JPH1123064A - Warm air heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a warm air heater of which temperature can be controlled steadily during the execution of energy saving operation. SOLUTION: In a warm air heater provided with a temperature sensor 13, a room temperature setter 28, a fuel cost saving setting means 40 dropping target temperature by the step of a predetermined first temperature after starting heating operation and a temperature regulation controlling means 41 adjusting the heating power of a heating source so that the detected temperature of a temperature sensor 13 roughly agrees with the target temperature during heating operation and interrupting the operation of the heating source by the time the detected temperature drops to a predetermined heating restarting temperature set near the target temperature when the detected temperature rises higher than the target temperature by a predetermined second temperature or more, the warm air heater is provided with a temperature setting means 44 setting the predetermined first temperature that is a step of dropping the target temperature may be lower than the predetermined second temperature that is used as the interrupting condition of the heat source by the temperature regulating controlling means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a warm air heater having a fuel-saving heating operation function and a temperature control function by turning on and off a heating source.

[0002]

2. Description of the Related Art Conventionally, for example, in a gas warm air heater, a gas burner as a heating source and a blower fan are provided in a main body case. The room temperature is raised by blowing the air heated by the air into the room.

[0003] In a gas warm air heater having a temperature control function, a target temperature set by a user with a temperature setting switch and a room temperature sensor provided near a suction port of room air are detected. So that the actual room temperature approximately matches
The amount of combustion of the gas burner and the amount of air blown by the blower fan are adjusted.

[0004] Further, even if the combustion amount of the gas burner is minimized, the temperature detected by the temperature sensor continues to rise, and when the temperature detected by the temperature sensor becomes higher than the target temperature by a second predetermined temperature or more, the combustion operation of the gas burner is stopped. After stopping, when the temperature detected by the temperature sensor drops to the heating restart temperature set near the target temperature, the combustion operation of the gas burner is restarted. There is also known an arrangement in which they substantially match each other.

However, in general, once the combustion operation of the gas burner is stopped, the combustion operation of the gas burner is prohibited until a predetermined time elapses after the combustion operation is stopped in order to prevent flashback. . When restarting the combustion operation of the gas burner, pre-purge may be performed by operating only the blower fan for a predetermined time before ignition.

[0006] Therefore, once the combustion operation of the gas burner is interrupted, the combustion operation cannot be resumed immediately, and there is a period in which the temperature control is not performed. It is desirable not to stop the combustion operation.

On the other hand, a hot air heater having a fuel-saving operation function is also known. This is such that after the temperature detected by the temperature sensor reaches the target temperature, the target temperature is slightly lowered with the passage of time.

More specifically, when 30 minutes have passed since the temperature detected by the temperature sensor reached the target temperature, the target temperature was set to 1 ° C.
In some cases, the temperature is lowered by 1 ° C. after 30 minutes.

In addition to the one in which the target temperature is decreased by a constant temperature, the one in which the degree of decrease in the target temperature is changed in accordance with the magnitude of the heating load, for example, the detected room temperature at the start of the heating operation and the one after the heating operation is started In some cases, the degree of decrease in the target temperature in fuel-saving operation is changed in accordance with the degree of increase in the detected room temperature.

As described above, even if the target temperature is slightly reduced, the user's perceived temperature does not change much. for that reason,
By providing the warm air heater with a fuel-saving driving function, the amount of combustion of the gas burner can be reduced, and the fuel efficiency can be improved without causing discomfort to the user.

However, the present inventors have found that the following inconvenience occurs when the above-described temperature control by turning on and off the gas burner and the fuel-saving driving function are used together.

That is, when the detected temperature of the temperature sensor is kept close to the target temperature by the temperature adjustment control and the target temperature is reduced by the fuel-saving operation, the detected temperature of the temperature sensor is decreased. Higher than the second predetermined temperature, and found that the on / off control is executed and the combustion operation of the gas burner is stopped.

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to provide a warm air heater capable of solving the above-mentioned disadvantages and performing stable temperature control even when fuel-saving operation is performed. .

