Returned and removed the old Rinnai tankless water heater. Installed a new Navien NPE 240A2. Reconnected to the existing gas and water lines. Cut a new tee, thermal expansion tank, and new shutoffs for the hot and cold lines feeding the tankless. Ran the intake inside the crawlspace and ran the exhaust out of the existing wall penetration. Used hydraulic cement inside of the existing gasket for the old penetration and used a shield to partially cover. Tested all work to ensure proper function and no leaks. None were found. #8928