JP2005055022A - Fan-forced heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent sudden temperature rise in an appliance in a state that an air filter is clogged, and to prevent the start of a safety device by abnormal heating in starting the operation. <P>SOLUTION: This fan-forced heater comprises a burner 1, a combustion chamber 2, an air fan 3 and a fan motor 4 for supplying the air taken from the external, a rotational frequency detecting unit 24 for detecting a rotational frequency of the fan motor 4, an air filter 8 mounted on an air intake port, a controller 13 for controlling a fuel supply amount and the rotational frequency to determine a burning capacity, a fan motor output detecting device 27 for detecting the output of the fan motor, a fan motor output storing device 28 for storing the output of the fan motor 4 at a specific timing, and a control means 20 for performing the operation by changing the rotational frequency of the fan motor to a specific rotational frequency, in a case when the output of the fan motor 4 is changed by a specific quantity from a stored value of the fan motor output storing device 28 in starting the operation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hot air heater such as an oil fan heater or a gas fan heater.

  As shown in FIG. 6, the conventional warm air heating apparatus has a combustion chamber 2 that burns the gas supplied by the burner 1 and mixes the exhaust gas generated by the combustion and air. A blower fan 3 for sending warm air is provided below the burner 1, and a fan motor 4 for driving the blower fan 3 is attached to a side surface of the blower fan 3. The fan motor 4 is provided with a rotation speed detector 14 for detecting the rotation speed. In addition, a hot air outlet 5 is attached in front of the blower fan 3, and an air filter 8 for taking in convection air 7 is provided on the rear surface of the case 6, and a room temperature detection for detecting the room temperature is provided inside the air filter 8. A vessel 9 is provided.

  A temperature detector 10 is provided in the upper part of the combustion chamber 2 to detect the temperature of the warm air heated by the combustion heat. When the temperature of the warm air rises above a predetermined temperature, the amount of air taken in from the air filter 8 decreases. That is, it is determined that dust is attached to the air filter 8, and a clogging indicator 11 is displayed to prompt cleaning. The operation unit has an operation switch 12 for instructing on / off of the heating operation. The control device 13, the burner 1, the fan motor 4, the room temperature detector 9, the temperature detector 10, and the operation switch 12 are electrically connected as shown by the dotted line in the figure, and each component is set so that the set room temperature is reached. I have control.

  In the above configuration, the operation will be described. When the operation switch 12 is pressed, the combustion operation is started by the burner 1 based on a predetermined sequence, and the generated high-temperature exhaust gas and the convection air taken in via the air filter 8 Are mixed in the combustion air path of the combustion chamber 2. The mixed warm air is sent out from the warm air outlet 5 at the lower part of the front surface to the room by the blower fan 4 for heating. The combustion amount of the burner 1 is controlled such that the room temperature detected by the room temperature detector 9 is compared with the set temperature and the room temperature becomes the set temperature. In the course of the combustion operation, the temperature detector 10 provided in the upper part of the combustion chamber 2 always detects the temperature of the warm air heated by the combustion gas. When dust adheres, the air necessary for combustion decreases, and the combustion becomes a state where the flame is extended, and the temperature of the combustion chamber 2 rises. At the same time, if dust adheres, it becomes difficult to suck the convection air necessary for combustion, the load on the fan motor 4 is reduced, and the rotational speed of the fan motor 4 is increased. This depends on the characteristics of the fan motor 4 and is a phenomenon that occurs in a drive system that does not perform feedback control of the rotational speed. When dust begins to adhere to the air filter 8, the rotational speed increases and a lot of convection air is generated. Acts to capture and performs self-correction. However, as described above, there is a limit depending on the characteristics of the fan motor 4.

  In the case of a DC motor that is driven by supplying a direct-current voltage to the fan motor 4, there is another rotation speed control system that controls the fan rotation speed to be constant. In this method, since the rotation speed detector 14 detects the rotation speed of the fan motor 4 and controls the rotation speed to match the amount of gas combustion, the rotation speed increases even if the air filter 8 becomes clogged with dust. Hard to do.

