LPG/Propane filling

[1st time RV]

We have a 2018 Interstate and have filled the propane tank for the first time. Took it to an RV dealer to fill. We told him to make sure it was not filled over 80% (according to the manual) He told us that they all have built in regulators that won't allow overfilling. So he hooked it up and filled it til it shut off. When we checked the level on the screen inside the coach it read 86% and by the time we got home it was up to 90%. We've had issues with our other tank readings so don't know if it is just reading incorrectly or it really is overfilled. The manuals scare you to death - don't want it to explode in the driveway. Does anyone know if the Interstates (or all RV's) really have a regulator that won't let it overfill??

[toskeysam]

As I understand the tank construction....they are required to have internal mechanisms that stop the filling when the tank reaches 80% full. That is what your dealer tech was referring too. They also have a bleeder valve that lets the tech have a “backup” indication the tank is full. It will blow gas until the tip of the probe is submerged in liquid propane. It is located to identify the 80% level as well.
My tank gage is not much more reliable than a “yes, I have” or “no I don’t have” a full tank.
If the newer gage (mine is a 2013) shows a digital readout of 86-90 I wouldn’t be too worried. I think your biggest worry with an overfull tank is possible damage to the regulator (the real regulator) in that it can be damaged by liquid entering the regulator. I may be wrong, but I don’t think you have a problem.

[vintagemotor]

All new LP tanks have "OPD" (Overfill Protection Device) valves with a pressure relief device built right in, so don't be overly concerned. I have not found an LP gauge that actually reads the correct fuel level other than physically weighing the cans to see how many pounds of actual fluid you get inside. There are several factors that are involved when filling LP that determine how much liquid fuel you get in the can, ambient temp and pressure during fill, and the rig used to fill. I have filled up at high speed digital pumps that never give me more than 26lbs. in a 30lbs. tank. Most gauges read pressure inside the can to tell you where the level is at and this method is the worst at accuracy.
The only time I have had an overfilled can was in the middle of summer, I had the can filled early in the morning when it was cool and then the can sat out in the afternoon hot sun, it started relieving pressure out of the OPD valve and all was fine, I just kept all flames away until it was equalized.

[Protagonist]

Originally Posted by 1st time RV

We have a 2018 Interstate and have filled the propane tank for the first time. Took it to an RV dealer to fill. We told him to make sure it was not filled over 80% (according to the manual) He told us that they all have built in regulators that won't allow overfilling. So he hooked it up and filled it til it shut off. When we checked the level on the screen inside the coach it read 86% and by the time we got home it was up to 90%. We've had issues with our other tank readings so don't know if it is just reading incorrectly or it really is overfilled. The manuals scare you to death - don't want it to explode in the driveway. Does anyone know if the Interstates (or all RV's) really have a regulator that won't let it overfill??

Ignore the posts about OPD valves; you have a built-in ASME tank, not portable DoT cylinders, so the regulatory requirements are different.

There is a bleeder valve that needs to be manually opened while filling an ASME tank. Propane will start to come out the open bleeder valve when the liquid level reaches 80% of the total tank volume. On the Interstate, the bleeder valve is located right next to the fill port.

[1st time RV]

Thanks to all I did talk to Airstream and they told me that the monitor inside the coach reads 100% when it is 80% full It is calibrated to do that. So we are definitely good to go- I can sleep tonight!

[Boxster1971]

Originally Posted by 1st time RV

Thanks to all I did talk to Airstream and they told me that the monitor inside the coach reads 100% when it is 80% full It is calibrated to do that. So we are definitely good to go- I can sleep tonight!

That is good information from Airstream as I was just about to add that they have the gauges calibrated that way.

[toskeysam]

Thanks Protagonist....as I said at the end.....I might be wrong...

[Aircruiser]

Here's a great article that explains how our LP tanks work. Note the statement that you should require anyone who fills your tank to open the bleeder and not rely solely on the stop-fill device. The last time I had our tank filled the guy didn't open the bleeder. He just waited for the shut-off to happen. Never again.

http://roadtreking.com/innards-rv-propane-tank/

[toskeysam]

And thanks Aircruiser......explains why I observed the fill stopping the last time my supplier filled it up. He also used the bleed valve. Hmmmmmmmm

[rideair]

I haven't had a propane dealer fill my trailer tanks in 20 years. It's easier for me just to take a propane tank used in a hot air balloon, connect the two via a standard POL copper connector tube after letting the balloon tank sit in the sun and the trailer tank in the shade, crack the bleeder valve on the trailer tank and let it roll.

