Abstract: An HVAC system includes an evaporator coil and a metering device. The HVAC system includes a variable-speed circulation fan and a condenser coil fluidly coupled to the metering device. A variable-speed compressor is fluidly coupled to the condenser coil and the evaporator coil. A controller is operatively coupled to the variable-speed compressor and the variable-speed circulation fan. A second temperature sensor is disposed in an enclosed space. The second temperature sensor measures temperature of the enclosed space and transmits the temperature of the enclosed space to the controller. The controller determines if the temperature of the enclosed space is below a minimum threshold. Responsive to a determination that the temperature of the enclosed space is below the minimum threshold, the controller modulates at least one of a speed of the variable-speed compressor and the variable-speed circulation fan to lower a discharge air temperature.

Abstract: An apparatus for reducing discharge pressure includes a compensator reservoir and a compensator line. The compensator line connects the compensator reservoir and a liquid line. The liquid line connects an outdoor heat exchanger and an indoor heat exchanger of a reversible HVAC system. The compensator line includes a connection to the compensator reservoir and a connection to the liquid line. A first expansion device is disposed in the liquid line and configured to only act on refrigerant flowing towards the outdoor heat exchanger. A second expansion device disposed in the liquid line and configured to only act on refrigerant flowing towards the indoor heat exchanger. The compensator is operable to receive refrigerant, driven by pressure, from the HVAC system, and further operable to allow refrigerant to flow back into the HVAC system.

Abstract: A method of determining presence of a flame in a furnace of a heating, ventilation, and air conditioning (HVAC) system. The method comprises determining, using a controller, whether a processor signal (G) is active, responsive to a determination that the processor signal (G) is active, determining, using the controller prior to assertion of a flame-test input control signal, an output state of a first comparator, responsive to a determination that the output state of the first comparator is high, determining, using the controller prior to assertion of the flame-test input control signal, an output state of a second comparator, and responsive to a determination that the output state of the second comparator is low, transmitting, using the controller, a notification that a flame is present.

Abstract: In one aspect, the present disclosure provides a controller for a HVAC system having an economizer with a damper and pressure sensors on opposing sides of the economizer. The controller comprise a diagnostics controller having a program configured to use pressure difference sensor data to determine if a pressure difference across the economizer is outside an operational design parameter of the HVAC system, and generate an error signal when the pressure difference is outside the operational design parameter.

Abstract: A control module for preventing acoustic resonance noise generation from a heat exchanger of a heating furnace, comprising a control signal generated by the control module. The control signal is configured to operate an induction fan of the heating furnace at more than one speed for a given heat demand mode of the heating furnace.

Abstract: The disclosure provides a proportional control signal circuit (PCSC), an HVAC controller employing the same and an HVAC system including the HVAC controller. In one embodiment, the PCSC includes: (1) a signal input configured to receive a pulse width modulated signal, (2) a control input configured to receive an integration signal, (3) a signal output and (4) control circuitry, coupled to the signal input, the control input and the signal output, configured to provide either the pulse width modulated signal or a DC signal to the signal output based on the integration signal.

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 method of initiating a low-energy cooling mode using a controller of an HVAC system includes measuring a temperature of ambient air proximal to a condenser coil and determining whether the temperature of the ambient air proximal the condenser coil is less than a temperature threshold. If the temperature of the ambient air is less than the temperature threshold, the HVAC system is configured to operate in a low-energy cooling mode. In the low-energy cooling mode, the controller opens a first bypass valve to allow a refrigerant to bypass a compressor and the compressor is powered off. The HVAC system is operated until a cooling demand has been met.

Abstract: A HVAC unit manufacturing method and a HVAC system are, disclosed herein. In one embodiment, the HVAC system includes: a controller having control board terminals, a parallel wiring harness having a first and a second connection header, the first connection header coupled to the control board terminals, and a switch having terminals. The terminals of the switch including: a pair of functional terminals configured to indicate a status of the switch and a pair of jumpered terminals independent of the pair of functional terminals and internally connected together within the switch, wherein designated combinations of the terminals indicate a circuit configuration for employing the switch in the HVAC system with each of the terminals having a particular design that dictates a specific corresponding connection header be used for each of the designated combinations, wherein a single one of the designated combinations of the terminals corresponds to the second connection header.

Abstract: An apparatus that includes a supply duct and a return duct fluidly coupled to the supply duct. A first evaporator is disposed between the supply duct and the return duct. A second evaporator is disposed between the supply duct and the return duct. A fresh-air intake is disposed between the supply duct and the return duct upstream of the first evaporator and the second evaporator. A first plurality of dampers are disposed upstream of the first evaporator. A second plurality of dampers are disposed upstream of the second evaporator. A divider panel is disposed between the first evaporator and the second evaporator.