When the temperature detector 10 detects that the temperature of the combustion chamber 2 has risen, a signal is sent to the control device 13 to control the clogging indicator 11 to display that prompts the necessity of cleaning. This is generally referred to as a filter sign, and the user knows that dust has adhered to the air filter 8 by this filter sign display, and removes dust to continue normal operation (for example, Patent Documents). 1).
JP-A-4-340053

  However, even if the filter sign is displayed, if the heating operation is continued as it is, the following problems occur. First, in the above-mentioned conventional example, in the drive system in which the rotation speed naturally increases depending on the characteristics of the fan motor, if the load on the fan motor is reduced due to clogging of the air filter, etc., the fan rotation speed depends on the characteristics of the motor accordingly. To increase. However, since the clogging state of the air filter gradually progresses, the number of rotations that increase is small, and in the case of minute clogging in the initial stage, the increase in the number of rotations is small compared to the amount of reduction in convection air. The air flow sufficient to cool the appliance cannot be obtained, and the temperature of the appliance rises.

  On the other hand, the rotation speed control method that controls the motor control voltage so that the fan rotation speed is constant controls the fan rotation speed regardless of the individual difference of the equipment, so the air filter is clogged and the load is reduced. Even so, the fan rotation speed is kept constant, and the reduction of the intake air due to the clogging of the air filter cannot be compensated, and the air volume is lowered according to the clogging state, and the temperature rise of the appliance is promoted.

  When the temperature of the appliance rises in this way, there is a drawback that a safety device that stops combustion frequently operates when abnormal overheating occurs. In addition, if combustion starts with the air filter clogged, the temperature of the temperature detector rises due to a delay in the rise of the fan motor speed, and a safety device that activates the filter sign or stops combustion Operate.

  The present invention solves the above-mentioned conventional problems, and prevents a sudden temperature rise of the instrument when the air filter is clogged, and prevents a combustion stop due to an operation of a safety device due to abnormal heating at the start of operation. The purpose is to provide a warm air heater that can be used safely.

  In order to achieve the above object, a hot air heater of the present invention comprises a burner for burning fuel, a combustion chamber for mixing combustion gas from the burner and air taken from outside, and air taken from outside to the burner. A blower fan and a fan motor for supplying warm air while supplying the air, a rotation speed detector for detecting the rotation speed of the fan motor, an air filter provided in an air suction port, a fuel supply amount to the burner, and A control device that controls the number of revolutions of the fan motor to set the combustion amount, a fan motor output detection device that detects the output of the fan motor, and a fan motor output storage device that stores the output of the fan motor at a predetermined timing When the output of the fan motor changes by a predetermined amount from the stored value of the fan motor output storage device at the start of operation The rotational speed of the Anmota is provided with a control means for operating to change a predetermined rotational speed.

  According to the above invention, when the air filter is clogged with dust, the fan motor output detection device detects this when starting the fan motor operation or starting combustion, and controls the rotational speed of the fan motor to be increased by a predetermined rotational speed. However, even if the air filter is clogged, the filter sign will not operate, and the safety device that stops combustion in the event of abnormal overheating will not operate.

  As described above, according to the present invention, at the start of operation or at the start of combustion, even if the air flow rate is reduced due to clogging of the air filter or the like, the fan motor is operated at a higher speed, and further the first detection is performed. By changing the threshold value, the second detection threshold value, and the third detection threshold value to predetermined values, it is possible to prevent the filter sign from being operated and further from being brought into the operation stop state.

  Furthermore, during normal combustion, even if dust adheres to the air filter or other parts, the temperature rise of the outer case can be suppressed so that there is no burn when touched. Machine can be provided.

