Further-improved control system for solar heating systems

For use in a solar-heating system having transferring means for transferring elsewhere solar-generated heat energy from solar-energy collecting means, control means for controlling said transferring means, said control means, including;

• terminal means adapted to receive operating power for said transferring means;
• a source of D.C. operating power for said control means;
• a relay having a solenoid and at least one pair of normally-open contacts;
• a sensor module including a phototransistor having a collector, an emitter and a base;
• said sensor module also including a temperature-sensitive resistor coupled between said emitter and said base of said phototransistor;
• time-delay means having first and second input terminals and first and second output terminals;
• said collector being coupled, through said first input and output terminals of said delay means and said solenoid to said source of D.C. operating power;
• said phototransistor being responsive to solar energy incident thereon to become conductive at a solar energy level dependent upon the magnitude of said temperature-sensitive resistor;
• said relay being responsive, following a delay by said delay means, to conduction by said phototransistor to close said normally open contacts with a corresponding delay;
• said normally open contacts being adapted for serial connection between at least one of said terminal means and said transferring means.