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

Claim 0:
1. A water heater system comprising:
a variable speed pump having a pump inlet and a pump outlet, wherein the variable speed pump is configured to be adjustable to pump fluid at a plurality of flow rates;
a heat exchanger, having a heat exchanger inlet and a heat exchanger outlet, wherein the heat exchanger outlet is fluidically connected to the pump inlet;
an output temperature sensor disposed downstream of the heat exchanger outlet and configured to measure a temperature of water output from the heat exchanger outlet; and
a controller configured to:
receive a first temperature reading from the output temperature sensor,
control both an amount of heat added via the heat exchanger and operation of the variable speed pump to adjust an output flow rate to one of the plurality of flow rates in response to the first temperature reading,
adjust an amount of heat introduced by the heat exchanger within a turndown ratio less than 13:1, and
maintain the temperature of water output from the heat exchanger within a threshold of a set point temperature, wherein the threshold is greater than five degrees Fahrenheit.