Integral water heater and water temperature sensor

摘要

A screwplug type water heater (10) has a heating element (12) immersible in a water heater tank (T) to heat water (L). Electrical terminals (28) on the outer end of the heater connect the heating element into a heater circuit (H) for a control unit (14). The control unit also includes a sensing circuit (S) for the unit to be responsive to water temperature inputs to turn-on the heater to heat water to a desired temperature and maintain it there. A thermistor (16) provides a temperature input to the control circuit. The thermistor is encapsulated in a bracket (32) mounted in, or integrally formed with, the screwplug to sense water temperature. Terminals (36) on the outer end of the heater allow the thermistor to be connected into the control circuit.