Water heating system

A water heating system, comprising:

• a burner assembly for providing a source of thermal energy, the burner assembly comprising a combustion chamber, an air intake to supply an air stream to an air fuel delivery system, and a fuel inlet to supply fuel to said air fuel delivery system wherein said air stream and said fuel are mixed to form an air/fuel mixture, and a blower to blow said air fuel mixture into the combustion chamber where said air/fuel mixture is ignited to produce products of combustion;
• a water inlet conduit coupled to a heat exchanger assembly for supplying fresh water to be heated, said heat exchanger assembly operatively coupled to the burner assembly, the heat exchanger assembly comprising a first fluid conduit in heat exchange relationship with a second fluid conduit, wherein said water to be heated flows in either of said first fluid conduit or said second fluid conduit and said products of combustion flow in the other of said first fluid conduit or said second fluid conduit;
• a water exit conduit coupled to the heat exchanger assembly for delivering the heated water to a point of use;
• a bypass conduit connecting the water exit conduit to the water inlet conduit and circulating only water flows from the water exit to the water inlet conduit;
• a constant flow pump disposed in the bypass conduit to circulate at least a portion of the heated water from the water exit conduit to the water inlet conduit, that continuously circulates a constant flow rate through the bypass conduit thereby providing a mix of fresh water and recirculated water to the heat exchanger assembly;
• a feed-forward sensor positioned in the water inlet conduit having flowing within said water inlet conduit said mix of fresh water and recirculated water, said feed-forward sensor disposed between the heat exchanger assembly and the bypass conduit for monitoring a parameter of said mix of fresh water and recirculated water entering the heat exchanger assembly;
• and
• a processor for controlling the operation of the burner assembly by a feed-forward control system to maintain a temperature of the heated water to the point of use in response to the feed-forward sensor.