JP2011047605A - Control device of hot air-type heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combustion control device for a heater capable of keeping a stable combustion state corresponding to change of use environment. <P>SOLUTION: A combustion control means 12 for controlling an operation and a combustion amount of a burner 2 has a plurality of combustion amount adjustment stages, and changes a flow rate of a fuel pump 3 and a rotational frequency of a combustion fan 4 when the combustion amount adjustment stage is decided on the basis of signals from an indoor temperature detecting means 9 and a temperature setting means 10. A CO2 sensor 13 for detecting CO2 concentration in a combustion gas, a selecting means 15 for selecting a reference CO2 concentration corresponding to the combustion amount adjustment stage from a plurality of reference CO2 concentration data set to a memorizing means 14, and a comparing means 16 for comparing the detected CO2 concentration with the selected reference CO2 concentration are further disposed. The rotational frequency of the combustion fan 4 is changed to be higher or lower by one stage when the CO2 concentration is outside of a range of the reference CO2 concentration, the rotational frequency of the combustion fan 4 is changed until the CO2 concentration reaches the reference CO2 concentration, and the rotational frequency when the CO2 concentration becomes the reference CO2 concentration is kept. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a control device for a hot air heater that controls the combustion by detecting the CO2 concentration in the combustion gas.

  The heater is provided with a burner that is a heat source, a fuel pump that supplies fuel to the burner, and a combustion fan that supplies combustion air to the burner, and the fuel supplied from the fuel pump and the combustion air from the combustion fan are disposed in the burner. The amount of heat required for heating is generated by mixing, vaporizing, and burning. The frame of the heater also has combustion control means for controlling the operation of the heater, indoor temperature detection means for detecting the temperature of the room in which the heater is installed, and temperature setting that is set to a desired room temperature by the user. And the combustion control means compares the temperature detected by the room temperature detection means with the set temperature set by the temperature setting means, and if the room temperature is lower than the set temperature, the flow rate of the fuel pump and the combustion fan When the room temperature is higher than the set temperature, the combustion amount is changed by lowering the flow rate of the fuel pump and the rotation speed of the combustion fan, and the room temperature is controlled to approach the set temperature. is doing.

  Combustion control means is set to the optimal fuel pump flow rate and combustion fan speed for each combustion amount, and burns with the optimal combustion balance, but the heater is used at high altitudes at high altitudes. In this case, the oxygen concentration in the air decreases, and in the case of a supply / exhaust type heater, if the amount of air supplied to the burner by an extension pipe or the like decreases, oxygen is insufficient and incomplete combustion occurs. There is a possibility of generating CO.

For this reason, conventionally, a damper is provided in the middle of the air supply path, and the amount of combustion air supplied to the burner is adjusted by changing the opening of the damper in accordance with the altitude at which the heater is installed. In addition, it has an altitude setting switch that sets the altitude in multiple stages, and if you set the altitude with the altitude setting switch corresponding to the altitude where the heater is installed, the rotation speed of the combustion fan can be switched to the set speed Some control the amount of combustion air. In addition, some supply / exhaust heaters adjust the amount of burned air by switching the number of revolutions of the combustion fan with a setting switch in response to the addition of the length of the extension pipe and the number of bends (Patent Document 1, Patent Document 2).
JP-A-3-233316 JP-A 63-247530

In the above conventional method, the position of the damper and the rotation speed of the combustion fan are set so that the optimal amount of combustion air can be obtained according to the altitude and piping conditions where the heater is installed. When multiple conditions such as pipe resistance and other conditions overlap, the amount of combustion air may vary, and the expected air amount cannot be ensured with the selected damper position and the rotation speed of the combustion fan, and the combustion balance is not maintained. It may collapse and become an unstable combustion state.
In such a case, it is necessary to adjust the damper position and the setting of the rotation speed of the combustion fan while checking the combustion state, but the optimal amount of combustion air should be adjusted while taking into account changes in temperature and piping resistance. It is difficult to find out and is often used in an unstable combustion state, and it is a problem to cope with changes due to use conditions.