[0014]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a heating source, a blower fan for sending air heated by the heating source into a room, a temperature sensor for detecting room temperature, and a target. A room temperature setter for setting a temperature, a fuel-saving setting means for decreasing the target temperature by a first predetermined temperature over time after the start of the heating operation, and a detection temperature of the temperature sensor during the heating operation. The heating amount of the heating source is adjusted so that the target temperature substantially coincides with the target temperature. When the detected temperature becomes higher than the target temperature by a second predetermined temperature or more even when the adjustment is performed, the detected temperature is increased. A temperature control unit for interrupting the operation of the heating source until the temperature decreases to a predetermined heating restart temperature set near the target temperature. The first predetermined temperature And characterized in that a temperature setting means for setting to be smaller than the second predetermined temperature used in a condition for stopping the heating source by the temperature control means.

According to the present invention, the temperature setting means sets the first predetermined temperature, which is a decrease in the target temperature by the fuel saving setting means, as a condition for stopping the heating source by the temperature control control means. The temperature is set to be lower than the second predetermined temperature to be used.

For this reason, when the temperature adjustment control means is in a state where the temperature detected by the temperature sensor and the target temperature are controlled to substantially match, the target temperature is set by the fuel saving setting means. Even if the first predetermined temperature drops, the possibility that the temperature detected by the temperature sensor is higher than the lowered target temperature by the second predetermined temperature or more is extremely low.

Therefore, according to the present invention, during fuel-saving operation, the temperature detected by the temperature sensor becomes higher than the target temperature by the second predetermined temperature or more, and the operation of the heating source is controlled by the temperature control means. It is possible to suppress stoppage and perform stable temperature control.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. 1 is a configuration diagram of a gas fan heater which is a hot air heater of the present invention, FIG. 2 is a control block diagram of the gas fan heater shown in FIG. 1, and FIGS. 3 and 4 are diagrams of the gas fan heater shown in FIG. FIG. 5 is an operation flowchart, and FIG. 5 is an explanatory diagram of the temperature control operation of the gas fan heater shown in FIG.

Referring to FIG. 1, a gas fan heater according to the present embodiment includes a duct 2, a blower fan 3, a gas burner 4 as a heating source, a duct 5, a gas supply It comprises a tube 6 and a control unit 7.

The duct 2 constitutes a ventilation path for warm air, and an intake port 8 for taking in room air s is opened at the back of the main body case 1. The outlet 9 is open. An air filter 10 is detachably attached to the intake port 8 in order to prevent dust and dirt from flowing into the duct 2. At the outlet 9
A movable louver 11 for adjusting the degree of opening is attached, and a gad motor 12 for driving the movable louver 11 is provided. Further, a temperature sensor 13 protruding from the main body case 1 to the outside and formed of a thermistor is provided.
Is attached.

The blower fan 3 has a fan motor 14 whose rotation speed changes in proportion to the amount of current supplied thereto, and a rotating blade 15 which is disposed in the duct 2 so as to face the air outlet 9 and is driven to rotate by the fan motor 14. And the indoor blade s is sucked into the duct 2 from the air inlet 8 by the rotation of the rotary blade 15.
Then, the sucked indoor air s is mixed with the combustion exhaust h of the gas burner 4 incorporated in the duct 2, and the mixed air is sent out from the outlet 9 into the room as the hot air m. The blower fan 3 is provided with a rotation speed sensor 16 constituted by a Hall element or the like for detecting the rotation speed thereof.
6 outputs a signal corresponding to the rotation speed of the fan motor 14 to the control unit 7.

Gas burner 4 incorporated in duct 2
Has an ignition electrode 19 for arranging a combustion plate 18 in a combustion cylinder 17 and igniting a mixture of combustion air and fuel gas.
Is disposed near the combustion plate 18. Gas burner 4
Is disposed in the duct 2 and its combustion exhaust h
Is discharged from the combustion cylinder 17 into the duct 2. Further, a thermocouple 20 for detecting the presence or absence of a combustion flame is disposed downstream of the combustion plate 18. When exposed to the combustion flame of the gas burner 4, the thermocouple 20 generates a thermoelectromotive force according to the temperature of the combustion flame, and outputs the thermoelectromotive force to the control unit 7.

The duct 5 is a passage for supplying room air s (combustion air) and fuel gas to the gas burner 4, communicates with the inside of the combustion cylinder 17 of the gas burner 4, and defines the duct 2. It has an air intake port 21 for room air s, which is incorporated in the main body case 1 and opened at the back of the main body case 1. At a location on the gas burner 4 side of the duct 5, a nozzle 22 attached to the tip of the gas supply pipe 6 is arranged.

