At my request, I got a Camco Little Red Campfire for Christmas. I wanted small and self-contained, as it's only a van, with little room to spare. It came with a relatively short hose with regulator with flow adjustment knob, and is designed for working off a DOT cylinder. Plenty of flame, and in fact, too much flame with the flow all the way up. Pretty loud, too.
Connected to the van's onboard ASME tank via the quick connect fitting under the rear bumper, using a 20 ft hose, the flame is pretty anemic. It's useable, but just too low. The van's regulator puts out about 11.5" or so water column per my own measurement (with an actual water column), which is pretty standard. The regulator the fire pit came with tops out at about 100" water column, which I also measured. Which explains why the flame was so wimpy on the van's regulated supply.
There is an orifice in the ell at the fire pit the end of the hose and immediately before the adjustable air inlet. The orifice measures 1.2mm [0.047in], which is pretty tiny. So I bought some metric brass pipe plugs, 10mm x 1 (fine thread), to experiment with orifice sizes without messing up the original.
I'll spare the play-by-play, but I worked my way up in orifice sizes by drilling those plugs and counter sinking the inlet side just a tiny bit so they weren't sharp edged.
Eventually I landed on 2.35mm [0.092in] which yields a flame about the same as that from the supplied regulator and a 20lb DOT cylinder, but I can adjust the flame size with the ball valve that's part of the quick connect I added at the fire pit. There isn't as much blue flame at the bottom as with the original orifice and portable cylinder, but that's probably due to the larger orifice at lower pressure not drawing as much air into the inlet. I may yet experiment with opening the air inlet a bit, when it's warmer out. Much quieter with the larger orifice, too.
I didn't want to cut into the high pressure side of the van's system, and this mod is completely reversible in case I want to use it on the back deck at home with a portable tank. I'll just save the plugs in my bag of tricks.
The first pic is the campfire on the van's system with the original orifice, though it's a bit light out to see how small that flame is, followed by the original regulator on a 20lb cylinder (original orifice), then running off low pressure van propane with the large orifice, followed by the drill bits for the visual comparison between the original and the oversized holes.
I tried many smaller sizes (last photo), including one smaller than the original just to see what it would do with the OEM regulator (it only cut the flame down a little), but ended up going even bigger. Plugs came from Belmetric. https://www.belmetric.com/m10-10mm-p...s-p-10059.html
They're tapered, while the original is straight, but they fit fine, and only need to be just snug as they thread into the male NPT end of the ell and any leakage past the plug is still within the plumbing.
Posted in case anyone wants to adapt either the Little or the Big Red Campfire to an RV's low pressure system.