  The present invention solves the above-mentioned problems. A burner 2 is provided in a frame 1, a fuel pump 3 for supplying fuel to the burner 2, and a combustion fan 4 for sending combustion air to the burner 2. A convection fan 6 is provided on the inlet side and a hot air outlet 7 is provided on the outlet side of the air passage 5 that passes through the front and rear of the frame body 1. Then, the indoor air blown into the blower path 5 by the convection blower 6 is exchanged with the burner 2 and the combustion chamber 8 to become a high temperature and blown out from the hot air outlet 7 into the room, and the room temperature is detected. Control of the operation of the burner 2 and adjustment of the combustion amount are performed by controlling the fuel pump 3 and the combustion fan 4 based on the signal of the temperature detection means 9, the temperature setting means 10 for setting the room temperature, and the operation switch 11. Combustion control means 12 for performing The control means 12 includes a plurality of combustion amount adjustment stages, and in the hot air heater that varies the flow rate of the fuel pump 3 and the rotation speed of the combustion fan 4 corresponding to each combustion amount adjustment stage, the combustion chamber 8 A CO2 sensor 13 for detecting the CO2 concentration in the combustion gas discharged from the combustion chamber 8 is provided in the exhaust path, and the combustion control means 12 has a plurality of reference CO2 concentration data set for each combustion amount adjustment stage. , Storage means 14 comprising: a selection means 15 for selecting reference CO2 concentration data corresponding to the combustion amount adjustment stage; CO2 concentration data detected by the CO2 sensor 13; and a reference CO2 selected by the selection means 15 A comparison means 16 for comparing the data, and the combustion control means 12 is configured so that the CO2 concentration of the CO2 sensor 13 is not changed when the CO2 concentration is out of the reference CO2 concentration range. The rotational speed of the combustion fan 4 is changed one step higher or lower, the rotational speed of the combustion fan 4 is changed until the CO2 concentration of the CO2 sensor 13 falls within the range of the reference CO2 concentration, and the CO2 concentration of the CO2 sensor 13 becomes the reference CO2 It is characterized by maintaining the number of rotations when the concentration is within the range.

  Further, the combustion control means 12 is provided with a rotation speed storage means 17 for storing the rotation speed when the CO2 concentration of the CO2 sensor 13 falls within the range of the reference CO2 concentration. Since the combustion fan 4 is operated at the rotational speed stored in the rotational speed storage means 17 corresponding to the stage, the rotational speed of the combustion fan 4 deviates greatly as the detection data of the CO2 sensor 13 deviates from the reference CO2 concentration. There is nothing, and the combustion state is easily stabilized.

The combustion control means 12 is configured such that the flow rate of the fuel pump 3 and the rotational speed of the combustion fan 4 are set for each combustion amount adjustment stage and burns with an optimal combustion balance. This is accompanied by the generation of CO2, and this CO2 is contained in the combustion gas at a constant concentration when burning with an optimal combustion balance. However, if the combustion balance is lost, the CO2 concentration in the combustion gas decreases or increases. Therefore, it is out of a certain range.
The present invention pays attention to the change in the CO2 concentration in the combustion gas. A CO2 sensor 13 for detecting the CO2 concentration in the combustion gas discharged from the combustion chamber 8 is provided, and the reference is provided for each combustion amount adjustment stage. When the CO2 concentration is determined and the CO2 concentration in the combustion gas detected by the CO2 sensor 13 deviates from this reference CO2 concentration, the rotational speed of the combustion fan 4 is changed one step higher or lower, and the reference rotational speed is also the reference When the CO2 concentration is deviated, the rotation speed is continuously changed until the reference CO2 concentration is reached. When the CO2 concentration is within the range of the reference CO2 concentration, the change of the rotation speed of the combustion fan 4 is stopped and this rotation speed is maintained. Is.
In this way, since the optimum amount of combustion air can be supplied by changing the rotational speed of the combustion fan 4 so that the reference CO2 concentration can be obtained, the amount of air is overlapped by a plurality of conditions such as altitude, extension piping, and changes in temperature. Even when it changed, stable combustion could be maintained.

