Abstract: The control utilizes sensed gas pressure downstream of the thermostat controlled valve as an indication of heat demand. A low limit transducer is placed at 50 to 90 percent of the tank height to maintain adequate heated water for casual uses without excessive burner cycling. A flow transducer is integrated with a heat trap. The control uses output of the flow transducer (combined with the timing out of an interval timer) to enable an excursion from the low limit set point to the thermostat high limit.

Abstract: Apparatus for controlling a water heater thermostat for increased efficiency in fuel usage. A mounting bracket is adapted to fit on several different common types of thermostat control boxes and to removably receive a controller housing. A motor in the housing is coupled to a slip ring engaging the thermostat knob to raise and lower the thermostat temperature setting in accordance with sensor actuated circuitry responsive to incoming and outgoing water temperature. The coupling enables the apparatus to accommodate thermostats with different size knobs and rotatable in opposite directions.

Abstract: Apparatus for controlling a water heater thermostat for increased efficiency in fuel usage. A mounting bracket is adapted to fit on several different common types of thermostat control boxes. In one embodiment the bracket removably receives a controller housing. In another embodiment the mounting bracket and the controller housing are a unitary structure. A motor in the housing is coupled to a slip ring engaging the thermostat knob to raise and lower the thermostat temperature setting in accordance with sensor actuated circuitry responsive to incoming and outgoing water temperature. The coupling enables the apparatus to accommodate thermostats with different size knobs and rotatable in opposite directions, in addition to coupling to various size thermostat housings.