Abstract: 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.

Abstract: One aspect, as provided herein, is directed to a multi-stage fluid control system for a fluid source heat pump system. This embodiment comprises compressors configured to operate as separate, heat exchange stages, condensers each being fluidly coupled to at least one of the compressors by refrigerant tubing and having intake ends coupled together by a fluid intake manifold. This embodiment further includes output conduits coupled to each of the condensers and that are couplable to a distal location. Further included is a modulating valve control system interposed the output conduits. The modulating valve control system is configured to stage a flow of fluid through the condensers based on a number of operating compressors.

Abstract: A system and method are described that help to alleviate pressure and strain spikes in and around dead tubes or frontiers between stages in a multi-stage condenser coil. Instead of cycling a fan off and on, fans associated with the condenser are kept running at a low speed instead of being turned off. Preventing the fans from turning off completely helps to even out the pressure and strain spikes. The present teachings can be especially beneficial in aluminum-based coils. The present teachings include both a unit controller that carries out the teachings, and a system based on temperature and/or pressure switches connected to a fan controller.

Abstract: 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.

Abstract: One aspect, as provided herein, is directed to a multi-stage fluid control system for a fluid source heat pump system. This embodiment comprises compressors configured to operate as separate, heat exchange stages, condensers each being fluidly coupled to at least one of the compressors by refrigerant tubing and having intake ends coupled together by a fluid intake manifold. This embodiment further includes output conduits coupled to each of the condensers and that are couplable to a distal location. Further included is a modulating valve control system interposed the output conduits. The modulating valve control system is configured to stage a flow of fluid through the condensers based on a number of operating compressors.

Abstract: One aspect, as provided herein, is directed to a multi-stage fluid control system for a fluid source heat pump system. This embodiment comprises compressors configured to operate as separate, heat exchange stages, condensers each being fluidly coupled to at least one of the compressors by refrigerant tubing and having intake ends coupled together by a fluid intake manifold. This embodiment further includes output conduits coupled to each of the condensers and that are couplable to a distal location. Further included is a modulating valve control system interposed the output conduits. The modulating valve control system is configured to stage a flow of fluid through the condensers based on a number of operating compressors.

Abstract: A system and method for a multistage condenser is described that reduces problems associated with temperature and pressure differential strains on tubes above and below a dead tube. Instead of connecting the dead tube to the I/O manifold, a physical separation is created. The physical separation can be created by shortening the dead tube, coring a portion of the I/O manifold where the dead tube is received, independent I/O manifolds, or other means.

Abstract: A heating, ventilation, and air-conditioning (HVAC) system comprises a plurality of sensors, a plurality of tandem compressor assemblies that each comprise a first compressor and a second compressor, and a controller communicatively coupled to the plurality of sensors and the plurality of tandem compressor assemblies. The controller determines an increase in a cooling demand of a structure associated with the HVAC system based on data received from at least one of the plurality of sensors. Also, the controller compares an ambient temperature outside of the structure to a first threshold. In response to determining that the ambient temperature is greater than the first threshold, the controller operates the HVAC system in a first mode and in response to determining that the ambient temperature is less than the first threshold, the controller operates the HVAC system in a second mode.

Abstract: A system and method are described that help to alleviate pressure and strain spikes in and around dead tubes or frontiers between stages in a multi-stage condenser coil. Instead of cycling a fan off and on, fans associated with the condenser are kept running at a low speed instead of being turned off. Preventing the fans from turning off completely helps to even out the pressure and strain spikes. The present teachings can be especially beneficial in aluminum-based coils. The present teachings include both a unit controller that carries out the teachings, and a system based on temperature and/or pressure switches connected to a fan controller.

Abstract: The present invention provides a control system for managing lubricant levels in tandem compressor assemblies of a heating, ventilation, and air conditioning (HVAC) system. In transitioning from a partial load that operates a first compressor but not a second compressor of a tandem assembly to a full load that operates both the first and the second compressor, a controller of the HVAC system turns OFF both compressors of the tandem compressor assembly to allow time for lubricant levels to equalize between the first and the second compressor.

Abstract: A system and method for a multistage condenser is described that reduces problems associated with temperature and pressure differential strains on tubes above and below a dead tube. Instead of connecting the dead tube to the I/O manifold, a physical separation is created. The physical separation can be created by shortening the dead tube, coring a portion of the I/O manifold where the dead tube is received, independent I/O manifolds, or other means.

Abstract: The present invention provides a control system for managing lubricant levels in tandem compressor assemblies of a heating, ventilation, and air conditioning (HVAC) system. In transitioning from a partial load that operates a first compressor but not a second compressor of a tandem assembly to a full load that operates both the first and the second compressor, a controller of the HVAC system turns OFF both compressors of the tandem compressor assembly to allow time for lubricant levels to equalize between the first and the second compressor.

Abstract: The present invention provides a control system for managing lubricant levels in tandem compressor assemblies of a heating, ventilation, and air conditioning (HVAC) system. In transitioning from a partial load that operates a first compressor but not a second compressor of a tandem assembly to a full load that operates both the first and the second compressor, a controller of the HVAC system turns OFF both compressors of the tandem compressor assembly to allow time for lubricant levels to equalize between the first and the second compressor.

Abstract: A heating, ventilation, and air-conditioning (HVAC) system comprises a plurality of sensors, a plurality of tandem compressor assemblies that each comprise a first compressor and a second compressor, and a controller communicatively coupled to the plurality of sensors and the plurality of tandem compressor assemblies. The controller determines an increase in a cooling demand of a structure associated with the HVAC system based on data received from at least one of the plurality of sensors. Also, the controller compares an ambient temperature outside of the structure to a first threshold. In response to determining that the ambient temperature is greater than the first threshold, the controller operates the HVAC system in a first mode and in response to determining that the ambient temperature is less than the first threshold, the controller operates the HVAC system in a second mode.

Abstract: The present invention provides a control system for managing lubricant levels in tandem compressor assemblies of a heating, ventilation, and air conditioning (HVAC) system. In transitioning from a partial load that operates a first compressor but not a second compressor of a tandem assembly to a full load that operates both the first and the second compressor, a controller of the HVAC system turns OFF both compressors of the tandem compressor assembly to allow time for lubricant levels to equalize between the first and the second compressor.

Abstract: One aspect, as provided herein, is directed to a multi-stage fluid control system for a fluid source heat pump system. This embodiment comprises compressors configured to operate as separate, heat exchange stages, condensers each being fluidly coupled to at least one of the compressors by refrigerant tubing and having intake ends coupled together by a fluid intake manifold. This embodiment further includes output conduits coupled to each of the condensers and that are couplable to a distal location. Further included is a modulating valve control system interposed the output conduits. The modulating valve control system is configured to stage a flow of fluid through the condensers based on a number of operating compressors.