Systems and Methods for Pre-Ignition Moisture Removal in Heating Alliances

Abstract

Systems and methods for pre-ignition moisture removal in heating appliances are provided. The heating appliance may be configured, prior to initiating a combustion process using a combustion system of the heating appliance, to determine whether a flame sensing unit is producing false positive outputs. In some instances, such false positive outputs may be caused by moisture within the combustion cabinet of the heating appliance. To attempt to eliminate any false positive outputs, the heating appliance may perform ana action to expel the moisture from the combustion cabinet. For example, an inducer may be activated to expel the moisture using airflow. This ensures that the flame sensing unit is producing accurate data before the combustion process is initiated.

Claims

1. A method comprising: determining, by a processor of a heating appliance, that a flame sensing unit for detecting a flame within a combustion cabinet of the heating appliance is producing a false positive output; determining, by the processor, that moisture is present within the combustion cabinet; and causing, by the processor, at a first time, and based on determining that moisture is present within the combustion cabinet, a component of the heating appliance to perform an action to reduce an amount of the moisture in the combustion cabinet.

2. The method of claim 1, wherein determining that the flame sensing unit is producing the false positive output is performed before a combustion process of the heating appliance.

3. The method of claim 1, further comprising: determining, by the processor and at a second time, that the flame sensing unit is no longer producing a false positive output; and initiating a pre-purge or a combustion process within the heating appliance.

4. The method of claim 1, wherein determining that the flame sensing unit is producing a false positive output comprises: determining, by the processor, that a gas valve of the combustion cabinet is closed; and determining, by the processor, that the flame sensing unit is producing an output indicating a flame is present.

5. The method of claim 1, wherein determining that moisture is present within the combustion cabinet is further based on data from one or more sensors.

6. The method of claim 1, wherein causing the component of the heating appliance to perform the action further comprises activating an inducer motor of the heating appliance.

7. The method of claim 1, further comprising: determining, by the processor, that moisture is still detected within the combustion cabinet after a threshold period of time has elapsed; and producing an alert.

8. A heating appliance comprising: a flame sensing unit for detecting a flame within a combustion cabinet of the heating appliance; and a processor configured to: determine that the flame sensing unit is producing a false positive output; determine that moisture is present within the combustion cabinet; and cause, at a first time and based on determining that moisture is present within the combustion cabinet, a component of the heating appliance to perform an action to reduce an amount of the moisture in the combustion cabinet.

9. The heating appliance of claim 8, wherein determining that the flame sensing unit is producing the false positive output is performed before a combustion process of the heating appliance.

10. The heating appliance of claim 8, wherein the processor is further configured to: determine, at a second time, that the flame sensing unit is no longer producing a false positive output; and initiate a combustion process within the heating appliance.

11. The heating appliance of claim 8, wherein determining that the flame sensing unit is producing the false positive output comprises: determine that a gas valve of the combustion cabinet is closed; and determine that the flame sensing unit is producing an output indicating a flame is present.

12. The heating appliance of claim 8, wherein determining that moisture is present within the combustion cabinet is further based on data from one or more sensors.

13. The heating appliance of claim 8, wherein causing the component of the heating appliance to perform the action further comprises activating an inducer motor of the heating appliance.

14. The heating appliance of claim 8, wherein the processor is further configured to: determine that moisture is still detected within the combustion cabinet after a threshold period of time has elapsed; and produce an alert.

15. A heating appliance comprising: a sensor for detecting a flame within the heating appliance; and a processor configured to: determine, prior to initiating a combustion process of the heating appliance, that the sensor is producing a false positive output; and cause, at a first time and based on determining that the sensor is producing the false positive output, a component of the heating appliance to perform an action to reduce an amount of moisture in the heating appliance.

16. The heating appliance of claim 15, wherein the processor is further configured to: determine, at a second time, that the sensor is no longer producing a false positive output; and initiate a pre-purge or the combustion process within the heating appliance.

17. The heating appliance of claim 15, wherein determining that the sensor is producing the false positive output comprises: determine that a gas valve of the heating appliance is closed; and determine that the sensor is producing an output indicating a flame is present.

18. The heating appliance of claim 15, wherein determining that moisture is present within the heating appliance is further based on data from one or more sensors.

19. The heating appliance of claim 18, wherein the one or more sensors include at least one of: a temperature sensor, an optical sensor, and a moisture sensor.

20. The heating appliance of claim 15, wherein causing the component of the heating appliance to perform an action further comprises activating an inducer motor of the heating appliance.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The detailed description is set forth with reference to the accompanying drawings. In some instances, the use of the same reference numerals may indicate similar or identical items. Various embodiments may utilize elements and/or components other than those illustrated in the drawings, and some elements and/or components may not be present in various embodiments. Throughout this disclosure, depending on the context, singular and plural terminology may be used interchangeably.

[0006] FIG. 1 illustrates a flow diagram for pre-ignition moisture removal in furnaces, in accordance with one or more embodiments of the disclosure.

