| 摘要 |
A water heater having a water tank 11,205 and multiple electric resistance heating elements 16,125,235,240 extending into the water tank for heating water in the tank. The water heater includes a proportional band temperature controller 260 for conducting electric power to the electric resistance heating elements 16,125,235,240 in bursts. Each burst of electric power is followed by a period during which the temperature controller does not conduct power to the electric resistance heating element 16,125,235,240. In one embodiment, each burst of electrical power lasts for about 95 % or less of a cycle comprised of one burst of electric power followed 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. |