  According to the first aspect of the present invention, a burner for burning fuel, a combustion chamber for mixing combustion gas from the burner and air taken in from the outside, air taken from outside is supplied to the burner and hot air is sent out To control the blower fan and fan motor, the rotation speed detector for detecting the rotation speed of the fan motor, the air filter provided in the air suction port, the fuel supply amount to the burner and the rotation speed of the fan motor A control device that sets the combustion amount, a fan motor output detection device that detects the output of the fan motor, a fan motor output storage device that stores the output of the fan motor at a predetermined timing, and a fan motor output at the start of operation. The number of rotations of the fan motor when the output changes by a predetermined amount from the value stored in the fan motor output storage device In which it characterized in that a control means for operating to change a predetermined rotational speed.

  The fan motor output storage device stores the air filter clogged state, that is, stores the initial value of the fan motor load, and if the output of the fan motor output detection device changes by a predetermined amount from the initial value at the start of operation. It is possible to control the fan motor that rotates the fan motor at a predetermined high speed, and even if the air filter is clogged and the load on the fan motor fluctuates, the filter sign will operate immediately, or combustion will occur when abnormal overheating occurs The operation time can be extended for a predetermined period of time so that the safety device to be stopped does not operate, and if the filter is cleaned during that time, the heating operation can be continued and the usability can be improved.

  The invention according to claim 2 is a clogging detecting means for detecting a decrease in the amount of air blown from the blower fan, a clogging storage device for storing the output of the clogging detecting means, and the output of the clogging detecting means is Control means for controlling the rotational speed of the fan motor according to the output of the clogging detection means when the first detection threshold value set at a level changed by a predetermined amount from the stored value of the clogging storage device is reached; Is characterized in that when the output of the fan motor changes by a predetermined amount from the stored value of the fan motor output storage device at the start of operation, the first detection threshold value is changed by a predetermined value.

  Then, by detecting a decrease in the amount of air blown from the blower fan due to clogging or the like in the early stage of combustion, and changing the first detection threshold to a predetermined value, the number of rotations of the fan motor is changed early, and normal combustion Then, it is possible to control so as not to notify the clogging at the start of operation although the clogging is not notified.

  According to a third aspect of the present invention, there is provided an informing means for informing a decrease in the amount of air blown from the blower fan, and the control means sets the output of the clogging detecting means to a second detection threshold value having a larger clogging amount than the first detection threshold value. When it reaches, the notification means and control of the rotation speed of the fan motor are performed, and when the output of the fan motor changes by a predetermined amount from the stored value of the fan motor output storage device at the start of operation, the second detection threshold is set. The predetermined value is changed.

  Then, by detecting a decrease in the amount of air blown from the blower fan due to clogging or the like at the beginning of combustion and changing the second detection threshold value to a predetermined value, clogging is not reported in normal combustion but clogged at the start of operation. It is possible to perform control so as not to be notified.

  According to a fourth aspect of the present invention, the control means stops combustion of the burner when the output of the clogging detector reaches a third detection threshold value where the amount of clogging is larger than the second detection threshold value. If the output of the fan motor changes by a predetermined amount from the stored value of the fan motor storage device at the start of operation, the third detection threshold value is changed by a predetermined value.

  Then, by detecting the clogging state at the initial stage of combustion and changing the third detection threshold to a predetermined value, control is performed so that clogging is not notified at the start of operation although clogging is not reported in normal combustion. It becomes possible to do.

  According to the fifth aspect of the present invention, the fan motor output detection device is configured to detect the current value of the fan motor, and can accurately detect the dust clogged state of the air filter even at the start of operation.

