US 11,781,785 B2
Feedback warning system using inducer pulse width modulation signal
Madhuka Manuranga Jayarathne, Wichita, KS (US); Andrew Michael Boyd, Wichita, KS (US); Theresa N. Gillette, Wichita, KS (US); and Thomas D. Chase, Rose Hill, KS (US)
Assigned to JOHNSON CONTROLS TYCO IP HOLDINGS LLP, Milwaukee, WI (US)
Filed by Johnson Controls Technology Company, Auburn Hills, MI (US)
Filed on Sep. 12, 2019, as Appl. No. 16/569,353.
Claims priority of provisional application 62/817,857, filed on Mar. 13, 2019.
Prior Publication US 2020/0292182 A1, Sep. 17, 2020
Int. Cl. F24D 19/10 (2006.01); F24F 11/30 (2018.01); F23N 3/08 (2006.01)
CPC F24D 19/1084 (2013.01) [F24F 11/30 (2018.01); F23N 3/082 (2013.01); F23N 2223/08 (2020.01); G05B 2219/2614 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A heating, ventilation, and air conditioning (HVAC) system, comprising:
a burner configured to generate a combustion airflow;
a heat exchanger comprising a tube configured to direct the combustion airflow therethrough and place the combustion airflow in a heat exchange relationship with a supply airflow directed across the tube of the heat exchanger;
an inducer motor configured to draw the combustion airflow through the tube of the heat exchanger;
a pressure sensor configured to measure an output airflow pressure of the combustion airflow drawn through the tube of the heat exchanger via the inducer motor;
a memory; and
a processor coupled with the memory and configured to:
initiate the burner and the inducer motor within the HVAC system to provide the combustion airflow through the tube of the heat exchanger;
establish an initial pulse width modulation (PWM) signal sent to the inducer motor as a baseline PWM signal, wherein the initial PWM signal corresponds to a predetermined airflow pressure of the combustion airflow drawn through the tube of the heat exchanger via the inducer motor;
send a PWM signal to the inducer motor associated with a monitored output airflow pressure of the combustion airflow;
compare the PWM signal to the baseline PWM signal in response to the monitored output airflow pressure of the combustion airflow reaching the predetermined airflow pressure of the combustion airflow;
control the inducer motor based on a comparison of the PWM signal and the baseline PWM signal; and
generate a status notification of the combustion airflow drawn through the tube of the heat exchanger in response to the comparison of the PWM signal and the baseline PWM signal.