JPH11248246A - Water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To see that the water heater can turn on or turn off, in proper timing, the warmth keeping function of the warmth of the water within a heat exchanger within a specified warmth temperature range, providing for the next hot water delivery by combusting a burner in condition that there is no water supply. SOLUTION: A warmth keeping controller 51 judges whether to turn on the warmth keeping function or not, based on the conditions detected by each kind of sensor such as a man-sensitive sensor 72, a water level sensor 37, an outside air temperature sensor 73, a photosensor 74, etc., and turns on the warmth keeping function, according to the judgment results. Moreover, when a specified time passes or it is subjected to the specified operation after start of warmth keeping action, or based on the detection information of the specified sensor, it turns off the warmth keeping function.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water supply having a heat retaining function of burning a burner in a state where there is no flow of water to keep the water in a heat exchanger within a predetermined temperature range for the next hot water. About the vessel.

[0002]

2. Description of the Related Art To supply hot water having a temperature as close to a set temperature as possible from the beginning of opening of a hot water supply device which has been conventionally used, the hot water in a heat exchanger is kept in a predetermined temperature range without flowing water. Some have a function to keep warm. In such a water heater, usually, the heat retention state is maintained from when the water supply is stopped until a certain time such as 5 minutes elapses.

[0003]

However, in such a conventional technique, if the tap water is to be discharged after a lapse of a predetermined time such as 5 minutes from the previous tapping, the tap is not already kept warm, so that the tap is opened. Initially, cold water that greatly deviates from the set temperature comes out. For example, when a long time has elapsed since the last bath, when a shower was started in a bathroom, there was a problem that cold water was initially discharged and caused discomfort.

The present invention has been made in view of such problems of the prior art, and burns the burner in a state where there is no flow of water to prepare the water in the heat exchanger for the next tapping. It is an object of the present invention to provide a water heater capable of turning on and off a heat retaining function for keeping the temperature within a predetermined temperature range.

[0005]

The gist of the present invention to achieve the above object lies in the following inventions. [1] In a water heater having a heat retaining function of burning a burner (12) in a state where there is no water flow and keeping the water in a heat exchanger (13) within a predetermined heat retaining temperature range in preparation for the next hot water supply. A heat retention control means (51) for controlling a heat retention operation for performing the heat retention function, and a sensor (37, 72, 73) for detecting a predetermined state serving as a basis for determining whether to start the heat retention operation. , 74), and the heat retention control means (51) is provided with the sensors (37, 72, 73, 7).
A water heater characterized in that it is determined whether or not to start the heat retaining operation based on the output of 4), and the heat retaining operation is started according to the result of the determination.

[2] The sensor (72) detects whether or not a person has entered the bathroom. The heat retention control means (51) detects that a person has entered the bathroom by the sensor (72). The water heater according to [1], wherein the warming operation is started when (2) is detected.

[3] The sensor (37) detects whether or not a person is in the bathtub, and the heat retention control means (51) detects that a person is in the bathtub by the sensor (37). The water heater according to [1], wherein the warming operation is started when (2) is detected.

[4] The sensor (74) detects brightness, and the heat retention control means (51) determines whether or not night has passed based on the output of the sensor (74). The water heater according to [1], wherein the warming operation is started when night comes.

[5] The sensor (73) detects the outside air temperature, and the heat insulation control means (51) starts the heat insulation operation when the outside air temperature falls below a predetermined value. The water heater according to [1], which is characterized in that:

[6] An operation receiving unit (60) for receiving various operations is provided.
[1], [2], [3], [4] or [5], wherein the heat retaining operation is stopped when the operation receiving unit (60) receives a predetermined operation. Water heater.

[7] When a predetermined time has elapsed since the start of the heat retaining operation, the heat retaining operation is stopped. [1], [2], [3], [4] or [5] ] The water heater described.

