Abstract: Systems and methods are disclosed that include providing a heating, ventilation, and/or air conditioning (HVAC) system with a controller that may adjust the defrost procedure algorithm by monitor the refrigeration coil temperature sensor and the ambient outdoor temperature sensor, calculate an Actual Coil Delta Temperature (ACDT); compare the calculated ACDT to an Initiate Delta Temperature (DTINIT) associated with the measured ambient outdoor temperature; initiate a defrost procedure in response to the calculated ACDT being greater than or equal to the DTINIT; determine if the duration of the defrost procedure is within a predetermined time threshold; and adjust the duration of a next defrost procedure in response to determining that a predetermined number of consecutive defrost procedures have occurred outside of the predetermined time threshold.

Abstract: Systems and methods are disclosed that include providing a heating, ventilation, and/or air conditioning (HVAC) system with a temperature sensor validation system that measures the ambient outdoor temperature using a first temperature sensor and the refrigeration coil temperature using a second temperature sensor at a plurality of time intervals following a refrigeration coil defrost procedure. A system controller may implement an algorithm to determine if the first temperature sensor and the second temperature sensor are reliable by comparing the temperature readings from the first temperature sensor and the second temperature sensor taken at the plurality of time intervals following the defrost procedure. The system controller may also implement so-called limp along modes if any temperature sensor is determined unreliable.

Abstract: Systems and methods are disclosed that include providing a heating, ventilation, and/or air conditioning (HVAC) system with a controller that may adjust the defrost procedure algorithm by monitor the refrigeration coil temperature sensor and the ambient outdoor temperature sensor, calculate an Actual Coil Delta Temperature (ACDT); compare the calculated ACDT to an Initiate Delta Temperature (DTINIT) associated with the measured ambient outdoor temperature; initiate a defrost procedure in response to the calculated ACDT being greater than or equal to the DTINIT; determine if the duration of the defrost procedure is within a predetermined time threshold; and adjust the duration of a next defrost procedure in response to determining that a predetermined number of consecutive defrost procedures have occurred outside of the predetermined time threshold.

Abstract: Systems and methods are disclosed that include providing a heating, ventilation, and/or air conditioning (HVAC) system with a temperature sensor validation system that measures the ambient outdoor temperature using a first temperature sensor and the refrigeration coil temperature using a second temperature sensor at a plurality of time intervals following a refrigeration coil defrost procedure. A system controller may implement an algorithm to determine if the first temperature sensor and the second temperature sensor are reliable by comparing the temperature readings from the first temperature sensor and the second temperature sensor taken at the plurality of time intervals following the defrost procedure. The system controller may also implement so-called limp along modes if any temperature sensor is determined unreliable.

Abstract: A heat exchanger has an upper region, a lower region disposed vertically lower than the upper region, and a passive charge management device. The passive charge management device has an internal volume, an upper tube connecting the internal volume to at least one of the upper region and the lower region at a first vertical height, and a lower tube connecting the internal volume to at least one of the upper region and the lower region at a second vertical height that is vertically lower than the first vertical height.

Abstract: Systems and methods are provided for operating a heating, ventilation, and/or air conditioning (HVAC) system that include recording a number of consecutive occasions in which a defrost mode is entered within a first predefined length of time after a heating cycle is entered, preventing operation of at least one component of the HVAC system for a second predefined length of time in response to entering the defrost mode a first predetermined consecutive number of occurrences within the first predefined length of time after a heating cycle is entered, recording a number of consecutive preventions of operation of the component of the HVAC system, and determining that a fault condition exists in the HVAC system in response to the number of consecutive temporary preventions of operation of the component of the HVAC system exceeding a second predefined number of occurrences.

Abstract: A heat exchanger has an upper region, a lower region disposed vertically lower than the upper region, and a passive charge management device. The passive charge management device has an internal volume, an upper tube connecting the internal volume to at least one of the upper region and the lower region at a first vertical height, and a lower tube connecting the internal volume to at least one of the upper region and the lower region at a second vertical height that is vertically lower than the first vertical height.

Abstract: An incipient failure indication apparatus for an environmental control system which includes a heat exchanger through which air flows and a temperature control thermostat. The indication apparatus includes an indicator having an alarm in communication with a control board, the control board in communication with the thermostat. The alarm has a visual indicator and/or an aural indicator, whereby the attention of a person is attracted to the indicator upon activation of the alarm. A first temperature sensor is disposed on the upstream side of the heat exchanger and a second temperature sensor is disposed on the downstream side of the heat exchanger, whereby the temperature sensors respectively sense the temperature of the air upstream and downstream of the heat exchanger. The first and second temperature sensors are in communication with the control board, and the control board has means for comparing the temperatures sensed thereby.