ROOM HEATER

Abstract

A room heater is controlled according to a difference between a detected temperature detected by a first room-temperature detector and a predetermined set temperature. When a detected temperature detected by a second room-temperature detector falls below a first reference temperature, the operation is started on receiving an on-command from a thermostat. When the detected temperature by the second room-temperature detector has raised above a second reference temperature which is set higher than the first reference temperature, the operation is stopped on receiving an off-command from the thermostat. The room heater is controlled to raise a set temperature by a predetermined value if it does not receive the off-command by passing of a first predetermined period of time after having received the on-command or if the detected temperature detected by the first room-temperature detector has been at the set temperature or higher without receiving the off-command for a second predetermined period of time.

Description

BACKGROUND

1. Technical Field

The present invention relates to a room heater including a room-temperature detecting means (a detector which detects a room temperature) and a control means (a controller) configured to control temperature by adjusting an amount of heat to be provided to room air according to a difference between a detected temperature detected by the room-temperature detecting means and a predetermined set temperature.

2. Related Art

As this kind of room heater, JP 2009-150591A discloses a room heater in which a control means is coupled to a thermostat that is also coupled to other appliances. The thermostat includes a second room-temperature detecting means provided independent of a first room-temperature detecting means of the room heater. The thermostat is configured to output an on-command when a detected temperature detected by the second room-temperature detecting means becomes a predetermined first reference temperature or below, and to output an off-command when the detected temperature detected by the second room-temperature detecting means becomes such a predetermined second reference temperature or above, or when the thermostat is manually operated to be switched off, the second reference temperature being set higher than the first reference temperature. On receiving an on-command from the thermostat, the control means operates the room heater, and on receiving an off-command from the thermostat, the control means stops the room heater. The room heater disclosed in JP 2009-150591A is further configured to update a set temperature of temperature control when an on-command from the thermostat is received again according to a difference between a detected temperature detected by the first room-temperature detecting means of the room heater on receiving the off-command from the thermostat and the set temperature.

The control means of the room heater can only receive the on-command and the off-command from the thermostat and cannot recognize the first reference temperature and the second reference temperature set in the thermostat. Therefore, in order to prevent the temperature control from being carried out by the set temperature that has already been set without relation to a room temperature even if the temperature of the room air has already been elevated, e.g., to the second reference temperature when the off-command was outputted from the thermostat, the above-described known room heater is arranged to update the set temperature.

If a user changes to raise the second reference temperature of the thermostat when the room heater is operating, the set temperature of the room heater becomes lower than the second reference temperature. However, the above-described known room heater cannot recognize the second reference temperature of the thermostat, and the set temperature cannot be changed when the room heater is operating. Consequently, the room temperature is hard to rise to the second reference temperature even after a long period of time has passed after receiving the on-command from the thermostat. Therefore, there will continue a state in which the control means receives no off-command from the thermostat. Further, if the detected temperature detected by the first room-temperature detecting means of the room heater reaches the set temperature, the control means of the room heater controls temperature by reducing an amount of heat to be provided to the room air. Therefore, the room temperature is hard to rise to the second reference temperature even after the temperature detected by the first room-temperature detecting means has been at the set temperature or higher for a long period of time. In this manner, the control means receives no off-command from the thermostat. That is, even when a user intends to warm the room by raising the second reference temperature of the thermostat, there will continue a state in which the room temperature will not rise to the second reference temperature.

SUMMARY

In view of the above-described problem, an object of the present invention is to provide a room heater which is configured to raise the room temperature close to a second reference temperature of the thermostat when the user changes to raise the second reference temperature.

