Control system for water heaters

Claim 1

A WATER HEATER SYSTEM COMPRISING, A TANK HAVING COLD WATER INLET AND HOT WATER OUTLET CONNECTIONS, GAS BURNER MEANS FOR HEATING SAID TANK INCLUDING A MAIN BURNER AND A PILOT BURNER, AN ELECTRICAL GENERATOR ENERGIZED BY SAID PILOT BURNER, A GAS SUPPLY LINE FOR SAID BURNER MEANS, A SAFETY VALVE IN SAID LINE HAVING MANUALLY OPERABLE MEANS FOR MOVING THE VALVE TO OPEN POSITION AND ELECTRICALLY OPERABLE MEANS CAPABLE ONLY OF MAINTAINING THE VALVE IN OPEN POSITION, A CONTROL VALVE IN SAID LINE OPENED WHEN ELECTRICALLY ENERGIZED, FIRST THERMOSTATIC SWITCH MEANS LOCATED TO SENSE WATER TEMPERATURE AT A RELATIVELY LOW POSITION ON SAID TANK AND ADJUSTED TO ACTUATE ITS CONTACTS AT A RELATIVELY LOW TEMPERATURE, SECOND THERMOSTATIC SWITCH MEANS LOCATED TO SENSE WATER TEMPERATURE AT A RELATIVELY HIGHER POSITON ON SAID TANK, SAID SECOND THEREMOSTATIC SWITCH MEANS HAVING FIRST AND SECOND SETS OF CONTACTS AND BEING ADJUSTED TO ACTUATE SAID FIRST SET OF CONTACTS AT A RELATIVELY HIGH TEMPERATURE AND SAID SECOND SET OF CONTACTS AT A STILL HIGHER TEMPERATURE, ELECTRICAL CONDUCTORS CONNECTING SAID GENERATOR, SAID FIRST THERMOSTATIC SWITCH MEANS THE FIRST SET OF CONTACTS OF SAID SECOND THERMOSTATIC SWITCH MEANS, AND SAID CONTROL VALVE NOR-