Gas furnace with variable speed draft inducer
AssigneeAmerican Standard International Inc.
InventorsG. Jeffrey Hugghins, Robert W. Helt, Leonard W. Holmes, James T. Vershaw, Timothy W. Storm
Life of this patent
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Abstract
A method of controlling a variable speed draft inducer motor and fan in a gas furnace. The method comprises the steps of: detecting a first fault driving the motor to a maximum operating range; detecting a second fault forcing the motor to operate towards a minimum operating range; and generating a fault signal if both faults are detected substantially simultaneously.
Claims23
A method of controlling a variable speed draft inducer motor and fan in a gas furnace comprising the steps of:
- detecting a first fault driving the motor to a maximum operating range;
- detecting a second fault forcing the motor to operate towards a minimum operating range;
- and
- generating a fault signal if both faults are detected substantially simultaneously.
The method of claim 7 includes the further step of verifying that the minimum pressure threshold has been reached by monitoring the opening of a low pressure switch.
A method of controlling a variable speed draft inducer motor and fan in a gas furnace comprising the steps of:
- determining if a motor is in a start-up condition;
- measuring the temperature of ambient air;
- determining if the measured air temperature is less than a cold temperature threshold;
- and
- enhancing the performance of the inducer fan motor if the measured ambient air temperature is less than the cold temperature threshold.
A method of ensuring proper operation of a motor comprising the steps of:
- detecting a first fault driving the motor to a maximum operating range;
- detecting a second fault forcing the motor to operate towards a minimum operating range;
- and
- generating a fault signal if both faults are detected substantially simultaneously.
A method of protecting the operation of a motor operatively coupled to and motivating a fan comprising the steps of:
- operating the motor at a desired motor speed;
- sensing the motor torque at the desired speed;
- determining, responsive to the sensed torque, whether the motor is operating at a first unfired condition;
- determining, responsive to the sensed torque, whether the motor is operating at a second fired condition;
- maintaining a first fan pressure drop if the motor is operating in the unfired condition;
- and
- maintaining a second fan pressure drop if the motor is operating in the fired condition;
- sensing the fan pressure drop.
A method of operating an inducer motor comprising the steps of:
- determining if the inducer motor is in a start-up condition;
- measuring the temperature of ambient air;
- determining if the measured air is less than a cold temperature threshold;
- and
- enhancing the performance of the inducer fan if the measured ambient air is less than the cold temperature threshold.
Dependencies are inferred from the claim text.