In order to solve the above-described problem, according to this invention, there is provided a room heater comprising: a first room-temperature detecting means; and a control means configured to control temperature by adjusting an amount of heat to be provided to room air according to a difference between a detected temperature detected by the first room-temperature detecting means and a predetermined set temperature. A thermostat including a second room-temperature detecting means provided separately from the first room-temperature detecting means of the room heater is coupled to the control means. The thermostat is configured: to output an on-command when a detected temperature detected by the second room-temperature detecting means becomes a predetermined first reference temperature or below; and to output an off-command when a detected temperature detected by the second room-temperature detecting means becomes a predetermined second reference temperature or above, the second reference temperature being set higher than the first reference temperature. The control means is configured to operate the room heater on receiving an on-command from the thermostat and to stop the room heater on receiving an off-command from the thermostat. The control means carries out temperature-raise control by raising a set temperature by a predetermined value or by increasing the amount of heat to be provided to room air by a predetermined value when the control means does not receive the off-command by passing of a first predetermined period of time after having received the on-command from the thermostat or when the detected temperature detected by the first room-temperature detecting means of the room heater has been at the set temperature or higher without receiving the off-command for a second predetermined period of time.

According to this invention, when the user changes to raise the second reference temperature of the thermostat, and when the control means does not receive the off-command by passing of the first predetermined period of time after having received the on-command from the thermostat or when the state in which the detected temperature detected by the first room-temperature detecting means of the room heater has been at the set temperature or higher without receiving an off-command at the set temperature or higher without receiving an off-command for the second predetermined period of time, the control means carries out the temperature-raise control by raising the set temperature by the predetermined value or by increasing the amount of heat to be provided to the room air by the predetermined value to enable to raise the room temperature. Therefore, when the user changes to raise the second reference temperature of the thermostat, the room temperature can be raised close to the second reference temperature.

This invention is preferably configured to carry out temperature-raise control again when no off-command is received by passing of a third predetermined period of time after a previous temperature-raise control. According to this arrangement, the set temperature can be raised stepwise or the amount of heat to be provided to the room air can be increased stepwise, thereby raising the room temperature to the second reference temperature.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a configuration of a room heater according to an embodiment of this invention; and

FIG. 2 is a flow diagram illustrating a control flow of the room heater in FIG. 1.

DETAILED DESCRIPTION

FIG. 1 illustrates a room heater 1 according to an embodiment of this invention. The room heater 1 contains therein: a combustion casing 2 having therein a burner 21; and a heat exchanger 3 in which combustion gas from a burner 21 flows. A supply passage 22 for supplying a fuel gas to the burner 21 has interposed therein: a solenoid valve 22a for opening/closing the supply passage 22; and a proportional valve 22b for varying the flow rate of the fuel gas. In this arrangement, air is supplied from an inlet passage 23 on an upstream of the combustion casing 2, and combustion gas is exhausted to an exhaust passage 32 via an exhaust fan 31 provided on a downstream of the heat exchanger 3. By operating a convection fan 4 provided above the heat exchanger 3, room air sucked from an air inlet 51 opened in a back face of the room heater 1 is heated by exchanging heat with the heat exchanger 3 and is then blown out of the room heater 1 as warm air from an air outlet 52 opened in a lower part of a front face of the room heater 1.

The room heater 1 includes: a first room-temperature detecting means 6 for detecting the temperature of the room air sucked from the air inlet 51; and a controller 7 which is generically called a control means to control the temperature by adjusting the proportional valve 22b to adjust an amount of heat to be provided to the room air according to a difference between the detected temperature detected by the first room-temperature detecting means 6 and a predetermined set temperature. The controller 7 has coupled thereto a thermostat 8. The thermostat 8 has a second room-temperature detecting means 81 which is different from the first room-temperature detecting means 6 in the room heater 1 (this room-temperature detecting means 6 is also called “a first room-temperature detecting means” to distinguish between the second room-temperature detecting means 81). The thermostat 8 outputs an on-command when the detected temperature detected by the second room-temperature detecting means 81 becomes a predetermined first reference temperature or lower, and outputs an off-command when the detected temperature detected by the second room-temperature detecting means 81 becomes a predetermined second reference temperature or higher, or when the thermostat 8 is manually operated to be switched off. The second reference temperature is set higher than the first reference temperature. On receiving an on-command from the thermostat 8, the controller 7 starts the room heater 1 by opening the solenoid valve 22a and by operating the exhaust fan 31 and the convection fan 4. On receiving an off-command from the thermostat 8, the controller 7 stops the room heater 1 by closing the solenoid valve 22a and by stopping the operation of the exhaust fan 31 and the convection fan 4. Further, the thermostat 8 is so arranged that the first reference temperature and the second reference temperature can be changed.