[0007] FIG. 2 illustrates a block diagram of a flame sensing system, in accordance with one or more embodiments of the disclosure.

[0008] FIG. 3 illustrates flame sense and flame strength detection by the flame sensing system, in accordance with one or more embodiments of the disclosure.

[0009] FIG. 4 illustrates a system showing exemplary components of a heating appliance, in accordance with one or more embodiments of the disclosure.

[0010] FIG. 5 illustrates an exemplary combustion cabinet including a flame sensing unit, in accordance with one or more embodiments of the disclosure.

DETAILED DESCRIPTION

[0011] Systems and methods are provided for pre-ignition moisture removal in heating appliances. A heating appliance may refer to any type of appliance that uses a combustion system to produce heat for various purposes. Examples of heating appliances include gas furnaces, water heaters, etc. In some instances, reference is specifically made to a furnace herein, however, this is not intended to be limiting and is merely for exemplary and consistency purposes. Recitation of a furnace may also be replaced by other types of heating appliances as well.

[0012] Prior to the ignition of the combustion chamber, the furnace may first determine if the flame sensing system (for example, flame sensing system 200 described in additional detail with respect to FIGS. 2-3) provided at the combustion chamber is producing accurate outputs. The flame sensing system indicates whether a flame is present in the combustion chamber. Accordingly, the data produced by the flame sensing system may be used to determine if the components of the combustion system (examples of such components are shown in FIG. 4) of the furnace are properly functioning. For example, during the ignition process, it is expected that a flame would be produced within the combustion chamber. If the flame sensing system indicates that a flame is detected, then it may be determined that the components are properly functioning. However, if the flame sensing system indicates that a flame is not detected, then one of the components may be malfunctioning and require technician maintenance. Therefore, it is important that the data produced by the flame sensing system is accurate such that the functionality of the components of the combustion system may be properly monitored by the furnace. Some flame sensing systems may operate at a higher frequency than conventional flame sensing systems and may be more susceptible to the effects of moisture and humidity at the flame rod.

[0013] The process for verifying the accuracy of the outputs of the flame sensing system may more specifically involve identifying false positive outputs produced by the flame sensing system. Such false positive outputs may occur, for example, as the result of moisture that exists within the combustion cabinet of the furnace (the portion of the furnace housing the combustion system). Any moisture that interacts with the flame sensing system may cause the flame sensing system to produce outputs that otherwise would indicate the existence of a flame in the combustion chamber.

[0014] To determine if the outputs being produced by the flame sensing system are false positives resulting from moisture in the combustion cabinet, the furnace may verify whether the gas valve that is used to regulate the flow of gas into the combustion chamber is open or closed. If the gas valve is determined to be closed (such that gas should not be flowing into the combustion chamber) and the flame sensing system is still producing an output indicating that a flame is being produced in the combustion chamber, then it is likely that the flame sensing system output is a false positive. This determination may also be made in any other manner (further examples are provided below with respect to at least FIG. 1).

[0015] Once it is determined that the flame sensing system is producing false positive outputs, the furnace may initiate an action to expel any moisture from the combustion cabinet (an exemplary illustration of a combustion cabinet is provided with respect to at least FIG. 4). For example, the furnace may activate an inducer motor that drives an inducer used to provide airflow into the combustion chamber in an attempt to expel the moisture from the combustion cabinet via airflow. The furnace may also use any other suitable method to expel the moisture from the combustion cabinet as well. As further non-limiting examples, a separate blower system may be added to remove moisture or a dehumidifier may be attached to the furnace.

[0016] Once sufficient moisture has been expelled from the combustion cabinet such that the flame sensing system is no longer producing false positive outputs, the pre-purge process may be initiated to remove any lingering gas from the combustion chamber, and then the ignition process may be performed. In some instances, the process of removing the moisture from the combustion cabinet and the pre-ignition process may be performed simultaneously given that the inducer may be used to expel both lingering gases and moisture. However, the removal of the moisture may also be performed before the pre-purge process as well.

[0017] While reference is made specifically to detecting moisture within a combustion cabinet, the approach may also involve detecting and removing moisture from other portions of the heating appliance as well.

[0018] Turning to the figures, FIG. 1 illustrates a flow diagram 100 for pre-ignition moisture removal in a furnace. The flow diagram 100 illustrates some of the high-level operations associated with detecting and removing moisture within a combustion cabinet of a furnace. In embodiments, the operations may be performed by a controller of the furnace, such as controller 430, for example.

[0019] As aforementioned, moisture within the combustion cabinet may cause a flame sensing system (for example, flame sensing system 200 or any other flame sensing system described herein or otherwise) to produce false positive outputs. A false positive output may refer to a scenario in which the flame sensing system is producing an output that indicates a flame is detected within the combustion chamber when no flame is actually present. The functionality of the furnace may be impacted if the flame sensing unit is producing such false positive outputs. For example, the data produced by the flame sensing system may be used to verify whether the combustion system is properly operating. If the flame sensing unit is producing inaccurate data, then the furnace may be unable to properly determine if the combustion system is operating properly. Therefore, it is important that any moisture that may result in inaccurate data from the flame sensing system be expelled from the combustion cabinet.