  Also provided is a rotational speed storage means 17 for storing the rotational speed of the combustion fan 4 when the CO2 concentration detected by the CO2 sensor 13 after changing the rotational speed of the combustion fan 4 falls within the range of the reference CO2 concentration. In the next operation, since the rotational speed of the combustion fan 4 is determined based on the rotational speed data stored in the rotational speed storage means 17, the installation location and the installation conditions of the heater are not changed. The amount of combustion air that provides the optimal combustion balance from the start of operation can be supplied, stable combustion is possible, and even if the combustion balance is lost, the amount of combustion air does not deviate significantly. Thus, stable combustion is possible, and generation of CO and soot due to incomplete combustion can be surely suppressed.

It is sectional drawing of the principal part of the supply / exhaust air heater which shows the Example of this invention. It is a block diagram which shows the structure of the heater of the Example of this invention. It is a flowchart which shows the structure of the heater of the Example of this invention.

  The present invention will be described with reference to an embodiment of a heater using petroleum fuel shown in FIG. 1. 1 is a frame of the heater, 2 is a burner disposed in the frame 1, and 8 is disposed above the burner 2 and burns. A combustion chamber through which flames and combustion gases are sent, 18 is a heat exchanging portion disposed in the upper part of the combustion chamber 8, 5 is an air passage formed penetrating from the rear surface of the frame body 1 to the front surface, and 6 is a frame body 1. A convection blower 7 provided on the inlet side of the air flow path on the back surface of the frame 1 is a hot air outlet formed on the outlet side of the air flow path 5 on the front surface of the frame 1.

  The oil heater of the embodiment shown in FIG. 1 is applied to a supply / exhaust hot air heater that takes in combustion air from the outside and discharges combustion exhaust gas to the outside, and 19 is an air supply provided on the back of the frame 1 , 20 is an exhaust port provided near the air supply port 19, 21 is an intake pipe connected to the air supply port 19, 22 is an exhaust pipe connected to the exhaust port 20, and 23 is an air supply / exhaust cylinder attached through the wall. The top 24 is a plurality of heat exchange pipes extending upward from the combustion chamber 8, and 25 is an exhaust gas chamber located above the heat exchange pipe 24. The top of the combustion chamber 8, the heat exchange pipe 24, and the exhaust gas chamber 25. Is located in the air blowing path 5 and constitutes the heat exchanging portion 18.

  26 is a constant oil leveler to which fuel is sent from a fuel tank (not shown), 3 is a fuel pump for supplying fuel to the burner 2 mounted on the constant leveler, 4 is a combustion fan for supplying combustion air to the burner 2 , 27 is an ignition heater that also serves as a preheating heater for the burner 2. The ignition heater 27 is energized to preheat the burner 2, fuel is supplied to the burner 2 by the fuel pump 3, and the top and bottom of the supply / exhaust cylinder 23 by the combustion fan 4. The outdoor air sucked from the air through the air supply pipe 21 is supplied to the burner 2, the fuel vaporized by the high temperature burner 2 is mixed with the air and starts combustion, and the high temperature combustion gas generated in the burner 2 is in the combustion chamber 8. Are collected in the exhaust gas chamber 25 through the heat exchange pipe 24 and discharged to the outside from the exhaust pipe 22. The wind sent into the ventilation path 5 by the convection blower 6 exchanges heat with the combustion chamber 8, the heat exchange pipe 24, and the exhaust gas chamber 25, and becomes hot air and blows out into the room from the warm air outlet 7. It is.

  12 is a combustion control means equipped with a microcomputer for controlling the operation of the heater, and 11 is an operation switch arranged in the operation part of the frame body 1 for instructing operation / stop of the heater. The signal is sent to the combustion control means 12, and the combustion control means 12 instructs on / off of the fuel pump 3, the combustion fan 4, the ignition heater 27, the convection blower 6 based on the signal of the operation switch 11, and the like. It controls the operation of the wind heater.

