For those who haven't seen one of my other threads about it, the hot water tank in my mobile home is presently sitting idle and empty in a corner while I rebuild the subfloor beneath it. That isn't done yet, but parts take time to ship, and I'd like to be ready with the plan sooner rather than later. The original install was a hack job to say the least, and has to get cut in half to allow the new subflooring in, so I'm starting from scratch and reworking the entire closet, including the entry and heating and pipes leaving the area. The system will also be getting a two stage filter, a PRV, and a backflow preventer, but let's ignore all that and focus on hot stuff. I've already ordered a vacuum relief valve, expansion tank, isolation valves, and a proper electrical whip. Also, I've gotten a pressure/temp gauge to sit right on top of the heater. I'm comparing models of master mixing valve (Watts LFMMVM1-US is looking good right now, the Honeywell isn't lead free) and there will be another temp gauge just after it. So, here's a list of "I think" that I'd like to hear others' thoughts on. I'm thinking to just use before-and-after valves on the entire hot water apparatus, so there wouldn't be more shutoffs around the mixing valve. I'm thinking the vacuum valve and temp/pressure gauge will be mounted on stubs right at the top of the heater, and the rest of it will be mounted on the wall. I think I want nice flexible braided hoses attaching the heater stubs to the wall mounted parts, but I'm not sure what the advantages of the flexible corrugated stuff might be in comparison. I know I don't want the heater hard piped, not even with unions. I think I want to put a pair of bent nose valves right above where the flex hoses attach to the wall piping, so I can let bulk amounts of air in while draining, and let air out at the highest point in the system, and tap the premixed hot water if I really need some. I think I want a check valve between the main cold pipe and the hot section to absolutely prevent heated water from ever coming back into the cold system, but I'm not sure if a single check would do or if it should be a real double-check backflow preventer. I think it should be a swing type, not a spring. Please, any of those "think" that spell DIYer about to shoot himself in foot, hit me with it before I put on new shoes. Anything else I haven't thought of is also open for debate - and, thanks in advance!