[0020] The flow diagram 100 begins with condition 102, which involves determining if the flame sensing system is producing a false positive output. This determination may be made in a number of different ways. In one approach, the determination may be made by verifying if the gas valve (for example, fuel valve 402 of FIG. 4) that is used to regulate the flow of gas into the combustion chamber is open or closed. For example, the valve may be electronically controlled by a controller (such as controller 430 or any other controller described herein or otherwise) of the furnace and therefore the controller may have information about the current status of the gas valve. However, the valve may also be mechanically controlled, and the status of the valve may be determined using any other mechanism. If the gas valve is determined to be closed (such that gas should not be flowing into the combustion system) and the flame sensing system is still producing an output indicating that a flame is being produced in the combustion chamber, then it is likely that the flame sensing system output is a false positive.

[0021] In another approach, it may be determined if the output of the flame sensing system is a false positive using one or more other sensors. For example, an optical sensor, such as a camera, may be provided in the heating appliance and images and/or video of the combustion cabinet may be captured to determine if a flame is actually being produced (e.g., by the burners provided in the combustion chamber). As another example, a temperature sensor may be provided and the temperature readings produced by the temperature sensor may be compared to a threshold value to determine if a flame is actually being produced. Any other number of different types of sensors may also be used. Additionally, any of these sensors may be used in combination as redundancies to further improve the accuracy of the determination. Similarly, these sensors may also be used in combination with the aforementioned approach involving verifying the status of the gas valve. These are merely two exemplary approaches for identifying a false positive output by the flame sensing system and any other suitable methods may also be employed.

[0022] While reference is made to determining if moisture is detected within the combustion cabinet generally, the determination may also be more specific. For example, it may instead be determined if moisture is detected specifically within the combustion chamber (which may be included within the combustion cabinet) and/or on any portion of the flame sensing system in particular, as the moisture being on the flame sensing system is more likely to cause the false positive than moisture in another portion of the combustion cabinet.

[0023] Additionally, in some instances, the process of expelling moisture from the combustion cabinet may be performed regardless of whether a false positive output is being produced by the flame sensing system. For example, if any moisture is detected (or a threshold amount of moisture is detected) within the combustion cabinet, in the combustion chamber, on the flame sensing system, etc., then the action may be taken to expel the moisture. That is, the determination that a false positive output is being produced is not necessarily a requisite condition for moisture removal. This moisture removal may instead always be performed as a part of the pre-purge process or a process that occurs prior to pre-purge.

[0024] If it is determined in condition 102 that the flame sensing system is not producing a false positive output, then the flow diagram 100 proceeds to operation 103, which involves initiating the pre-purge process of the furnace. The pre-purge process involves exhausting any flammable gas from the combustion chamber prior to ignition within the combustion chamber during a subsequent combustion process. For example, in a furnace, the inducer motor that drives the inducer responsible for providing air to the combustion chamber may be activated such that the inducer produces airflow that exhausts the lingering gas from the combustion chamber. Once the pre-purge process is complete, the combustion process may be initiated in the combustion chamber (if the pre-purge process was already simultaneously performed).

[0025] If it is determined in condition 102 that the flame sensing system is producing a false positive output, then the flow diagram 100 proceeds to operation 104, which involves automatically performing an action to expel the moisture from the combustion chamber that is causing the false positive output. The moisture may be removed from the combustion chamber in any number of different ways. For example, the inducer motor may be activated such that the inducer produces airflow to exhaust the moisture from the combustion chamber.

[0026] Following (or during) operation 104, condition 106 may involve determining if the flame sensor is still producing a false positive output. This determination may be made in any suitable aforementioned manner and may be made continuously or periodically. Alternatively, or additionally, the furnace may directly determine if moisture is still detected within the combustion cabinet (or any other specific location, as aforementioned, such as within the combustion chamber, on the flame sense circuit, etc.). That is, the furnace may only determine whether false positive outputs are being produced, only whether moisture is still detected in the combustion cabinet, or both if false positive outputs are being produced and if moisture is detected in the combustion cabinet. Any of this information may be used to determine if the flame sensing system is likely to produce accurate data during the combustion process (or at any other time).

[0027] If during the moisture removal process it is determined that the flame sensing system is no longer producing false positive outputs (and/or moisture or a threshold amount of moisture is not detected within the combustion cabinet), the flow diagram may proceed to operation 103 and the pre-purge process may be initiated. That is, once it is determined that the flame sensing system is properly functioning, the furnace may proceed through the typical process of pre-purging the combustion chamber and then initiating the combustion process.

