A refrigeration cycle apparatus in which a refrigerant having potential for disproportionation reaction circulates a first refrigerant flow path connected between a discharge side of the compressor and the condenser; a second refrigerant flow path connected between the condenser and the expansion valve; a third refrigerant flow path connected between the expansion valve and a suction side of the compressor; a jetting unit; a pressure measuring unit; and a temperature measuring unit. The jetting unit is configured to jet the refrigerant drawn from the second refrigerant flow path or the third refrigerant flow path to at least one of the compressor, the first refrigerant flow path and the second refrigerant flow path when at least one of a measured value of the pressure measuring unit and a measured value of the temperature measuring unit exceeds an allowed value.

An air conditioning apparatus is equipped with an indoor fan, an indoor heat exchanger, and a control unit. The indoor heat exchanger generates conditioned air by exchanging heat between refrigerant and room air. The control unit sets operating modes. The control unit controls the rotational speed of the indoor fan. More specifically, in a case where the operating mode has been switched from one to the other of a normal heating mode and a hot air mode in which the conditioned air higher in temperature than in the normal heating mode is generated, the control unit lowers the rotational speed at a second rate that is slower than a first rate which is a rate of decrease in the rotational speed in a case where the operating mode is set to the normal heating mode.

Methods and systems for detecting and correcting improper operation of a compressor in a refrigeration system and/or an HVAC system include a component level detection and prevention and a system level detection and prevention. The system level detection and prevention can be a backup or a confirmation of the component level detection and prevention. The component level detection and prevention can detect and prevent improper compressor operation within a predetermined time so that the compressor's operation period in an improper direction can be minimized, thereby minimizing wear and damage to the compressor.

A pressure control device for controlling a compressor includes a pressure sensor configured to measure pressure of a pressure line and a processing circuit. The processing circuit is configured to receive the measured pressure of the pressure line from the pressure sensor and control the compressor based on a set-point and the measured pressure. The pressure control device includes a mechanical switch sensitive to the pressure of the pressure line and configured to move between an open position and a closed position responsive to the pressure of the pressure line. Movement of the mechanical switch into one of the open position or the closed position causes the compressor to turn off and overrides the control of the compressor by the processing circuit.

The present teachings provide a modular air source heat pump system (ASHP system) with a plurality of connectors, a plurality of system components, a plurality of sensors, and a control system. The plurality of connectors are quick connectors. a plurality of system components that are individually connected together by one or more of the plurality of connectors so that the plurality of system components are connectable and/or disconnectable from the ASHP system. The plurality of sensors in communication with one or more of the plurality of system components. The control system in communication with the plurality of sensors, the control system being configured to analyze data provided by the plurality of sensors and to control the ASHP system.

The present teachings provide a modular air source heat pump system (ASHP system) with an internal assembly, an external assembly, a refrigerant module, sensors, and a control system. The refrigerant module is removably connected to the external assembly. The sensors are located within the internal assembly and configured to monitor internal conditions, internal system conditions, or both. The sensors are located within the external assembly and configured to monitor external conditions, external system conditions, or both. The control system in communication with the sensors located within the internal assembly and the external assembly. The control system is configured to: change a heat transfer fluid charge in the internal assembly, the external assembly, or both by adding or subtracting heat transfer fluid from the refrigerant module in response to changes in the external conditions, the external system conditions, the internal conditions, the internal system conditions, or a combination thereof.

A method for controlling a vapour compression system (1) is disclosed. Malfunctioning of a gas bypass valve (8) is registered. An actual opening degree of the gas bypass valve (8) is derived, and a target opening degree of the gas bypass valve (8) is derived, based on one or more control parameters of the vapour compression system (1). The actual opening degree is compared to the target opening degree, and the vapour compression system (1) is controlled based on the comparison, and in order to match a mass flow of gaseous refrigerant through the gas bypass valve (8) to the actual opening degree of the gas bypass valve (8).

A compressor system for an air conditioning service system includes a compressor having a compressor case and a compressor head, an inlet, an outlet, a low side passage fluidly connecting the inlet to the compressor head, and a high side passage fluidly connecting the outlet to the compressor head. A low side return passage fluidly connects the compressor case with the low side passage and a first valve is positioned at least partially in the low side return passage and configured to control flow in the low side return passage.

Described is a regulation apparatus for a refrigeration plant having defined therein a refrigerant fluid path and a plurality of devices arranged along the refrigerant fluid path. The regulation apparatus includes a first sensor arranged in a first point (P1), and preferably a second sensor arranged in a second point (P3), both along the refrigerant fluid path. The control unit controls a first value measured by the first sensor and obtains a first regulation request of a device deriving from the first measured value as well as a second value measured by the second sensor, or calculated for the second point, and derives a second regulation request of the device deriving from the second measured value, compares the first and second regulation requests and establishes which regulation request is greater. A control unit commands an actuation device to actuate the most effective regulation request of the refrigeration plant devices.

A heat pump controller for use in a heat exchange system includes a computing device and a user interface coupled to the computing device. The computing device is configured to initiate a defrost cycle based on one of a plurality of user-selectable defrost modes, and the user interface is configured to display the user-selectable defrost modes and receive a user selection corresponding to one of the user-selectable defrost modes.