JP3248291B2 - Automatic filling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic hot water filling apparatus for supplying a set amount of hot water to a bathtub and circulating the hot water at a set temperature.

[0002]

2. Description of the Related Art As an example of an automatic hot water filling apparatus for controlling a water level and a hot water temperature in a bathtub to a set water level and a hot water temperature set in a bathtub at a set time, the applicant of the present invention has disclosed Japanese Patent Application No. Hei 3-75.
933 has been filed earlier.

[0003] In this example, by setting the bathing scheduled time in advance, the reheating time is calculated based on the amount of water when the cold water is filled in the bathtub to the set water level and a predetermined temperature difference, and the bathing time is calculated. Since the automatic operation is started retroactively by the reheating time from the scheduled time, the automatic hot water filling operation is surely completed by the scheduled bathing time regardless of the size of the bathtub.

[0004] Further, since the warm-up operation is performed retroactively for a certain period of time from the scheduled bathing time, the temperature becomes appropriate at the scheduled bathing time.

[0005]

However, in the above conventional example, the water level and the predetermined temperature difference when the cold water is filled in the bathtub to the set water level without using the detection value of the water level sensor or the like are used. Although the reheating time is calculated, as described in the specification text, the water amount at the set water level is the water amount required to reach the set water level at the time of the first automatic hot water supply and hot water stored in the control unit. Based on Therefore, if the water amount stored in the control unit has an error compared to the accurate water amount required for the first set water level, the water level at the end of automatic hot water filling has a disadvantage that the error is maintained. I was

Further, in the above-mentioned conventional example, the warm-up operation is performed for a certain period of time from the scheduled bathing time.
In other words, additional heating is performed so that the hot water temperature in the bathtub becomes the set temperature, but if the time at the end of the warming operation is slightly before the bathing scheduled time, the hot water temperature will slightly increase during that short time. This has the disadvantage that the hot water temperature at the scheduled bathing time is slightly lower than the set temperature.

Further, in the conventional example, when the scheduled bathing time is set to, for example, time 2:00, the calculated automatic operation start time is, for example, time 23:50, the current time is, for example, time Despite 0:10, it is erroneously determined that the time is not 23:50 and automatic hot water filling is not performed, and there is a drawback that hot water is not filled in the bathtub even at the scheduled bathing time. Was inconvenient for people.

On the other hand, in the conventional example, since the calculated reheating time is not specifically examined, if the calculated reheating time is inaccurate due to a defect of a sensor or the like, the bathing time is not determined. There has been a drawback that the automatic boiling water in the bathtub has not been finished even though the time has risen for a long time or the scheduled bathing time has come, and this has been extremely inconvenient for the user.

Accordingly, an object of the present invention is to provide an automatic filling system which solves the above-mentioned disadvantages.

[0010]

The above object is achieved.
The present invention for a bathtub, a hot water supply device for supplying hot water to the bathtub,
Water level detecting means for detecting the water level of the bathtub, flow rate detecting means for detecting the flow rate of hot water supplied to the bathtub, heating means for heating the bathtub water, temperature detecting means for detecting the temperature of the bathtub water, and the water level detecting means Control means for controlling the water heater and the heating means in accordance with an input signal of the temperature detecting means; scheduled bathing time setting means for setting a scheduled bathing time in the control means; a bathtub set water level and a bathtub at the scheduled bathing time An automatic hot water filling apparatus that includes an automatic hot water filling start time setting unit that calculates a time required to reach a set temperature and sets an automatic hot water filling start time, when the remaining water does not exist in the bath tub, The automatic filling level is automatically stored every time the automatic filling is performed so that the average value of the stored automatic filling rate (average automatic filling rate) is used. An automatic hot water filling start time setting means for setting is provided, a bath tub dropping hot water supply time A required for automatically filling the water level in the bath tub to the bath tub setting water level, and a bath tub required for heating remaining water in the bath tub to the bath tub set temperature. The remaining water boil-up time B and the set-up water level at the end of automatic hot-watering required to heat up to the bathtub set temperature after automatically filling the bathtub to the set water level are defined as follows. The automatic hot water filling apparatus is characterized in that the start time is {scheduled bathing time− (bath tub drop hot water supply time A + bath tub remaining water heating time B + setting water level automatic hot water ending heating time C)}. Hot water supply time A = (average automatic hot water flow rate-residual water flow rate) / automatic hot water filling speed, bathtub remaining water heating time B = residual water flow rate x (bath tub set temperature-
(Remaining water temperature) / heating means capacity, boil-up time at the end of the automatic water filling at the set water level C = average automatic water filling flow rate x radiation coefficient at the end of the automatic water filling at the set water level