  According to the sixth aspect of the present invention, the clogging detecting means is constituted by a temperature detector attached to the upper part or the front part of the combustion chamber, and can detect the clogging state accurately at low cost.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

(Example 1)
FIG. 1 is a side cross-sectional view showing a basic configuration of a hot air heater according to a first embodiment of the present invention. In FIG. 1, reference numeral 14 denotes an exterior case, and the panel 15 and the bottom plate 16 constitute an exterior of the device. The outer case 14 has an air suction port 17 at a position corresponding to the upper back of the device and a warm air outlet 5 at a position corresponding to the lower front portion, and an air filter 8 is attached to the air suction port 17. The air filter 8 is structured to be attached to the exterior case 14 so that it can be easily removed and maintained. 2 is a combustion chamber provided in the outer case 14, 1 is a burner provided in the combustion chamber 2, 18 is a proportional valve for adjusting and supplying gas to the burner 1, and 19 is an electromagnetic valve for shutting off the gas. 3 is a blower fan comprising a cross flow fan provided in the lower part of the combustion chamber 2, 4 is a fan motor for driving the blower fan 3, and this fan motor 4 is provided with a rotational speed detector 24 for detecting the rotational speed. ing. There is an operation switch 11 in front of the panel 15. Reference numeral 13 denotes a control device, and 20 denotes control means provided in the control device 13. Reference numeral 9 denotes a room temperature detector comprising a thermistor provided near the air intake. Reference numeral 25 denotes a temperature detector that is disposed at the upper part of the combustion chamber 2 and detects the temperature of the hot air, and forms a clogging detector that detects a decrease in the amount of air blown from the blower fan due to clogging of the air filter and the like. A clogging storage device 26 stores the output of the clogging detector 25 when there is no clogging. A fan motor output detection device 27 detects the output of the fan motor 4 and detects the current value of the fan motor 4 to obtain the output value. A fan motor output storage device 28 stores the output of the fan motor output detection device 27 when the air filter 8 is not clogged. The panel 15 is provided with a temperature setter 23, a clogging indicator 12, and a notification means 29. Displaying the clogging indicator 12 is generally called a filter sign.

  Next, the operation will be described. When the operation switch 11 is turned on, the control device 13 starts the fan motor 4 and supplies gas to the burner 1. Indoor air is sucked into the outer case 14 from the air suction port 17 by the blower fan 3, part of which enters the combustion chamber 2, and is mixed with gas fuel and burned by the burner 1. Further, the control device 13 adjusts the gas supply amount and the rotational speed of the fan motor 4 so as to continue the combustion. After the combustion gas in the burner 1 is discharged, it merges with the air flowing through the passage formed by the combustion chamber 2 that cools the combustion chamber 2 and the cover plate 21 and is sucked into the blower fan 3. Then, the warm air discharged from the blower fan 3 is guided along the fan case 22 to the warm air outlet 5 and discharged into the room.

  During such heating operation, the control device 13 determines the gas consumption in the burner 1 according to the magnitude of the temperature difference between the temperature set by the temperature setter 23 and the temperature detected by the room temperature detector 9. As shown in FIG. 2, for example, in the case of heating a room of 8 to 10 tatami mats, the gas consumption is adjusted in multiple stages in the range of 0.64 kW (minimum combustion) to 3.49 kW (maximum combustion). The Then, the control device 13 adjusts the valve opening of the proportional valve 18 to control the gas supply amount to the burner 1 so as to obtain this gas consumption amount, and also performs the rotation speed control of the fan motor 4 so that the blower fan. 3 controls the amount of air supplied to the burner 1. The rotational speed control of the fan motor 4 compares the rotational speed signal from the rotational speed detector 24 with the target rotational speed, and adjusts the control value of the fan motor 4 so that the rotational speed of the fan motor 4 becomes the target rotational speed. . The target rotational speed of the blower fan 3 is in the range of 550 rpm (minimum combustion) to 950 rpm (maximum combustion) during normal combustion.

