Provided is an RPM control method for an inducer for a gas furnace that induces a flow of combustion gas produced in a burner from a heat exchanger to an exhaust pipe. The RPM control method for an inducer for a gas furnace includes: (a) initiating a heating operation for the gas furnace; (b) determining whether the operation time during which the heating operation is performed is equal to or longer than a first time period; (c) if it is determined that the operation time is equal to or longer than the first time period, detecting whether a pressure switch is turned OFF; and (d) if the pressure switch is detected as turned OFF, increasing the RPM of the inducer by a first value.

A method of determining presence of a flame in a furnace of a heating, ventilation, and air conditioning (HVAC) system. The method comprises determining, using a controller, whether a processor signal (G) is active, responsive to a determination that the processor signal (G) is active, determining, using the controller prior to assertion of a flame-test input control signal, an output state of a first comparator, responsive to a determination that the output state of the first comparator is high, determining, using the controller prior to assertion of the flame-test input control signal, an output state of a second comparator, and responsive to a determination that the output state of the second comparator is low, transmitting, using the controller, a notification that a flame is present.

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 system includes a modulating furnace and control circuitry. The control circuitry is configured to receive a call for heating associated with a quick heat cycle. In response to the call for heating, the control circuitry is also configured to operate the modulating furnace in a quick heat operating mode for a threshold time period. Subsequent to the threshold time period, the control circuitry is also configured to operate the modulating furnace in a modulating heat operating mode.

A method of calibrating a furnace includes determining a first flame stabilization period for the furnace that avoids detachment of a flame from a burner within a burner box of the furnace, determining a second flame stabilization period that is longer than the first flame stabilization period and avoids emission of a combustion tone from the furnace, and configuring a controller of the same or another furnace to utilize a flame stabilization period that has a duration between the first and second flame stabilization periods. Each flame stabilization period commences upon ignition of a premixed mixture of air and fuel at the burner while an inducer fan operates within a first range of fan speeds, and terminates when the rotational speed of the inducer fan increases to a second range speeds that is greater than the entire first range.

A stove (1) having a combustion chamber (2) supplied by one or more air supply paths (9, 14, 16). One or more valves (11, 15, 17) are provided for controlling airflow through the one or more air supply paths (9, 14, 16). A temperature sensor (4) is used to determine the air temperature associated with the combustion chamber (2), and a flame sensor (3) is used to determine the burn intensity of a fuel in the combustion chamber (2). A controller (5) controls the one or more valves (11, 15, 17) to adjust the airflow through the one or more air supply paths (9, 14, 16) based on inputs from the flame and temperature sensors (3, 4).

This invention relates to a heater. A combustion air blower feeds combustion air to a burner device. The burner device burns a gas-air mixture from the combustion air and a fuel and serves for heating air. A circulating air blower discharges heated air from the heater. A control device acts on at least one component of the heater, wherein a night mode parameter set associated with an operation of the heater in a night mode and a default parameter set are stored in a data storage device. After an activation of the night mode, the control device accesses the night mode parameter set and uses the same for acting on the component. The night mode parameter set effects a reduction of background noise generated by the heater.

A coaxial gas valve assembly includes a gas inlet, a gas outlet, a valve tube, and a shaft member. A main valve is movable between a closed position and an open position (broadly, openable and closable). A main spring is positioned to resiliently bias the main valve in its closed position. A redundant valve is movable between a closed position and an open position (broadly, openable and closable). A redundant spring is positioned to resiliently bias the redundant valve in its closed position. A solenoid coil is positioned to electromagnetically move the shaft member within the valve tube. A balance diaphragm is connected to the valve tube. A gas path through at least the valve tube allows gas flow from a first side of the balance diaphragm to a second side of the balance diaphragm to reduce a pressure difference between the first and second sides of the balance diaphragm.

A method for controlling a gas furnace that performs a heating operation by receiving a first heating signal; calculating a certain heating capacity smaller than a maximum heating capacity of the gas furnace, according to the first heating signal; and operating a heating of the gas furnace with the calculated certain heating capacity. The calculating of the certain heating capacity includes calculating the certain heating capacity according to a difference between an intake air temperature sucked into the gas furnace and a reference temperature.

A method for evaluating a quasi-stationary pressure difference detectable by a sensor at a gas boiler. The gas boiler has a mixing device (4), a fan (5), a main flow regulator (3), .a control valve (2) and a safety valve (1). The sensor detects a differential pressure between a pressure (p2) at a measuring point upstream of the main flow regulator (3) and downstream of the control valve (2) and a reference pressure (p0, p1) at a reference measuring point. The sensor transmits a signal to an electronic evaluation system. The electronic evaluation system compares the differential pressure during a pre-purge phase, wherein the safety valve (1) is closed, with the differential pressure after the pre-purge phase and detects an error by the comparison.