I just checked my 2 aluminium 40Lbs, sure enough, we have the wrong valves (both bought on the road in NY, 2 different dealers: we' re stuck with them). We will fill only by weight.
But, I have a few questions:
There seem to be some numbers going around which don't match :
Pick mentioned a 5.8" dip tube, where "WBCCI ....on...OPD Valves" talk about 6" for a 30Lbs. Likewise, the valve for a 40Lbs steel
is supposed to be 6.5'' but the 2 valves we've end up with read 6.4" [40Lbs alu should be 7'].
These are of course small differences, but there should be only one
set of numbers. If it is supposed to be 6", then it is not 5.8" ; 6.5" is not 6.4''.
What I mean to say is: this creates only more confusion and cast doubts on any information published.
besides Airstream, aluminium tanks are used on boats. I just checked this forum:
They are as confused as us about OPD valves. They made 2 statements [true or false, no idea, their words, not mine
"I took one of my ... tanks to Suburban Propane to see if the valve could be changed. They said it could, but your aluminium tank is not a consumer product, but rather a commercial product, and the law does not apply to commercial products
Will every Suburban Propane make this statement ? My local independant propane dealer told us he checked with the Propane Association, and the law leaves a lot of leaway about filling tanks without OPD valves (may vary by State). Even if true, good luck having them filled on the road.
The 2nd interesting statement from those boat people:
"... there are two different styles of dip tubes, one made by Sherwood and the other by Manchester." You can read the long description, here is a summary:
The Manchester valve has an arm that sticks out like the shutoff valve in a toilet tank. As the tank fills up, this float rises and shuts the input off when the tank is about half full [sic].
The Sherwood valve doesn't have an arm, there is a float that rises up around the dip tube like the float on a Fluidmaster valve in a toilet. It's like the float needle in a carburetor on a gas engine. It surrounds the dip tube in the center of the tank.
2 valves makers: can that explain why we see different numbers on castings?
I hope at least this bit of info can be useful: boat supplies are another source of valves,
Good luck, we keep our "steel" valves,