a lot of instructions and then just said, “They work.” Admittedly, he did include some caveats, but they were very optimistic. Basically, these gauges will tell you when your tank is almost empty, and nothing more. Look up Boyle’s Law, Charles’s Law, Lussac’s Law, Avogadro’s Law, and the ideal gas law.

    1. I would have gone with Raoult’s Law but this is correct; at equilibrium, the pressure above a two phase mixture of a pure component (liquid propane and propane vapor) is equal to the vapor pressure. The vapor pressure is only a function of temperature. As long as there is a two phase mixture (that is, as long as there is any liquid in the tank), the pressure will not change. When the pressure drops, you are out of liquid and very shortly will be out of vapor as well. If these gauges work, I have no idea how unless there is some odd non-equilibrium behavior (as Rob T. implies above). However, I imagine propane liquid comes to equilibrium with its vapor very quickly. If you have a mixture of components (that is, not just propane), the pressure is the sum of the products of the vapor pressures and their liquid phase mole fractions. The result for this case (not pure component) is that the total pressure will drop as the more volatile component is vaporized at a higher rate. I assume a propane tank is just propane. As an example of a multi-component mixture, LPG is a mixture of butane and propane. The pressure of a two phase mixture of LPG will drop as you withdraw vapor because the vapor has a higher concentration of the more volatile component (propane) than the liquid.

      My guess is that what people are seeing is that as gas is evaporated, the temperature goes down and therefore so does the vapor pressure. So the gauge reads a lower and lower pressure. After the user stops using the gas and the tank heats back up and comes to thermal equilibrium, the pressure goes back up to wherever it started unless you sucked it nearly gone. If you put this gauge on a small propane tank and starting draining it quickly enough for the bottle temperature to drop, you would see the pressure go down and down and then suddenly it would go down very quickly when it was basically empty. If you stopped before it was empty, the pressure would eventually go back to where it started. It’s basically physics and chemistry.

  8. It’s nice to see a few cooks who know their physics. Yes, in theory, at a constant temperature these gauges should read the same pressure until the liquid is completely depleted. Theory aside, I’ve had a couple of smokers that came with gauges and they do show decreasing pressure as the propane is used up. Not sure why. Might have something to do with heat transfer differentials between the liquid and vapor portions of the tank, but who cares (good project for a Chem E major)? Just buy a hand-held luggage scale for $10-$15. The tare weight of the tank is stamped on the top ring. Do the arithmetic and you will know exactly what percent full your tank is.

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