I have a system with two gas hot water heaters teed into a common inlet and outlet with separate valves.
I only need one of these for the foreseeable future and hope to keep the other as a spare. I have turned one off (gas and outlet valve.) Is it better to leave it pressurized or turn off the inlet and drain the tank?
I probably won't use the spare until the other fails and they are both pretty new.
Thanks for the advice.
John