Specifications for new OPD valves

[Phrunes]

Hi all,

In my quest to update my tanks I received a lot of misinformation from the local propane dealer...some fast checking on the web, and I uncovered complaints from AS owners having trouble with the newer OPD valves filling and overfilling their ALUMINUM tanks. I sent an email to Worthington and they replied...although a steel tank specifies a certain dip tube length ie 30# steel calls for a 4.7" DT length....ALUMINUM TANKS ARE DIFFERENT here are the specs from Worthington...30# requires .5.8 DT, 40# requires 7.0 DT....some tanks are not stamped, like my 30's, and the OPD would have been wrong using the steel tank specs of 4.7". Hope this helps others.

[eubank]

Sounds right. The aluminum tanks I've filled are somewhat skinnier and taller than their respective steel tanks. As a result, the tube will have to stick down further into the tank in order to reach the 80% level, I'd think.

Of course, if filling by weight rather than by volume, then it shouldn't make much difference.


Lynn

[altnbndr]

I just checked my two #30 aluminum tanks and found that I have the 4.7 OPD dip tubes mentioned. The tanks are marked with a manufacture date of 9-72.
They are also marked 10-07 which is when I suspect the OPD upgrade was installed. Since I am due for a five year re-certification I think that I will have the proper OPD with 5.8 dip tubes installed when they are re-certified. I did notice that the last time that I had the tanks refilled the empty one only took just over 5 gallons, not the 7 gallons that I expected. I measured my #30 steel tanks and found that they are 3" shorter than the #30 aluminum tanks." Phrunes" I really appreciate this heads up because I hate to think that I have been running out of lp even though there was still some in the tank. Your info has solved my missing 2 gallon mystery. Thank you.

[Phrunes]

Originally Posted by altnbndr

I just checked my two #30 aluminum tanks and found that I have the 4.7 OPD dip tubes mentioned. The tanks are marked with a manufacture date of 9-72.
They are also marked 10-07 which is when I suspect the OPD upgrade was installed. Since I am due for a five year re-certification I think that I will have the proper OPD with 5.8 dip tubes installed when they are re-certified. I did notice that the last time that I had the tanks refilled the empty one only took just over 5 gallons, not the 7 gallons that I expected. I measured my #30 steel tanks and found that they are 3" shorter than the #30 aluminum tanks." Phrunes" I really appreciate this heads up because I hate to think that I have been running out of lp even though there was still some in the tank. Your info has solved my missing 2 gallon mystery. Thank you.

You are very welcome. You should have seen the curt response I got from the local "expert" regarding this issue...I forwarded him Worthingtons email, and he simply replied that he had called his supplier and the proper dip tubes would be ready for install in a couple of days. I just wonder how many are out there with the wrong tubes.

[altnbndr]

"Phrunes" since I live near you I was wondering, where you are having your tanks serviced and if you would share how much it cost?

[Phrunes]

Originally Posted by altnbndr

"Phrunes" since I live near you I was wondering, where you are having your tanks serviced and if you would share how much it cost?

I'm getting it done for $30 - $35 at Kamps in Antioch.

[altnbndr]

Wow, the local dealers in Sacramento want $60 ea.
Antioch here I come. Thanks again.

[Phrunes]

Originally Posted by altnbndr

Wow, the local dealers in Sacramento want $60 ea.
Antioch here I come. Thanks again.

Give Ken Hitchen a call or email him, tell him that he was mentioned on Airforums. I'm sure he would appreciate it.

Khitchen@kampspropane.com

[idroba]

I have accumulated quite a collection of Worthington AL tanks over the years. Four 40#, four 30# and one 20#. I have had them all converted with new valves and the propane dealers I had it done at all knew that the valves were not the same for the AL tanks vs. the steel ones. Maybe I was lucky, who knows. The most I have paid for the conversion was $35, some a bit less, like $28.

[eubank]

You might be able to replace the valve yourself if you've got the means to hold the tank stationary while you twist out the old one. Check online for "OPD valves for sale." And check your state's or province's legal code to find out if it's permitted.

Of course, the big problem with replacing the valve is that the cylinder has to be dead empty.

But as I mentioned earlier, an OPD of a slightly incorrect length might permit a slight overfill of the tank, but if the tank is being filled by weight (use a scale) rather than by volume (open the little screw on the side), then it shouldn't make any great difference: Weight is weight, and the slightly shorter length of the OPD will play only a very small role, I'd bet. Just tell the filler to fill it to a half pound less than full, if you want.