Another invention for achieving the same object
Is a bathtub, a water heater that supplies water to the bathtub, and a water level of the bathtub.
Water level detection means to detect and flow rate to supply hot water to the bathtub
Flow rate detecting means, heating means for heating bath water, and bathtub
Temperature detecting means for detecting the temperature of water, and the water level detecting means
And the input signal of the temperature detecting means and the
Control means for controlling the heating means;
A scheduled bathing time setting means for setting a scheduled time;
The bathtub set water level and bathtub set temperature
And calculate the time required for automatic filling.
Automatic hot water filling with automatic hot water filling start time setting means
Tub when there is no residual water in the tub
Automatic setting when automatic filling is performed to reach the set water level
Stores the filling flow rate every time, and stores the stored automatic filling flow rate
Automatic filling starts using the average value (average automatic filling flow rate)
Automatic hot water filling start time setting means for setting the time is provided, and time determining means for comparing the current time, the scheduled bathing time, and the automatic hot water filling start time is provided, and the current time is set in a range satisfying any of the following three conditions. An automatic hot water filling apparatus, further comprising a time determining means for starting automatic hot water filling if there is any. First condition: Current time <Scheduled bathing time <Starting time of automatic hot water filling Second condition: Automatic hot filling start time ≦ Current time <Scheduled bathing time Third condition: Scheduled bathing time <Automatic hot water filling start time ≦ Current time

Another invention achieving the same object
Is then bathtubs and a water heater for hot water supply to the tub, and the water level detecting means for detecting the water level of the tub, and the flow rate detecting means for detecting the flow rate of hot water to the bathtub, and heating means for heating the bath water, bath water Temperature detection means for detecting the temperature of the water, control means for controlling the water heater and the heating means based on the input signals of the water level detection means and the temperature detection means, and a bathing schedule for setting a scheduled bathing time in the control means. An automatic hot water filling apparatus comprising: time setting means; and automatic hot water filling start time setting means for calculating a time required to reach a bathtub set water level and a bathtub set temperature at the scheduled bathing time to set an automatic hot water filling start time. In the above, if the calculation time required for setting the bathtub set water level and the bathtub set temperature is not within a predetermined fixed range, the calculation time is corrected to a time within the predetermined fixed range. And an automatic water filling apparatus characterized by comprising an automatic water filling the total time changing means for setting changes the automatic water filling start time by time.

[0013]

According to the present invention, in the case where there is no remaining water in the bathtub, the automatic filling flow rate when the automatic filling is performed so as to reach the set water level in the bathtub is stored, and the stored automatic filling flow rate is stored. Since the automatic hot water filling start time is set using the average value (average automatic hot water filling flow rate), the bathtub water level at the scheduled bathing time becomes accurate.

Further, the automatic hot water filling start time is set to a bathing scheduled time, a bathtub dropping hot water supply time A required for automatically filling the bathtub water level to the bathtub set water level, and remaining water in the bathtub is heated to the bathtub set temperature. It is set by the bathtub remaining water heating time B required for raising, and the setting water level at the end of automatic filling, which is required for heating up to the bathtub set temperature after automatically filling the bathtub to the set water level. Since the time C is corrected using the heat radiation coefficient at the end of the automatic hot water filling, the bathtub hot water temperature and the bathtub water level at the scheduled bathing time match the bathtub set water level and the bathtub set temperature, respectively.

The present invention further comprises time determination means for comparing the current time, the scheduled bathing time, and the automatic hot water filling start time, and the automatic hot water is provided if the current time exists within the range of the three conditions described in claim 3. Since the hot water supply is started, the automatic hot water filling is not performed even when the automatic hot water filling start time has come.

Further, if the calculation time required for setting the bathtub set water level and the bathtub set temperature is not within a predetermined fixed range, the calculation time is corrected to a predetermined fixed range.
It does not happen that the bath water has been boiling many hours before the scheduled bathing time, or that the automatic hot water filling in the bathtub has not been completed even though the scheduled bathing time has come.

