I want to add a hot water recirc line to my trailer

C Oneil- if you are hooked up to city water, chances are that using a bit extra water isn't a big deal, as you are also probably hooked up to a septic system. This valve idea (in my case) would be specifically used for boondocking. If you were hooked up to utiliites, I could see the other circ ideas of having extra circ pumps installed, so not waste water.