Replaced aging tank-type water heater with a Rinnai RUR199iN condensing tankless unit. Upgraded gas line from 1/2" to 3/4" black iron pipe to meet BTU requirements. Installed new Rheem RTG20220AB condensate neutralizer to protect plumbing from acidic condensate. Implemented Webstone 44443WPR isolation valves for easy servicing. Vented unit using 3" PVC pipe with Centrotherm ISEL0387 concentric termination kit. Reconfigured hot water lines using 3/4" copper pipe and ProPress fittings. System now delivers on-demand hot water with 96% thermal efficiency, significantly reducing energy consumption and operational costs.