Abstract: Embodiments are directed to receiving, by a device comprising a processor, an indication that an air conditioning unit should turn on, commanding, by the device, a valve to open a specified extent based on the received indication, and subsequent to the valve opening to the specified extent, powering-on a piece of equipment that has an impact on refrigerant flow in the air conditioning unit.

Abstract: Embodiments are directed to receiving, by a device comprising a processor, an indication that an air conditioning unit should turn on, commanding, by the device, a valve to open a specified extent based on the received indication, and subsequent to the valve opening to the specified extent, powering-on a piece of equipment that has an impact on refrigerant flow in the air conditioning unit.

Abstract: A heating/cooling system includes a closed circuit refrigeration system including an evaporator. Water circulating through a closed water circuit exchanges heat with refrigerant in the evaporator, cooling the water for a cooling application. The water can also be heated by a boiler, and the heated water is used to heat a space. A water pump flows the water through the water circuit. When a current sensing relay detects a power failure, a boiler control algorithm is initiated to “trick” a motor of the compressor into believing the heating/cooling system is operating in a heating mode. Therefore, a compressor failure alarm is not generated. The water pump is powered by a battery pack during the power failure. Water continues to flow through the water circuit, preventing the water from freezing.

Abstract: A heating/cooling system includes a closed circuit refrigeration system including an evaporator. Water circulating through a closed water circuit exchanges heat with refrigerant in the evaporator, cooling the water for a cooling application. The water can also be heated by a boiler, and the heated water is used to heat a space. A water pump flows the water through the water circuit. When a current sensing relay detects a power failure, a boiler control algorithm is initiated to “trick” a motor of the compressor into believing the heating/cooling system is operating in a heating mode. Therefore, a compressor failure alarm is not generated. The water pump is powered by a battery pack during the power failure. Water continues to flow through the water circuit, preventing the water from freezing.

Abstract: An improved cooler with level sensor for measuring variation in the liquid refrigerant level of a refrigerant within the cooler, comprises a cooler shell for holding the refrigerant, heat exchanger tubes for carrying the liquid to be cooled, and a liquid refrigerant level sensor comprising a probe extending to a point above the heat exchanger tubes, one or more thermistors; and a heating element. When the probe is totally within the vapor refrigerant above the heat exchanger tubes, the heater raises the temperature of the thermistors above the saturation temperature of the refrigerant. As the liquid refrigerant level begins to rise, the liquid refrigerant comes in contact with the outside of the probe. Since the heat transfer coefficient of the liquid refrigerant is significantly higher than that of the vapor refrigerant, the probe in that area is quickly cooled to the saturation temperature.

Abstract: A process is disclosed for checking communications that a controller receives from elements in an HVAC system. The process includes storing the communications and thereafter checking each stored communication against a range of permitted values for that particular communication. The thus checked communication is made available for use by the controller only if it is within the range of permitted values. A count of times that a particular element does not comply with the check is maintained with a warning being generated in the event that the element continues to communicate unacceptable signal values.

Abstract: Programmable system and process are disclosed for adapting a generally written HVAC control program to a number of different HVAC systems. The system and process include a separate interface to the control program and a separate interface to the control elements of each particular HVAC system. Configuration data for the particular HVAC system defines the relationship between software variables of the control program and the control elements of the particular HVAC system. The configuration data is utilized when information is to be transferred between the interfaces.

Abstract: A control for the expansion valve of an air conditioning system interrupts a decision to deactivate one or more stages of compression and proceeds to calculate a new expansion valve position based upon the amount of capacity to be lost by the deactivated stages of compression. The expansion valve is commanded to the calculated position before the compressors are deactivated.