| 摘要 |
A water heater having a water tank and multiple electric resistance heati ng elements extending into the water tank for heating water in the tank. The water heater includes a proportional band temperature controller for conducting electric power to the electric resistance heating elements in bursts. Each burst of electric power is followed by a period during which the temperature controller does not conduct power to t he electric resistance heating element. In one embodiment, each burst of electrical powe r lasts for about 95% or less of a cycle comprised of one burst of electric power follow ed by the period during which the temperature controller does not conduct electric power. Further, activation of the heating elements by the controller is carried out in a sequential or other timed or controlled fashion to permit uniform heating of the water in the tank.
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