Patent ID: 11867429
Assignee: RINNAI AMERICA CORPORATION
Field: Thermal processes and apparatus (Mechanical engineering)
Classification: CPC F | IPC F

Claim 12:
13. A method of heating water comprising:
receiving a signal to initiate circulation;
generating a signal to a variable speed pump to circulate a flow of water at a first flow rate from an outlet of a heat exchanger to an inlet of a storage tank and from an outlet of the storage tank to an inlet of the heat exchanger, wherein the variable speed pump is configured to be adjustable to pump fluid at a plurality of flow rates;
controlling an amount of heat added by the heat exchanger to the flow of water to be within a turndown ratio less than 13:1;
receiving a first temperature reading from an output temperature sensor downstream of the heat exchanger and configured to measure a temperature of water output from the outlet of the heat exchanger; and
generating a signal to the variable speed pump to circulate the flow of water at least at one additional flow rate of the plurality of flow rates in response to the first temperature reading, wherein the temperature of water output from the outlet of the heat exchanger is maintained within a threshold of a set point temperature, and wherein the threshold is greater than five degrees Fahrenheit.