US 12,442,561 B1
Water heating system and method of operating the same
Brian Branecky, Oconomowoc, WI (US)
Assigned to A. O. SMITH CORPORATION, Milwaukee, WI (US)
Filed by A. O. SMITH CORPORATION, Milwaukee, WI (US)
Filed on May 15, 2024, as Appl. No. 18/665,183.
Application 18/665,183 is a continuation of application No. 17/555,711, filed on Dec. 20, 2021, granted, now 12,098,867.
Claims priority of provisional application 63/129,160, filed on Dec. 22, 2020.
Int. Cl. F24H 15/36 (2022.01); F24H 1/00 (2022.01); F24H 9/20 (2022.01); F24H 15/238 (2022.01); F24H 15/31 (2022.01); F24H 15/421 (2022.01)
CPC F24H 15/36 (2022.01) [F24H 1/0027 (2013.01); F24H 9/2035 (2013.01); F24H 15/238 (2022.01); F24H 15/31 (2022.01); F24H 15/421 (2022.01)] 15 Claims
OG exemplary drawing
 
1. A water heating system comprising:
a burner;
a gas valve fluidly connected to the burner to deliver a flow of combustible gas thereto, the gas valve including an adjustable throttle for the flow of combustible gas and a motor operatively coupled to the throttle in order to adjust a position of the throttle; and
a controller operatively coupled to the motor, the controller configured to:
determine a first throttle position corresponding to a target air-fuel ratio of the burner during a calibration sequence;
control the motor to operate the gas valve at a second throttle position during a start sequence, the second throttle position corresponding to a richer air-fuel ratio than the first throttle position;
initiate ignition of the burner while the gas valve is at the second throttle position;
control the motor to transition the gas valve from the second throttle position to the first throttle position during the start sequence after ignition of the burner;
while the gas valve is at the first throttle position, measure a value of a characteristic of the burner operation during the start sequence to determine if an error threshold is exceeded; and
initiate the calibration sequence only in response to the error threshold being exceeded.