[0028] As aforementioned, the process of removing the moisture from the combustion cabinet and the pre-purge process may be performed simultaneously given that the inducer may be used to expel both lingering gases and moisture. Accordingly, operation 103 may also involve proceeding straight to the initiation of the combustion process rather than performing the process to expel the moisture and then performing the pre-purge as two independent steps.

[0029] As the moisture removal process is being performed, condition 108 may involve determining if a pre-determined amount of time has elapsed since the initiation of the moisture removal process. The threshold amount of time may be the time period within which any moisture within the combustion cabinet is expected to be removed. For example, the threshold time period may be 180 seconds given that, even in situations of excess moisture, the moisture is likely to be removed from the combustion cabinet within 30 seconds using suitable moisture removal actions (such as turning on the inducer). Therefore, if the flame sensing system is still producing false positive outputs even after the threshold time period has passed, then it is likely that there is another type of fault that is causing the malfunctioning of the flame sensing system.

[0030] Accordingly, once it is determined that this threshold time period has elapsed in condition 108, operation 110 involves producing an alert. For example, the alert may be a visual alert that is presented via a display of the furnace (such as user interface 436) or a display of another device, such as a thermostat or a mobile device including an application used to control the furnace (for example, an application accessed by a homeowner, etc.), a technician device (that is, the alert may be provided to a homeowner, technician, and/or any other type of user), and/or any other type of device. The alert may also be an auditory alert produced by any of these devices. For example, the alert may be produced by alarm device 440 of FIG. 4. The alert may also be any other type of alert.

[0031] FIG. 2 is a block diagram illustrating a flame sensing system 200. The flame sensing system 200 can be a part of or supportive of a gas combustion control circuitry for use in heating appliances (which may be any heating appliance described herein or otherwise), such as gas water heaters and gas furnaces. As aforementioned, the flame sensing system 200 can detect or sense a flame and can detect or measure flame strength of the flame in a heating appliance (for example, in a combustion chamber of a furnace or any other location within a heating appliance). The flame sensing system 200 can be configured to control a heat transfer system.

[0032] The flame sensing system 200 can include a power source 202, a flame sensing unit 204 including a flame sensing device 206 and a flame sense probe 208, a processor 210, and a display unit 212. The power source 202 can be electrically coupled to the flame sensing unit 204 and a processor 210. The processor 210 may be a part of a controller of the heating appliance that is responsible for controlling operation of the heating appliance, such as controller 430 of FIG. 4, for example. However, in some instances, a separate processor 210 may be provided to control the flame sensing system 200. Further, the processor 210 can be electrically coupled to the display unit 212. As an example, the processor 210 can be or include a microprocessor or a microcontroller. In some instances, the processor 210 may be separate from the heating appliance. For example, the heating appliance may be controlled by a separate device, such as a thermostat or any other type of device.

[0033] The power source 202 can be configured to supply input power to the flame sensing unit 204. The power source 202 can supply 24 Volt Alternating Current (AC) or 120 Volt AC. The flame sense probe 208 can be strategically mounted in a path of a flame such that the slightest of flame comes in contact with the flame sense probe 208. The flame sensing device 206 can be configured to generate a regulated voltage from an input voltage received from the power source 202. The flame sensing device 206 can be configured to output the regulated voltage to the flame sense probe 208 such that a flame current along a flame can be measured, the flame being proximate to the flame sense probe 208.

[0034] The flame sensing device 206 can be configured to measure the flame current and generate an output voltage corresponding to the flame current. Further, in response to the flame current, the flame sensing device 206 can be configured to determine whether there has been a change in flame status. The flame sensing device 206 can generate the output voltage in the form of one or more dynamic signals. The dynamic signals can be understood as pulsating signals having rising and falling edges. The one or more dynamic signals can be indicative of flame status (i.e., whether or not there is a flame and strength of the flame) and/or whether the flame sensing device 206 is functioning correctly. As an example, the flame sensing device 206 can generate a square wave. The presence of the square wave and pulse percentage of the square wave can be an indication of the flame, strength of the flame, and/or operating condition of the flame sensing device 206. Alternatively or additionally, the flame sensing device 206 can be configured to generate a sinusoidal signal or other type of signals for use in detection of the flame and/or measurement of the strength of the flame.

[0035] The processor 210 can be configured to receive the one or more dynamic signals and monitor a change in the flame current and/or a change in each of the one or more dynamic signals. The processor 210 can then generate a digital output indicative of a working condition of the flame sensing device 206 and/or the flame status, which is indicative of the strength of the flame. Further, the display unit 212 can be configured to display the digital output. For example, the processor 210 can display (e.g., via the display unit 212) the digital output indicative of the flame status, the strength of the flame, and/or the operating condition of the flame sensing device 206. The digital output can be in a form of a number, and/or a graphical characterization of the flame or flame strength (e.g., color coding, various icons). A visual alarm can be displayed on the display unit 212 to indicate the start/stop of the flame, increase in the flame, decrease in the flame, abrupt changes in flame, and the like.

