A method of controlling a gas furnace system includes determining a first pressure in a conduit coupled to a draft inducer from signals output by a pressure transducer positioned to sense a pressure within the conduit with a motor of the draft inducer in a stopped condition. A first status of the pressure transducer is determined based at least in part on the first pressure. The motor of the draft inducer is controlled to increase a speed of the motor from the stopped condition in response to a call for heat when the first status does not indicate that the pressure transducer is unreliable, and the motor is maintained in a stopped condition when the first status indicates that the pressure transducer is unreliable.

A method of controlling a gas furnace system includes controlling a motor of a draft inducer coupled to a conduit to increase a speed of the motor from a stopped condition in response to a call for heat, and receiving pressure signals output by a pressure transducer responsive to pressure in the conduit. Signals indicating whether a pressure switch responsive to pressure in the conduit is in a first state or a second state are received. A first status of the pressure transducer is determined based on the received pressure signals from the pressure transducer and the signals indicating whether the pressure switch is in the first state or the second state. The method includes continuing to operate the motor when the first status does not indicate that the pressure transducer is unreliable, and stopping the motor when the first status indicates that the pressure transducer is unreliable.

An apparatus includes a heat exchange member at least partially defining a passageway, and structure defining a first plurality of holes and a second plurality of holes. The first and second pluralities of holes provide fluid communication from the passageway to the exterior of the apparatus, i.e., to the atmosphere. A blower is operatively connected to the heat exchange member and configured to blow air into the passageway. The apparatus is configured such that, when the heat exchange member is sufficiently positioned with respect to a campfire, air exiting the first plurality of holes is directed downward and away from the campfire and air exiting the second plurality of holes has an upward velocity component.

A fuel-fired heating appliance comprises a fuel source, an air source, a chamber in which fuel and air mix, a burner downstream from the mixing chamber, an igniter proximate the burner, a heat exchanger, a blower and a flue pipe. An ambient air inlet may be defined by at least one of the outlet end of the blower and the flue pipe extending between the interior of the flue pipe and an area ambient to the flue pipe. A flow rate of combustion gas may be controlled to a level below a steady-state flow rate during appliance warm-up.

A furnace includes a gas burner exposed to a heat-exchange tube. An inducer is fluidly coupled to the heat-exchange tube and configured to induce draft air through the heat-exchange tube. A regulator is fluidly coupled to the gas burner. A rollout shield is disposed adjacent to the gas burner. A rollout switch is disposed in the rollout shield. The rollout switch is electrically coupled to the regulator. At least one vent is formed through the rollout shield adjacent to the rollout switch. The vent provides a path for a rollout flame to the rollout switch. The at least one vent is disposed on at least two sides of the rollout switch.

A high efficiency heating apparatus for heating fluids and cooking mediums, such as oil or shortening within a fryer, includes a natural draft (non powered) combustion chamber with internal baffles that is affixed to an exterior surface of a fry tank.

A fuel-fired heating appliance comprises a fuel source, an air source, a chamber in which fuel and air mix, a burner downstream from the mixing chamber, an igniter proximate the burner, a heat exchanger, a blower and a flue pipe. An ambient air inlet may be defined by at least one of the outlet end of the blower and the flue pipe extending between the interior of the flue pipe and an area ambient to the flue pipe. A flow rate of combustion gas may be controlled to a level below a steady-state flow rate during appliance warm-up.

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.

A nozzle assembly for a fan unit includes an inner nozzle having a tapered outer diameter and a flow path radially inward from the tapered outer diameter with respect to a longitudinal axis of the nozzle assembly. The flow path is configured to guide a fluid flow and to expel the fluid flow through an inner outlet of the inner nozzle to a surrounding environment. The nozzle assembly also includes an outer nozzle disposed radially outward from the inner nozzle with respect to the longitudinal axis. The outer nozzle and the tapered outer diameter of the inner nozzle define an annular flow path therebetween. The annular flow path is configured to guide the fluid flow and to expel the fluid flow to the surrounding environment through an outer outlet of the outer nozzle. A cross-sectional area of the outer outlet is adjustable via movement of the inner nozzle, the outer nozzle, or both along the longitudinal axis of the nozzle assembly.

A draft inducer blower assembly for use with a water heater has a housing, a motor, and a fan. The housing has an exhaust volute surrounding the fan and a base adapted to be mounted atop a water heater. The base has an inlet port adapted to receive exhaust gas from the water heater. The fan is connected to the motor for rotation about a rotation axis. The exhaust volute and the base are non-adjustably fixed relative to each other. The exhaust volute has a cut-off at a cut-off angle relative to the rotation axis. The exhaust volute has an exhaust outlet passageway that extends to an exhaust port. The exhaust port is lower than the top of the exhaust volute.