I have a gas grill that uses a single fuel tank. Last time I tried to grill, I noticed it was difficult to get the temperature up to an appropriate level, and thought I might be low on fuel. However, when I took the tank out just now to trade it in, it still seems to be quite heavy.
Is there any definite way of telling, besides the grill not getting as hot? It doesn’t seem like I’ve used it that much, since I got this tank.
How long is a tank expected to last if you barbecue, say, twice a week through spring and summer?
One way is to pour very hot water down the side of the tank – the propane is quite cool, and will thus chill the water. There are temp-sensitive LCD strips that can help you. Also, weight is a pretty good indicator – many higher-end grills have a built-in spring scale that will tell you roughly how much fuel is left; you might be able to find a kit that will retrofit to your existing grill.
Not quite. The propane is the same temperature as the rest of the cylinder and the ambient air, assuming it’s just been sitting around and not being used at a high flow rate–which will cause the propane to cool off under the same principle as an air conditioner. However, the liquid propane has a much higher thermal capacity than the gas above it, so when you pour hot water on the tank the metal backed by gas gets hot quickly, but the liquid absorbs the heat readily so the metal there doesn’t get as hot.
You don’t even need that. A grill-size tank of propane should weigh about 20 lbs plus the cylinder weight (marked on the tank with TW and generally about 18 pounds) when full or close to full. Empty, of course, it should just be the cylinder weight. Stepping on your bathroom scale with and without the tank in hand should give you a good enough idea. Each gallon of propane left weighs about five pounds. So, for example, if your cylinder’s tare weight is 20 pounds and the whole thing weighs 30 pounds, you’ve got half a tank left.
The new OPD valve is designed to prevent the flow of gas out of the tank if it isn’t connected to a device. This link will give some explanation.
How-ever, if the tank onnection isn’t tight the flow may also be restricted. You probley won’t find this information on a site related to OPD valves.
I have many times hooked up a tank and had problems with flow, I have been able to remedy this by loosening the tank connection and re tighten it and “Open The Tank Valve Very Slowly”. The OPD valve also is a flow restricting valve and just doesn’t let the flow through like the old valves.
If your tank is mounted in a bracket that holds it tilted, You Could also have problems. The float lever could close the valve just enough to give you problems.
These valves have some great features but over all they are a PITA
>the propane is quite cool, and will thus chill the water.
>Not quite.
Not quite not quite. The propane is indeed quite cool, compared to the water, which is the relevant comparison. It will chill the water more effectively than the gas-filled part of the tank will.
The OPD valve can also be triggered by opening the tank valve when the burner valve(s) are turned on. It reacts to sudden flow by shutting off the flow of gas. Make sure all burner valves are closed, and slowly open the main gas valve first before opening the burner valve.
I see no reason to make this more complicated than it needs to be.
asterion nailed it. The “Tare Weight” (TW) is the weight of the empty tank.
You want to know how much more you have left? Take a digital bathroom scale and weigh the tank. It’s just that easy.
Anything above the tare weight is propane. Take the total weight, subtract the tare weight and divide by 5, and you have the amount of propane. (expressed in pounds)
Opening the valve tells you if there is some propane left, not if there is enough to last until the meat is cooked.
The pressure gauges are useless. As long as there is any liquid propane (LP) in the bottom of the tank, the pressure is determined by the temperature, not by the remaining fuel. Pressure gauges work fine for products that do not liquefy at room temperature, such as oxygen, nitrogen, helium, argon. Some of these are available as liquid in Dewar bottles, which again make pressure meaningless as to gauging the quantity remaining.
CO2, Propane, Butane, and refrigerants are the most common “gasses” delivered in a non refrigerated liquid state.
Kevbo makes an excellent point. In fact, I have the same problem with CO2 (for my beer). The gage doesn’t mean anything until all the liquid is gone, and by then, it’s just too late. Luckily I have a spare bottle, and so don’t worry about tare weights and scales. My propane grill must be one of the high-end ones, as it has a basic scale that tells me fairly well whether the tank is running close to empty. I’d like a spare tank, but just haven’t gotten around to it (I keep telling myself I’m going to change the burner and run natural gas to it).
No it doesn’t, it is just an ugly float on a hinge that extends from the threads on the valve. That’s like saying a toilet valve shuts off if you flush too fast.
I’ve had valves close when filling them from, presumable, the propane rushing IN too fast and splashing up forcing the float upwards. But closing the valve and then opening it again quickly fixed that. I used to work at an Ace Hardware store filling propane all the damn time.
There are many problems associated with the OPD valves.
This is some interesting information i found,
*Q: Roofers and other commercial customers are trying to use OPD equipped tanks on
torch applications and they are not getting an adequate flow through the valve. What
can we do about this?
A: Some of the early OPD valves had an insufficient flow capacity for certain types
of service such as high-pressure torch applications. Market competition has
resulted in OPD’s becoming available that have significantly greater rates of flow.
*
Although several tank distributors claim there valve has a high(er) flow rate, I find nothing that would indicate how one would tell one from the other :dubious:
Mighty Flame Blue Rino and Jet Gas make this claim.
The OPD valve has a safety feature that sometimes restricts gas flow if the tank is turned all the way on. We recommend that you turn the tank valve one turn (360 degrees), light up, and then use smaller turns for a higher flame. The normal procedure is to turn the tank on and then turn the grill controls on, but doing this with a tank equipped with an excess flow device will sometimes cause the “check valve” to prematurely activate.*
*In reference to the second possibility, please check to be sure your connector to the tank is over an inch long. This should be enough to push back the check valve inside the valve. If it is too short, then you will need to get another connector.
*
This is something I am going to check on my grill.
*Does the outside temperature have any effect on pressure?
According to NFPA 58, for a tank with 20 pounds of gas, at -
* 70 degrees F - the pressure would be about 145 psi.
* 90 degrees F - approximately 180 psi.
* 105 degrees F - approximately 235 psi.
* 130 degrees F - approximately 315 psi.*
It is worth noting that tanks equipped with OPDs hold only about 17 pounds of fuel, which results in lower pressures at the above temperatures.
**Now this one has me wondering why we are still paying for 20 lbs of propane. :dubious: **
It’s not the OPD that does it, but many tanks have another valve that activates, and stops the flow if it exceeds some rate. Also, many are set up like a schreader (tire) valve and require that a mating connector depress a pin in order to allow any flow.
All you have to do is pick it up. You won’t know much the first time until it runs out but afterwards it should be obvious. I get Blue Rhino tanks and I have never had a problem just lifting it and feeling the weight. They also feel hollow and empty when they are spent. My wife has problems with that concept however and often runs them dry. However, I still think it is very easy just to pick one up with one hand to know if you need to do an exchange.