  In this embodiment, the fan motor 4 is constituted by a DC motor having a built-in rotation speed detector 24, and a load power supply (0 to 45V) and a built-in control IC power supply (5V) are connected. Yes. When the fan motor 4 is started, the rotation speed detector 24 outputs a signal corresponding to the rotation speed and transmits the rotation speed to the control device 13. The control device 13 inputs a rotational speed signal, processes it into rotational speed data, and adjusts the rotational speed of the fan motor 4 so as to be the target rotational speed in each combustion state of the device to which the rotational speed is given. The rotation speed can be kept constant. In the present embodiment, the configuration using the DC motor has been described. However, the rotational speed may be controlled by performing phase control using an AC motor.

  By the way, when the device is used while performing the heating operation, the air filter 8 is gradually clogged, and the output of the clogging detector 25 is increased. In FIG. 3, the output change of the clogging detector 25 in the maximum combustion / minimum combustion will be described. The horizontal axis of the graph indicates the state of clogging of the air filter 8, and the vertical axis indicates the degree of clogging detected by the clogging detector 25. In many cases, a temperature detector is used as the clogging detector 25. As the clogging progresses, the output of the clogging detector 25 increases approximately in proportion. Therefore, the clogging detector 25 can accurately detect the clogging state. However, this graph shows a stable state in which the device is burned for about 10 minutes.

  FIG. 4 shows the operation. When the air filter 8 is not clogged, for example, when measurement is performed at a constant room temperature on the production line, the clogging storage device 26 stores the output of the clogging detector 25. When a predetermined amount changes from the output of the clogging storage device 26, it is detected as the first detection threshold value, and the rotation speed of the fan motor 4 is continuously increased according to the output of the clogging detector 25. Since there are individual differences between devices even at the same room temperature, the output of the clogging detector 25 is not constant. When the first detection threshold value is determined by the absolute value of the output of the clogging detector 25, the first detection threshold value is reached although the clogging is not caused by the variation, the rotational speed of the fan motor 4 is increased, the noise is increased, and the warm air Therefore, a predetermined temperature is added on the basis of the state of no clogging stored by the storage device as the first detection threshold value. Therefore, the degree of clogging can be accurately detected, and the fan motor can be appropriately controlled.

  In addition, the first detection threshold may be determined by the absolute value of the output of the clogging detector 25 without the clogging storage device 26 storing the output of the clogging detector 25 in the assembled state without clogging. it can.

  When the clogging of the air filter 8 further progresses and the second detection threshold temperature in which the output of the clogging detector 25 changes by a predetermined amount from the output of the storage device 26 is detected, the clogging indicator 12 is displayed, A filter sign that prompts the user to clean the air filter 8 is issued. Here, the rotation speed of the fan motor 4 may be further increased, or control may be performed such that the fan motor 4 is increased in a stepwise manner. Since the rotation speed of the fan motor 4 is increased according to the degree of clogging, it is possible to prevent the temperature of the outer case 14 from rapidly increasing. Even when about 10 sheets of gauze are covered on the air filter 8, the temperature can be kept at a level that is not dangerous when the outer case 14 is touched. Here, the number of revolutions of the fan motor 4 may be reduced, and the amount of gas supplied to the burner 1 by the proportional valve 18 may be reduced to limit the combustion amount. By doing so, the temperature rise of the outer case 14 can be suppressed even when clogged.

  When the clogging further proceeds by a predetermined amount than the second detection threshold and the clogging detector 25 detects the third detection threshold that causes abnormal overheating of the airframe due to excessive clogging, the control means 20 stops the heating operation. The solenoid valve 19 is closed, the gas supply is shut off, and combustion is stopped. The third detection threshold is set to an output that may cause burns if touched when the temperature of the outer case 14 becomes higher when clogging occurs. Thus, even if the user uses the air filter 8 without cleaning it, the combustion is stopped in advance so that the device can be handled safely and no trouble occurs in the device.

