Abstract: A furnace system that generates heat by combustion is provided. The furnace system includes a sensor (100) that detects a gas concentration. The sensor is in communication with the flue gas (15). A controller is in communication with the sensor. The controller monitors the gas concentration and acts to control or deactivate the furnace.

Abstract: A furnace system that generates heat by combustion is provided. The furnace system includes a sensor (100) that detects a gas concentration. The sensor is in communication with the flue gas (15). A controller is in communication with the sensor. The controller monitors the gas concentration and acts to control or deactivate the furnace.

Abstract: Apparatus for mounting one or more component parts of a unit in assembly. The apparatus includes a mounting plate containing one or more extruded holes each having a raised lip surrounding the hole which protrudes upwardly from the top surface of the plate for receiving a threaded fastener that is used to secure a part to the bottom mounting surface of the plate. An endless depression surrounds each hole which also protrudes outwardly from the top surface of the plate. The size and shape of the depression is such that the plate area surrounding the fastener receiving hole is strong enough to resist high impact loads.

Abstract: A method and system for detecting flame rollout is disclosed. The detection system includes a processor programmed to execute a furnace lockout when the flame proving signal is lost three times after successful burner ignition has been established on each of three heating cycles within a predetermined period of accumulated burner on-time. In one embodiment the period of accumulated burner on-time is 60 minutes. The program executed by the processor resides in firmware. The system and method of present invention mitigates the potentially harmful accumulation of flue gasses when flame sense is lost due to flame rollout.

Abstract: A mount for a disc-type switch having a body that is centered upon a mounting flange. The mount includes a substrate having a central opening that permits the switch and mounting flange to be inserted into the opening. The substrate has a depression formed therein on one side of the opening that complements the shape of the flange and has a size that will accept about one half of the flange therein when the switch is passed into the opening and the flange rotated. At this time the other half of the flange is brought into contact with the top surface of the substrate. A threaded fastener secures the flange to the substrate so that at least one half of the flange is supported by the substrate to resist the downwardly directed forces acting upon the switch and the other half of the flange is supported in the housing to resist upwardly directed forces upon the switch.

Abstract: In a molded element containing therein a horizontally disposed bore, the improvement comprising: a plurality of downwardly disposed first elements having distal ends, and being spaced apart from one another, and a plurality of upwardly disposed second elements having distal ends and being spaced apart from one another, wherein the plurality of first elements are offset from the plurality of second elements, whereby a horizontally disposed bore is formed by the distal ends of the plurality of first elements and the distal ends of the plurality of second elements.

Abstract: The present invention is a method and apparatus for controlling the flow of combustion air and/or combustion products through a furnace which may experience changing flow restrictions. The method provides constant flow through an induced-draft furnace by determining torque values applied to an inducer motor of the furnace from a lookup table, which is established by operating a test furnace under changing flow restrictions, typically by measuring furnace flue gas carbon monoxide concentration. A lookup table according to the invention may include motor operating performance plots for controlling inducer speed under operating conditions, and threshold plots, which may be employed for determining activation of furnace events such as ignition, gas valve energizing, and shutdown. In an adaptive method of the invention, an adaptive lookup table is provided by averaging torque values from each of several lookup tables.

Abstract: A thermostat monitors the indoor air temperature indicated by the thermostat's indoor air temperature sensor. The monitored indoor air temperature must be within a predefined range of acceptable temperatures to be considered valid. In the event the monitored temperature is outside this predefined range, the thermostat proceeds to read the outdoor air temperature and activate a heating system if the outdoor air temperature reading is below a predefined level.

Abstract: In a two-stage furnace system, including a thermostat, at least one gas burner with a low and high-fire operating capability, an inducer fan having low and high speed operating settings, and a high-fire pressure switch, a method for handling the high-fire pressure switch being in an inappropriately open condition. The method has the steps of: determining whether the thermostat is issuing a call for high heat and, if it is, determining if the high-fire pressure switch is open. If the high-fire pressure switch is open, waiting a predetermined time, determining if the high-fire pressure switch is still open and, if it is, completing a furnace shutdown procedure, then initiating a normal shutdown, then an ignition sequence in high-speed inducer pre-purge mode, determining if the high-fire pressure switch remains open, and if so, running at least one gas burner in low-fire mode. If, while these steps are being performed, the high-fire pressure switch closes, running the system in high-fire mode.

Abstract: A two-stage induced draft furnace is operated at either high heat or low heat with the gas valve switched to high-fire or low-fire. High-fire and low-fire combustion pressure switches sense the collector box flue gas pressure and actuate respective solenoids of the gas valve. Under some conditions the inducer can produce sufficient negative pressure at low fire to prove the high fire pressure switch and cycle the burners on high fire. To prevent this, relay contacts are interposed between the high fire pressure switch and the gas valve solenoid to deny thermostat power to the high-fire solenoid whenever there is a call for low heat.