In this video I install a hot water recirculation system in my 2013 Jayco Seneca to save water while boondocking. While it does not circulate the water back to the hot water heater itself, it does still recapture the water by returning it back to the fresh water tank.

Here is the 12volt 1/2 Solenoid that I used:
https://www.amazon.com/gp/product/B00...

This is the website I used to order the custom made rocker switch:
https://rockerswitchpros.com/product/...