[8] A sensor (3) for detecting a predetermined state serving as a basis for determining whether to stop the heat retaining operation.
7, 72, 73, 74), and the heat retention control means (5
1) determines whether to stop the warming operation based on the output of the sensor (37, 72, 73, 74),
[1], [2], [3], [4] or [5], wherein the heat retaining operation is stopped according to the determination result.
The water heater described.

[9] A sensor (3) for detecting a predetermined state serving as a basis for determining whether to stop the heat retaining operation.
7, 72, 73, 74), and the heat retention control means (5
1) is characterized in that the heat retention operation is stopped after a predetermined time has elapsed from the time when it is determined that the heat retention operation should be stopped based on the outputs of the sensors (37, 72, 73, 74). [1], [2], [3], [4]
Or the water heater according to [5].

The present invention operates as follows. The burner (12) is burned in a state where there is no water flow, and the heat exchanger (1) is burned.
3) A heat retention control means (51) for controlling a heat retention operation for performing a heat retention function for keeping the water in the predetermined temperature range in preparation for the next hot water supply is provided with a predetermined state serving as a basis for determination. It is determined based on the output of the sensor (37, 72, 73, 74) to be detected whether or not the warming operation should be started, and the warming operation is started according to the result of the determination.

For example, a sensor (72) for detecting whether or not a person has entered the bathroom is provided.
When the entry of a person into the bathroom is detected, the warming operation is started. Thus, even when a shower or the like is used for the first time after entering the bathroom, hot water at a substantially set temperature can be discharged from the beginning.

Further, a sensor (37) for detecting whether or not a person is in the bathtub is provided, and when it is detected that a person is in the bathtub, a warming operation is started. For example, the pressure sensor (37) detects the water pressure in the reheating path that circulates the hot water in the bathtub and reheats the water. turn on. This makes it possible to raise the temperature of the hot water in the heat exchanger (13) to the heat retaining temperature range before a person goes out of the bathtub and starts using the shower.

In addition, an optical sensor (74) for detecting brightness is used as the sensor (74), and it is determined whether or not night has occurred based on the output of the sensor. Start. The shower is often used at night, and the outside temperature and the temperature of water supply tend to decrease at night. By turning it on when it becomes cold, it is possible to appropriately operate the heat retention function when it is cold or when the shower is used. Further, the outside air temperature is detected by the sensor (73), and when the outside air temperature falls below a predetermined value, the warming operation is started. Thereby, when it is cold, the heat retention function can be appropriately turned on.

The warming operation started in this way is stopped, for example, when a predetermined time has elapsed after the warming operation started. When it is detected that a person enters a bathroom or bathes in a bathtub, the use of hot water is considered to be terminated within a few tens of minutes thereafter. Is stopped, the warming operation can be operated only when necessary.

Further, when a predetermined operation is received after starting the heat retaining operation, the heat retaining operation may be stopped. For example, when a dedicated operation for stopping the warming operation is received, the warming operation is stopped. In addition, when an operation for exiting the driving state is performed or when an operation for canceling the bath priority state is performed, the heat retention operation is stopped. Since these operations mean that no hot water is supplied in the bathroom and no hot water is subsequently supplied, stopping the heat retaining operation by the operation does not cause the heat retaining operation to be wastefully continued.

Further, predetermined sensors (37, 72, 7)
The information detected in (3, 74) may be used as a criterion for determining whether to stop the heat retaining operation. For example, when it is detected by the sensor (72) arranged in the bathroom that no one has left the bathroom, it is determined that the shower is not used thereafter, and the warming operation is stopped. In addition, sensors (73, 2
The heat retaining operation is stopped based on the information from 7). Alternatively, the heat retaining operation may be stopped after a predetermined time has elapsed after it is determined that the heat retaining operation should be stopped based on the information detected by the sensors (37, 72, 73, 74). .

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Each drawing shows an embodiment of the present invention. The water heater 10 according to the present invention has a function of supplying hot water into a faucet or a bathtub of a bath and a function of reheating hot water in the bathtub.
Heating is performed by two heat exchangers, so-called one-can-two-water-channel type. As shown in FIG. 1, the water heater 10 includes a combustion chamber 11
And the lower part of the combustion chamber 11 has a burner 1
In the upper part of the combustion chamber 11, heat exchangers 13 for transmitting heat from the burners 12 to water supply and the like are arranged.

