A water heating apparatus, comprising: an enclosure; a water inlet port of a fluid inlet conduit configured to split into a first supply leg and a second supply leg, said water inlet port disposed above said supply legs and below a top of said water heating apparatus; a plurality of heat exchangers including a first heat exchanger and a second heat exchanger, said heat exchangers being disposed above said supply legs; a first pipe section and a second pipe section, the first pipe section being connected to the water inlet port and extending within the enclosure to approximately the centerline of the heat exchangers (16a, 16b), then bending downward to a base of the enclosure and then being connected to the second pipe section; two piping sections comprising the first supply leg and the second supply leg symmetrically extending from the base of the second pipe section and forming longitudinal runners to the respective inlet of each heat exchanger, wherein the first supply leg being connected to the first heat exchanger, extends laterally away from the second pipe section to an inside wall of the enclosure, bends downward to a floor of the enclosure, then bends in a longitudinal direction to extend or run partially underneath the heat exchangers, which are somewhat elevated; and wherein the second supply leg being connected to the second heat exchanger is symmetric to the first supply leg, that is, the second supply leg extends laterally away from the second pipe section in an opposing direction to the first supply leg to the opposite inside wall of the enclosure, bends downward to the floor of the enclosure, then bends in a longitudinal direction to extend or run partially underneath the heat exchangers, the first and second supply legs having equal lengths and equal bends; wherein comprises: an outer housing; a heat exchanger inlet (124a,124b), each heat exchanger inlet connected to a different respective supply leg (118, 126) of the fluid inlet conduit for receiving an inlet flow of liquid into the outer housing; an outlet port for allowing an outlet flow of liquid to leave the outer housing; a heat exchange element positioned within the outer housing and configured to heat a flow of liquid passing through the outer housing from the heat exchanger inlet to the outlet, said heat exchanger inlet disposed above said supply legs (118, 126) and below a top of said water heating apparatus; a burner assembly comprising a combustion chamber housing and a burner positioned internally within the combustion chamber housing, the burner assembly coupled to the heat exchangers for supplying heat to the flow of liquid; wherein the heat exchangers (16a, 16b) are configured for parallel operation an enclosure; a water inlet port of a fluid inlet conduit configured to split into a first supply leg and a second supply leg, said water inlet port disposed above said supply legs and below a top of said water heating apparatus; a plurality of heat exchangers including a first heat exchanger and a second heat exchanger, said heat exchangers being disposed above said supply legs; a first pipe section and a second pipe section, the first pipe section being connected to the water inlet port and extending within the enclosure to approximately the centerline of the heat exchangers (16a, 16b), then bending downward to a base of the enclosure and then being connected to the second pipe section; two piping sections comprising the first supply leg and the second supply leg symmetrically extending from the base of the second pipe section and forming longitudinal runners to the respective inlet of each heat exchanger, wherein the first supply leg being connected to the first heat exchanger, extends laterally away from the second pipe section to an inside wall of the enclosure, bends downward to a floor of the enclosure, then bends in a longitudinal direction to extend or run partially underneath the heat exchangers, which are somewhat elevated; and wherein the second supply leg being connected to the second heat exchanger is symmetric to the first supply leg, that is, the second supply leg extends laterally away from the second pipe section in an opposing direction to the first supply leg to the opposite inside wall of the enclosure, bends downward to the floor of the enclosure, then bends in a longitudinal direction to extend or run partially underneath the heat exchangers, the first and second supply legs having equal lengths and equal bends; an outer housing; a heat exchanger inlet (124a,124b), each heat exchanger inlet connected to a different respective supply leg (118, 126) of the fluid inlet conduit for receiving an inlet flow of liquid into the outer housing; an outlet port for allowing an outlet flow of liquid to leave the outer housing; a heat exchange element positioned within the outer housing and configured to heat a flow of liquid passing through the outer housing from the heat exchanger inlet to the outlet, said heat exchanger inlet disposed above said supply legs (118, 126) and below a top of said water heating apparatus; a burner assembly comprising a combustion chamber housing and a burner positioned internally within the combustion chamber housing, the burner assembly coupled to the heat exchangers for supplying heat to the flow of liquid; wherein the heat exchangers (16a, 16b) are configured for parallel operation