Water heating apparatus with parallel heat exchangers

A water heating apparatus comprising:

• a water inlet port and a hot water supply connection water outlet port;
• a burner assembly comprising a burner disposed within a combustion chamber housing;
• at least two heat exchangers operated in parallel, each of the at least two heat exchangers fluidly coupled to said water inlet port, at least two of said at least two heat exchangers having at least a first heat exchanger water inlet port on a same side of the water heating apparatus, each of the heat exchangers having an outer housing and disposed within a plurality of heat exchange tubes and a portion through which a heated water exits each of the at least two heat exchangers;
• a water jacket defined by an area between an outer containment vessel and the combustion chamber housing;
• wherein a hot combustion gas from the burner assembly flows through each of the at least two heat exchangers to heat a cold water from the at least a first heat exchanger water inlet to a heated water;
• and
• wherein the heated water flows out of each of each of the at least two heat exchangers through the portion of each of the at least two heat exchangers into the water jacket, where the heated water flowed into the water jacket is further heated by the combustion chamber housing and the further heated water exits the water heating apparatus at the hot water supply connection water outlet port.