Lennox Industries Inc.

Zer Kai Yap

Aylan A Him

David Mackey

Marcus Troxell

Wenqian Liu

William Toombs, Jr

William Clay Toombs

Aylan Him

A method of controlling an HVAC circuit, comprises allowing refrigerant to circulate within the HVAC circuit, wherein the HVAC circuit comprises an evaporator coil, a condenser coil, at least one fan configured to provide airflow to the condenser coil, at least one expansion valve, and at least one compressor. The method continues by receiving a temperature measurement and determining based on the temperature measurement, a minimum fan speed configured to avoid pressure spikes within the condenser coil. The method concludes by sending a signal to the at the least one fan to direct the at least one fan to spin at a rate greater than or equal to the minimum fan speed when the measured temperature is less than a predetermined temperature, wherein, when the refrigerant circulates through the condenser coil, the minimum fan speed is greater than zero rotations per minute.

Method to avoid fan cycling during low ambient operation

According to certain embodiments, a system comprises a controller and an HVAC system with components comprising an evaporator unit comprising an evaporator coil, an indoor fan, and a discharge air duct and a condenser unit comprising a compressor, a condenser coil, and an outdoor fan. The system is configured to determine that a first or a second level of evaporator coil freeze risk is present and to communicate an instruction to the HVAC system with a first or a second action to counteract the freeze risk. For example, in certain embodiments, the actions comprise changing the indoor fan speed, changing the compressor speed, and changing the outdoor fan speed.

Evaporator coil protection for HVAC systems

A system based on temperature and/or pressure switches connected to a fan controller. An HVAC circuit includes at least one condenser coil with a plurality of tubes, one or more stages coupled to one or more compressors, at least one temperature sensor, at least one fan configured to provide airflow across the plurality of tubes, and a controller. Instead of cycling the fan off and on, fans associated with the condenser are kept running at a low speed.

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Allen, TX, United States of America

Zer Kai Yap