Patent ID: 7567751

Claim:
A tankless liquid heater comprising: a first inlet manifold; a first outlet manifold; and a first plurality of liquid heaters each having a liquid inlet and a liquid outlet, the liquid inlets of the first plurality of electric liquid heaters being connected in a parallel flow relationship by the first inlet manifold, the liquid outlets of the first plurality of electric liquid heaters being connected in a parallel flow relationship by the first outlet manifold, and each of the first plurality of liquid heaters having one or more electrical resistance heating elements for heating liquid flowing through said liquid heater; and a majority of the first plurality of liquid heaters having a controller adapted to regulate the amount of electrical current flowing through the one or more electrical resistance heating elements of a liquid heater of the first plurality of liquid heaters; wherein the controllers are configured to prevent energizing an electrical resistance heating element until the flow rate of liquid through the inlet channel of the liquid heater exceeds about 0.5 gallons per minute; and wherein the tankless liquid heater provides a temperature rise of between about 41 degrees and about 71 degrees Fahrenheit to liquid flowing through the tankless liquid heater at flow rates between about 6 gallons per minute and about 10 gallons per minute with total power dissipation in the electrical resistance heating elements between about 36 kilowatts and about 63 kilowatts.