The indoor air s is sucked into the duct 5 from the intake port 21 by the rotation of the blower fan 3, and the sucked indoor air s is mixed with the fuel gas ejected from the nozzle 22 of the gas supply pipe 6. The mixture is supplied to the gas burner 4. The air inlet 21 is covered with the air filter 10 together with the air inlet 8 of the duct 2.

The solenoid valve 2 is connected to the gas supply pipe 6 from the upstream side.
4, 25 and a proportional control valve 26 are provided.

The solenoid valves 24 and 25 are opened by energization. The solenoid valves 24 and 25 allow the fuel gas to pass in the direction of the nozzle 22 when the valve is open, and shut off the fuel gas when the energization is stopped and the valve is closed.

The proportional control valve 26 is a valve whose opening increases in proportion to the amount of current supplied, and regulates the amount of fuel gas supplied to the gas burner 4.

An operation switch 2 is provided on the outer surface of the main body case 1.
7, a temperature setting switch 28 and a filter lamp 29 are provided.

The operation switch 27 is turned on / off by the user.
The control unit 7 is turned off to start and stop the heating operation.
To instruct.

Temperature setting switch 28 which is a room temperature setting device
Is for setting a desired temperature of the room temperature, and the desired temperature is increased or decreased by, for example, 1 ° C. by a user operation. The set desired temperature is immediately transmitted to the control unit 7.

The filter lamp 29 is provided for the air filter 10.
When the air volume during the rotation operation of the blowing fan 3 is normal, such as when clogging of the air filter 3 is progressing, the light is turned on when the air flow is reduced to some extent.
Notify the user that replacement is required.

Next, referring to FIG. 2, the control unit 7 is constituted by using a microcomputer or the like, and comprises a fuel-saving setting means 40, a temperature control control means 41, a combustion control section 42, and a ventilation control. A part 43 is provided.

The fuel saving setting means 40 comprises a saving amount determining section 44 which is a temperature setting means of the present invention, and a target temperature determining section 45.
And Although the details will be described later, the save amount determining means 44 lowers the target temperature at the time of performing the heating operation to perform the fuel-saving operation, and performs a first predetermined temperature (hereinafter, referred to as a save amount) which is a temperature range to be reduced. To determine. Further, the target temperature determination unit 45 determines a target temperature for the heating operation from the set temperature set by the temperature setting switch 28 and the save amount.

The temperature control means 41 includes a combustion amount determining section 46,
Operation interruption temperature determination unit 47 and operation resumption temperature determination unit 48
Is provided.

The combustion amount determining section 46 includes a target temperature determining section 45.
The target combustion amount of the gas burner 4 is determined so that the target temperature determined by (1) substantially matches the temperature detected by the temperature sensor 13. Thus, the temperature detected by the temperature sensor 13 is normally stabilized within the range of the target temperature ± 0.5 ° C. However, when the detected temperature of the temperature sensor 13 continues to rise even when the combustion amount of the gas burner 4 is minimized, for example, when the target temperature is low, the target combustion amount of the gas burner 4 is set to 0 and the gas burner 4
The combustion operation of the gas burner 4 is interrupted, and when the temperature detected by the temperature sensor 13 decreases to near the target temperature, the combustion operation of the gas burner 4 is restarted.

The operation interruption temperature determining section 47 determines the temperature obtained by adding the second predetermined temperature to the target temperature as the operation interruption temperature, and the operation restart temperature setting section 48 determines the temperature near the target temperature as the operation restart temperature. .

When the temperature detected by the temperature sensor 13 rises to the operation interruption temperature, the combustion amount determination unit 46 sets the target combustion amount of the gas burner 4 to 0, and sets the target combustion amount to 0.
When the temperature detected by the temperature sensor 13 falls to the operation restart temperature after the stop, the combustion operation of the gas burner 4 is restarted to perform the on / off control.

The combustion control unit 42 controls the electromagnetic valve 24 provided in the gas supply pipe 6 so that the gas burner 4 burns at the target combustion amount determined by the combustion amount determination unit 46 provided in the temperature control unit 41. , 25, and the proportional control valve 26 and the igniter 19, so that the ignition of the gas burner 4 is controlled.
Extinguish fires, adjust combustion amount (adjust fuel gas supply amount), etc.