Abstract: One embodiment of the present disclosure comprises a method of managing defrost operations in HVAC systems. In one embodiment a primary defrost operation comprises allowing a cooling cycle of the heat pump and a secondary defrost operation comprises allowing fans of the heat pump to operate at a low speed.

Abstract: According to certain embodiments, a refrigeration system comprises first and second evaporators, first and second compressors, and a gas cooler. The first and second evaporators receive liquid refrigerant from a flash tank and evaporate the refrigerant to cool a first case and a second case, respectively. The second case has a higher temperature set point than the first case. The first compressor compresses the refrigerant discharged from the first evaporator. The second compressor compresses the refrigerant discharged from the first compressor, flash gas from the flash tank, and the refrigerant discharged from the second evaporator. The gas cooler comprises an air-cooled stage that cools the refrigerant discharged from the second compressor and an evaporative stage that cools the refrigerant discharged from the air-cooled stage. The gas cooler further comprises an outlet that supplies the cooled refrigerant to the flash tank through an expansion valve.

Abstract: A method of monitoring component health of a heating, ventilation, and air conditioning (HVAC) system. The method includes measuring, by an accelerometer associated with at least one component of the HVAC system, of vibration of the at least one component, receiving, by a controller, actual vibration data reflective of the measured vibration, determining, using the controller, whether the actual vibration data differs from pre-defined acceptable baseline vibration data by more than an acceptable amount, and responsive to a positive determination in the determining step, forwarding, by the controller, information regarding the determination to a monitoring device to monitor operation of the component.

Abstract: A heating, ventilation and air conditioning (HVAC) controller, a method of receiving signals from a keypad and an HVAC system incorporating the controller or the method. In one embodiment, the HVAC controller includes: (1) a keypad having at least first and second banks, (2) a reference signal source configured to generate a time-varying untransformed reference signal and provide the untransformed reference signal to the first bank, (3) transformation circuitry configured to transform the untransformed reference signal into a transformed reference signal and provide the transformed reference signal to the second bank and (4) a processor having interrupt pins coupled to corresponding keys of both the first and second banks and a further interrupt pin coupled to receive one of the untransformed and transformed reference signal.

Abstract: An HVAC system includes a plurality of sensors, a tandem compressor, and a controller. The tandem compressor comprises a first and second compressor, each comprising a crankcase heater. The controller determines that one of the sensors has failed, and in response, initiates the first and second crankcase heaters and transmits an alert indicating that one of the sensors has failed. Further, the controller may disable threshold logic such that the first and second compressors are controlled independently of a determination whether the tandem compressor is operating outside of a threshold range. The controller operates the first and second compressors according to a safe mode, wherein first on or off settings of the compressors are determined based on a first required load operation of the tandem compressor. The first required load operation is determined from a first temperature demand of a structure associated with the HVAC system.

Abstract: In various implementations, a heat pump may include heating operations and defrost operations. The heat pump may monitor cycle time(s) for one or more of the operations. Defrost operation(s) in the heat pump may be automatically adjusted based at least partially on cycle times.

Abstract: A reversing valve comprising a valve body having an internal cavity therein and an input port, output port and first and second reversing ports. A baffle is located within the internal cavity and is configured to rotate around a pivot point within the internal cavity. At least one electromagnet is coupled to the valve body. The electromagnet is configured to cause the baffle to rotate in one of the clockwise direction or counter-clock wise direction when a voltage is applied to the electromagnet.

Abstract: The present invention provides for a system for calibrating operation of a compressor unit in a heating, ventilation, and air conditioning (HVAC) system. A measuring device measures an operating parameter of the HVAC system at a position where the measuring device is mounted on a refrigerant line of the HVAC system. The measuring device switches states when the value of the measured operating parameter reaches a switching value. A controller estimates a value of the first operating parameter at the position where the first measuring device is mounted on the refrigerant line, and the controller determines whether the estimated first operating parameter is within a threshold percentage of the switching value.

Abstract: A method of controlling a heating, ventilation and air-conditioning (HVAC) system includes measuring an ambient temperature and determining whether the ambient temperature is below a threshold temperature value. Responsive to a determination that the ambient temperature is below the threshold temperature value, measuring a condenser-fan cycle time of the HVAC system and setting a speed of the compressor based on the measured condenser-fan cycle time.

Abstract: A wiring connector housing including a housing body having first and second ends and at least one interference tab extending outwardly from the second end is provided. The wiring connector housing further comprises spaced apart channels located through the housing body extending from the first end to the second end with the first end of the channels each configured to receive a quick connector therein. Each of the second ends of the spaced apart channels being located to register with and receive corresponding quick connect terminals therein. The at least one interference tab is configured to contact an isolation ridge of an electrical relay and thereby prevent the second ends of the spaced apart channels from being improperly registered with the corresponding quick connect terminals.