The heat exchanger 13 has both a hot water supply pipe 21 for flowing hot water and a reheating circulation pipe 31 for circulating water in the bathtub for reheating.
The heat exchanger 13 has a function of transferring heat from the burner 12 to the fluid in the pipes 21 and 31 to heat the pipes.

A fixed bypass passage is provided between the water supply side flow path 21a of the hot water supply pipe 21 connected to the inlet side of the heat exchanger 13 and the hot water supply side flow path 21b extending from the outlet side of the heat exchanger 13. Two bypass paths 22 and a bypass path 24 in which the flow control valve 23 is inserted are connected. Heat exchanger 1
Water is mixed with the hot water heated in 3 through the fixed bypass passage 22 and the bypass passage 24, and the bypass ratio can be controlled by the flow control valve 23. A flow control valve 25 for controlling the total flow rate and the bypass ratio of hot water is provided on the hot water supply pipe 21 on the hot water supply pipe 21 side.

In the vicinity of the inlet and outlet of the hot water supply pipe 21, flow sensors 26a and 26b for detecting the presence or absence of water flow and the amount of water flow are provided. In the vicinity of the inlet of the hot water supply pipe 21, a water input thermistor 27 for detecting the temperature of the hot water is provided.
A tapping thermistor 28 for detecting a tapping temperature is attached to each of the vicinity of the outlet 1. Further, a heat exchange thermistor 29 for detecting the temperature of the hot water immediately after leaving the heat exchanger 13 is provided in the tapping-side flow path 21b near the outlet of the heat exchanger 13.

The recirculating pipe 31 includes a bath return pipe section 31a for returning water in the bathtub 40 to the heat exchanger 13;
A bath-out pipe portion 31 b for sending hot water heated by the heat exchanger 13 to the bathtub 40. A circulation pump 32 and a bath return pipe 3 are provided in the middle of the bath return pipe 31a.
A bath water switch 33 for detecting the presence or absence of water flow in 1a is provided. A bath temperature thermistor 34 for detecting the temperature of hot water flowing from the bathtub 40 is attached near the bath water switch 33. Further, a water level sensor 37 for detecting a water level (water pressure) in the bathtub 40 is arranged near the bath temperature thermistor 34.

A tapping-side flow path 21b of the hot-water supply pipe 21;
It is connected to the bath return pipe portion 31a by a pouring pipe 36 provided with a pouring solenoid valve 35, and the hot water supplied by the heat exchanger 13 is poured into the bathtub 40 through the pouring pipe 36. Is available.

The supply and exhaust are forcibly performed by blowing supply air from below the combustion chamber 11 by the combustion fan 14, and the exhaust is discharged from the upper part of the combustion chamber 11. An ignition device 15 is provided near the burner 12. The combustion gas supplied to the burner 12 is
On / off control is performed by the gas solenoid valve 16, the original gas solenoid valve 17, and the gas switching valve 18. Further, the amount of combustion gas supplied to the burner 12 is adjusted by a gas proportional valve 19.

The water heater 10 has a control board 50 for integrally controlling various operations such as tapping a hot water and filling a bath. The control board 50 includes a heat retention control unit 51, a normal combustion control unit 52, and a communication unit 53. Among them, the heat retention control unit 51 performs an operation (a hot water retaining operation) for igniting the burner 12 and keeping the hot water in the heat exchanger 13 within a predetermined temperature range without flowing water. It is a circuit part. The normal combustion control unit 52 is a circuit part that controls the combustion of the burner 12 when hot water is supplied according to the flow of water, or when pouring or reheating the bath. The communication unit 53
This is a circuit portion for receiving a remote operation through the telephone line 71, and realizes so-called telecontrol.