In this embodiment, the combustion control unit 42
The combustion amount (fuel gas supply amount) of the gas burner 4 is set in 12 stages from a first setting (minimum combustion amount) to a twelfth setting (maximum combustion amount). Further, from the output of the thermoelectromotive force of the thermocouple 20, confirmation of ignition / extinguishing of the gas burner 4 and detection of misfire during combustion are performed.

The blower controller 43 rotates the fan motor 14 at a target rotation speed (corresponding to the amount of combustion air supplied to the gas burner 4) according to the combustion amount of the gas burner 4 set by the combustion controller 42. Thus, the amount of current supplied to the fan motor 14 is adjusted. That is, the target fan speed and the actual fan motor 1 detected by the fan speed sensor 16
The amount of current supplied to the fan motor 14 is adjusted so that the rotation speed of the fan motor 4 matches the rotation speed of the fan motor 14.

Incidentally, the rotational speed of the fan motor 14 corresponds to the first to twelfth setting of the combustion amount of the gas burner 4, and corresponds to the first speed (minimum rotation speed) to the twelfth speed (maximum rotation speed). Are set in 12 steps.

Next, the control operation of the hot air heater by the control unit 7 will be described with reference to the flowcharts of FIGS.

When the user operates the operation switch 27 in STEP 1 of FIG. 3, the control operation of the hot air heater by the control unit 7 is started, and the set temperature of the temperature setting switch 28 is sent to the target temperature determination unit 45 in STEP 2. It is input and determined as the target temperature for the heating operation. Further, a save flag F indicating whether or not the fuel-saving driving is being executed in STEP3.
Is reset (F = 0, meaning that the fuel-saving operation is not executed).

In STEP 4, before blowing the gas burner 4, the blower controller 43 performs a prepurge to rotate the fan motor 14 for a predetermined time. Then, the combustion control unit 42 opens the solenoid valves 24 and 25 in STEP5,
In STEP6, the opening of the proportional control valve 26 is set to the maximum (seventh setting). In STEP7, the rotation speed of the fan motor 14 is set to the maximum (seventh speed). Ignition.

The combustion control unit 42 determines in step 8 that the igniter 1
After the start of energization in step 9, the gas burner is ignited in step 10 until 30 seconds elapse in step 20, and the thermocouple 20
When it is detected from the thermoelectromotive force level, the process proceeds to STEP 11 to continue the heating operation at the maximum combustion amount for one minute. On the other hand, when the timer of 30 seconds has expired in STEP 20 before the ignition of the gas burner 4 is detected in STEP 10, it is determined that the ignition has failed, and the process proceeds to STEP 21 to stop the heating operation.

In STEP 12, the target combustion amount of the gas burner 4 is determined by the temperature control unit 41 based on the difference between the target temperature of the heating operation determined by the target temperature determination unit 45 and the room temperature detected by the temperature sensor 13. Is determined.
Then, the combustion control unit 42 varies the opening of the proportional control valve 26 in a range from the first setting to the twelfth setting according to the determined target combustion amount. Further, the blower control unit 43 varies the target rotation speed of the fan motor 14 in a range from the first speed to the twelfth speed according to the target combustion amount, and
The amount of current supplied to the fan motor 14 is adjusted so that the actual rotation speed detected by the rotation speed sensor 16 matches the actual rotation speed.

In STEP 13, when the operation is the first operation after the installation of the warm air heater, the save amount determining unit 44 calculates and determines the save amount necessary for executing the fuel-saving operation. It should be noted that the save amount may be calculated not only at the time of the first operation but also every time the operation is started. In the warm air heater of the present embodiment, the heating operation is performed continuously for 5 minutes, and the heating load in the room is calculated from the degree of increase in the temperature detected by the temperature sensor 13 during the 5 minutes, and the heating load is calculated according to the heating load. The save amount is calculated.

STEP15 to STEP18 are processing routines of the temperature control operation by turning on / off the gas burner 4. Even if the opening of the proportional control valve 26 is minimized (first setting), when the temperature detected by the temperature sensor 13 continues to rise and exceeds the operation interruption temperature determined by the operation interruption temperature setting unit 47, the temperature control is performed. The control means 42 sets the target combustion amount of the gas burner 4 to 0. As a result, the combustion control unit 43 executes STEP 1
At 6, the solenoid valves 24 and 25 are closed to stop the combustion operation of the gas burner 4.

