Unit for converting a fossil fuel burning furnace into an electrical furnace

In a fossil fuel burning, forced air heating system, such system including a fossil fuel burner associated with a heat exchanger supplying heated air to an air plenum and duct system for distribution, a fan for circulating air through the system over the heat exchanger and through the air plenum and duct system and a control system for controlling operation of the fan and burner to maintain a desired temperature in a space being heated by the system, the improvement comprising an electrical heating unit inserted into the plenum and duct system downstream of the heat exchanger and fan for use when the burner is inoperative, said heating unit comprising:

• a. an electrical power distribution means;
• b. a first and a second source of electrical power, said distribution means arranged to deliver power from said second source at selected intervals;
• c. a plurality of heating elements being positioned in the plenum system and extending substantially across the plenum;
• d. said heating elements being arranged in vertical, staggered relation to one another whereby a tortuous air flow path thereover is established;
• e. an air deflector member arranged generally centrally of the unit and positionally extensible to permit said air deflector member to extend substantially across the plenum in parallel relation to said heating elements and sets of said heating elements being arranged respectively along the sides of said deflector;
• f. first switch means actuated by said distribution means for delivery of electrical power to said heating elements from said second power source;
• g. control means responsive to delivery of a signal thereto indicative of the availability of power from said second source to selectively ready either said distribution means for transmission of power to said heating elements from said second power source when the signal is indicative of power availability therefrom or energization of said fossil fuel burner for heat generation when the signal is indicative of power unavailability from said second source;
• h. signal transmission means including signal generating means communicating with and deliverying said signal to said control means for selectively readying either said distribution means to energize said heating elements or said burner in response to the availability of power from said second source of power;
• and,
• i. thermostatic switch means associated with the space to be heated and arranged in circuit with said control means and said distribution means for controlling actuation of said first switch means in response to the temperature level within the space to be heated.