Patent ID: 8485178

Claim:
A solar water heating system with a forced recirculation backup water, comprising: a solar panel, and a solar panel storage tank, wherein the solar panel is disposed below the solar panel storage tank to achieve a thermosiphon effect between the solar panel and solar panel storage tank; a backup heater system having a corrosion resistant tank with a multi-tube heat exchanger, a burner, and a gas feed valve system including at least one electrovalve configured to deliver a gas to said burner; a plurality of bimetallic temperature detectors, wherein a first bimetallic temperature detector detects temperature of water in said solar panel, a second bimetallic temperature detector detects temperature of water in said solar panel storage tank, and a third bimetallic temperature detector detects temperature of water in said back up heater system tank; a first spark plug positioned to ignite said burner, and a second spark plug positioned to detect current changes in said first spark plug generated by ionization effect after said burner is ignited; a backup heater controller in operative communication with said electrovalve, said third bimetallic temperature detector, and said first and second spark plugs to send a current to said first spark plug upon detection of a low setpoint temperature from said third bimetallic temperature detector, said backup heater controller causing gradual opening of said electrovalve to supply gas to said burner to ignite said burner with said first spark plug; said backup heater controller configured to detect the change of current from said second spark plug and to close said electrovalve and terminate operation of said water heater if the change of current is not detected within a defined time and to generate a visual display of equipment error; and a forced recirculation system between said solar panel and said solar panel storage tank that includes a recirculator configured to recirculate water between said solar panel and said storage tank as a function of a detected temperature difference between said first and second bimetallic temperature detectors.