[0036] In addition, the processor 210 can be connected to other hardware peripherals such as alarm devices such as speakers, sirens, or horns to alert professionals of changes in status and/or strength of the flame. The processor 210, through the peripheral device, can produce an alarm sound to alert an operator of a heating appliance (in which the flame sensing system 200 can be implemented) in case of potential combustion problems or flame out. Alternatively or additionally, the processor 210 can send a message and/or a visual alert to the operator of the heating appliance on his or her mobile device to alert the operator in case the flame goes out or the flame sensing device 206 stops functioning as desired. Other methods and examples of alerting the operator of the heating appliance are contemplated herein. The processor 210 can be coupled to a gas control unit (not shown) to control the flow of gas to have desired levels of the flame. Based on the heating requirements, the processor 210 can control the gas control unit using the inputs from the flame sensing unit 204.

[0037] Although it has been described that the processor 210 and the display unit 212 are implemented external to the flame sensing unit 204, the processor 210 and the display unit 212 can be implemented within the flame sensing unit 204. Further, the flame sensing device 206 can be a hard-wired device, an Integrated Circuit (IC), or a circuit that is constructed using various electronic components such as transistors, resistors, capacitors, diodes, etc., or a combination thereof. The manner in which the flame sense and flame strength detection is performed by the flame sensing system 200 is explained in greater detail in conjunction with FIG. 3.

[0038] FIG. 3 is a detailed illustration of flame sense and flame strength detection by the flame sensing system 200. As described above, the flame sensing system 200 can include the power source 202, the flame sensing unit 204 including the flame sensing device 206 and the flame sense probe 208, the processor 210, and the display unit 212. For example, the flame sense probe 208 can be mounted in the path of the flame. The flame sensing device 206 can include a power regulating device 302 (e.g., power regulating device), a flame current detector 304, a first level detector 306, a second level detector 308, a third level detector 310, and a peak detector 312. The power regulating device 302 can include a rectifier/filter and can include a regulated inverter. The regulated inverter can include a high frequency transformer. As an example, the high frequency transformer can be a discrete implementation of a push-pull switching transformer.

[0039] The flame current detector 304 can be electrically coupled to the first level detector 306, the second level detector 308, the third level detector 310, and the peak detector 312. Further, the first level detector 306, the second level detector 308, the third level detector 310, and the peak detector 312 can be electrically coupled to the processor 210. Further, the processor 210 can be electrically coupled to the display unit 212.

[0040] In operation, the power source 202 can be configured to provide input power to the flame sensing unit 204. The power regulating device 302 of the flame sensing device 206 can receive the input power from the power source 202. The power source 202 can be configured to supply 24 Volt AC line signal or 120 Volt AC line signal, for example, depending on the design of the flame sensing device 206. The power regulating device 302 can be configured to generate a regulated voltage from an input voltage received from the power source 202. In an example, the power regulating device 302 can generate a regulated voltage AC. As described above, the power regulating device 302 can include a rectifier/filter and a regulated inverter. The rectifier of the power regulating device 302 can be configured to convert the AC line signal into a regulated low voltage DC signal. Using the regulated low voltage DC signal, the regulated inverter of the power regulating device 302 can be configured to generate regulated high voltage AC signal of high frequency for flame sensing. Since the regulated inverter runs from the regulated DC signal, the output signal (i.e. the regulated high voltage) of the inverter can be stable and immune to fluctuations or variations in the input power. For example, the power regulating device 302 can operate at a higher frequency than some conventional flame sense systems. For example, the power regulating device 302 can generate 120 Volt AC 500 Hertz output signal for the flame detection and the flame strength detection. Alternatively or additionally, the power regulating device 302 can generate a different voltage and frequency based upon what is optimal for a given system. However, the operational frequency can be set higher for faster detection of flame and/or detection of the strength of flame.

[0041] Further, the power regulating device 302 can output the regulated voltage to the flame sense probe 208 such that a flame current along a flame can be measured, with the flame being proximate to the flame sense probe 208. The flame sense probe 208 can be shaped for sensing the flame efficiently. For example, the flame sense probe 208 can be shaped in cylindrical shape, cone shaped, flat circular shaped, and the like, depending on a type of a flame or a burner. Further, the flame sense probe 208 material can be designed as a sheet, a mesh, a rod, a wire(s) and the like, as appropriately for effective reception of the flame. In an example, the flame sense probe 208 can be made of any of a stainless-steel material, a tungsten material, a nichrome material, etc. When a flame is lit, the gas is burnt releasing ions (known as flame ionization). The flame with ions can come into contact with the flame sense probe 208. The flame comprising ions due to combustion of gas can cause a conduction due to ionization. In other words, the flame can act as a path for electric current to ground (not shown). The conduction causes a rectified AC current to be conducted from the flame sense probe 208, through the flame, and back to ground. Also, the flame can have a high resistance and can thus act as a load for the flame sensing device 206.