[0017]

FIG. 1 is a diagram showing the configuration of an automatic hot water filling apparatus according to the present invention. Hereinafter, the automatic hot water filling device of the present invention will be described with reference to this drawing. Reference numeral 1 denotes an automatic hot-water filling device, which is provided with a hot-water supply device 2 for supplying hot water to a bathtub, a kitchen and other plugs.

The hot water supply apparatus 2 is provided with a main water channel 3, and the main water channel 3 is provided with a hot water supply heat exchanger 4 and a hot water supply temperature sensor 5 for detecting the temperature of hot water heated by the hot water supply heat exchanger 4. . Heating of the hot water supply heat exchanger 4 is performed by the hot water supply burner 6, the amount of gas to the hot water supply burner 6 is opened by opening the original solenoid valve 7.
The required gas amount is obtained by varying the opening of the proportional valve 8.

Reference numeral 9 denotes a dropping hot water supply passage branched from the downstream side of the hot water supply temperature sensor 5 of the main water passage 3, and is provided with an open / close type water solenoid valve 10 and a dropping flow rate sensor 11 for detecting a dropping flow rate dropped into a bathtub 19. ing.

The drop hot water supply passage 9 is connected to a reheating circuit 12, and includes a pump 13 for circulating bath water, a bath temperature sensor 14 for detecting bath water temperature, a water level sensor 15 for detecting bath water level, and a bath water temperature. The additional heat exchangers 16 for heating the heat exchangers are arranged. Refired heat exchanger 16
Is heated by the reburning burner 17, and the amount of gas to the reburning burner 17 is obtained by opening the original solenoid valve 18.

The bathtub 19 is connected to the reheating circuit 12.

Reference numeral 20 denotes a controller for controlling a controlled device such as the above-mentioned solenoid valve, which is connected to a remote controller 21. In the remote controller 21, a display unit 22 for displaying an appliance operation state, a reserved bathing time, etc., an automatic hot water filling switch 23, and a scheduled bathing time setting switch 24
, A bathtub setting water level switch 25, a bathtub setting temperature switch 26, and a current time setting switch 27.

FIG. 2 is an explanatory diagram showing the configuration of the controller 20 in detail. Reference numeral 28 denotes a current time setting unit for setting the current time according to a transmission signal of the current time setting switch 27. Reference numeral 29 denotes an automatic hot water filling flow storage section for storing an automatic hot water filling flow every time the automatic hot water filling is performed so as to reach the bathtub set water level when there is no remaining water in the bathtub. Here, when there is no residual water in the bathtub,
This is when the water level sensor 15 does not emit a water level detection signal. Reference numeral 30 denotes an average automatic filling flow rate calculating means for calculating the average value of the automatic filling flow stored in the automatic filling flow storage section 29, that is, the average automatic filling flow rate.

Reference numeral 31 denotes a bathtub dropping hot water supply time calculating means for calculating a bathtub dropping hot water supply time A required for automatically filling the water level in the bathtub 19 to the water level set by the bathtub setting water level switch 25. The bathtub dropping hot water supply time A is calculated by the following equation. Hot water supply time A =
(Average automatic hot water flow rate-residual water flow rate) / auto hot water filling rate Here, the automatic hot water filling rate means that the hot water heated by the hot water supply heat exchanger 14 with the water solenoid valve 10 opened is set to the bath tub 1 at the hot tub set hot water temperature.
9 means the flow rate of the hot water supply per unit time when the hot water supply is performed.

Numeral 32 denotes a bathtub remaining water heating time calculating means for calculating a bathtub remaining water heating time B required to heat the remaining water in the bathtub 19 to the bathtub set water level. It is calculated by the following equation. Bathtub residual water heating time B = residual water flow rate x (bathtub set temperature-
(Remaining water temperature) / reheating heat exchanger heating capacity

Numeral 33 is a set-up water level heating means at the end of the automatic water filling, which is used to calculate the setting water level at the end of the automatic water filling, which is required for heating up to the bathtub setting temperature after the automatic water filling to the bathtub setting water level. Yes, the heating time C at the end of the set water level automatic filling is calculated by the following equation. Heating time at the end of the set water level automatic filling, C = Average automatic filling water flow rate x Heat dissipation coefficient at the end of the set water level automatic filling

