A device management apparatus manages a specific device that changes a state of a heat medium circulating through a heat source system. The device management apparatus receives a state value of the heat medium measured by a sensor included in the heat source system. The device management apparatus prohibits a change operation of a capacity of the specific device based on a parameter related to a change in the state value.

An air conditioner water system, a control method therefor, and a control device thereof, the method includes acquiring the pressure difference and temperature difference between a water intake pipe and a water discharge pipe of an air conditioner water system, the water intake pipe being connected to an inlet of a host module of the air conditioner water system, and the water discharge pipe being connected to an outlet of the host module; detecting and confirming that the pressure difference is less than or equal to a preset pressure difference, and controlling the operating frequency of a water pump of the air conditioner water system according to the pressure difference; and detecting and confirming that the pressure difference is greater than the preset pressure difference, and controlling the operating frequency of the water pump of the air conditioner water system according to the temperature difference.

A refrigerant control system includes: a charge module configured to determine an amount of refrigerant that is present within a first portion of a refrigeration system within a building; and an isolation module configured to selectively open and close an isolation valve of the refrigeration system and to, via the isolation valve, maintain the amount of refrigerant within the first portion within the building below a predetermined amount of the refrigerant.

A controller of an HVAC system is communicatively coupled to a liquid-side sensor and a shutoff switch. The controller stores measurements of a liquid-side property over an initial period of time. The controller detects that the shutoff switch is tripped at a first time stamp corresponding to an end of the initial period of time. The controller accesses the measurements of the liquid-side property. The controller determines, based on the measurements of the liquid-side property, whether the liquid-side property has an increasing or a decreasing trend. In response to determining that the liquid-side property has the decreasing trend, a malfunction of a blower of the system is determined to have caused the shutoff switch to trip. In response to determining that the liquid-side property has the increasing trend, a blockage of the refrigerant conduit subsystem is determined to have caused the shutoff switch to trip.

An air-conditioning apparatus includes a refrigerant circuit in which a compressor, a refrigerant flow switching device, a heat source side heat exchanger, an expansion device, a heat medium heat exchanger, and an accumulator are connected, a heat medium circuit in which a pump, the heat medium heat exchanger, a heat medium flow control device, and a load side heat exchanger are connected, at least one or more bypass pipes provided in the refrigerant circuit so that the refrigerant discharged from the compressor bypasses at least either one of the heat source side heat exchanger and the heat medium heat exchanger, a bypass opening and closing device provided at the bypass pipe, and a controller configured to control the bypass opening and closing device to carry out a start-up control function of causing low-pressure gas refrigerant with a high degree of superheat to flow into the accumulator.

An air conditioner of an embodiment includes a plurality of outdoor units, one or more indoor units, and a control unit. The outdoor unit includes a compressor, a four-way valve, an outdoor heat exchanger, an outdoor expansion valve and an outdoor blower, and the outdoor units exchange heat between the outside air and a refrigerant. The indoor unit is an indoor unit connected to the plurality of outdoor units by a refrigerant pipe, includes an indoor heat exchanger, an indoor expansion valve, and an indoor blower, and exchanges heat between the indoor air and the refrigerant. The control unit controls the plurality of outdoor units and the one or more indoor units. The control unit controls the condensation pressure of the outdoor unit in a heating operation or the suction pressure of the outdoor unit in a defrosting operation to be equal to or smaller than an upper limit pressure, which is 1/1.5 times the rated maximum pressure during the heating operation when any of the outdoor units is in the defrosting operation.

An air conditioner and a method for detecting an incorrectly connected pipe in an air conditioner are provided. The air conditioner may detect an incorrectly connected pipe by performing a serial pipe inspection when three or less indoor units are connected to an outdoor unit through pipes and performing a group pipe inspection when four or more indoor units are connected to the outdoor unit through the pipes. The structure may enable detecting the incorrectly connected pipe among pipes connecting the outdoor unit to the indoor units within a shorter time.

A refrigerant leak management system includes a controller is configured to receive a signal indicative of a refrigerant pressure within a refrigerant circuit and determine whether the refrigerant pressure is indicative of a refrigerant leak in the refrigerant circuit. In response to determining that the refrigerant pressure is indicative of the refrigerant leak, the controller is configured to activate a fan configured to motivate air proximate the refrigerant circuit.

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.

An air-conditioning apparatus includes: a heat-source-side device that heats or cools a heat medium; a pump that sucks and transfers the heat medium; use-side heat exchangers; a heat medium circuit; flow rate control devices; indoor-side pressure sensors; a pump inlet-side pressure sensor and/or a pump outlet-side pressure sensor; a flow rate detection device that detects a pump flow rate; and a controller that performs a first operation in which the flow rate control devices are individually opened or closed and data regarding a flow passage resistance at a path related to each of the heat exchangers is obtained, and a second operation in which heat is supplied to indoor air, and calculates calculate flow rates of the heat medium that flows through the heat exchangers in the second operation, from pump flow rates and pressures detected by the pressure sensors in the first and second operations.