Patent ID: 7779790

Claim:
A tankless liquid heater comprising: an inlet manifold; a plurality of liquid heaters each having a liquid inlet and a liquid outlet, the liquid inlets of the plurality of liquid heaters being connected in a parallel flow relationship by the inlet manifold and each of the plurality of liquid heaters having one or more electrical resistance heating elements for heating liquid flowing through said liquid heater; each of the plurality of liquid heaters further comprising: a housing having a liquid inlet channel integrally including the liquid inlet and a liquid outlet channel integrally including the liquid outlet, the housing defining a central passage opening into an exterior housing surface; and a heating cartridge resident in the central passage, the heating cartridge supporting interiorly of the housing the one or more electrical resistance heating elements; and a separate outlet conduit connected to the liquid outlet of each liquid heater; wherein the plurality of liquid heaters is adapted to deliver water with less than about a 3° F. increase in output water temperature upon about a two-fold or greater decrease in water demand, the decrease in water demand occurring in less than about 2 seconds.