System and method for controlling outlet water temperature of an instantaneous water heater

An apparatus for accurately controlling output water temperature of an instantaneous water heater to maintain a desired outlet temperature at a hot water outlet, the instantaneous water heater having a heat exchanger with water tubing and being capable of automatically adjusting a burner means output for changes in water flow and incoming water temperature, the apparatus comprising:

• a. a first electronic sensing device for sensing a flow of water through the water tubing of the heat exchanger and providing a flow signal to a control module;
• b. means for starting an ignition sequence when a predetermined flow rate has been detected by the first electronic sensing device;
• c. a second electronic sensing device for sensing an outlet water temperature at an outlet of the water tubing of the heat exchanger and for providing outlet water temperature information to the control module;
• d. a third electronic sensing device for sensing a midway water temperature at an approximate half way point in the water tubing of the heat exchanger and for providing midway water temperature information to the control module;
• and
• e. an adjustment means for receiving the flow signal from the control module, the outlet water temperature information from the control module, and the midway water temperature information from the control module to control the burner means output to maintain the desired outlet temperature.

An apparatus for accurately controlling output water temperature of an instantaneous water heater to maintain a desired outlet temperature, the instantaneous water heater having a heat exchanger with water tubing and being capable of automatically adjusting a burner means output for changes in water flow and incoming water temperature, the apparatus comprising:

• a. a plurality of electronic sensing devices for sensing water flow through the water tubing of the heat exchanger and providing a flow signal to a control module in response thereto, and further for sensing water temperature and providing water temperature information to the control module in response thereto;
• b. means for starting an ignition sequence when a predetermined flow rate has been detected by at least one of the plurality of electronic sensing devices;
• c. a control adjustment means for receiving the flow signal from the control module, and the water temperature information from the control module to control the burner means output to maintain the desired outlet temperature;
• d. staging means associated with the control adjustment means for adjusting a percentage of the burner means output of the instantaneous water heater to maintain the desired outlet temperature.

An apparatus for accurately controlling output water temperature of an instantaneous water heater to maintain a desired outlet temperature, the instantaneous water heater having a heat exchanger with water tubing and being capable of automatically adjusting a burner means output for changes in water temperature, the apparatus comprising:

• a. an outlet thermistor for sensing an outlet water temperature at an outlet of the water tubing of the heat exchanger and for providing outlet water temperature information to a control module;
• b. a midway thermistor for sensing a midway water temperature at an approximate half way point in the water tubing of the heat exchanger and for providing midway water temperature information to the control module;
• and
• c. a control adjustment means for receiving the water temperature information from the control module to control the burner means output to maintain the desired outlet temperature.