Lennox Industries Inc.

Lennox Manufacturing, Inc.

Eljer Manufacturing, Inc.

Eljer Industries, Inc.

Glenn Will Kowald

Hans Juergen Paller

Payam Delgoshaei

Darko Hadzidedic

Ian Burmania

Darcy Quentin Easterling

Eric M Perez

Eric Berg

Sridhar Venkatesh

Steven Schneider

John W Whitesitt

Eric Chanthalangsy

Floyd E Cherington

Peter Hrejsa

Randal Poirier

James T Barth

Randy D Smith

Lars Noergaard Oernbo

Matthew S Riepenhoff

Charles Post

Jianmin Zhang

Kapil Sahu

Jeff P Gedcke

Donald N Zimmer

George Lee Joyner, Jr

Shailesh S Manohar

Cyril E Fowble, Iv

Hugh E Vinson

Kirankumar Annarao Muley

Ajay C P Swornalatha

Nagarajan Rajendran

Ashoka Thimmareddy

Sailendra Meduri

Abdul Rehman Rajkafur

An HVAC system includes a blower configured to provide a flow of air into a conditioned space. A temperature sensor measures a discharge air temperature of the flow of air provided to the conditioned space. The blower provides the flow of air at a predefined flow rate. The controller determines that the measured discharge air temperature satisfies predefined stability criteria associated with a change in the discharge air temperature during a first period of time being less than a threshold value. If the stability criteria are satisfied, a temperature offset is determined between the discharge air temperature and an indoor temperature. The temperature offset is stored in a memory and is associated with the flow rate of air provided by the blower and the outdoor temperature.

HVAC system and method for determining a temperature offset between a discharged air temperature and an indoor temperature

An HVAC system includes a heating element, a discharge air temperature sensor, and a return air temperature sensor. A controller of the HVAC system determines that the HVAC system has been operating in the heating mode for at least a predefined amount of time. The controller receives measurements of the discharge air temperature and the return air temperature. A temperature rise value is determined using the discharge air temperature and return air temperature. If the temperature rise value is less than a predefined minimum threshold value, the controller determines that a first fault of the HVAC system is detected and provides a corresponding alert. If the temperature rise value is greater than a predefined maximum threshold value, the controller determines that a second fault of the HVAC system is detected and provides a corresponding alert.

HVAC system prognostics and diagnostics based on temperature rise or drop

A burner assembly according to aspects of the disclosure includes a burner surface carried by a burner, the burner surface extending outward from a front side of the burner, a housing coupled to the burner on a side opposite the front side of the burner, a gasket disposed between the burner and the housing, a thermally anisotropic protective covering located on the front side of the burner and surrounding a perimeter of the burner surface, and an igniter positioned adjacent to the burner surface.

Pre-mix burner assembly for low NOx emission furnace

A method of monitoring a HVAC system to detect erroneous sensor installation. The method includes determining whether a circulation fan has been operational for a first predetermined time interval. If the circulation fan has been operational for the first predetermined time interval, determining whether a cooling demand is present. If the cooling demand is present, determining whether the HVAC system has been conditioning air for the first predetermined time interval responsive to the cooling demand. If the HVAC system has been conditioning the air for the first predetermined time interval, determining whether a difference between an indoor air temperature value corresponding to an enclosed space and an air temperature value from a discharge air temperature (DAT) sensor is greater than a predetermined temperature value. If the difference is not greater than the predetermined temperature value, forwarding a message indicating that the DAT sensor positioned within a duct of the HVAC system is improperly installed.

Method and apparatus for identifying erroneous discharge air temperature (DAT) sensor installation

An HVAC system includes a blower configured to provide a flow of air into a conditioned space. A temperature sensor measures a discharge air temperature of the flow of air provided to the conditioned space. A controller of the HVAC system determines that heating or cooling mode operation is not requested. Following this determination, the blower provides the flow of air at a predefined flow rate. The controller determines that the measured discharge air temperature satisfies predefined stability criteria associated with a change in the discharge air temperature during the first period of time being less than a threshold value. If the stability criteria are satisfied, a temperature offset is determined between the discharge air temperature and an indoor temperature. The temperature offset is stored in a lookup table such that the temperature offset is associated with the flow rate of air provided by the blower and the outdoor temperature.

