Lennox Industries Inc.

Jon Douglas

Umesh Gokhale

Eric Berg

Yi Qu

Jeff Mangum

H Gene Havard

Rakesh Goel

A method of initiating a defrost cycle using a controller of a heat pump system includes measuring a temperature of an evaporator coil and determining whether the temperature of the evaporator coil is less than a freezing temperature. Responsive to a determination that the temperature of the evaporator coil is less than the freezing temperature, determining whether a current dew point temperature of air is greater than the temperature of the evaporator coil. Responsive to a determination that the current dew point temperature of air is greater than the temperature of the evaporator coil, calculating a frost-collection rate. Determining whether the frost-collection rate is greater than a frost-collection-rate threshold, and, responsive to a determination that the frost-collection rate is greater than the frost-collection-rate threshold, initiating a defrost cycle.

Intelligent defrost control method

A method of generating an alarm based on temperature conditions within an enclosed space. The method includes receiving, by a processor of a heating, ventilation, and air conditioning (HVAC) system, operating-condition information of the HVAC system, determining, by the processor from the received operating-condition information, whether temperature within the enclosed space is approaching a setpoint temperature. Responsive to a determination that the temperature within the enclosed space has failed to approach the setpoint temperature, determining by the processor, whether anomaly conditions exist and responsive to a determination that the anomaly conditions do not exist, generating the alarm.

HVAC system and an HVAC controller configured to generate master service alarms

In various implementations, frost in a vapor compression system may be controlled. A property of a fan may be determined. A determination may be made whether a frost event and/or a nonfrost event has occurred based at least partially on the determined fan property.

Defrost control using fan data

A heating, ventilation, and air-conditioning (HVAC) system comprises an outdoor unit with a fan and a coil, and a controller communicatively coupled to the fan and coil. The controller is operable to receive feedback data from the fan, where the feedback data from the fan corresponds to a power and a speed of the fan. The controller is further operable to store a fan model and a plurality of thresholds and determine a virtual sensor measurement, based at least in part upon the feedback data from the fan and the fan model. The controller is operable to determine that the virtual sensor measurement is greater than a frost threshold or a fouling threshold. The controller is finally operable to, in response to determining that the pressure difference is greater than the frost threshold or the fouling threshold, determine a blocked condition on the coil.

Detecting and handling a blocked condition in the coil

The present invention provides for a control system for a compressor assembly of an heating, ventilation, and air conditioning (HVAC) system. A control assembly comprises a controller for varying the capacity of a compressor unit of the compressor assembly. The controller determines a first pressure of the compressor unit based on a first operating state of the compressor unit.

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Lewisville, TX, United States of America

Jon Douglas