Lynn

[Phrunes]

Originally Posted by eubank

You might be able to replace the valve yourself if you've got the means to hold the tank stationary while you twist out the old one. Check online for "OPD valves for sale." And check your state's or province's legal code to find out if it's permitted.

Of course, the big problem with replacing the valve is that the cylinder has to be dead empty.

But as I mentioned earlier, an OPD of a slightly incorrect length might permit a slight overfill of the tank, but if the tank is being filled by weight (use a scale) rather than by volume (open the little screw on the side), then it shouldn't make any great difference: Weight is weight, and the slightly shorter length of the OPD will play only a very small role, I'd bet. Just tell the filler to fill it to a half pound less than full, if you want.


Lynn

Good info. To be legal in all 50 states, you'll need the certification stamp. I found the valves online, but honestly the price I'd pay for just the valves was within $5 of having them professionally installed and certified...just my personal experience, your results may vary.

[altnbndr]

I bought my aluminum tanks used for $100 so I have no idea by who or where the opd's were installed, but the valves definitely have (4.7 DT) marked on them. Even having to pay another $75 or so I think I came out pretty good on the deal.

[altnbndr]

Ok folks please be patient with me on my "Quest for Airstream knowledge". I have some questions:
1- Does the automatic changeover regulators switch to the next tank before the first tank is completely empty? which would explain why my "empty" tank only took just over 5 gallons.
2-Since we draw vapor out of the tank and not liquid, wouldn't it be an advantage having shorter dip tubes to draw more vapor off the top of the tank?
3-What is the danger in over filling the tank? Before opd's the tanks could be "packed" to full volume. Were tanks exploding? or is this just adding a extra safety factor?
4- How do you know if your tank has been overfilled? Would liquid be drawn past the regulator?

[4RXLA]

My auto changeover occurs when the empty tank is completely empty and it takes 7 gallons, sometimes a little more before the gas starts coming out of the screw hole. I've never seen a propane filling location that has a scale to weigh the tank, only a meter to measure the # of gallons pumped.

[idroba]

1.Sometimes in very cold weather, the liquid propane will freeze solid in the bottom of the tank and you can't get it to liquify, so the pressure drops and the regulator changes over to the other tank. When it warms up, there may be a small amount of propane left in the tank which froze. Otherwise, the tank should be pretty empty when the changeover takes place.
2. No
3. When the tank warms up, the liquid expands and will over pressure the tank, forcing the overpressure valve to pop off. It is not fun to have a tank on the front of your trailer spewing propane to relieve the pressure. Trust me on that one, I had an idiot overfill one of my tanks once.
4. The tank leaks propane when overfilled (see above). The regulator will not allow liquid propane into the main lines (thank goodness, the pressure would be very high and very dangerous).

[strshpntrprz]

All the info seems correct and very informational, the reason opd's were introduced was to help tanks get refilled to the correct level, overfilling was great cause for concern, not enough empty space at the top of the tank would cause pressure to raise to levels that caused the pressure relief valve to vent the excess pressure out into the air, NEVER a good thing if open flame were nearby. One correction to mention is a propane tank will always empty itself, it is a liquid under pressure in the tank and gasses off as vapor to be used by your trailers equipment as needed, so there is no pipe to the bottom, like your garden sprayer has. One note- I have heard of tanks not delivering propane after being refilled, it seems the float inside the tank may prevent the flow of gas out, and maybe a little shake of the tank will get things going again, there is also the valve at the connection that may not open if not tight enough. Love the info available here. Gene

[eubank]

Actually, it's kind of an interesting story here.

OPDs were first mandated by the National Fire Protection Association (Pub 58). States were free to adopt that standard or not. Most did. Manufacturers of cylinders immediately adopted it.

But what about filling? If you look at the publication, certified fillers were never supposed to fill by relying on the OPD valve. Rather, the only two methods ever permitted in the publication were volume or weight: Volume by opening the small screw at the side, and weight by using a repeatedly certified scale. And that makes sense: Fillers were to rely on gravity, which is always there, or on a certified scale, but not on a valve installed who-knows-when and never checked again. (Again, the standards in the publication are voluntary in the sense that individual states are free to adopt them in whole, in part, or not at all.)

So why the OPD at all? Pretty simple. There are lots of folks who fill at home, and those folks were doing a lot of overfilling in the false belief that an overfilled tank was a safe tank. Not!


Lynn