[0042] The flame current can flow from the flame sense probe 208, through the flame, and to ground. Due to size of the flame sense probe 208 and the high resistance offered by the flame, the current can flow in one direction, resulting in rectification of the AC current and leading to a pulsating DC signal. The resulting pulsating DC signal can be considered as being rectified.

[0043] The flame current detector 304 can be configured to measure and/or detect the flame current from the flame sense probe 208 and generate an output voltage corresponding to the flame current. The flame current detector 304 can provide the output voltage as a function of the flame current. In response to any change in the flame current due to a change in flame levels, the flame current detector 304 can provide the output voltage corresponding to the flame current. As an example, a stronger flame can correspond to a lower output voltage from the flame current detector 304, and a weaker flame can correspond to a higher output voltage from the flame current detector 304. In other words, when the flame is stronger, a stronger path (higher conductivity) can be formed by ions, leading to higher current flow through the flame, and thus leading to a lower output voltage. Conversely, when the flame is weaker, a weaker or less conductive path can be formed by ions, leading to lower current flow through the flame, and thus leading to a higher output voltage. The flame current detector 304 can provide the output voltage to the first level detector 306, the second level detector 308, the third level detector 310, and/or the peak detector 312. The first level detector 306, the second level detector 308, the third level detector 310, and/or the peak detector 312 can have different sensitivity characteristics (e.g., they have different circuitry and/or they show different levels of sensitivity to the output voltage). As a result, the first level detector 306, the second level detector 308, the third level detector 310, and the peak detector 312 can be configured to read the output voltage differently.

[0044] The first level detector 306 can be configured to generate a flame strength output signal (also referred to as a flame condition output signal) based on the output voltage (e.g., received from the flame current detector 304). As an example, the first level detector 306 can generate the flame strength output signal based on peak detection, RMS (Root Mean Square) calculation, and/or duty cycle measurement. The flame strength output signal can be indicative of a strength of the flame, which can be located proximate the flame sense probe 208. The first level detector 306 can be configured to generate the flame strength output signal based on a comparison of the output voltage to a pre-determined strength threshold.

[0045] The second level detector 308 can be configured to provide a flame presence output signal indicative of the presence of the flame at the flame sense probe 208. The second level detector 308 can be configured to provide the flame presence output signal based on a comparison of the output voltage to a pre-determined presence threshold. For example, if the output voltage is equal to or less than the pre-determined presence threshold, it can be determined that the flame is present. Otherwise, if the output voltage is greater than the pre-determined presence threshold level, it can be determined that the flame is absent. Also, if the output voltage is lower than the pre-determined strength threshold and higher than the pre-determined presence threshold, then the output voltage indicates that the flame strength is minimum (i.e., the flame is a weak flame). As another example, if the output voltage is lower than both the pre-determined strength threshold and the pre-determined presence threshold, then it can be determined that the flame strength is strong. The pre-determined presence threshold can be set high to detect high output voltage due to a weak flame or absence of the flame. The pre-determined presence threshold can be set such that the second level detector 308 can provide the flame presence output signal in response to a slightest presence/strength of the flame.

[0046] Although a single pre-determined strength threshold is described herein, more than one pre-determined strength threshold can be set for detecting the strength of the flame. For example, if the output voltage is less than or equal to a lowest pre-determined strength threshold, then the output voltage can indicate that the strength of the flame is maximum. If the output voltage is greater than the highest strength pre-determined strength threshold, then it can be determined that the strength of the flame is minimum or nil. The range of voltage output values between the highest and the lowest pre-determined strength thresholds can indicate different strengths of flame (e.g., corresponding to a scale of flame strength).

[0047] Further, the third level detector 310 can be configured to generate a diagnostic output signal indicative of the operationality of the flame sensing system 200. The diagnostic output signal can provide an indication that whether or not the flame sensing system 200 (or any component therein such as the flame sensing device 206 or the flame sense probe 208) is working properly or not. The third level detector 310 can be configured to generate the diagnostic output signal based on a comparison of the output voltage to a pre-determined diagnostic threshold. As an example, the pre-determined diagnostic threshold can be set low such that the pre-determined diagnostic threshold can be used to determine if the flame sensing system 200 is functioning properly or not. For example, in case of loss of excitation of the power regulating device 302 (and in the absence of the flame), the pre-determined diagnostic threshold can be used in determining that the power regulating device 302 is not functioning. For example, if the output voltage is greater than the pre-determined diagnostic threshold, then it can be determined that the flame sensing system 200 is functioning correctly. Conversely, if the output voltage is less than the pre-determined diagnostic threshold, then it can be determined that the flame sensing system 200 (or any component therein, for example the power regulating device 302) is not functioning correctly.