Here, the radiation coefficient at the end of the automatic setting of the set water level will be described. In other words, if the automatic hot water filling switch 23 is pressed when there is no remaining water in the bathtub 19, the hot water is automatically supplied to the bathtub setting water level at the hot water temperature set by the bathtub setting temperature switch 26. At the time when the temperature of the bathtub is reached, the temperature of the bathtub is lower than the set temperature due to the heat radiation action.The lowered bathtub temperature is estimated from the outside air temperature, and the set water level is used to correct the bathtub temperature to the bathtub set temperature. This is the heat radiation coefficient per unit volume at the end of filling. When there is no residual water in the bathtub 19,
The time required for automatic hot water supply at the bathtub set temperature to the bathtub set water level is almost constant, and the bathtub hot water temperature per unit volume that decreases during the fixed time is constant in proportion to the rate of decrease in the bathtub outside air temperature. The above-mentioned heat radiation coefficient is also corrected by the decrease rate of the bathtub outside air temperature, and the heating time at the end of the set water level automatic filling is the above-mentioned heat radiation coefficient and the amount of water required to reach the bathtub set water level when there is no residual water in the bathtub. Should be determined by In other words, the heating time at the end of the set water level automatic hot water filling is proportional to the decreasing rate of the bathtub outside air temperature, and is proportional to the average automatic hot water flow rate. Further, as a method of detecting the outside air temperature of the bathtub, the outside air temperature is detected by a temperature sensor of the atmosphere temperature inside the appliance or a detection value of a water inlet temperature sensor (not shown in the present invention) on the water inlet side of the hot water supply device 2. It is preferable to predict the rate of decrease in the bathtub outside air temperature from the predicted outside air temperature.

Numeral 34 denotes a scheduled bathing time setting means for setting the scheduled bathing time transmitted by the scheduled bathing time setting switch 24 in the controller 20.

Numeral 35 denotes an automatic hot water filling start time setting means, which comprises an average automatic hot water filling flow rate, a bath tub dropping hot water supply time A
And the bathtub remaining water heating time B, the set water level automatic hot water filling end heating time C, and the expected bathing time.
Here, the automatic hot water filling start time is calculated by the following equation. Automatic hot water filling start time = bathing scheduled time-(bath tub drop hot water supply time A + bath tub remaining water heating time B + set water level automatic hot water ending heating time C)

Numeral 36 denotes time determination means for comparing the current time, the scheduled bathing time, and the automatic hot water filling start time. The time judging means 36 starts the automatic filling operation when the current time exists within the range of the following three conditions.

The first condition is, as shown in FIG.
As shown in FIG. 4, the scheduled bathing time <the automatic bathing start time, the second condition is as follows: the automatic bathing start time ≦ the current time <the bathing scheduled time, and the third condition is as shown in FIG. Hot water filling start time ≦ current time.

In FIG. 3, FIG. 4, and FIG. 5, the time is displayed using a 24-hour display from 0:00 to 24:00. That is, when the current time reaches the automatic hot water filling start time calculated from the bathing scheduled time, the automatic hot water filling hot water supply is started. If the current time exists, as shown in FIG. This is a well-known fact.

However, the bathing scheduled time set as shown in FIG. 3 or FIG. 5 is, for example, time 3:00, and the automatic hot water filling start time calculated based on the bathing scheduled time is time 23:00. If the current time is time 0:
3, or the current time is time 23:
5, the automatic hot water filling start time 2
Despite the past 3:00, time 23:
In the prior art, there is a drawback that the automatic hot water supply is not started until 00 is reached, and thus the automatic hot water filling is not completed even at the scheduled bathing time of 3:00. If the current time is present in the condition or the third condition, the automatic hot water supply will be performed.
This is the content of claim 3 of the present invention.

In FIG. 6, the vertical axis represents the total time of the automatic hot water filling, and the horizontal axis represents the amount of water required to reach the bathtub set water level, that is, the average automatic hot water filling flow rate. Here, the total time of the automatic hot water filling means the total time of the bathtub drop-in hot water supply time A, the bathtub remaining water heating time B, and the set water level automatic hot water finishing heating time C. Further, the total automatic filling level with respect to the average automatic filling rate is within a range of a straight line and a hatched portion surrounded by the straight line.