Suppose that, during the operation of the room heater 1, the user changes to raise the second reference temperature in the thermostat 8 so that the set temperature of the room heater 1 becomes lower than the second reference temperature. It is impossible on the side of the room heater 1 to recognize the second reference temperature of the thermostat 8. Therefore, even after a lapse of a long period of time on receiving of the on-command from the thermostat 8, the room temperature may not be raised to the second reference temperature. Consequently, there will continue a state in which the off-command is not received from the thermostat 8. When the temperature detected by the first room-temperature detecting means 6 of the room heater 1 reaches the set temperature, the controller 7 of the room heater 1 controls the temperature by reducing the amount of heat to be provided to the room air. It follows that, even if a state in which the temperature detected by the first room-temperature detecting means 6 is the set temperature or higher continues for a long period of time, the room temperature may not be raised to the second reference temperature, and the controller 7 receives no off-command from the thermostat 8. That is, even if the user intends to warm the room by raising the second reference temperature of the thermostat 8, there will continue the state in which the room temperature does not rise to the second reference temperature.

As a solution, the embodiment of this invention is so arranged that the controller 7 carries out the temperature-raise control by raising a set temperature by a predetermined value or by increasing the amount of heat to be provided to the room air by a predetermined value when: the controller 7 does not receive the off-command by passing (i.e., by the time of completion) of a first predetermined period of time after having received the on-command from the thermostat 8; or when the state in which the detected temperature detected by the first room-temperature detecting means 6 of the room heater 1 is the set temperature or above has continued for a second predetermined period of time without receiving the off-command. Further, the controller 7 carries out the temperature-raise control again when no off-command is received by passing of a third predetermined period of time after having carried out the previous temperature-raise control. The controller 7 updates a set temperature for controlling temperature on receiving the on-command again according to a difference between a detected temperature detected by the first room-temperature detecting means 6 of the room heater 1 when the off-command from the thermostat 8 is received and the set temperature. The control carried out by the room heater 1 will hereinafter be described referring to FIG. 2.

First, when, e.g., the user turns on a main power of the room heater 1, determination is made at STEP 1 whether or not the controller 7 has received the on-command from the thermostat 8, that is, whether or not the detected temperature detected by the second room-temperature detecting means 81 of the thermostat 8 has become the predetermined first reference temperature or lower. Once the controller 7 has received the on-command from the thermostat 8, the operation of the room heater 1 is started at STEP 2. The control of the temperature by adjusting the amount of heat to be provided to the room air is then carried out according to the difference between the detected temperature Tr detected by the first room-temperature detecting means 6 and the predetermined set temperature Ts. In this manner, when the controller 7 starts operating the room heater 1 on receiving the on-command from the thermostat 8, a timing operation with a timer A equipped in the controller 7 is started at STEP 3 (timer-A-start).

Then, at STEP 4, the controller 7 determines whether or not the first predetermined period of time (e.g., 20 minutes) has passed since the timer-A-start and whether or not the detected temperature Tr detected by the first room-temperature detecting means 6 of the room heater 1 is at the set temperature Ts or higher and that state has continued for the second predetermined period of time (e.g., 10 minutes). Until the first predetermined period of time passes or until the state Tr≧Ts continues for the second predetermined period of time, the controller 7 determines at STEP 5 whether or not the off-command from the thermostat 8 has been received, that is, whether or not the detected temperature detected by the second room-temperature detecting means 81 of the thermostat 8 has become the predetermined second reference temperature or higher. When the controller 7 receives the off-command from the thermostat 8, the room heater 1 is stopped at STEP 6. Then, at STEP 7, the set temperature Ts, which is used for controlling temperature when the on-command is received again, is updated according to the difference between the detected temperature Tr detected by the first room-temperature detecting means 6 of the room heater 1 when the off-command from the thermostat 8 is received and the set temperature Ts, and then returns to STEP 1. The set temperature Ts is updated, e.g., by adding to the previous set temperature Ts a half of the difference between the detected temperature Tr and the previous set temperature Ts. The updating of the set temperature Ts can alternatively be made by adding to the previous set temperature Ts the difference between the detected temperature Tr and the previous set temperature Ts. In other words, the updating can also be made by updating the set temperature Ts to the detected temperature Tr detected by the first room-temperature detecting means 6 when the off-command from the thermostat 8 is received.