Determination of return air temperature

Provided herein are embodiments of, a multistage gas furnace, a controller therefor and a computer-usable medium having non-transitory computer readable instructions stored thereon for execution by a processor to perform a method for operating a gas furnace. In one embodiment, the gas furnace includes: (1) a burner, (2) a circulation fan and (3) a furnace controller. The furnace controller having: (3A) an interface configured to receive heating calls and a blower control signal, the blower control signal corresponding to an operating speed of the circulation fan and (3B) a processor configured to respond to the heating calls and the blower control signal by setting and adjusting a gas input rate for the burner that is based on the blower control signal and that corresponds to a discharge air temperature determined by a dedicated discharge air sensor associated with the furnace.

Furnace controller and a furnace that controls a gas input rate to maintain a discharge air temperature

A flue shield and mesh baffle are described for use within HVAC systems and inside of a combustion chamber. The shield or baffle can be installed around the burner and within the combustion chamber to help dissipate heat that builds up as a result of the combustion of gas and air. An air gap is created between the flue shield and the inner surfaces of the combustion chamber and heat exchanger tubes. A mesh baffle can provide heat insulation and noise dampening. Installation of a flue shield or mesh baffle provides better efficiency than insulation solutions, reduces stresses on the heat exchanger, and provides safety benefits.

Flue baffle

A flue shield is described for use within HVAC systems and inside of a combustion chamber. The flue shield can be installed around the burner and within the combustion chamber to help dissipate heat that builds up as a result of the combustion of gas and air. Extensions from the flue shield extend through holes in the combustion chamber and into tubes of a heat exchanger. An air gap is created between the flue shield and the inner surfaces of the combustion chamber and heat exchanger tubes. Installation of a flue shield provides better efficiency than insulation solutions, reduces stresses on the heat exchanger, and provides safety benefits.

Premix burner internal flue shield

Systems and methods are described for a screen assembly for gas-air mixers in HVAC systems, such as for furnaces. A screen assembly can comprise a mesh screen, a housing, and a pressure tap. The mesh screen can allow for the intake of an air supply while also blocking unwanted foreign matter such as dust or leaves. The housing can receive the air supply and direct it into a gas-air mixer or other component. The pressure tap can be coupled to a gas valve or regulator in order to modulate the flow of gas when air flow is restricted.

Inlet screen assembly for ultra low NOx gas-air mixing system

Systems and methods are described related to a premix combustion system used in a furnace system. Prior systems have to create a negative pressure in the premix chamber to draw gas into the chamber. Embodiments under the current disclosure can use an amplifier that is pneumatically coupled to an air supply and a secondary location (besides the gas valve). Coupling to the amplifier to a location apart from the gas valve allows the system to avoid a negative pressure in the mixing chamber. The amplifier can apply an amplified pressure or signal to a gas valve regulator and thereby raise the gas pressure so that the gas supply is driven into the premix chamber.

Positive pressure amplified gas-air valve for a low NOx premix combustion system

An alternative-fuel gas orifice, a gas furnace configured to employ the same and a method of designing a gas orifice. In one embodiment, the gas orifice includes: (1) a body having an aperture extending therethrough and including: (1a) a metering neck having a cross-sectional area such that a given flow rate of a gas is established when the gas is delivered to the gas orifice at a given alternative-fuel delivery pressure and (1b) a diffuser having a cross-sectional area larger than the cross-sectional area of the metering neck and a length such that the gas achieves a substantially laminar flow before exiting the diffuser.

Alternative-fuel gas orifice having principal-fuel gas orifice temperature profile and a heating, ventilation and air conditioning system incorporating the same

A controller for a gas furnace, a computer-usable medium for implementing a method and a gas furnace are disclosed herein. In one embodiment, the controller includes: (1) an interface configured to receive a heating call and (2) a processor configured to enable an inducer of the gas furnace at a low speed based on the heating call and ignite the gas furnace at a high fire operation when determining a low fire pressure switch of the gas furnace is open.

Furnace, a method for operating a furnace and a furnace controller configured for the same

Growing community of inventors

Carrollton, TX, United States of America

Glenn Will Kowald