The straight line indicates the total time of automatic hot water filling when residual water is present in the bathtub up to the bathtub set water level and the residual water temperature has dropped to near the bathtub outside air temperature. That is,
The additional heating heat exchanger 17 has a lower heating capacity than the hot water supply heat exchanger 4, so if there is cold water in the bathtub up to the bathtub set water level, the longest total hot water filling time is required to heat this to the set temperature. And

The straight line indicates the case where the total time of the automatic filling is the shortest. In other words, the straight line indicates a state in which the automatic hot water supply to the bathtub set water level has already been performed by the user at the automatic hot water filling start time to the bathtub set water level and has been completed by the user, and the total automatic hot water filling time in the straight line is the set water level. This shows the heating time at the end of automatic hot water filling.

In FIG. 6, if the total automatic filling time calculated by the controller is present in the shaded area surrounded by the straight line and the straight line, the automatic filling time is calculated using the calculated automatic filling time. Should be set.

However, in the case where the total automatic filling time calculated in the hatched portion in FIG. 6 does not exist,
It is determined that an erroneous calculation result has been calculated due to noise due to electromagnetic waves or noise generated by peripheral devices, or a detection error of a sensor or the like.
, The calculation result is corrected within the range indicated by the hatched portion, the corrected calculation result is transmitted to the automatic hot filling start time setting means 35, and the automatic hot filling start time is changed.

[0039]

In the present invention, the bathtub set water level and the required amount of hot water are corrected using the average automatic hot water flow rate, so that the detection error of the flow rate sensor is corrected, and the bath water level at the end of the automatic hot water filling is thus corrected. It matches the bathtub setting water level.

In the present invention, the automatic hot water filling total time is calculated and calculated from the bath tub drop-in hot water supply time A, the bath tub remaining water heating time B, and the set water level automatic heating hot water ending time C. The automatic filling start time is set according to the total filling time. In particular, the heating time C at the end of the set filling automatic filling is calculated and corrected together with the average automatic filling flow using the radiation coefficient at the setting filling automatic filling. Therefore, the total time of the automatic hot water filling becomes accurate, and at the scheduled bathing time, the water level in the bathtub and the hot water temperature match the respective set values.

Further, in the present invention, the time judging means for starting the automatic hot water filling when the current time exists within the range satisfying any one of the three conditions described in claim 3 is provided.
The disadvantage that automatic filling is not started even though the automatic filling start time has come is eliminated.

In the present invention, when the calculated total time of the automatic filling is not within a predetermined range, an erroneous calculation result may be calculated due to a detection value error of a sensor or noise due to electromagnetic waves or the like. Assuming that it was done, the automatic hot water filling total time is corrected to within the certain range,
Since the automatic hot water filling start time is changed and set according to the corrected time, it is possible to eliminate the dissatisfaction that the automatic hot water filling has not been finished at the scheduled bathing time or the hot water has been heated many hours before the scheduled bathing time.

In short, in the automatic hot water filling apparatus of the present invention, accurate automatic hot water filling is completed at the scheduled bathing time even if a calculation error due to a detection error of a sensor or the like or noise occurs.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an automatic hot water filling device of the present invention.

FIG. 2 is a diagram showing a configuration diagram of a controller.

FIG. 3 is a diagram showing a relationship among a current time, a scheduled bathing time, and an automatic hot water filling start time.

FIG. 4 is a diagram showing a relationship among a current time, a scheduled bathing time, and an automatic hot water filling start time.

FIG. 5 is a diagram showing a relationship among a current time, a scheduled bathing time, and an automatic hot water filling start time.

FIG. 6 is a diagram showing the relationship between the total automatic filling level and the average automatic filling flow rate.