More specifically, the control board 50 includes a CPU (Central Processing Unit) that performs a central function of various controls,
It is composed of a ROM that stores a program to be executed by the PU and various fixed data, and a circuit mainly including a RAM and the like for storing data temporarily necessary for executing the program.

The control board 50 is connected to a remote control unit 60 having an operation section 61 for receiving various operations such as setting of hot water temperature and ON / OFF of automatic operation and a display section 62 composed of a liquid crystal display. In addition, the control board 50 includes a human sensor 72 for detecting whether or not there is a person in the bathroom, an external temperature sensor 73 for detecting the external temperature, and further, for determining whether it is nighttime or daytime. An optical sensor 74 and the like are connected. In addition, the control board 50
, Various control parts and sensors such as a water input thermistor 27, a water level sensor 37, a gas proportional valve 19, and a flow control valve 23 are connected through a wiring 75.

FIG. 2 shows the remote control unit 60. On the display unit 62, various displays such as a display 62a of the set temperature and a combustion display 62b indicating that the burner 12 is burning by a flame pattern are displayed. In addition, the display unit 62 displays an error code or the like indicating the content when an abnormality has occurred. Various operation switches as an operation unit 61 are arranged below the display unit 62. Among them, the switch with the pattern of the upward arrow is an up switch 63a for increasing the set temperature, and the switch with the pattern of the downward arrow is a down switch 63b for decreasing the set temperature.

Priority switch 6 with the word "priority" written
Reference numeral 4a is a switch for setting a priority so that when two or more remote control units such as a main remote control and a bath remote control are attached, the temperature of the hot water to be supplied follows the temperature set on the own unit side. The priority lamp 64b disposed immediately above the priority switch 64a is a lamp for indicating that the own unit is prioritized.

The operation switch 6 with the word "operation" written thereon
Reference numeral 5 denotes a switch for switching the water heater 10 between an operating state in which operations such as tapping, filling the bathtub 40, and reheating can be performed, and a non-operating state in which these operations are not performed. The automatic switch 66 marked with "auto" is a switch that is pressed when performing automatic bath operation. When the automatic switch 66 is depressed, the water heater 10 performs pouring or reheating so that the hot water at the set temperature is filled in the bathtub 40 to the set water level.

Call switch 6 with the character "call"
Reference numeral 7 denotes a switch for talking from a bathroom or the like to a person in the kitchen. That is, when the call switch 67 is pressed, a sound picked up by a microphone (not shown) arranged on the bath remote controller is played from a speaker (not shown) provided on a main remote controller installed in a kitchen or the like,
A message such as "I want you to bring a towel" from a person in the bathroom can be transmitted to a person in the kitchen or the like.

An attraction switch 68a marked with "atsu" is a switch for increasing the temperature of the hot water in the bathtub 40 by 2 ° C. from the current temperature by reheating. on the other hand,
The melody switch 68b on which the word "melt" is written is
The switch is used to lower the temperature of hot water in the bathtub 40 by about 2 ° C. When the filling switch 68b is depressed, the pouring solenoid valve 35 is opened without igniting the burner 12, and the unheated water is poured into the bathtub 40. The comfort switch 69 marked with “comfort” is a dedicated switch for turning on and off the heat retaining function.

Although not shown, the motion sensor 72
Is attached to the remote control unit 60 on the bath side,
Here, an infrared sensor is used as a human sensor.

Next, the operation will be described. While the heat retention function is on, the heat retention control unit 51 controls the combustion of the burner 12 so as to maintain the hot water in the heat exchanger 13 within a predetermined heat retention temperature range. Here, when the temperature of the hot water in the heat exchanger 13 falls below the lower limit value of the heat retaining temperature range, the burner 12 is burned at a predetermined minimum combustion amount for about 2 seconds. Thereby, while the hot water retention operation is in operation (while the heat retention function is on)
In this case, short combustion of about 2 seconds is performed intermittently. Further, the heat retention temperature range is set to a temperature considerably higher than the set temperature of hot water supply, and the flow control valves 23, 2
By adjusting the mixing amount of the water supply by 5, the hot water temperature is lowered to the set temperature and the hot water is discharged.

