Propane tanks venting!

[Resorts]

I just filled both prpane tanks yesterday. It was cloudy and kinda cool. Today its sunny and hotter here if VA. I just walked out and both of my propane tanks are sputtering. They were not doing that yesterday. I can see the shadow of the gas comming out. Is that normal with tempature changes and particularly after having them filled?
New to rv's and Airstreams.
Thanks, Jason

[vajeep]

Jason,
This happened to a friend of mine (ZoominC6) Some one overfilled his tank and when the tank was in the sun it vented. Can you use some of the propane? Either way this should stop when the excess propane vents off.
Abe

[Silvertwinkie]

It's my understanding that any venting is not a normal every day thing. It's hard to overfull the new tanks.

I'd have someone take a look who know more that I do, but again, it doesn't sound normal. I have yet to see any tank I've ever owned do this FWIW.

[jcanavera]

Yes this is surprising since with the new OPD valves, you shouldn't be able to fill a tank over 80% full. I thought that this would in most cases eliminate any venting. I know I haven't experienced this since going to the new valves. This might be worth checking further.

Jack

[BillTex]

It has been my experience, even with the OPD valves, that with a temp delta you will also see a pressure delta=venting for a good 24 hours or so...
I am pretty sure the new valves did not change the laws of physics...

OPD valves are a secondary safety device for filling propane tanks. The primary measure is still volume, most easily measured by retailers via weight.

[ZoominC6]

We were told by one individual that there had been a recall on our OPD valves and the valve was faulty thus causing the bleed off. After obtaining a second opinion from a respected propane dealer we found that our tank in question had indeed been overfilled. The dealer bled off quite a bit of gas and then we used gas from the tank in question which further eliminated pressure. No gas bleed off can be detected either by smell or visually.

[dwightdi]

Easiest thing to do is weigh the tank. The tare weight is stamped on the tank. The maximum weight I think is also there. If it exceeds the max. then you should use up the excess as soon as possible.

[eubank]

If I were there, I'd work on it for you. For now, I'd strongly suggest that you extinguish ANY AND ALL sources of ignition within 50 feet of your rig, then very carefully remove the bottle and set it away from all ignition sources.

Once the venting stops, take the bottle to a licensed dealer, tell them what happened, and have them look it over. Be sure to transport the bottle upright; do not under any circumstances transport it on its side or upside down. You should also not transport the bottle in any enclosed vehicle.

I'd tell you what to do, but that would probably be irresponsible (and, as a licensed filler myself, might even make me legally liable for any accident that might occur).

Good luck with it!
Lynn

[TomW]

Originally Posted by dwightdi

Easiest thing to do is weigh the tank. The tare weight is stamped on the tank. ....

The tare weight is the bottle empty with no LPG.

You probably have "30 pound" tanks. Add 30 to the tare weight, and you should have the the weight reading your bathroom scale shows.

What eubank might want to say is "bleed off the excess" by opening the valve and cramming a blunt object in the valve's opening to overcome the latest safety feature. While I could do something like that, my preference would be to move the bottle to my "Cajun Cooker" LPG burner and invite everyone over for a low country boil. Why vent good gas?

Tom

[Resorts]

Thanks for all the input. I get a ton of info on this forum! I went out this evening and the tanks had stopped venting. It was very slight when it happened but I had just never seen an LP tank do that before. I think the guy over filled the tanks. What are the chances of both venting at the same time if there was a problem with a valve? I'll be extra carful and watch them over the next couple of days. I do remember that when the guy filled the tanks that it seemed like alot of gas blowing out when he disconnected and had already shut the valve on the feed line.

[jcanavera]

Bottom line though, if the propane seller stated that the tank was overfilled, the OPD valve didn't work right. While it serves several functions it is supposed to prevent overfilling.

To me, anytime a tank vents you have a hazzard. While there is the saftey factor that venting is performing you also now have a new hazzard with the vented propane. So to me you still have an issue of a questionable OPD valve and if it didn't do one of its functions in preventing an overfill, you still have a chance that other function such as preventing a sudden discharge of propane due to a broken or ruptured gas hose or line may now be in question.

Don't settle on an overfill as a reason to stop you from pursuing this situation.

Jack

[Resorts]

What is OPD? Im not familiar with what that is. Does it mean (over pressure dump) or somthing like that? I saw it on the side of the valve.

[uwe]

Originally Posted by Resorts

What is OPD? Im not familiar with what that is. Does it mean (over pressure dump) or somthing like that? I saw it on the side of the valve.

