Water heating system

A method of substantially maintaining a selected temperature of water in the water container of the system having a water container having a cold water inlet that connects to a water supply, a hot water outlet, a water heater outlet and a water heater inlet;

• an instantaneous water heater and having a tank supply inlet connected to the water heater outlet, a tank supply outlet connected to the water heater inlet;
• a pump connected between the water container and die Instantaneous water heater that moves water between the water container and the instantaneous water heater, and a controller that operates the pump and the burner:
• the method comprising the steps of:
• sensing temperature of the water in the water container:
• comparing a sensed water temperature to a selected water set temperature;
• engaging the pump if the sensed water temperature is less than the selected water set temperature;
• and igniting the burner.

A method of preventing water in the instantaneous water heater from freezing, having a water container having a cold water inlet that connects to a water supply, a hot water outlet, a water heater outlet and a water heater inlet;

• an instantaneous water heater and having a tank supply inlet connected to the water heater outlet, a tank supply outlet connected to the water heater inlet;
• a pump connected between the water container and the instantaneous water heater that moves water between the water container and the instantaneous water heater, and a controller that operates the pump and the burner;
• the method comprising the steps of:
• sensing temperature of water proximate to or in the heat exchanger:
• comparing the sensed water temperature to a first selected water temperature;
• comparing the sensed water temperature to a second selected water temperature if the sensed water temperature is less than the first selected water temperature:
• 1) engaging the pump if the sensed water temperature is greater than the second selected water temperature;
• 2) sensing temperature of water in the water container;
• 3) comparing the water container sensed temperature to a third selected water temperature;
• and 4) disengaging the pump if the water container sensed temperature is greater than the third selected water temperature;
• or 1) engaging the pump if the sensed water temperature is less than the second selected water temperature;
• 2) sensing temperature of water proximate to or in die heat exchanger;
• 3) comparing sensed heat exchanger water temperature to the third selected water temperature;
• and 4) disengaging the pump in the sensed heat exchanger water temperature is greater than the third selected water temperature.