Abstract: A water heater including a water inlet line having an inlet opening that introduces cold water to a tank, a water outlet line having an outlet opening that withdraws heated water from the tank, and a heating element. The water heater further includes a control circuit. The heating element can be an electrical resistance heating element, a gas heating element, or a combination thereof. In one construction, the gas heating element includes a first combustive section and a second combustive section separately controlled from the first combustive section.

Abstract: A water heater includes a tank and a jacket surrounding the tank. Between the tank and jacket is defined an annular space in which a seal is positioned. The seal extends between the tank and the jacket and defines a bottom of the annular space. The seal includes a depending flange that retains a fiberglass batt against the water tank so that the batt does not interfere with lowering the jacket around the tank. The seal also includes a plurality of arms that center and round out the jacket as it is lowered over the tank. A liquid-based insulation is pumped into the annular space under pressure, and the seal substantially prevents any of the insulation from leaking through the bottom of the annular seal. The arms may be progressively longer and/or thicker from the top down to permit some of the insulation to bypass the upper arms and fill the spaces between the arms.

Abstract: A removable dam provides a way to prevent liquid insulation from interfering with electrical components and from squirting out an opening in the jacket of a hot water heater.