The Noritz Combination Boiler delivers hot water for both plumbing and hydronic residential heating applications, while managing the switch between uses without a perceivable difference in performance. With 95-percent annual fuel utilization efficiency (AFUE), it is ENERGY STAR rated to deliver maximum operational cost savings to homeowners. The Noritz Combination Boiler’s compact, 90-pound package delivers up to 9.2 gallons per minute of domestic hot water – nearly twice the flow of comparable units. A unique flow control valve also facilitates maximum domestic hot water flow rate at stable temperatures and regardless of incoming water temperature. The boiler’s external and booster pump drive terminals (up to 2 amps) do not require a relay, and its integrated condensing technology lowers exhaust temperatures to a level at which stainless steel venting material is no longer required.