  Reference numeral 9 denotes a room temperature detecting means composed of a temperature sensor installed behind the frame 1, and 10 denotes a temperature setting means for storing a temperature desired by the user, which is operated by a button provided in the operation unit. The temperature data set by the means 10 and the current room temperature data detected by the room temperature detecting means 9 are compared by the combustion control means 12, and if the set temperature is higher than the room temperature, the flow rate of the fuel pump 3 The combustion amount of the burner 2 is increased by increasing the rotational speed of the combustion fan 4, and when the indoor temperature is higher than the set temperature, the flow rate of the fuel pump 3 and the rotational speed of the combustion fan 4 are decreased. 2 is reduced so that the room temperature approaches the set temperature.

  The combustion control means 12 determines a plurality of fuel flow rates including a minimum combustion state, a maximum combustion state, and several combustion states therebetween, and sets the number of revolutions of the combustion fan 4 corresponding to the fuel flow rate, thereby providing a plurality of stages. If the combustion amount adjustment stage is selected based on the difference between the room temperature and the set temperature, the burner 2 burns in stages toward the selected combustion amount adjustment stage. The fuel flow rate of the fuel pump 3 and the rotational speed of the combustion fan 4 are set for each combustion amount adjustment stage.

  Normally, the heating fan is designed with the rotational speed of the combustion fan 4 on the assumption that the altitude is about 400 m or less, but the oxygen concentration in the air decreases as the altitude of the place where the heater is used increases. However, in high altitudes where the altitude exceeds 1000 m, the amount of oxygen in the air supplied to the burner 2 is insufficient, the balance between the fuel and the amount of oxygen in the air is lost, combustion becomes unstable, and the heating capacity is reduced. Problems such as CO are likely to occur. Therefore, in order to ensure the amount of air that can maintain an optimal combustion balance even when used at high altitude, it is necessary to increase the amount of air supplied to the burner 2 by the amount that the oxygen concentration decreases.

As a conventional measure, there is one in which a damper is provided at an air supply port through which combustion air supplied to the burner 2 passes, and each of the dampers has a scale indicating an altitude such as 1000 m and 1500 m, and a heater is provided. The amount of air supplied to the burner 2 can be adjusted by changing the position of the damper according to the altitude to be installed. The higher the altitude, the larger the opening area of the air inlet and the air supplied to the burner 2 By increasing the amount, we are trying to eliminate the lack of oxygen.
However, the damper method only changes the position of the damper according to the altitude, and does not adjust the air amount in accordance with all combustion amount adjustment stages, so the combustion state is stabilized at a certain combustion amount adjustment stage. Even in this case, the combustion state may become unstable in another combustion amount adjustment stage.

  In addition, there is an altitude setting switch in the operation section etc., and when the altitude setting switch is operated, the altitude switches between 1000m and 1500m, and the altitude setting switch is operated according to the altitude where the heater is installed, and the altitude is set Then, the number of revolutions of the combustion fan 4 at each combustion amount adjustment stage is changed according to the set altitude, and the amount of air supplied to the burner 2 can be adjusted. When set, the rotational speed of the combustion fan 4 is changed to be high, and the amount of air supplied to the burner 2 is increased, thereby eliminating the oxygen shortage. In this measure, since the rotational speed of the combustion fan 4 is set for each combustion amount adjustment stage, the combustion state is more stable than the damper system.

  However, there are various places and conditions where the heater is installed. In particular, in the case of a supply / exhaust type heater, if the length or the number of bends of the pipe increases, the pipe resistance increases and the amount of air supplied to the burner 2 increases. May decrease. Also, when the outside air temperature is extremely low or due to changes in piping resistance due to accumulation of soot in the piping, the air volume may change. When the plurality of conditions overlap, the amount of air supplied to the burner 2 may change.

  In the conventional method, only the amount of air supplied to the burner 2 is adjusted by a damper or an altitude setting switch, so there is no guarantee that the adjusted amount of air is necessarily the optimum amount of combustion air. When a plurality of conditions such as extension piping and temperature overlap, the expected air amount cannot be secured and the combustion state may become unstable. Even in such a case, it is often used as it is, and there are problems such as accumulation of soot and generation of CO.

