We dry camp on a beach in Baja California for a couple months in the winter. Propane filling facilities are not available in the area. In our previous RV- a Class A we used an external 20 lb propane tank and a Y valve to feed propane into the rig. Can this be done with our new Unity FX using the fitting for an external grill as long as we had a regulator installed at the tank to keep the proper gas pressure with the propane tank switch turned off? If that doesn’t work is there another way to feed into the propane system without using the tank mounted in the RV?
Good question which I've wondered about myself. I'll be watching for a definitive answer (as opposed to an educated guess). I'm not very knowledgeable about the propane plumbing except that the external free is already regulated. So it would seem that a regulated external tank should work to feed LP appliances downstream of the onboard tank. However I don't know if the onboard regulator has some sort of "backflow preventer".
You can only have 1 regulator in nline so if the auxiliary tank has one it will not work.