So for the long camping trips where we'll be running the heat 24/7, it's not uncommon to find an extra 10gal. balloon tank in the back of the truck.

I've even know balloonist at the end of the year to top-off their household tank at the end of the season this way before putting the balloon basket a way for the winter.

We draw liquid, not vapor

Enjoy,

[itsmeok]

I have always wondered about the physics of connecting 2 tanks. 1 low and 1 full. Does the pressure matter or is that equalized as soon as you connect and then it is gravity that lets the fluid go from the top one with the tank inverted to the bottom one?

Example. RV tank low and you go get a full portable tank from walmart hook it up, hold it upside down and let the liquid flow to the rv tank and then return the walmart tank as a quick and easier fill than finding a dealer.

[dznf0g]

Originally Posted by itsmeok

I have always wondered about the physics of connecting 2 tanks. 1 low and 1 full. Does the pressure matter or is that equalized as soon as you connect and then it is gravity that lets the fluid go from the top one with the tank inverted to the bottom one?

Example. RV tank low and you go get a full portable tank from walmart hook it up, hold it upside down and let the liquid flow to the rv tank and then return the walmart tank as a quick and easier fill than finding a dealer.

It's not that easy...and since opd valves became mandatory, not feasable...maybe impossible, safely anyway. I used to fill (partially) the disposable 1 lb bottles with the old style 20 lb tanks. It involved chilling the small bottles. Not very safe though.

[duckdave]

I too have questions about the built in LPG/Propane system and this seemed like an appropriate thread to post these questions. This is on an 06 Airstream Interstate, mid-bath/rear lounge (the one with the couch across the back).

My tank was telling me it was empty, or near empty. My fridge and stove were still working, but I decided it was time to figure out the LP fill routine. I took the Interstate over to the LP store where I'd had good luck getting my trailer tanks refilled/serviced. The guy hooked it up and pumped in 5 gallons (at least I think it was gallons, might it have been pounds?). He said my bleed valve was clogged and not giving him any information about the status of the fill (had it reached 80% yet), so he would not attempt to put any more into the tank. When I asked about getting the valve repaired, he stated that they do not work on RVs.

So, has anyone else encountered such a problem? What is the fix, or where do I take it to get it fixed? Finally, does anyone know the capacity of the tank? I cannot find that answer in the owners manual.

As always, thanks for sharing your knowledge!

[eubank]

Your state might be like mine in that "doing" propane breaks down into a bunch of different areas. Here in NM, for instance, there are nine different licenses for propane; I hold only one, namely, the one that permits me to fill cylinders. No transport. No repairs. No installations. No recerts. No nothing else.

So, then, it could be that your propane place simply isn't permitted to work on those cylinders. (In addition, I don't know about your state, but mine does not recognize RV propane systems as anything particularly different from other propane systems, at least in terms of licensing.)

Get on the phone and do some calling around.


Lynn

Originally Posted by duckdave

I too have questions about the built in LPG/Propane system and this seemed like an appropriate thread to post these questions. This is on an 06 Airstream Interstate, mid-bath/rear lounge (the one with the couch across the back).

My tank was telling me it was empty, or near empty. My fridge and stove were still working, but I decided it was time to figure out the LP fill routine. I took the Interstate over to the LP store where I'd had good luck getting my trailer tanks refilled/serviced. The guy hooked it up and pumped in 5 gallons (at least I think it was gallons, might it have been pounds?). He said my bleed valve was clogged and not giving him any information about the status of the fill (had it reached 80% yet), so he would not attempt to put any more into the tank. When I asked about getting the valve repaired, he stated that they do not work on RVs.

So, has anyone else encountered such a problem? What is the fix, or where do I take it to get it fixed? Finally, does anyone know the capacity of the tank? I cannot find that answer in the owners manual.