  The present invention proposes a heater that can maintain a stable combustion state without being affected by changes in various usage environments such as altitude and piping conditions. CO2 is generated when petroleum fuel burns. During combustion, when the fuel flow rate and combustion air are balanced and the combustion state is stable, the combustion gas contains a certain concentration of CO2, but if the balance between the fuel flow rate and combustion air is lost, combustion occurs. It has been confirmed that the CO2 concentration in the combustion gas increases when the amount of air is insufficient, and the CO2 concentration in the combustion gas decreases when the amount of air is excessive.

This invention pays attention to the point that the CO2 concentration in the combustion gas changes depending on the combustion state, and proposes a heater in which the amount of combustion air can be adjusted in response to the change in the CO2 concentration. A CO2 sensor disposed in an exhaust path from 25 to the exhaust port 19 and detects the concentration of CO2 contained in the combustion gas during combustion.
Reference numeral 14 denotes storage means having a plurality of reference CO2 concentration data determined for each combustion amount adjustment stage, and reference numeral 15 denotes a plurality of reference CO2 provided to the storage means 14 when the combustion control means 12 selects a certain combustion amount adjustment stage. Selection means 16 for selecting the corresponding reference CO2 data from the concentration data, and 16 is a comparison means for comparing the CO2 concentration data detected by the CO2 sensor 13 with the reference CO2 concentration selected by the selection means 15.
When the combustion state is stable, the CO2 concentration in the combustion gas is within a certain range, so the CO2 concentration when this combustion state is stable is calculated for each combustion amount adjustment stage, For example, the maximum combustion amount is set to 8% ± 0.2%, the minimum combustion amount is set to 3% ± 0.2%, and the reference is set for each of the plurality of combustion amount adjustment stages between the maximum combustion amount and the minimum combustion amount. The CO2 concentration is set and stored in the storage means 14.

In FIG. 2 showing the embodiment of the present invention, when the operation of the heater is started, the combustion control means 12 determines the combustion amount adjustment stage based on the temperature data of the temperature setting means 10 and the indoor temperature data of the indoor temperature detection means 9. Instructing the change of the flow rate of the fuel pump 3 and the rotational speed of the combustion fan 4 so as to reach the determined combustion amount adjustment stage, the selection means 15 selects from the plurality of reference CO2 concentration data set in the storage means 14. The reference CO2 concentration data corresponding to the combustion amount adjustment stage is selected.
Since the combustion state is not stable immediately after the fuel pump 3 and the combustion fan 4 are changed to the determined flow rate and rotational speed in the combustion amount adjustment stage, and the CO2 concentration in the combustion gas is not stable, the CO2 sensor 13 is It is necessary to start operation after the combustion amount adjustment stage is changed and combustion is stabilized.
Reference numeral 28 denotes timer means that operates when the fuel pump 3 and the combustion fan 4 are changed to the flow rate and rotation speed at each combustion amount adjustment stage, and counts for a predetermined time. The output of the timer means 28 counts up the CO2 sensor 13. And the detection of the CO2 concentration in the combustion gas is started, and the CO2 sensor 13 operates after the combustion amount adjustment stage is changed and the combustion of the burner 2 is stabilized, so that an accurate CO2 concentration can be detected.
Then, the comparison means 16 compares the CO2 concentration detected by the CO2 sensor 13 with the reference CO2 concentration selected by the selection means 15, and the CO2 concentration detected by the CO2 sensor 13 is within the reference CO2 concentration range. Means that the fuel flow rate and the amount of combustion air are balanced and the combustion state is stable, and it is not necessary to change the rotational speed of the combustion fan 4, so combustion is performed while maintaining this rotational speed. continue.