[0048] The flame strength output signal, the flame presence output signal, and the diagnostic output signal can be dynamic (pulsating) signals. Further, the peak detector 312 can be configured to generate an analog secondary flame strength output signal based on fast analog flame strength analysis. The analog secondary flame strength output signal may provide an analog indication of the maximum strength of the flame. The peak detector 312 may compare the output signal to a maximum signal threshold to identify and detect when the strength of the flame reaches maximum. The first level detector 306, the second level detector 308, the third level detector 310, and the peak detector 312 can have different sensitivity characteristics, i.e., they show different levels of sensitivity to the output voltage. As a result, the first level detector 306, the second level detector 308, the third level detector 310, and the peak detector 312 can read the output voltage differently. Accordingly, the first level detector 306, the second level detector 308, the third level detector 310, and the peak detector 312 can generate different output signals based on the analysis and processing of a single output voltage.

[0049] Although it has been described that the flame sensing device 206 includes three level detectors, namely, the first level detector 306, the second level detector 308, and the third level detector 310, the flame sensing device 206 can include more or less than three level detectors for interpreting various other flame characteristics not described herein.

[0050] The processor 210 can be configured to receive the flame strength output signal, the flame presence output signal, the diagnostic output signal, and/or the analog secondary flame strength output signal. Further, the processor 210 can be configured to monitor a change in the flame current, a change in the flame strength output signal, a change in the flame presence output signal, a change in the diagnostic output signal, and/or a change in the analog secondary flame strength output signal. Based on the monitoring, the processor 210 can be configured to generate a digital output for the flame strength output signal, the flame presence output signal, the diagnostic output signal, and/or the analog secondary flame strength output signal. As an example, the digital output can be indicative of a working condition of the flame sensing device 206 and/or the flame status (i.e., flame absent, flame present, flame strength marginal, flame strength weak, or flame strength good). As an example, the digital output can be indicative of a strength of the flame. The processor 210 can then send the digital output to the display unit 212. The display unit 212 can be configured to display the digital output. The manner in which the digital output can be displayed on the display unit 212 is illustrated in following example figures. FIGS. 3-5 illustrate dynamic signals in the form of a square wave that can be generated by the first level detector 306, the second level detector 308, and/or the third level detector 310.

[0051] FIG. 4 illustrates a system 400 showing exemplary components of a heating appliance. In embodiments, the system 400 may have a fuel inlet 401 that is in fluid communication with elements such as a fuel valve 402, a fuel enrichment valve 404, an air/fuel mixing chamber 416, a burner 418, and a combustion chamber 420. The system 400 can also have an air inlet 402 and an air filter 404. The system 400 can be configured to draw air through the system 400 by an air moving device 406. Furthermore, the system 400 can have a controller 430 having a memory 432, a processor 434, and a communication interface 438. The controller can be in communication with the fuel valve 402, a flame sensor 422, a user interface 438, and/or an alarm device 440. While reference may be made to singular or plural elements (e.g., a burner), this is not intended to be limiting and any other number of such elements may also be provided in the system 400.

[0052] The system 400 can be operated to create a flame during a combustion process of the heating appliance. For instance, the air moving device 406 can cause air to be drawn through the system, fuel valve 402 can open to pass an amount fuel to the burner 418, and the mixture of air and fuel can be ignited at the burner 418 to create a flame.

[0053] The heat generated by the flame can be detected by a flame sensor 422 (which may be the same as the flame sensing unit 204 (part of flame sensing system 200) and/or any other flame sensing unit described herein or otherwise) and the temperature data can be transmitted to the controller 430. The flame sensor 422 can be any type of flame sensor or temperature sensor capable of detecting the temperature of the flame. For example, the flame sensor 422 can be or include a thermocouple, a resistor temperature detector (RTD), a thermistor, an infrared sensor, a semiconductor, or any other suitable type of sensor for the application. As will be appreciated, the type of flame sensor 422 chosen for the application can be capable of withstanding and detecting the temperatures of the flame in the specified application.

[0054] The air moving device 406 can be any type of air moving device configured to draw air through the system. For example, the air moving device 406 can be a draft inducer, fan, a blower, or any other air moving device configured to move air through the system.

[0055] The controller 430 can have a memory 432, and a processor 434 (which may be the same as processor 210 in some instances but may be a separate processor as well), and be in communication with a user interface 438. The controller 430 can be a computing device configured to receive data, determine actions based on the received data, and output a control signal instructing one or more components of the system to perform one or more actions. One of skill in the art will appreciate that the controller 430 can be installed in any location, provided the controller 430 is in communication with at least some of the components of the system 400. Furthermore, the controller 430 can be configured to send and receive wireless or wired signals and the signals can be analog or digital signals. The wireless signals can include Bluetooth, BLE, WiFi, ZigBee, infrared, microwave radio, or any other type of wireless communication as may be appropriate for the particular application. The hard-wired signal can include any directly wired connection between the controller and the other components. For example, the controller 430 can have a hard-wired 24 VDC connection to the flame sensor 422. Alternatively, the components can be powered directly from a power source and receive control instructions from the controller 430 via a digital connection. The digital connection can include a connection such as an Ethernet or a serial connection and can utilize any appropriate communication protocol for the application such as Modbus, fieldbus, PROFIBUS, SafetyBus p, Ethernet/IP, or any other appropriate communication protocol for the application. Furthermore, the controller 430 can utilize a combination of wireless, hard-wired, and analog or digital communication signals to communicate with and control the various components. One of skill in the art will appreciate that the above configurations are given merely as non-limiting examples and the actual configuration can vary depending on the application.

