Control system for a heater

A heater comprising first and second heating elements, means for circulating air over the heating elements to heat it and supply heated air to an environment, first and second bi-directional switching devices for independently switching the first and second heating elements in accordance with heating requirements to generally maintain a desired temperature of the environment, and circuit means for controlling the operation of the circulating means in response to switching of the first and second heating elements, the circuit means including a third bi-directional switching device for switching the circulating means and means for limiting an electrical characteristic of the circulating means to control the volume of ambient air circulated over the heating elements such that a greater volume of air is circulated when both the first and second heating elements are activated than when only one of the heating elements is activated.

A heater of the type including first and second heating elements and means for circulating a volume of air past the heating elements to heat the air and supply heated air to an environment wherein the improvement comprises a system for controlling the operation of the heating elements and the circulating means in response to heating requirements to maintain substantially a desired temperature in the environment, the control system including first circuit means for sensing ambient temperature, for selecting a desired temperature, and for causing the first and second heating elements and the circulating means to operate in first and second modes, respectively, when first and second temperature differences are detected between the sensed ambient temperature and the selected temperature, second circuit means for independently activating and deactivating the first and second heating elements in accordance with the heating requirements determined by the first circuit means, means for coupling the second circuit means to the first circuit means, third circuit means for activating, deactivating, and variably controlling the volume of air circulated by the circulating means past the heating elements in response to activation and deactivation of the first and second heating elements, and means for coupling the third circuit means to the second circuit means.

A heater comprising a main housing portion for housing heating elements, and means for circulating a volume of ambient air through the housing and past the heating elements to supply heated air to an environment, said main housing portion providing an ambient air intake opening and a heated air vent, and a secondary housing portion mounted exterior to the main housing and in spaced relation to the intake opening so that ambient air is drawn from the environment past the secondary housing portion into the intake opening to maintain the secondary housing portion at ambient temperature, and a system for controlling the operation of the heating elements and the circulating means, the control system including a temperature sensitive device coupled to the secondary housing portion in heat transfer relation for sensing ambient temperature of the environment, the temperature sensitive device and the secondary housing portion cooperating to provide a temperature sensor for sensing ambient temperature.

A method of controlling a heater of the type having two heating elements for providing heat and means for circulating a volume of air past the heating elements to heat the air and supply heated air to an environment, comprising the steps of sensing ambient temperature of the environment, comparing the sensed ambient temperature to a selected desired temperature, activating a first one of said heating elements when a first difference exists between sensed ambient temperature and the desired temperature and operating the circulating means at a first speed when said first heating element is activated, activating a second one of said heating elements when a second difference exists between sensed ambient temperature and the desired temperature, and operating the circulating means at a second speed when said second heating element is activated.