  Further, when the CO2 concentration detected by the CO2 sensor 13 deviates from the reference CO2 concentration, it means that the balance between the fuel flow rate and the air amount is lost and the combustion state becomes unstable, and the combustion fan 4, and when the detection data of the CO 2 sensor 13 is higher than the reference CO 2 concentration, the burner 2 is in an air-deficient state, so the rotation speed of the combustion fan 4 is increased by one step. change. Conversely, when the detection data of the CO2 sensor 13 is lower than the reference CO2 concentration, the burner 2 is in an excessive air state, so that the rotational speed of the combustion fan 4 is changed by one step.

  Then, after changing the rotation speed of the combustion fan 4, the comparison means 16 again compares the CO2 concentration detected by the CO2 sensor 13 with the reference CO2 concentration, and the detection data of the CO2 sensor 13 is within the range of the reference CO2 concentration. If it is in, the rotational speed at that time is maintained, and if it is out of the reference CO2 concentration range, the rotational speed of the combustion fan 4 is changed one step higher or lower, and the detection data of the CO2 sensor 13 is within the reference CO2 concentration range. This operation is repeated until entering.

  Further, when the difference between the set temperature and the room temperature becomes a constant temperature difference and the combustion control device 12 instructs to change the combustion amount adjustment stage, the CO2 sensor 13 and the comparison means 16 stop the operation and are selected. The means 15 reselects the reference CO2 concentration data corresponding to the changed combustion amount adjustment stage from the storage means 14, and the fuel flow rate of the fuel pump 3 and the combustion air amount of the combustion fan 4 are changed to adjust the target combustion amount. When the stage is changed, the timer means 28 starts counting, the CO2 sensor 13 is activated by the output counted by the timer means 28 and starts detecting CO2, and the reference newly selected by the comparing means 16 Compared with the CO2 concentration data, stable combustion can be maintained at all combustion amount adjustment stages.

  The present invention does not adjust the amount of air supplied to the burner 2 in accordance with the change in altitude or piping conditions as in the prior art, but is based on the reference CO2 concentration data when the combustion state is stable. In the conventional configuration, the amount of air expected to deviate from the set conditions, such as when multiple conditions such as changes in altitude, piping conditions and changes in temperature overlap, Although the combustion balance has been lost, in the present invention, since the rotational speed of the combustion fan 4 is automatically changed so as to achieve an optimal combustion balance, there is a change in the temperature or the like during use of the heater. As a result, it was possible to ensure the amount of air that would ensure a stable combustion state.

  Further, even when the damper or the altitude setting switch for securing the combustion air amount cannot be dealt with alone, the combustion control means 12 automatically finds the rotational speed of the combustion fan 4 in a stable combustion state, so that a special operation is performed. There is no need, and the handleability can be improved.

  In the embodiment of the present invention, the maximum rotation speed and the minimum rotation speed of the combustion fan 4 have a margin with respect to the rotation speed at the maximum combustion amount and the minimum combustion amount in the normal combustion amount adjustment stage, It is set so that it can be further changed by one or two steps from the maximum combustion amount and the minimum combustion amount. This makes it possible to change the rotational speed of the combustion fan 4 by one step when the CO2 concentration becomes higher than the reference CO2 concentration during combustion at the maximum combustion amount, while at the minimum combustion amount. When the CO2 concentration becomes lower than the reference CO2 concentration during combustion, the rotational speed of the combustion fan 4 can be changed by one step lower, and it is possible to cope with the maximum or minimum combustion amount in the combustion amount adjustment step. If the reference CO2 concentration does not reach even when the rotational speed of the combustion fan 4 is changed to the maximum or minimum speed, the intake / exhaust pipe may not be able to perform normal combustion due to accumulation of soot, etc. An error is output to stop the operation of the heater so that it can be inspected and repaired.

  Reference numeral 17 denotes a rotational speed storage means for storing the rotational speed of the combustion fan 4 when the CO2 concentration detected by the CO2 sensor 13 falls within the range of the reference CO2 concentration. The rotational speed storage means 17 includes a plurality of stages of combustion amounts. The rotational speed is stored for each adjustment stage, and the rotational speed data stored in the rotational speed storage means 17 is retained even after the operation of the heater is stopped. The rotational speed data stored in 17 is used.

