Propane - when is a fill a true fill

[RoamingGnomes]

Over the years (12) I have had my propane tanks filled using two methods to determine when the tank is full, by weight using a scale and the second filling until propane escapes from a bleeder valve. When I picked up the tanks after filling I noticed that when they were filled using the bleeder valve method the tanks were heavier & lasted longer. I know which filling method I prefer, but is there a correct method? I have never had any problems using the tanks filled by either method.
Skeptics might doubt about the ability to feel the difference but over time you learn to notice differences visually and physically and although I have never weighted the tanks when filled by the bleeder method the weight feels about 2 pounds heavier. All I know they last longer.

[belfert]

mowermech wrote:
If a propane cylinder is properly filled, whether by weight or volume, it is filled until the 80% valve shows liquid propane OR the OPD shuts off the flow, whichever comes first. IF the flow is stopped at that point, the cylinder is NOT overfull! In fact, if the cylinder has a properly functioning OPD, it can not be overfilled!
If it does not have an OPD, it should not be filled!

Yes, these both had OPD valves. The issue is that propane contracts when cold and expands when warm. When I had my tank filled at zero degrees it was possible to get more gas in the cylinder because it was cold. The total volume started to expand as I drove further south and it got much warmer.

Had the tank been filled by weight I don't think this would have been an issue.

[Tvov]

Around me (Connecticut), all the fill places do it by weight. I THINK the weight chart on the pump accounts for the weight of the hose and nozzle -- next time I go to fill up, I'll ask about that. I think the last time I looked a "30lb" tank was listed as a "33lb" tank, but I'm not sure. The scales are certified by the state (well, at least supposed to be certified yearly).

[mowermech]

belfert wrote:
I have for years been getting my propane tanks filled at Flying J or Love's and they charge by the gallon rather than flat rate. The issue of getting a totally full tank is less important when paying by the gallon.

Flying J typically just fills until gas starts bleeding out. Twice this has caused my tanks to later start venting gas due to being overfull. The one time the tank was filled at around zero degrees and started venting when it was 70 degrees in Florida. Another time the tank started venting sitting in the sun. Neither one of these tanks would have had an issue if filled properly by weight.

If a propane cylinder is properly filled, whether by weight or volume, it is filled until the 80% valve shows liquid propane OR the OPD shuts off the flow, whichever comes first. IF the flow is stopped at that point, the cylinder is NOT overfull! In fact, if the cylinder has a properly functioning OPD, it can not be overfilled!
If it does not have an OPD, it should not be filled!

[colliehauler]

noplace2 wrote:

colliehauler wrote:
I disagree, it is very necessary when you buy a new tank to purge the air out of the tank unless it has a Nitrogen fill from factory.

No one here has been discussing new, un-purged tanks.

Your statement is misleading. If someone buys a new tank it needs to be purged properly.

[belfert]

I have for years been getting my propane tanks filled at Flying J or Love's and they charge by the gallon rather than flat rate. The issue of getting a totally full tank is less important when paying by the gallon.

Flying J typically just fills until gas starts bleeding out. Twice this has caused my tanks to later start venting gas due to being overfull. The one time the tank was filled at around zero degrees and started venting when it was 70 degrees in Florida. Another time the tank started venting sitting in the sun. Neither one of these tanks would have had an issue if filled properly by weight.

[fireman41]

I know that what i do for a living is nothing like filling a propane tank, but but what I do fill the liquid Nitrogen,Argon,Oxygen but mostly I do liquid Hydrogen tanks that many industry use.
Now everone of these tanks have what we call a full try cock valve. At the start of the delivery open this valve up and when the gas truns to a liquid we then know that the tank is full. The liquid hydrogen is set up a bit differnt than the lin lox or lar but it works mostly the same way.
Now if that purge on a proprane tank is indeed a full try cock valve, the correct way to fill it would be to open it and wait till the liquid comes out. Any other way may just be over filling the tank.

[noplace2]

colliehauler wrote:
I disagree, it is very necessary when you buy a new tank to purge the air out of the tank unless it has a Nitrogen fill from factory.

No one here has been discussing new, un-purged tanks.

[pkunk]

I still have some old 100# cylinders that are way before OPD and have a 10% dip tube. The local propane place will fill them but mostly I fill at home. 20 & 30# cyls are a bit more regulated and must have 20% valve & OPD.

[colliehauler]

noplace2 wrote:
Make sure that your tank/cylinder is empty. In this example (30lb.), tell them that you want exactly 7.0 gallons and tell them not to vent the cylinder. If they balk at that, go elsewhere. I'm certified to dispense propane in 11 states and that "venting" procedure only increases revenue to the dispenser. It is absolutely unnecessary.

I disagree, it is very necessary when you buy a new tank to purge the air out of the tank unless it has a Nitrogen fill from factory.

[Chris_Bryant]

Shadow Catcher wrote:
We have a translucent tank, I can see the level.

I trust you don't have one of the ones under an emergency recall, made by the Lite cylinder company.

[lakeside013104]

Had mine filled in Weston, WV. I watched as attendant filled. Asked him, "when do you stop pumping LPG"? He told me he pumps until pump shuts off. I asked him to fill to when the bleeder spits out LPG. He said "O.K.".

Tank full at 7.4 gallons according to pump reading. When I go inside, he charged me for 8.4 gallons @ 3.89 a gallon. When I informed him the pump was at 7.4 gallons, He says "szat hoo we does it ear, take it or leeve r youn tnk ear."

I left while I could before his clan buddies showed up. Lesson learned.

Lakeside

[wa8yxm]

The proper name for what everyone calls the bleeder or spitter valve is, as best I recall

The Visual Overfill indicator Valve.

And when it spits white,, that is when the tank is full. No other method is as good.

I know folks who yammer about how you have to open that valve to let the air out cause air can not be compressed (or so they say) And I wonder how many classes they slept through in school because :1: No air in the tank (At least if it was properly purged at the initial fill there is no air in it). and 2: Air can not be compressed???? What are my 22.5" Mitchlins full of if not compressed air?

It is that cloud of white (Actually liquid propane vaporizing and freezing moisture out of the air) that says "I'm Full". However if you are paying by the gallon... Well, No need to make a fuss.

[Shadow_Catcher]

We have a translucent tank, I can see the level.

[mowermech]

noplace2 wrote:
Make sure that your tank/cylinder is empty. In this example (30lb.), tell them that you want exactly 7.0 gallons and tell them not to vent the cylinder. If they balk at that, go elsewhere. I'm certified to dispense propane in 11 states and that "venting" procedure only increases revenue to the dispenser. It is absolutely unnecessary.

http://www.propane101.com/propanecylinderfilling.htm

LP-Gas Basic Filling Procedures General Information
www.publicsafety.utah.gov/firemarshal/documents/Online...
from the propane tank or point of transfer. ... Only personnel trained in the proper filling procedures of DOT cylinders should engage in this activity. 3.

those two references seem to disagree.