Then, the temperature control control means 42
At 8, the process proceeds to STEP 4 after waiting for the detected temperature of the temperature sensor 13 to become lower than the operation restart temperature determined by the operation restart temperature determination unit 48, and restarts the combustion operation of the gas burner 4.

The on / off control of the gas burner 4 in steps 15 to 18 prevents the room temperature from continuing to rise due to the continuous combustion of the gas burner 4 even when the temperature set by the temperature setting switch is low. it can.

On the other hand, if the detected temperature of the temperature sensor 13 is equal to or lower than the operation interruption temperature in STEP 15,
Proceed to STEP 30 in FIG. STEP30 to STEP3
7 is a routine showing a fuel-saving driving operation by the fuel-saving setting means 40, the target temperature determining section 41, and the temperature control control means 42.

The hot-air heater of this embodiment performs the fuel-saving operation by gradually lowering the target temperature, but the reduction is limited to a save amount × 6. STEP30
Is a process for confirming whether or not the target temperature has been lowered to this limit. After the target temperature has been lowered to this limit, the process branches from STEP 30 to STEP 12, and the reduction of the target temperature ends. Then, it becomes constant thereafter.

STEP 31 is a process for confirming whether or not the fuel-saving operation has already been started. STEP31
If the save flag F is in the set state (F = 1, fuel-saving operation is being performed), the process proceeds to STEP 40, and if the save flag F is in the reset state (F = 0, fuel-saving operation is not performed), the process proceeds to S40.
Proceed to TEP32.

If the detected temperature of the temperature sensor 13 exceeds the target temperature in STEP 32, and if 30 minutes have elapsed in STEP 33, the target temperature determining section 45 provided in the fuel saving setting means 40 in STEP 34, the current temperature is determined. A temperature obtained by subtracting the save temperature (for example, 0.3 ° C.) from the target temperature is set as a new target temperature. Then, in STEP 35, the fuel-saving setting means 40 starts a 10-minute timer provided therein, sets the save flag F (F = 1) in STEP 36, and starts the fuel-saving operation.

The target temperature determination unit 45 determines at step 37
Every time the 0 minute timer times out, in STEP38,
The temperature obtained by subtracting the save amount from the previous target temperature is instructed to the temperature control controller 41 as a new target temperature.

That is, every time 10 minutes elapse, the target temperature of the temperature adjustment control means 41 decreases by the save amount.
Since the target combustion amount determined by the combustion amount determination unit 46 of the temperature control controller 41 decreases, the supply amount of the fuel gas to the gas burner 4 decreases, and the fuel efficiency improves. In addition, as described above,
Since the save amount is calculated in STEP 14 according to the indoor heating load, even if the target temperature is gradually decreased in this way, the user will not feel uncomfortable.

After the start of fuel-saving driving, STEP 40
The temperature detected by the temperature sensor 13 is
When the temperature is lower than the set temperature of 8 ° C. by 5 ° C. or more, the fuel saving setting unit 40 determines that the indoor environment has changed (for example, the user has opened the window), and sets the save flag F in STEP 41. The fuel saving operation is stopped by resetting (F = 0), and the target temperature is set to the temperature setting switch 2 in STEP42.
Return to the set temperature of 8.

Next, FIG. 5 is a graph showing a change in the temperature detected by the temperature sensor 13 when the target temperature is reduced every 10 minutes by the fuel saving setting means 40. In the figure,
Ta0 is the set temperature of the temperature setting switch 28, and TC0 is the target temperature T at the time of starting the heating operation by the operation interruption temperature determination unit 47.
The operation interruption temperature determined by adding the second predetermined temperature T2 to a0, and TS0 is the temperature detected by the temperature sensor 13.

Further, Ta is a change graph of the target temperature determined by the target temperature determination section 45, Tc is a change graph of the operation interruption temperature determined by the operation interruption temperature determination section 47,
Ts is a change graph of the temperature detected by the temperature sensor 13.

When the heating operation is started and five minutes have elapsed, the save amount T1 is determined by the save amount determining section 44. Thereafter, the detected temperature TS of the temperature sensor 13 gradually increases, and is maintained near Ta0, which is the target temperature, by the control operation of the temperature adjustment control means 41. After the detected temperature of the temperature sensor 13 reaches the target temperature Ta0 (in FIG. 5, 10 minutes have elapsed from the start of heating), after 30 minutes have elapsed, the target temperature Ta is increased every 10 minutes. The determination unit 45 reduces the save amount T1.

