A refrigerant cycle apparatus includes a refrigerant circuit that circulates a refrigerant, and a leak sensor that detects a refrigerant leaking from the refrigerant circuit, in which the refrigerant cycle apparatus includes, as an operating mode, a recovery mode for recognizing occurrence of an abnormality in the leak sensor and recovering a refrigerant to a predetermined location in the refrigerant circuit.

A building monitoring system, wherein the system comprises an HVAC monitor, which comprised a condensing unit connector, an air handler connector, a thermostat connector and a control module, a wetness detector; and a communicator. The communicator accesses a location of the building monitoring system and selectively communicates with a technician based at least in part on the location. A monitor system for use with an existing HVAC unit, wherein the HVAC unit has a condenser or furnace, an air handler, and a thermostat, the HVAC monitor system comprising at least one condenser or furnace sensor, at least one air handler sensor and at least one control module. A wetness monitor system, comprising at least one wetness detector connected to a control, wherein the control is also connected to a network and the network is connected to a flow shutoff valve. A method of monitoring a location for wetness comprising detecting wetness through at least one wetness detector, monitoring the state of a shutoff valve.

A building monitoring system, wherein the system comprises an HVAC monitor, which comprised a condensing unit connector, an air handler connector, a thermostat connector and a control module, a wetness detector; and a communicator. The communicator accesses a location of the building monitoring system and selectively communicates with a technician based at least in part on the location. A monitor system for use with an existing HVAC unit, wherein the HVAC unit has a condenser or furnace, an air handler, and a thermostat, the HVAC monitor system comprising at least one condenser or furnace sensor, at least one air handler sensor and at least one control module. A wetness monitor system, comprising at least one wetness detector connected to a control, wherein the control is also connected to a network and the network is connected to a flow shutoff valve. A method of monitoring a location for wetness comprising detecting wetness through at least one wetness detector, monitoring the state of a shutoff valve.

An HVAC system includes a high-pressure subsystem and a low-pressure subsystem. After determining that refrigerant leak diagnostics should be performed, a controllable valve is closed between a condenser and compressor of the HVAC system. The compressor then operates until a predetermined input refrigerant pressure is reached. After the predetermined input refrigerant pressure is reached, operation of the compressor is stopped. After stopping operation of the compressor and waiting at least a predetermined wait time, the pressure in the low-pressure subsystem of the HVAC system is monitored. A rate of change of the pressure in the low-pressure subsystem is determined. If the rate of change is negative and a magnitude of the rate of change is greater than a threshold value, a leak location is determined to be in the low-pressure subsystem.

An HVAC system includes a high-pressure subsystem and a low-pressure subsystem. After determining that refrigerant leak diagnostics should be performed, a controllable valve is closed between a condenser and compressor of the HVAC system. The compressor then operates until a predetermined input refrigerant pressure is reached. After the predetermined input refrigerant pressure is reached, operation of the compressor is stopped. After stopping operation of the compressor and waiting at least a predetermined wait time, the pressure in the low-pressure subsystem of the HVAC system is monitored. A rate of change of the pressure in the low-pressure subsystem is determined. If the rate of change is negative and a magnitude of the rate of change is greater than a threshold value, a leak location is determined to be in the low-pressure subsystem.

A heat pump system and a method for operating this system type includes a heat pump circuit for a heat pump circuit medium flowing through a primary side of a heat exchanger, and a heating circuit for a heating circuit medium flowing through the heat exchanger secondary side. A heat circuit pump is connected upstream of the exchanger secondary side when viewed in the heating circuit medium operating flow direction. When viewed in the heating circuit medium operating flow direction, a check valve connected downstream of the heating circuit pump and upstream of the secondary side closes when a heating circuit medium flows opposite the operating flow direction, and a degassing unit connected downstream of the secondary side when viewed in the operating flow direction prevents a flow of the heating circuit medium in the operating flow direction from a predefined gas amount in the heating circuit medium.

A heat pump system and a method for operating this system type includes a heat pump circuit for a heat pump circuit medium flowing through a primary side of a heat exchanger, and a heating circuit for a heating circuit medium flowing through the heat exchanger secondary side. A heat circuit pump is connected upstream of the exchanger secondary side when viewed in the heating circuit medium operating flow direction. When viewed in the heating circuit medium operating flow direction, a check valve connected downstream of the heating circuit pump and upstream of the secondary side closes when a heating circuit medium flows opposite the operating flow direction, and a degassing unit connected downstream of the secondary side when viewed in the operating flow direction prevents a flow of the heating circuit medium in the operating flow direction from a predefined gas amount in the heating circuit medium.

A valve unit for a heat-pump system, includes: a liquid refrigerant pipe portion; a gas refrigerant pipe portion; a liquid control valve disposed in the liquid refrigerant pipe portion; a gas control valve disposed in the gas refrigerant pipe portion; a casing accommodating the liquid control valve and the gas control valve; and an air-discharge mechanism that discharges air in an internal space of the casing to an external space outside the casing in response to a refrigerant leakage in the casing.

A valve unit for a heat-pump system, includes: a liquid refrigerant pipe portion; a gas refrigerant pipe portion; a liquid control valve disposed in the liquid refrigerant pipe portion; a gas control valve disposed in the gas refrigerant pipe portion; a casing accommodating the liquid control valve and the gas control valve; and an air-discharge mechanism that discharges air in an internal space of the casing to an external space outside the casing in response to a refrigerant leakage in the casing.

A refrigerant leak detection system includes a sensor configured to detect a leaked portion of refrigerant external to a closed-loop refrigeration circuit of a heating, ventilation, and/or air conditioning (HVAC) system, memory circuitry having instructions stored thereon, and processing circuitry configured to execute the instructions to perform various functions. The functions include receiving, from the sensor, sensor feedback indicative of the leaked portion of the refrigerant. The functions also include transmitting, based on the sensor feedback, a notification indicative of the leaked portion of the refrigerant to a third party security server.