The water heater 10 has various operation modes depending on the timing of turning on and off such a heat retaining function. Regardless of the operation mode, the heat retention control unit 51 automatically turns on the heat retention function for five minutes after the last hot water supply is stopped, and keeps the hot water in the heat exchanger 13 ready for the next hot water supply. It is supposed to.

First, the case where the heat retention function is turned on based on the detection result of the motion sensor 72 will be described. When the human sensor 72 detects that a person has entered the bathroom, the heat retention control unit 51 turns on the heat retention function. Thus, when a shower or the like is used in the bathroom, hot water of approximately the set temperature can be discharged from the beginning of the first hot water discharge.

Next, a case where the heat retention function is turned on based on the detection result of the water level sensor 37 will be described. People bathtub 40
When entering, the water level rises, and when leaving the bathtub 40, the water level decreases. Therefore, the water level in the bathtub 40 is monitored by the water level sensor 37, and when the water level rises, the heat retention function is turned on. Accordingly, when a shower or the like is used after a person has left the bathtub 40, hot water having a substantially set temperature can be discharged from the beginning of the tap.

Next, a case where the heat retention function is turned on based on the detection result of the outside air temperature sensor 73 will be described. If the outside temperature is high to some extent, even if the heat retention function is off,
There is no danger of extremely cold water coming out at the beginning of tapping, but if the outside temperature is low, such as in the morning of winter, cold water will come out at the beginning of tapping. Therefore, when the outside air temperature detected by the outside air temperature sensor 73 is lower than a predetermined temperature,
Turn on the heat retention function. Thereby, when there is a possibility that cold water may flow out, the heat retention function is turned on, and a comfortable hot water supply state can be obtained even in a cold season.

Further, since the shower is considered to be frequently used at night, and the outside air temperature and the temperature of the water supply tend to decrease at night, the heat retention control unit 51 is turned on by the optical sensor 74 at night. Turn on the heat retention function when detecting that

Next, various timings for turning off the heat retaining function will be described. First, when detecting that a person has entered the bathroom and turning on the heat retention function, the motion sensor 7 is activated.
When it is detected by step 2 that the person has left the bathroom, the heat retention function is turned off. Thus, the heat retention function can be appropriately operated only while a person is in the bathroom, that is, during a period in which there is a possibility that the shower or the like can be used.

When the water level sensor 37 detects that a person has entered the bathtub 40 and turns on the heat retention function,
After a certain period of time has passed since turning on, the heat retention function is turned off. That is, a person usually leaves the bath within a few tens of minutes after entering the bathtub 40. Therefore, the heat retention function is turned off after a certain period of time has elapsed since the entry into the bathtub 40 was detected. An operation mode for turning off the heat retention function after a lapse of a predetermined time from the detection of exit from the bathtub 40 is also provided. Even after getting out of the bathtub 40, there is a possibility that a shower or the like may be used in the washing room.
The heat retention function is turned off after a lapse of a predetermined time from exiting from the vehicle.

If the hot water is supplied immediately before the timing to turn off the heat retaining function comes, a warming operation based on the hot water is performed for 5 minutes after the completion of the hot water supplying operation. Therefore, the operation time of the heat retention function is extended until the five minutes have elapsed.

When the heat retaining function is turned on when the outside air temperature falls below a predetermined temperature, the heat holding function is turned off when the outside air temperature becomes higher than a predetermined temperature. Thus, the heat retaining function can be operated only during a period when the outside air temperature is low and there is a possibility that cold water may flow at the beginning of hot water supply, and energy saving can be achieved.

When the nighttime is detected by the optical sensor 74 and the heat retention function is turned on, the heat retention function is turned off when the light sensor 74 detects that it is not nighttime. Thus, the warming function can be turned on only during the night when cold water is likely to flow at the beginning of hot water supply.