In the above configuration, when the operation of the heater is started and the combustion control means 12 determines the combustion amount adjustment stage based on the temperature data of the temperature setting means 10 and the indoor temperature data of the indoor temperature detection means 9, the combustion fan 4 rotates. Driving is performed at the rotational speed stored in the number storage means 17.
For this reason, if the installation location and the installation conditions have not changed since the previous stop of operation, the rotational speed of the combustion fan 4 stored in the rotational speed storage means 17 is greatly out of the range of the reference CO2 concentration by the detection data of the CO2 sensor 13. Since there is no such error, by using the rotation speed data stored in the rotation speed storage means 17, the CO2 concentration in the combustion gas does not greatly deviate from the range of the reference CO2 concentration, and is stable in a short time from the start of operation. It is easy to maintain the combustion state, and the generation of CO and soot can be suppressed without greatly reducing the combustion balance and causing incomplete combustion.

DESCRIPTION OF SYMBOLS 1 Frame body 2 Burner 3 Fuel pump 4 Combustion fan 5 Air supply path 6 Convection fan 7 Hot air outlet 8 Combustion chamber 9 Indoor temperature detection means 10 Temperature setting means 11 Operation switch 12 Combustion control means 13 CO2 sensor 14 Storage means 15 Selection means 16 Comparison means 17 Rotation speed storage means

Claims (2)

A burner (2), a fuel pump (3) for supplying fuel to the burner (2), and a combustion fan (4) for sending combustion air to the burner (2) are provided in the frame (1),
In the air passage (5) penetrating the front and rear of the frame (1), a convection fan (6) is provided on the inlet side, a hot air outlet (7) is provided on the outlet side, and provided on the upper part of the burner (2). The combustion chamber (8) is arranged in the blower passage (5), and the indoor air blown into the blower passage (5) by the convection blower (6) exchanges heat with the burner (2) and the combustion chamber (8). Then, it becomes hot and blows out into the room from the warm air outlet (7).
An indoor temperature detecting means (9) for detecting the indoor temperature, a temperature setting means (10) for setting the indoor temperature, the fuel pump (3) and the combustion fan (4) based on the signal of the operation switch (11) And a combustion control means (12) for controlling the operation of the burner (2) and adjusting the combustion amount by controlling
The combustion control means (12) includes a plurality of combustion amount adjustment stages, and hot air that varies the flow rate of the fuel pump (3) and the rotational speed of the combustion fan (4) in accordance with each combustion amount adjustment stage. In the heater,
A CO2 sensor (13) for detecting the CO2 concentration in the combustion gas discharged from the combustion chamber (8) is provided in the exhaust path of the combustion chamber (8), and the combustion control means (12) adjusts each combustion amount. Storage means (14) having a plurality of reference CO2 concentration data set for each stage, selection means (15) for selecting reference CO2 concentration data corresponding to the combustion amount adjustment stage, and the CO2 sensor (13) A comparison means (16) for comparing the CO2 concentration data detected in step (1) with the reference CO2 data selected by the selection means (15),
The combustion control means (12) changes the rotational speed of the combustion fan (4) one step higher or lower when the CO2 concentration of the CO2 sensor (13) is out of the range of the reference CO2 concentration,
The rotation speed of the combustion fan (4) is changed until the CO2 concentration of the CO2 sensor (13) falls within the range of the reference CO2 concentration, and the CO2 concentration of the CO2 sensor (13) falls within the range of the reference CO2 concentration. A control device for a hot air heater, characterized in that the number of rotations is maintained. The combustion control means (12) is provided with a rotation speed storage means (17) for storing the rotation speed when the CO2 concentration of the CO2 sensor (13) falls within the range of the reference CO2 concentration,
The hot air heating according to claim 1, wherein the combustion fan (4) is operated at the rotational speed of the rotational speed storage means (17) stored corresponding to each combustion amount burning adjustment stage at the next operation. Machine control device.

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