Embodiments of the invention provide a system capable of reducing negative pressure. The system includes a make-up air system that can be configured and arranged to be installed within a structure, such as a building. The system can also include a pressure switch that is configured and arranged to sense a pressure within an exhaust duct coupled to an exhaust device. The pressure switch can also be configured to communicate an activation signal and a deactivation signal to the make-up air system. In some embodiments, communication of the activation and deactivation signals can be at least partially dependent on the pressure within the exhaust duct. Moreover, the pressure switch can be configured and arranged to be retroactively coupled to at least one of the exhaust duct and the exhaust device.

A method of controlling a heating, ventilating, and air conditioning system on a customized schedule utilizes a master controller and a plurality of satellite vents. Each of the plurality of satellite vents is associated with a vent address which can be addressed through the master controller. A plurality of actuation commands, wherein each of the actuation commands contains a vent position which is transmitted to a specific vent of the plurality of satellite vents. The master controller utilizes a wireless transmitter to broadcast the actuation commands. Next, each of the plurality of satellite vents periodically listen for the actuation commands. A specific command of the actuation commands is executed if the vent address of the actuation command matches the physical address of the specific vent and a current time matches a set time of the specific command.

The air flow of an HVAC system for a multi-story building B is controlled by optimizing the pressure setpoint at the return air plenum PL-1 used for removing or recirculate air from the building, by measuring a pressure differential between the building B air and atmosphere A air at a sensor location P-2, computing a desired pressure differential between the building B air and atmosphere A air, based upon a computed stack effect pressure that is expected to develop at the sensor location on the building for the current inside and outside air temperature in the absence of mechanical action, and controlling the return air fan and damper D-1 to pressurize the air in at the sensor location to produce the desired pressure differential between the building B air and atmosphere A air at the sensor P-2 location.

An inside unit of an air conditioner that includes a cabinet in which an fan installed on the ceiling of the inside space and a heat exchanger are accommodated, a front panel mounted on an opening surface of the cabinet, and forming an inlet port through which inside air is suctioned into a depressed inside area and a panel outlet port through which heat-exchanged air is discharged, a vane provided on the panel outlet port and controlling opening degree of the panel outlet port by the rotation, an air guide formed to be extended along an outside end of the panel outlet port and formed of a heat insulating material, a slide preventing protrusion formed to protrude from the front panel in which the air guide is mounted, and a protrusion accommodating groove depressed in the bottom surface of the air guide corresponding to the slide preventing protrusion and the slide preventing protrusion is received in the protrusion accommodating groove.

A mass airflow measuring device includes an air passageway and a body positioned in the passageway. The body includes a peripheral section including a first channel, a sample section located radially inward of the peripheral section, and including an inlet port and a support section connecting the sample section to the peripheral section. The support section includes a second channel which communicates at a first end with the inlet port and at a second end with the first channel. A mass airflow sensor is mounted to the body.

Embodiments of a HVAC electrical system power supply packaging system within an ultimate enclosure are provided. The HVAC electrical system power supply packaging system provides serviceability, safety, manufacturability, and system management failure diagnostic reporting enhancements over conventional packaging systems while conforming to agency safety requirements. The embodiments disclosed herein also reduce equipment and service costs for HVAC electrical system power supply components provided within the HVAC electrical system power supply packaging system by reducing delays in servicing these components. Thus, customer uptime of the HVAC system can be increased.

An indoor unit or device of an air conditioner is provided that may include an outer plate configured to form an exterior of a cabinet configured to be installed at a ceiling of an indoor space; an inner case accommodated inside of the outer plate, and configured to form an internal space of the cabinet; a fan provided inside of the inner case; a heat exchanger provided to cover an outer side of the fan; a panel configured to shield the cabinet, and having an inlet port through which indoor air may be suctioned in and a panel outlet port through which heat-exchanged air may be discharged; and a drain pan assembly seated on an upper end of the inner case, and configured to collect condensate generated from the heat exchanger. An extension that extends to an open end of the outer plate may be formed at a side surface of the inner case corresponding to the panel outlet port, and a recess, which may be recessed in a shape corresponding to the panel outlet port, may be formed at an outer end of the drain pan assembly. Both ends of the extension may be in contact with an inner side surface of the recess, and form an outlet port which is in communication with the panel outlet port.

An air-conditioning apparatus has a heating only temporary operation mode in which, in changing from a heating main operation mode to a heating only operation mode, when an outside air temperature is at or above a predetermined temperature, at least one of heat exchangers functioning as a condenser in the heating main operation mode continues functioning as the condenser, and the refrigerant is not supplied to the intermediate heat exchanger functioning as an evaporator in the heating main operation mode and a cooling only temporary operation mode in which, in changing from a cooling main operation mode to a cooling only operation mode, when the outside air temperature is at or below a predetermined temperature, at least one of heat exchangers functioning as the evaporator in the cooling main operation mode continues functioning as the evaporator, and the refrigerant is not supplied to the intermediate heat exchanger functioning as the condenser in the cooling main operation mode.

A system and method for monitoring performance of an HVAC unit by receiving outdoor temperature data from an outdoor temperature source and indoor temperature data from an indoor temperature source, tracking performance data of the HVAC unit based at least in part on the outdoor temperature data and the indoor temperature data, receiving power consumption data from the power measuring device, tracking the power consumption data based at least in part on the outdoor temperature data, determining whether there is a change in the performance data and the power consumption data, and generating a fault signal based at least in part on the change in the performance data and the power consumption data.

An apparatus for monitoring a heating, ventilation, or air conditioning (HVAC) system includes an indoor unit monitor module electrically connected to a current sensor and first and second refrigerant temperature sensors. The current sensor generates a first current signal based on aggregate current consumed by components of an indoor unit of the HVAC system. The refrigerant temperature sensors generate first and second refrigerant temperature signals, respectively, based on measured temperatures of refrigerant circulating within the HVAC system. The indoor unit monitor module receives, from a secondary monitoring module, a second current signal based on aggregate current consumed by components of an outdoor unit of the HVAC system. The indoor unit monitor module transmits data to a remote server to assess whether a failure has occurred or is likely to occur in the components of the HVAC system. The data is based on the current signals and the refrigerant temperature signals.