How to install a second additional water heater in series
Dual water heaters installed in series. That is how mine is hooked up. [you can also do it in a way called parallel, but that will be a different video]
It’s fairly simple once you see it. First you will need the space. That alone will end this project for many people. But if you have the room, its not too hard. If you are messing with gas, it’s a great idea to hire someone to do that part for you. In fact, in many places, it’s the only legal way to do it.