  In FIG. 5, the relationship between the clogging of the air filter 8 and the output of the fan motor output detection device 27 is shown. The output of the fan motor output detection device 27 decreases as clogging occurs. This output is almost constant both at the start of operation and when burned for a long time. The fan motor output storage device 28 stores the output of the fan motor output detection device 27 when it is not clogged, for example, when assembled in a factory. When the operation (combustion) is started in a state where the air filter 8 is clogged, the output of the fan motor output detection device 27 decreases. If this output is compared with the output stored in the fan motor output storage device 28 without clogging and if the output has changed by a predetermined amount, the fan motor 8 is operated at a higher rotational speed.

  If this control is not performed in the early stage of combustion, the output of the clogging detector 25 provided in the combustion chamber 2 becomes high, the output of the clogging detector 25 reaches the first detection threshold value, and the rotational speed of the fan motor 4 is set to a predetermined value. Although it is transmitted so that the rotation becomes higher, since the operation of the fan motor 8 is delayed and the rotation speed does not reach the target rotation speed, it reaches the second detection threshold value or further the third detection threshold value, and is safe. The device operates and stops operating. This phenomenon continues many times unless the air filter 8 is cleaned.

  However, when this control is performed, the fan motor 4 can be operated at a high rotational speed at the start of operation, so the output of the clogging detector 25 does not increase, combustion does not stop, and the temperature of the outer case 14 increases. Can be prevented.

  Further, when the front portion of the outer case 14 is not attached, this corresponds to the case of manufacturing or maintenance, but the output of the fan motor output detection device 27 becomes high. When the combustion is performed in this state, since the rotation speed is controlled to be constant, the air becomes excessive, and even if gas is supplied to the burner 1, it does not ignite. At this time, if the number of rotations of the fan motor 4 is lowered by a predetermined value and the operation is started, ignition can be performed smoothly.

  Next, when the operation (combustion) is started in a state where the air filter 8 is clogged, the output of the fan motor output detection device 27 decreases. The output is compared with the output stored in the fan motor output storage device 28 in a state where there is no clogging. If the output has changed by a predetermined amount, the first detection threshold value is changed by a predetermined value. Here, the value is reduced, and even if the change in the output of the clogging detector 25 is small, the rotational speed of the fan motor 4 is controlled to increase the rotational speed at an early stage, and the second detection threshold value or the third detection value. Avoid reaching the threshold.

  Thereby, the output of the clogging detector 25 does not increase, the combustion is not stopped, and the temperature rise of the outer case 14 can be prevented, so that the usability is improved.

  Furthermore, the control means 20 is provided with the notification means 29 which notifies the clogging state, and the control means 20 after the output of the clogging detector 25 reaches the second detection threshold value with a larger amount of clogging than the first detection threshold value, the notification means. 29, and the number of rotations of the fan motor 4 is controlled. When the operation (combustion) is started in a state where the air filter 8 is clogged, the output of the fan motor output detection device 27 decreases. This output is compared with the output stored in the fan motor output storage device 28 in a state where there is no clogging. If the output has changed by a predetermined amount, the second detection threshold value is changed by a predetermined value. Here, the second detection threshold value is increased to make it difficult to reach the second detection threshold value even if the value of the clogging detector 25 increases. As a result, even if the output of the clogging detector 25 increases, the notification means 29 is less likely to notify than before. Moreover, since the temperature rise of the exterior case 14 can be prevented, usability is improved.

  Moreover, after the output of the clogging detector 25 reaches the third detection threshold value where the amount of clogging is larger than the second detection threshold value, the controller 20 stops the combustion of the burner 1.

  The control means 20 sets the third detection threshold value to a predetermined value when the operation of the fan motor 4 starts (when combustion starts) and the output of the fan motor output detection device 27 changes by a predetermined amount from the output of the fan motor storage device 28. change.

  Here, the third detection threshold value is increased to make it difficult to reach the third detection threshold value even if the value of the clogging detector 25 increases. As a result, even when the output of the clogging detector 25 becomes high at the start of operation, the operation is stopped more than before and the temperature rise of the outer case 14 can be prevented, so that the usability is improved.