Here, the save amount determining section 44 sets the save amount T1 so as to be lower than the second predetermined temperature T2. Then, by the temperature control operation of the temperature control controller 41, the detected temperature TS of the temperature sensor 13 is kept substantially in agreement with the target temperature Ta in accordance with the decrease of the target temperature Ta. Therefore, even if the target temperature decreases by the save amount T1, the detected temperature TS of the temperature sensor 13 becomes lower than the operation interruption temperature Tc.
Is extremely low.

Therefore, when the target temperature Ta is lowered by the save amount T1, the temperature Ts detected by the temperature sensor 13 exceeds the operation interruption temperature Tc, and the steps 15 to 11 in FIG.
By the process of 17, it is possible to prevent the combustion operation of the gas burner 4 from being stopped.

Here, once the combustion operation of the gas burner 4 is stopped, the combustion cannot be restarted immediately thereafter, and it is necessary to perform a pre-purge in STEP 4 before ignition. During the execution of the prepurge, the temperature control cannot be performed, so that stable temperature control cannot be performed.

Therefore, by setting the save temperature T1 to a value lower than the second predetermined temperature T2 and minimizing the stop of the combustion operation of the gas burner 4, stable temperature control can be performed. It can be performed.

In this embodiment, the saving amount is determined 5 minutes after the start of the heating operation, and when the temperature detected by the temperature sensor 13 reaches the target temperature, the fuel-saving operation is started.
Although the target temperature is reduced by the save amount every 10 minutes, these conditions are not particularly limited to this time.

In the above embodiment, the temperature sensor 1
3 shows that the reduction of the target temperature by the fuel-saving operation is permitted only when the detected temperature is equal to or lower than the operation interruption temperature (FIG. 3, STEP 15), but the save flag F is set (F
= 1, during fuel-saving operation), a decrease in the target temperature may be permitted even if the temperature detected by the temperature sensor 13 is equal to or lower than the operation interruption temperature.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is a control block diagram of the hot air heater shown in FIG.

FIG. 3 is an operation flowchart of the hot air heater shown in FIG. 1;

FIG. 4 is an operation flowchart of the hot air heater shown in FIG. 1;

FIG. 5 is a graph showing a temperature control operation of the hot air heater shown in FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main body case, 2 ... duct, 3 ... blower fan, 4 ... gas burner, 5 ... duct, 6 ... gas supply pipe, 7 ... control unit, 8 ... intake port, 9 ... outlet, 10 ... air filter,
11: movable looper, 12: gad motor, 13: temperature sensor, 14: fan motor, 15: rotating blade, 16 ...
Rotation speed sensor, 17: combustion cylinder, 18: combustion plate,
19: igniter, 20: thermocouple, 21: intake port, 22: nozzle, 24, 25: solenoid valve, 26: proportional control valve, 27 ...
Operation switch, 28: Temperature setting switch, 29: Filter lamp, 40: Fuel saving setting means, 41: Temperature control means, 42: Combustion control section, 43: Ventilation control section, 44: Saved quantity determination section, 45: Target Temperature determination unit, 46: combustion amount determination unit, 47: operation interruption temperature determination unit, 48: operation resumption temperature determination unit

Claims (1)

[Claims] 1. A heating source, a blower fan for sending air heated by the heating source into a room, a temperature sensor for detecting a room temperature, a room temperature setting device for setting a target temperature, and a time after starting the heating operation. Fuel economy setting means for lowering the target temperature by a first predetermined temperature as time elapses, and heating the heating source so that the temperature detected by the temperature sensor substantially matches the target temperature during the heating operation. Adjust the amount,
When the detected temperature becomes higher than the target temperature by a second predetermined temperature or more even after the adjustment, the heating source is turned on until the detected temperature falls to a predetermined heating restart temperature set near the target temperature. A temperature control unit for interrupting the operation, wherein the first predetermined temperature, which is a decrease in the target temperature by the fuel saving setting unit, is stopped by the temperature control unit. A hot air heater comprising a temperature setting means for setting the temperature to be lower than the second predetermined temperature used for the condition.