In addition, the heat retaining function can be turned off based on an operation from the remote control unit 60 or a remote operation through a communication line. For example, the heat retention function is turned off when the operation switch 65 is operated to turn off the operation or when the priority switch 64a is operated to turn off the priority. Telephone line 7
When the same operation is performed through 1, the heat retention function is turned off.

It is to be noted that the various operation modes for determining on / off of the above-mentioned heat retaining function can be set by appropriately combining them. That is, the above-mentioned on-condition and off-condition can be selected and set independently of each other.
The above conditions can be combined. For example, if the two on-conditions, that is, the outside air temperature is equal to or lower than a predetermined temperature and that a person enters the bathroom, are set so as to operate by a logical OR, then there is a possibility that cold water may flow out during bathing Even when high, you can turn on the heat retention function. If these are set so as to operate by logical product, it is possible to set such that the heat retention function is turned on only when the outside temperature is low and a person is entering the bathroom, for example, when taking a bath in winter. The same applies to the OFF condition.

In the embodiment described above, the human sensor 72, the water level sensor 37, the outside air temperature sensor 73, the light sensor 74 and the like are used as sensors for turning on the heat retaining function, but other sensors are used. It may be something. Further, in the embodiment, the infrared sensor is used as the human sensor 72. However, the present invention is not limited to this. For example, entry and exit from the bathroom may be detected by a door switch provided on a bathroom door. Further, a switch linked to a bathroom lighting switch or the like may be used as the motion sensor 72.

In addition, after the heat retaining function is turned on by the sensor, the heat retaining function may be turned off when the first hot water is supplied or when a predetermined number of hot water is supplied. Further, in the embodiment, the example in which the heat retention function is turned on / off according to the outside air temperature has been described. However, the heat retention function may be turned on / off based on the temperature of the water supply or the like.

Further, in the embodiment, an example has been shown in which the heat retention function is turned off based on a switch operation provided for another purpose, such as a priority off operation or a driving off operation.
The heat insulation function is turned on / off based on the operation of the comfort switch 69 provided on the remote control unit 60 exclusively for turning on / off the heat insulation function
It may be turned off.

Instead of providing the dedicated switch 69, a special operation different from the normal operation, such as pressing the up switch 63a and the down switch 63b simultaneously, can be performed.
It may be set as an operation for turning off the heat retention function.

Further, in the embodiment, various operation modes for turning on and off the heat retention function are provided, and an appropriate one can be selected and set from among them. However, all the operation modes described above are provided. It is not necessary, and may have only one or two or more operation modes.

In addition, in the embodiment, the burner 12
Is intermittently burned for 2 seconds at the minimum combustion amount to keep the hot water in the heat exchanger 13 intact. However, if the hot water in the heat exchanger 13 can be maintained in the heat retaining temperature range, the form of combustion control Is not limited to this. Further, after stopping the tapping operation, the heat retention function is forcibly turned on for 5 minutes, but the ON time at that time is not limited to 5 minutes. In addition, it may be possible to select whether or not to enable the warming operation for 5 minutes after stopping the hot water by a predetermined operation, and it is not always necessary to provide the warming function for 5 minutes.

Further, in the embodiment, the heat retention temperature in the heat exchanger 13 is set higher, and the hot water is cooled to the set temperature by the bypass mixing to discharge the hot water. However, no bypass mixing is performed, or the mixing ratio is reduced. It may be fixed. However, in these cases, the tapping temperature cannot be arbitrarily adjusted depending on the mixing amount.
The hot water in the heat exchanger 13 must be kept at an appropriate temperature according to the set temperature. The water heater is not limited to the one-can-two water channel type as described in the embodiment.

[0057]

According to the water heater according to the present invention, the heat retaining function of burning the burner in a state where there is no water flow and keeping the water in the heat exchanger within a predetermined temperature retaining temperature range in preparation for the next hot water supply. Is turned on based on the detection results of various sensors, so that the thermal insulation function operates at the appropriate timing even without manual operation, improving convenience and from the beginning of the first hot water supply Hot water at the set temperature can be supplied.