  The fan motor output detection device 27 is configured to detect the current value of the fan motor 4. In the case of a DC motor, the current supplied to the fan motor 4 changes depending on the load of the combustion chamber 2 when the rotational speed is controlled to be constant. The current value decreases as the air filter 8 is clogged, and the current value increases when the front portion of the outer case 14 is opened. With this current value, it is possible to detect the state of dust in the initial stage of operation and the state of the device.

  Further, the clogging detector 25 is composed of a temperature detector attached to the upper part or the front part of the combustion chamber 2.

  When the air filter 8 is clogged, the amount of air taken in from this is reduced, the flame formed in the burner 1 is extended, the temperature of the upper part or the front part of the combustion chamber 2 is increased, and the air filter 8 is attached here. The temperature of the temperature detector also rises. The degree of clogging can be detected accurately at a low cost.

Sectional drawing which shows the structure of the warm air heater in Example 1 of this invention The figure explaining the control characteristic of the same warm air heater The figure explaining the characteristic of the clogging detector of the same warm air heater The figure explaining the control characteristic of the same warm air heater The figure explaining the characteristic of the fan motor output detection device of the same warm air heater Side view showing a schematic configuration of a conventional hot air heater

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Burner 2 Combustion chamber 3 Blower fan 4 Fan motor 8 Air filter 13 Control device 20 Control means 24 Rotation speed detector 25 Clogging detector 26 Clogging storage device 27 Fan motor output detection device 28 Fan motor output storage device

Claims (6)

A burner that burns fuel, a combustion chamber that mixes combustion gas from the burner and air taken from outside, a blower fan and a fan motor for supplying the air taken from outside to the burner and sending out hot air And a rotational speed detector for detecting the rotational speed of the fan motor, an air filter provided at an air suction port, a fuel supply amount to the burner and a control for setting the combustion amount by controlling the rotational speed of the fan motor Device, a fan motor output detection device for detecting the output of the fan motor, a fan motor output storage device for storing the output of the fan motor at a predetermined timing, and an output of the fan motor at the start of operation, the fan motor output storage device If the specified value changes from the stored value, the fan motor speed is changed to the specified speed. Warm-air heating apparatus, wherein a control means is provided for. Clogging detection means for detecting a decrease in the amount of air blown from the blower fan, a clogging storage device for storing the output of the clogging detection means, and the output of the clogging detection means from the stored value of the clogging storage device Control means is provided for controlling the rotational speed of the fan motor in accordance with the output of the clogging detection means when the first detection threshold set at a level changed by a predetermined amount is reached, and the control means outputs the fan motor at the start of operation. The warm air heating device according to claim 1, wherein the first detection threshold value is changed to a predetermined value when a predetermined amount has changed from a stored value of the fan motor output storage device. Informing means for informing a decrease in the amount of air blown from the blower fan is provided, and the control means uses the notifying means when the output of the clogging detecting means reaches a second detection threshold value that is larger than the first detection threshold value. Notification and control of the rotational speed of the fan motor are performed, and when the output of the fan motor changes by a predetermined amount from the stored value of the fan motor output storage device at the start of operation, the second detection threshold value is changed by a predetermined value. The hot air heating apparatus according to claim 1 or 2. The control means stops combustion of the burner when the output of the clogging detection means reaches a third detection threshold value that is greater in the amount of clogging than the second detection threshold value. Further, the control means outputs the fan motor output at the start of operation. The warm air heating device according to claim 1 or 2, wherein the third detection threshold value is changed by a predetermined value when a predetermined amount is changed from a stored value of the fan motor storage device. The warm air heater according to any one of claims 1 to 4, wherein the fan motor output detection device is configured to detect a current value of the fan motor. The hot air heater according to any one of claims 1 to 4, wherein the clogging detection means comprises a temperature detector attached to the upper part or front part of the combustion chamber.

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