On the other hand, when the controller 7 judges at STEP 4 that the first predetermined period of time has passed or the state Tr≧Ts has continued for the second predetermined period of time, the temperature-raise control will be performed at STEP 8 by raising the set temperature Ts by the predetermined value ΔT (e.g., 1° C.). According to this arrangement, the second reference temperature of the thermostat 8 is changed to be raised by the user. As a result, when the state in which the off-command is not received until after passing of the first predetermined time or when the state Tr≧Ts continues for the second predetermined period of time without receiving the off-command, there will be performed the temperature-rise control to raise the set temperature Ts by the predetermined value ΔT. It is therefore possible to raise the room temperature. Accordingly, when the user has changed to raise the second reference temperature of the thermostat 8, the room temperature can be made closer to the second reference temperature. Although not illustrated, the temperature rise control may be made by increasing the opening degree of the proportional valve 22b so as to increase the amount of heat to be provided to the room air by a predetermined value, instead of raising the set temperature Ts by the predetermined value ΔT. According to this arrangement, in the same manner as described above, the room temperature can be made closer to the second reference temperature.

Then at STEP 8, when the controller 7 carries out the temperature-raise control by raising the set temperature Ts by the predetermined value ΔT or by increasing the amount of heat to be provided to the room air by the predetermined value, a timing operation is started at STEP 9 with a timer B equipped in the controller 7 (timer-B-start). Then at STEP 10, the controller 7 determines whether the off-command from the thermostat 8 is received or not, and at STEP 11, the controller 7 determines whether or not the third predetermined period of time (e.g., 20 minutes) has passed after the timer-B-start. If the controller 7 receives the off-command from the thermostat 8 by passing of the third predetermined period of time, the process proceeds to STEP 6. If the controller 7 receives no off-command from the thermostat 8 by passing of the third predetermined period of time after the timer-B-start, the process returns to STEP 8. According to this arrangement, the set temperature Ts can be raised stepwise or the amount of heat to be provided to the room air can be increased stepwise, thereby raising the room temperature to the second reference temperature.

The embodiment of this invention has been described with reference to the drawings. This invention shall not, however, be limited to the above-described embodiment. For example, in the above embodiment, the first room-temperature detecting means 6 is configured to detect the temperature of the room temperature sucked from the air inlet 51. It may, however, be so arranged that the room-temperature detecting means may be disposed on an outer surface of the room heater 1 so that the temperature outside the room heater 1 may be detected.

Claims

1. A room heater comprising:

a first room-temperature detecting means; and

a control means configured to control temperature by adjusting an amount of heat to be provided to room air according to a difference between a detected temperature detected by the first room-temperature detecting means and a predetermined set temperature wherein

a thermostat including a second room-temperature detecting means provided separately from the first room-temperature detecting means of the room heater is coupled to the control means,

the thermostat is configured: to output an on-command when a detected temperature detected by the second room-temperature detecting means becomes a predetermined first reference temperature or below; and to output an off-command when a detected temperature detected by the second room-temperature detecting means becomes a predetermined second reference temperature or above, the second reference temperature being set higher than the first reference temperature,

the control means being configured to operate the room heater on receiving an on-command from the thermostat and to stop the room heater on receiving an off-command from the thermostat,

wherein the control means carries out temperature-raise control by raising a set temperature by a predetermined value or by increasing the amount of heat to be provided to room air by a predetermined value when the control means does not receive the off-command by passing of a first predetermined period of time after having received the on-command from the thermostat or when the detected temperature detected by the first room-temperature detecting means of the room heater has been at the set temperature or higher without receiving the off-command for a second predetermined period of time.

2. The room heater according to claim 1, wherein

the control means carries out temperature-raise control again when no off-command is received by passing of a third predetermined period of time after a previous temperature-raise control.