Further, the heat insulation function is turned off when a predetermined time has elapsed after the start of the heat insulation operation or when a predetermined operation is received, or the heat insulation function is turned off based on detection information of various sensors. In addition, it is possible to stop the heat retaining function at an appropriate timing when the function is no longer required.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a water heater according to one embodiment of the present invention.

FIG. 2 is a front view showing a remote control unit of the water heater according to the embodiment of the present invention.

[Description of Signs] 10 hot water heater 12 burner 13 heat exchanger 21 hot water supply pipe 27 incoming water thermistor 28 hot water thermistor 29 heat exchange thermistor 31 circulating pipe for reheating 37 water level sensor 40 bathtub 50 ... Control board 51 ... Insulation control section 52 ... Normal combustion control section 53 ... Communication section 60 ... Remote control unit 61 ... Operation section 62 ... Display section 63a ... Up switch 63b ... Down switch 64a ... Priority switch 65 ... Operation switch 66 ... Automatic switch 67 ... Call switch 68a ... Summer switch 68b ... Uru switch 69 ... Comfort switch 71 ... Telephone line 72 ... People sensor 73 ... Outside air temperature sensor 74 ... Light sensor

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yukinobu Noguchi 3-4 Fukamidai, Yamato-shi, Kanagawa Prefecture Inside Gaster Co., Ltd. (72) Inventor Takeo 3-4-4 Fukamidai, Yamato-shi, Kanagawa Prefecture Gaster Co., Ltd. ( 72) Inventor Yoshihiko Tanaka 3-4 Fukamidai, Yamato City, Kanagawa Prefecture Inside Gaster Co., Ltd.

Claims (9)

[Claims] 1. A water heater having a heat retaining function of burning a burner in a state where there is no flow of water to keep water in a heat exchanger in a predetermined heat retaining temperature range in preparation for the next hot water supply. And a sensor for detecting a predetermined state serving as a basis for determining whether or not to start the heat retaining operation, wherein the heat retaining control means comprises: A water heater comprising: determining whether to start the heat retaining operation based on an output of a sensor, and starting the heat retaining operation in accordance with a result of the determination. 2. The sensor according to claim 1, wherein said sensor detects whether a person has entered the bathroom, and said heat retention control means starts said heat retention operation when said sensor detects that a person has entered the bathroom. The water heater according to claim 1, wherein: 3. The sensor detects whether or not a person is in the bathtub, and the heat keeping control means starts the heat keeping operation when the sensor detects that a person is in the bathtub. The water heater according to claim 1, wherein: 4. The sensor according to claim 1, wherein said sensor detects brightness, and said heat retention control means determines whether or not night has been reached based on an output of said sensor, and said heat retention operation has been performed when night has come. The water heater according to claim 1, wherein the water heater is started. 5. The apparatus according to claim 1, wherein said sensor detects an outside air temperature, and said heat insulation control means starts said heat insulation operation when the outside air temperature falls below a predetermined value. Water heater. 6. An operation reception unit for receiving various operations, wherein the heat retention control means stops the heat retention operation when the operation reception unit receives a predetermined operation. The water heater according to claim 1, 2, 3, 4 or 5. 7. The water heater according to claim 1, wherein the heat retaining operation is stopped when a predetermined time has elapsed since the start of the heat retaining operation. 8. A sensor for detecting a predetermined state serving as a basis for determining whether or not to stop the heat retaining operation, wherein the heat retaining control means should stop the heat retaining operation based on an output of the sensor. And determining whether or not the heat retention operation is stopped, and stopping the warming operation according to the determination result.
The water heater according to 2, 3, 4 or 5. 9. A sensor for detecting a predetermined state serving as a basis for determining whether or not to stop the heat keeping operation, wherein the heat keeping control means stops the heat keeping operation based on an output of the sensor. The water heater according to any one of claims 1, 2, 3, 4, and 5, wherein the heat retaining operation is stopped after a predetermined time has elapsed from a point in time when it is determined that power should be applied.