Gas for the on-demand water heater at my rural vacation rental is supplied in 100-lb cylinders or "tanks". As auto-switch regulators are not available locally, it seemed a good idea--and it was--to order via Amazon. However, as product information is sketchy, requests for guidance from "Mendel" at Flame King were a wasted effort, and since there is a good deal of misinformation re installation in the buyer comments, I offer what I wish I had found all in one place. It took days to learn what Flame King should have told me.
Installation is easy, takes only a few minutes, IF you have at hand all the fittings you need.
1. MOUNTING bracket attached to the regulator is a horizintal flat metal plate with a pre-drilled bolt hole, easily affixed to any horizontal wooden or metal bar or shelf with a a bolt, a nut and a couple of washers. Time involved: depends on whether you need to a drill a hole on the mounting surface; otherwise 30 seconds.
2. INLETS: Regulator is shipped with PERMANENT brass female reverse-flair (concave) inlet fittings to accommodate threaded ¼" brass reverse-flare (convex) "pigtail" fittings. Some purchasers complain about difficulty in removing these permanent fittings, which is hard to do, will break the factory seals, and is a waste of effort. If your existing pigtails or new ones your order (see below) are of the male ¼" NPT (flat-end) type, you will need TWO ADAPTERS, ¼" female NPT to male ¼" reverse-flare (convex), available locally or via Amazon. Using yellow wrapping tape for gas, install the adapters (if needed) to the inlet fittings, wrap the pigtail connectors and install. Total time, maybe 3 minutes.
3. In some countries (not the US, but the one where I live), propane cylinders ("tanks") have reverse-thread connections (left or ccw to tighten, right or cw to loosen) called POL connections for the original manufacturer. If you use existing or new POL pigtails, see the note above about NPT vs. reverse-flair fittings. Time involved: for connecting pigtail to tanks, 15-30 seconds each side.
4. OUTLET. Regulator outlet has a ⅜" female pipe-thread fitting, and details of connection to the gas line supplying one or more appliances, depends on the nature of the existing installation. Whether cast iron, yellow
polyethylene plastic pipe or (obsolete) copper piping, you will need a ⅜" male brass or polyethylene fitting to connect to the regulator. (Galvanized steel pipe not rec. for propane).
5. Finally, Amazon offered a "buy together" package including the POL reverse-thread pigtails I needed, 2 NPT-to-reverse flair adapters for the regulator inlets, and a roll of wrapping tape, all of which simplified ordering, worked perfectly and saved a whole lot of time.