Overfill Protection Device.
Basically a float that shuts off the gas fill when it's full.
In a percet world, your bottles hsould never be more than about 80% full. In reality, this does not always happen, espacially when a OPD is defective, like it might be in your case. Not the dealer's fault. They fill until it stops, basically.
I had the same thing happen afer having the bottles filled and going to Baja in 100F heat. Both bottles started sputtering quite spectacularly, I might add. After the water heater, furnace and stove ran for a while, all was good, but I did have to switch back and forth between the bottles by turning them on and off alternatively. The sputtering stopped the next day. I now realize that what I did was a bad idea, but it seemed like the only way to stay energized while out of the country.
Basically, use as much propane as you can during the cool hours of the day ( when the bottles are not sputtering). But please, at your own risk, and discretion. mJust because it worked for me, does not mean that you won't blow up half your block while doing it.

[thecatsandi]

The place in La Grande where I get my tanks filled has a pile of failed valves. I asked the lady and she told me at least one a week fails to do it's job.
Last fall when I went to Yellowstone and had my little accident. The night before it was 15 degrees. The next day as a result of the jarring of the accident, one of my tanks vented it's contents. The valve went bad. It gave signs and failed shortly there after.

[rideair]

I still like the "old style" POL valve. Then again, I still fill my own. Still not sure why they went with the OPD other than the old style lasted forever and they needed to sell more valves and tanks. They talked about how safe the new one are to fill. How hard can it be, screw on fitting, open bleeder valve, open valve on tank, turn on fuel flow, fill to spit, cut off fuel flow, close valve, close bleeder, unscrew fitting.

[eubank]

Originally Posted by uwe

Overfill Protection Device.
Basically a float that shuts off the gas fill when it's full.
In a percet world, your bottles hsould never be more than about 80% full. In reality, this does not always happen, espacially when a OPD is defective, like it might be in your case. Not the dealer's fault. They fill until it stops, basically. (snip)

It's sort of mixed here. In most states (NM being one of them), fillers are not supposed to rely on the OPD in order to determine what is full (80%). Indeed, the National Fire Protection Association, which issues the national guidelines for handling propane (see NFPA 58), specifies that the only two safe means to fill bottles are by weight or by volume. While NFPA requires that newer bottles (up to a certain size, including all of the usual bbq and RV bottles) have the OPD, it does not license commercial handlers to rely on the OPD for purposes of filling bottles.

Lynn

[jcanavera]

The bleeder valve used to also go by the name "80% valve". The problem is at one time, most folks that I experienced when filling tanks used to never open that valve when filling the tank. Worse case many never looked at the tank coller to check the amount of weight necessary to fill the tank. Most of the time the guys dispensing propane would have the scale preset. Sort of a one size fits all. In those days it wasn't unusual to find a newly filled tank that would vent when exposed to sun on a hot day.

Even today some folks use the OPD shut off as a sign that the tank is full. Lately my local propane vendor has become a lot more careful and opens the bleeder valve when filling and shuts down just as the escaping gas turns white.

Jack

[Tim A.]

Jcanavera, BillTex, and others have made good points about the effect of temperature on volume. The liquid propane in a tank will expand when warming up, without any increase in weight. So if tare weight or the OPD or bleeding gas is used as the measure for fill, but the propane was cold as it was pumped into the tank, any increase in temperature resulting in warming of the propane in the tank will cause its volume to increase. In other words, a tank filled to full with cold propane will be overfull when that same weight of propane warms up. That will happen no matter what the condition of the valves.

Many years ago we had the permanently mounted tank on our VW camper filled with propane that was at about 28 degrees Fahrenheit. We got home where the temperature was 70 degrees and had that tiny tank venting for about two days. While that was going on, we did not drive the camper, have any flame or heat near the tank (it was outside), and held our breath until it quit venting.

[Tim A.]

I got a little carried away in the post above! "Tare" weight (actually gross weight minus tare weight) should work, if you know the "tare" weight for the temperature you are going to be storing the tanks at. For example, the "tare" weight for a full tank at 70 degrees will be more than the "tare" weight for a full tank at 100 degrees. Because the liquid propane expands with increasing temperature, a fixed volume of it (the amount in a full tank) will weigh less and less with increasing temperature.

Probably the greatest problem with "tare" weight is the accuracy of the scales, if the places where I have had tanks filled is any indication. I put the quotes around "tare" because the commercial definition of tare weight is, "The weight of a container and/or packing materials without the weight of the goods it contains."

[Resorts]

Im starting do wonder if the OPD valve did its job and was right at the 80% point. Then with the higher tempature they released a small amout. ?????
I'll make a few calls to find out who can check out the valves just for peace of mind.