Example embodiments of the present disclosure relate to an assembly for sealing a rigid pipe, a furnace, and a gasket for use in an HVAC fluid conduit. Some embodiments include a furnace with an inducer blower drawing combustion air through the furnace, and the assembly is used to connect one or more flue conduit(s) and an exhaust pipe. In one embodiment, the gasket used in the assembly includes a tubular body, at least a portion of which is engaged along an inner surface of the fluid conduit, a rim extending outwardly from a tubular body end, and two or more ears extending from the rim, wherein the ears are spaced apart from the tubular body and extend in substantially the same direction as the tubular body. The ears further include a first rib located proximate a distal end of the ear.

A condensate drain system for a heating, ventilation, and/or air conditioning (HVAC) system includes a heat exchanger having a plurality of tubes configured to receive ambient air and fluidly coupled to a drain via a conduit, a valve positioned along the conduit between the plurality of tubes and the drain, where the valve is configured to enable a flow of condensate from within the plurality of tubes toward the drain in an open position and the block the flow in a closed position, and a controller configured to adjust a position of the valve based on feedback indicative of an operational state of the HVAC system.

A device that includes a pressure sensor that adds dynamic pressure sensing capability to a furnace. In some examples the device may include a relay and other circuitry to replace the single-setpoint pressure switch used to sense the operation of an inducer fan. The pressure sensor may measure the pressure from the inducer fan and send a signal to the other circuitry, such as a microcontroller. The other circuitry may determine when the pressure from the inducer fan reaches a predetermined threshold and allow the main gas valve of the furnace to open. The other circuitry may be configured to set the pressure sensor to a variety of predetermined pressure thresholds, and thereby replace multiple pressure switches. In some examples, the other circuitry may record pressure values received from the pressure sensor over time and provide performance data, as well as other signals or indicators.

The disclosed technology includes a variable refrigerant flow (VRF) conditioning system including a single outdoor unit and a VRF path extending between the single outdoor unit and a plurality of terminals. The plurality of terminals can include a first terminal configured to condition air of an interior room and a second terminal configured to heat or cool a liquid. The VRF system can provide heating or cooling of air in different rooms or zones within a building or home while also providing heating or cooling of water. In response to a demand for heating or cooling at each terminal, the VRF system can vary the supply of refrigerant to each terminal, such that efficient and precise temperature regulation of air and liquid can be provided.

A method is provided for controlling combustion in a modulating gas furnace. The method includes receiving an indication of a firing rate setpoint for a burner assembly, and applying the firing rate setpoint to first and second continuous functions that map the firing rate setpoint to air-to-fuel ratio and combustion system pressure setpoints. A variable-speed draft inducer blower is set to drive to a combustion system pressure setpoint, and the modulating gas valve is controlled during combustion in the combustion system. In this regard, a combustion system pressure measurement is obtained and applied to an inverse of the first continuous function that outputs an adjusted firing rate for the combustion system pressure measurement. The adjusted firing rate is applied to a third continuous function that maps the firing rate to gas valve position, and outputs a gas valve position to which the modulating gas valve is set.

Various ways to control the ambient temperature of a room in a structure are described. In one embodiment, a method for intelligently controlling an ambient room temperature in a structure is described, comprising receiving a future outdoor temperature forecast related to a geographic area where the structure is located, and altering a temperature profile for controlling the ambient room temperature based on the future outdoor temperature forecast.

An illustrative HVAC controller may include a communication module for wirelessly communicating with a network and wiring terminals for receiving a wired connection to a remote temperature sensor that is situated remote from the HVAC controller and in a living space of the building. A controller may be operably coupled to the communication module and the wiring terminals and may be configured to implement a thermostat control algorithm to generate one or more control signals, wherein the one or more control signals are provided by a wired connection to the HVAC system to control one or more HVAC components of the HVAC system. The thermostat control algorithm may be configured to compare a sensed temperature received from the remote temperature sensor via the wiring terminals and a temperature setpoint received from the server via the network.

The disclosed technology includes a variable refrigerant flow (VRF) conditioning system including a single outdoor unit and a VRF path extending between the single outdoor unit and a plurality of terminals. The plurality of terminals can include a first terminal configured to condition air of an interior room and a second terminal configured to heat or cool a liquid. The VRF system can provide heating or cooling of air in different rooms or zones within a building or home while also providing heating or cooling of water. In response to a demand for heating or cooling at each terminal, the VRF system can vary the supply of refrigerant to each terminal, such that efficient and precise temperature regulation of air and liquid can be provided.

Methods and related systems for operating a furnace are disclosed. In an embodiment, the method includes activating a burner assembly and a first fan of the furnace to combust fuel and air and circulate combustion gases along a flow path extending through a heat exchanger of the furnace. In addition, the method includes operating a second fan of the furnace to circulate air across an external surface of the heat exchanger of the furnace and produce a conditioned airflow. Further, the method includes monitoring one or more parameters of a motor of the second fan indicative of an airflow rate of the conditioned airflow, and deactivating the burner assembly, whereby combustion of the fuel and air in the furnace ceases, in response to the one or more parameters indicating that the airflow rate is less than a minimum airflow rate.

A high turndown furnace for an air handling system. In one example, the furnace includes a plurality of tubes divisible by four with a first modulating valve supplying gas to ¼ of the tubes and a second modulating valve supplying gas to ¾ of the tubes. In one aspect, the furnace is capable of providing a 16:1 turndown. In one aspect, the furnace is capable of providing seamless turndown operation throughout the entire firing range.