As always, thanks for sharing your knowledge!

[InterBlog]

Originally Posted by duckdave

I too have questions about the built in LPG/Propane system and this seemed like an appropriate thread to post these questions. This is on an 06 Airstream Interstate, mid-bath/rear lounge (the one with the couch across the back).

...

Number one, please check the physical condition of your tank. On rigs as old as yours, we've seen LP tanks that appear near-virginal, ranging on a continuum into tanks that look like complete degenerated train wrecks. Unfortunately, the original tank on our 2007 Interstate was a lot close to the latter end of the spectrum. Blog post here regarding our rusty, leaking tank replacement job.

Number two, please check the physical condition of your propane distribution hoses in order to verify two things: that they have been replaced in the past five years, and that the replacement hoses are the correct spec for the application.

The manufacturer of the hoses installed by Airstream stated to me by phone that those hoses have an expected serviceable lifespan of 5 years (and NO, you won't find that tidbit in your Airstream owner's manual). Now, on an age-related question like this, a manufacturer is going to err on the side of caution for liability reasons. We've never heard of Interstate-installed hose problems occurring around the 5 year mark, but they definitely occur at later times. One of our buddies had a hose spring multiple leaks around its 10 year birthday. Ten years is arguably not safe based on this data point (it's just one data point, but it's compelling). Blog description here of that event, which includes a video embed of the Roadtrek that went up in flames in California last year, presumably because of a propane issue of some sort, as suggested by the context (I tried to track down the owner to ask him what happened, but I was not successful).

We contracted an authorized manufacturer to re-fabricate our original hoses, and then I re-installed them myself. The step-by-step process is described here.

Number three, once you've got 1 and 2 dealt with, then it becomes time for a discussion of the question you raised about bleed valve etc. resources, if those questions haven't otherwise been overcome by the events associated with 1 and 2.

[Sebtown]

I too have an 06 too.. My propane tank is 6 gallons. At 80% it should take 4.8 gallons when empty. Interestingly my last fill-up took 5.2 gal. My main fill hose sprung a leak at the 10 year mark. I had a local shop frabricate new houses and unstalled them myself. If you are handy replaceing the relief valve should be a relatively straight forwrd dyi as well. I agree with IB that this would be a good time to replace the hoses.

[eubank]

Likely an artifact of temperature on how much it took to fill your tank.

LP is very sensitive to ambient temperature. As a result, when professional LP filling equipment is inspected, it includes a temperature-dependent examination of the pump and related gallon counter. (It involves pumping out a measured amount of propane according to the counter, then checking the actual temperature of the propane that was pumped out, and then applying a formula to convert the measured amount to the adjusted.)

As long as your filler is using inspected equipment and knows how to use it, I wouldn't sweat it that much. (Both inspection and knowledge vary by the state / country, but all of them try to keep on top of these two in one way or another. I hope.)


Lynn

Originally Posted by Sebtown

I too have an 06 too.. My propane tank is 6 gallons. At 80% it should take 4.8 gallons when empty. Interestingly my last fill-up took 5.2 gal. My main fill hose sprung a leak at the 10 year mark. I had a local shop frabricate new houses and unstalled them myself. If you are handy replaceing the relief valve should be a relatively straight forwrd dyi as well. I agree with IB that this would be a good time to replace the hoses.

[InterBlog]

I stand corrected... Sebtown was not the owner I was referring to above, so this is TWO compelling data points for the 10-year mark.

There's nothing more compelling than an actual propane leak. Depending on the circumstances, it could kill you.

[rmkrum]

Front row seats to a rapidly expanding propane fireball are not my idea of a “great experience “. I need to check and replace a set of old, stiff propane hoses on my 10 year old AS. Thanks for the reminder...

[xrvr]

Originally Posted by Protagonist

Ignore the posts about OPD valves; you have a built-in ASME tank, not portable DoT cylinders, so the regulatory requirements are different.

There is a bleeder valve that needs to be manually opened while filling an ASME tank. Propane will start to come out the open bleeder valve when the liquid level reaches 80% of the total tank volume. On the Interstate, the bleeder valve is located right next to the fill port.

Someone who knows! Interstates are a dif deal than trailers.