Systems and methods for checking status of a pressure transducer

A controller for a gas furnace system including a combustion chamber, a conduit in fluid communication with the combustion chamber and operable as an air inlet for the combustion chamber, a draft inducer having a motor, a pressure transducer positioned to sense a pressure within the conduit and output signals proportional to the sensed pressure, and a pressure switch positioned to sense the pressure within the conduit, the pressure switch having a first state and a second state, and configured to be in the first state when the sensed pressure is below a predetermined pressure and to switch to the second state when the sensed pressure reaches or exceeds the predetermined pressure, the controller comprising a processor programmed to:

• control the motor of the draft inducer in response to a call for heat;
• receive pressure signals output by the pressure transducer;
• receive signals indicating whether the pressure switch is in the first state or the second state;
• determine a first pressure corresponding to the pressure signals output by the pressure transducer when the pressure switch switches from the first state to the second state;
• compare the first pressure to a first threshold a first amount different from the predetermined pressure and a second threshold a second amount different from the predetermined pressure, where the second amount is greater than the first amount;
• and
• determine the first status of the pressure transducer as unreliable when the first pressure is greater than or equal to the second threshold;
• determine the first status of the pressure transducer as questionable when the first pressure is greater than the first threshold and less than the second threshold;
• and
• determine the first status of the pressure transducer as reliable when the first pressure is less than or equal to the first threshold.

A method of controlling a gas furnace system comprising:

• controlling a motor of a draft inducer coupled to a conduit to increase a speed of the motor from a stopped condition in response to a call for heat, wherein the conduit is in fluid communication with a combustion chamber and operates as an air inlet for the combustion chamber;
• receiving pressure signals output by a pressure transducer responsive to pressure in the conduit;
• receiving signals indicating whether a pressure switch responsive to pressure in the conduit is in a first state or a second state;
• determining a first pressure corresponding to the pressure signals output by the pressure transducer when the pressure switch switches from the first state to the second state;
• comparing the first pressure to a first threshold a first amount different from the predetermined pressure and a second threshold a second amount different from the predetermined pressure, where the second amount is greater than the first amount;
• determining a first status of the pressure transducer as unreliable when the first pressure is greater than or equal to the second threshold;
• determining the first status of the pressure transducer as questionable when the first pressure is greater than the first threshold and less than the second threshold;
• and
• determining the first status of the pressure transducer as reliable when the first pressure is less than or equal to the first threshold;
• continuing to operate the motor when the first status of the pressure transducer is determined to be reliable or questionable;
• and
• stopping the motor when the first status of the pressure transducer is determined to be unreliable.