For a number of years, I thought it was not feasible to connect external propane sources to our 2007 Airstream Interstate Class B camper van. Several years ago, we dissected this issue in a lengthy and detailed Air Forums thread titled "Carrying extra propane--2006 T1N Interstate Parkway" (the Parkway was a contemporaneous short-lived model produced at the same time as first-gen Interstates). At that time, we concluded that we just didn't have the clearance required to plumb the correct fitting on our tightly-configured vans.
|See the measuring tape at top right? Too tight to do anything useful with that space.
But of course, back in 2016 when that thread was hatched, we were still thinking inside the box, weren't we? It took a full-blown humanitarian crisis and emergency in which one-quarter of the Texas population found itself without electricity and without water service in many cases in sub-zero weather, and approx. 1.3 million people in greater Houston alone were left without basic utilities, as a polar vortex crippled the Texas power grid,... it took ALL THAT to push us outside of our original box.
And by "us", I really mean my husband, who invented this approach I describe below. Rather than trying to install a fitting AFTER the freakin' OEM propane regulator, as we had originally aspired to do, he figured out that we could tap into the T-fitting that we abandoned when we removed the original Dometic propane fridge and installed a compressor-driven Vitrifrigo instead (see this other post).
The sequence goes as shown in the scribble images below. I have referenced the corresponding part numbers as those parts were found at Lowes hardware store in February 2021. Note that there are probably more elegant ways to plumb this thing, but in our electrical grid failure emergency, a lot of supplies were sold out, especially items relating to alternate energy that people were trying desperately to cobble together at the scale of their households.
|There's the other end of the line shown in (1), with the protective plug (black) still shown in the quick disconnect fitting.
|This just shows how that line snakes from the T junction amidships back to the rear end of the van where the terminal quick-connect is located.
|There's the quick disconnect (QD) hooked to the line that runs to the peripheral propane supply.
|The line connecting to the 20-pound external propane bottle.