DESCRIPTION OF SYMBOLS 1 Automatic hot water filling device 2 Hot water supply device 11 Flow rate detecting means 15 Water level detecting means 19 Bathtub 20 Controller 29 Automatic hot water filling flow rate storage unit 30 Average automatic hot water filling flow rate calculating means 31 Bathtub drop-in hot water supply time calculating means 32 Bath tank remaining water heating time calculating means 33 Setting water level Automatic hot water filling end heating time calculating means 34 Expected bathing time setting means 35 Automatic hot water filling start time setting means 36 Time judgment means 37 Automatic hot water filling time changing means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-185808 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F24H 1/00 602

Claims (3)

(57) [Claims] 1. A bathtub, a hot water supply device for supplying hot water to the bathtub, a water level detecting means for detecting a water level of the bathtub, a flow rate detecting means for detecting a flow rate for supplying hot water to the bathtub, a heating means for heating bathtub water, and a bathtub Temperature detection means for detecting the temperature of water, control means for controlling the water heater and the heating means in accordance with input signals of the water level detection means and the temperature detection means, and bathing for setting a scheduled bathing time in the control means Automatic hot water filling means comprising scheduled time setting means, and automatic hot water filling start time setting means for calculating a time required to reach a bathtub set water level and a bathtub set temperature at the bathing scheduled time and setting an automatic hot water filling start time. In the apparatus, when the bathtub is set to the bathtub setting water level when there is no remaining water in the bathtub, the automatic bathing flow is stored every time, and the average value of the stored automatic bathing flow ( Automatic bath filling start time setting means for setting the automatic bath filling start time using the average bath filling flow rate is provided, and a bath tub dropping hot water supply time A required for automatically filling the bath tub water level to the bath tub set water level; The bathtub remaining water boil-up time B required to boil the remaining water in the bathtub to the set temperature, and the set water level required to boil the bathtub to the set temperature after automatically filling the bathtub to the set water level. The time C is defined as follows, and the automatic hot water filling start time is further set as {scheduled bathing time- (bath drop-in hot water supply time A + bath tub remaining water heating time B + set water level automatic hot water ending heating time C)}. Automatic filling system characterized by performing. Hot water supply time A = (average automatic hot water flow rate-residual water flow rate) / automatic hot water filling speed, bathtub remaining water heating time B = residual water flow rate x (bath tub set temperature-
(Remaining water temperature) / heating means capacity, boil-up time at the end of the automatic water filling at the set water level C = average automatic water filling flow rate x radiation coefficient at the end of the automatic water filling at the set water level 2. A bathtub, a water heater for supplying water to the bathtub, and a bath
Water level detection means for detecting the water level in the tub,
Flow rate detecting means for detecting the amount and a heating means for heating bath water
A stage, a temperature detecting means for detecting a temperature of the bath water, and the water
The supply signal is supplied by input signals of the position detecting means and the temperature detecting means.
Control means for controlling the hot water apparatus and the heating means;
Scheduled bathing time setting means for setting a scheduled bathing time in a row
And the bathtub setting water level and bathtub setting
Calculates the time required to reach a constant temperature and automatically opens hot water
Automatic hot water filling start time setting means for setting a start time
There is no residual water in the bathtub in automatic hot water filling equipment
Automatic hot water filling was performed to reach the bathtub setting water level in the case
Automatic hot water flow rate is stored every time,
Automatically using the average value of the filling flow (average automatic filling flow)
Automatic hot water filling start time setting means for setting hot water filling start time
The provided, the current time, and bathing scheduled time, includes a time determination means for comparing the automatic water filling start time, time determination for starting the automatic water filling if the current time in the range satisfying one of the following three conditions An automatic hot water filling device comprising means. First condition: Current time <Scheduled bathing time <Starting time of automatic hot water filling Second condition: Automatic hot filling start time ≦ Current time <Scheduled bathing time Third condition: Scheduled bathing time <Automatic hot water filling start time ≦ Current time 3. A bathtub, a hot water supply device for supplying hot water to the bathtub, a water level detecting means for detecting a water level in the bathtub, a flow rate detecting means for detecting a flow rate for supplying hot water to the bathtub, a heating means for heating bathtub water, and a bathtub. Temperature detection means for detecting the temperature of water, control means for controlling the water heater and the heating means in accordance with input signals of the water level detection means and the temperature detection means, and bathing for setting a scheduled bathing time in the control means Automatic hot water filling means comprising scheduled time setting means, and automatic hot water filling start time setting means for calculating a time required to reach a bathtub set water level and a bathtub set temperature at the bathing scheduled time and setting an automatic hot water filling start time. In the device, if the calculation time required for setting the bathtub set water level and the bathtub set temperature is not within a predetermined range, the calculation time is corrected to a time within the predetermined range. An automatic hot water filling apparatus which comprises an automatic hot water filling total time changing means for changing and setting the automatic hot water filling start time according to the time taken.