[0056] The controller 430 can include a memory 432 that can store a program and/or instructions associated with the functions and methods described herein and can include one or more processors 434 configured to execute the program and/or instructions. The memory 32 can include one or more suitable types of memory (e.g., volatile or non-volatile memory, random access memory (RAM), read only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, floppy disks, hard disks, removable cartridges, flash memory, a redundant array of independent disks (RAID), and the like) for storing files including the operating system, application programs (including, for example, a web browser application, a widget or gadget engine, and or other applications, as necessary), executable instructions and data. One, some, or all of the processing techniques or methods described herein can be implemented as a combination of executable instructions and data within the memory.

[0057] The controller 430 can also have a communication interface 436 for sending and receiving communication signals between the various components. Communication interface 436 can include hardware, firmware, and/or software that allows the processor(s) 434 to communicate with the other components via wired or wireless networks, whether local or wide area, private or public, as known in the art. Communication interface 236 can also provide access to a cellular network, the Internet, a local area network, or another wide-area network as suitable for the particular application.

[0058] Additionally, the controller 430 can have or be in communication with a user interface 438 for displaying system information and receiving inputs from a user. The user interface 438 can be installed locally on the system 400 or be a remotely-control device such as a mobile device.

[0059] The alarm device 440 can be any form of alarm device configured to provide a notification to a user. For example, the alarm device 440 can be a light bulb or light emitting diode (LED) indicator configured to illuminate on the system 400 or another location likely to be seen by a user. As another example, the alarm device 440 can be an audible alarm or alert. Alternatively, or in addition, the controller can transmit instructions for displaying a notification on the user interface 438 and/or can transmit a notification to a user's mobile device. As will be appreciated, the alarm device 440 can be any type of alarm device configured to provide notification to a user that the flame sensor 422 continues to produce false positive outputs during the pre-ignition process described with respect to FIG. 1.

[0060] The fuel valve 402 and the fuel enrichment valve 404 can be configured to control a flow of fuel from a fuel source. Both the fuel valve 402 and the fuel enrichment valve 404 can be configured for any type of fuel used in the burner assembly 400, such as, for example, propane, butane, natural gas, coal gas, biogas, acetylene, gasoline, diesel fuel, or any other type of fuel suitable for the application. Furthermore, the fuel valve 402 and the fuel enrichment valve 404 can be any type of fuel valve as would be suitable for the particular application. For example, the fuel valve 402 and the fuel enrichment valve 404 can be a solenoid operated valve configured to be normally closed such that a loss of power causes the solenoid operated valve to close and prevent fuel from passing through the burner assembly 400. The fuel valve 402 and the fuel enrichment valve 404 can be controlled by the controller 230 based on inputs received at the controller 230 from the flame sensor 422.

[0061] FIG. 5 illustrates an exemplary combustion cabinet 500 of a heating appliance. In this particular example, the heating appliance is a gas furnace. The combustion cabinet 500 includes components of the gas furnace that may be used with the combustion process of the gas furnace. For example, the combustion cabinet 500 includes the combustion chamber 502. One or more burners 504 may be aligned with the combustion chamber 502. The burners 504 may produce flames used to heat air that is circulated within a building that is heated by the furnace. The combustion cabinet 500 also includes a flame sensor 505 (which may be the same as flame sensing unit 104, flame sensor 422, etc.). The combustion cabinet may also include an inducer motor 506 and an inducer 508 that is driven by the inducer motor 506. These are merely some exemplary components that may be included in a combustion cabinet 500 and any other components may also be included depending on the type of heating appliance, the specific configuration of the heating appliance, etc.

[0062] It should be apparent that the foregoing relates only to certain embodiments of the present application and that numerous changes and modifications may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the disclosure.

[0063] Although specific embodiments of the disclosure have been described, numerous other modifications and alternative embodiments are within the scope of the disclosure. For example, any of the functionality described with respect to a particular device or component may be performed by another device or component. Further, while specific device characteristics have been described, embodiments of the disclosure may relate to numerous other device characteristics. Further, although embodiments have been described in language specific to structural features and/or methodological acts, it is to be understood that the disclosure is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as illustrative forms of implementing the embodiments. Conditional language, such as, among others, can, could, might, or may, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments could include, while other embodiments may not include, certain features, elements, and/or steps. Thus, such conditional language is not generally intended to imply that features, elements, and/or steps are in any way required for one or more embodiments.