Even using Google I can't find the thread I'm fairly certain I started
But there was a good conversation about return lines to the hot water tank from the furthest used outlet point as a way to speed up hot water delivery.
I didn't put the thread in my watch list, the baked in site search sucks, and Google wants to tell me all about coolant lines and radiators instead of home stuff when I search the site there.
Main question, does there need to be some sort of recirculation pump to make it work? Or do I just run a T by the output to the input side of the HWT and call it a day?
As long as your water heater is below your last device in the line you should be good. That return line will be cooler than the feed line so there will be a natural convection current that will act as a pump. The hotter water will want to rise, displacing the colder water into the return line. It can help to insulate the hot water lines and leave the last ten feet or so of the return line uninsulated. My dad has this setup and it's slick as hell. He had a recirc pump and when it went bad I recommended just removing the pump and replacing it with a straight piece of pipe and sure enough he has instant hot water upstairs despite no pump.
