JPH11264607A - Hot-water supply machine with reheating function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent useless freezing prevention operation by operating a circulation pump for setting operation time for preventing freezing when detection temperature after the lapse time of a timer reaches a specific value is the maximum temperature or less and at the same time is higher than the minimum temperature where freezing can be made, and by stopping the circulation pump when the detection temperature is the minimum temperature or less. SOLUTION: When the detection temperature of a bath thermistor 25 is at a setting temperature or less, a timer is started. When the detection temperature of the bath thermistor 25 is at the setting temperature or less while the timer reaches setting time, it is judged whether the detection temperature is higher than the minimum temperature or not. When the detection temperature is higher than the minimum temperature, it is judged that freezing does not occur in a bath circuit 21, a circulation pump 26 is driven for set operation time for preventing the freezing of the bath circuit 21, and useless freezing prevention operation is prevented. When the detection temperature of the bath thermistor 25 is lower than adjustment temperature, it is judged that the freezing has already occurred in the bath circuit 21, thus preventing the idling operation of the circulation pump 26 without driving the circulation pump 26.

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 apparatus having a reheating function for reheating and supplying hot water to a bath.

[0002]

2. Description of the Related Art Conventionally, in this type, after tap water supplied from a hot water supply port is heat-exchanged in a hot water supply heat exchanger heated by combustion of a burner in a water heater main body, a mixing valve is provided. A part of the tap water from the water inlet was mixed to set the temperature to the set temperature and the hot water was supplied from the hot water outlet, and the water in the bathtub was heated by the combustion of the burner in the water heater body by the circulation pump. After exchanging heat with the bath heat exchanger, return to the bath tub again, the bath thermistor detects the temperature of the bath water sent from the bath tub to the bath heat exchanger, and when it reaches the set temperature, the circulation pump is turned on. A bath circuit to stop was provided.

In order to prevent the bath circuit from freezing, for example, the temperature of bath water in the bath circuit is detected by a bath thermistor provided in the main body of the water heater, and when the temperature falls below a predetermined temperature, a circulation pump is driven. Thus, bath water was circulated in the bath circuit to prevent freezing.

[0004]

By the way, in this conventional apparatus, the predetermined temperature is set to a temperature at which freezing may occur in the bath circuit, and when the detected temperature of the bath thermistor falls to the predetermined temperature, the temperature is further increased. After the temperature has dropped to a predetermined temperature,
Even if the temperature rises above the predetermined temperature, the circulating pump is driven once the temperature has dropped to the predetermined temperature, even though no freezing occurs in the bath circuit, and a useless freezing prevention operation is performed. There was a problem.

[0005]

The present invention focuses on this point and solves the above-mentioned drawbacks. In particular, the present invention has a configuration in which a circulating pump and a bathtub water are supplied while returning from the bathtub to the bathtub through the bath heat exchanger. A bath circuit provided with a bath thermistor that detects the temperature of the bath, and a control unit that operates a circulating pump based on the detected temperature of the bath thermistor to prevent freezing; Has a timer,
When the detected temperature of the bath thermistor is equal to or lower than a predetermined temperature, a timer is started, and when the elapsed time of the timer elapses a predetermined time, the detected temperature is equal to or lower than an upper limit temperature, which is a temperature at which freezing may occur, and freezing has already occurred. When the temperature is higher than the lower limit temperature, the circulation pump is operated for the set operation time to prevent freezing, and when the temperature is lower than the lower limit temperature, the circulation pump is kept stopped.

[0006]

[Action] The detected temperature X of the bath thermistor 25 is the set temperature A
In the following cases, the timer 33 is started, and when the elapsed time of the timer reaches the set time T, if the detected temperature X of the bath thermistor 25 is equal to or lower than the set temperature A, the detected temperature X of the bath thermistor 25 further becomes lower than the lower limit temperature C. If the temperature is higher than the lower limit temperature C, it is determined that freezing has not yet occurred in the bath circuit 21 and the set operation time M circulation pump 26
Is driven to prevent the bath circuit 21 from freezing, so that useless freezing prevention operation can be prevented.

If the detected temperature X of the bath thermistor 25 is lower than the lower limit temperature C, it is determined that the bath circuit 21 is already frozen, and the circulation pump 26 is not driven and the circulation pump 26 is emptied. Operation can be prevented, and damage to the circulation pump due to idle operation can be prevented.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a water heater with a reheating function according to the present invention. Reference numeral 1 denotes a main body frame of a water heater with a reheating function, and a drum 5 having a heat exchanger 3 for hot water supply and a heat exchanger 4 for bath formed integrally with the same fins 2 is provided inside. ing.

Reference numeral 6 denotes a petroleum vaporizing burner 7 provided below the drum 5, a blower 8 for blowing combustion air to the burner 7, and a fuel pump 9 as a fuel supply means for supplying fuel to the burner 7. And heats the hot water supply heat exchanger 3 and the bath heat exchanger 4 by the heat of the combustion gas and the combustion in the burner 7.

Reference numeral 10 denotes a hot water supply circuit extending from the water supply port 11 to the hot water supply port 12 via the hot water supply heat exchanger 3, and a flow sensor 13 for supplying tap water supplied from the water supply port 11 directly connected to the water pipe.
Detects water flow to prevent empty burning, and feeds water thermistor 1
After detecting the temperature at 4 and exchanging heat with the hot water supply heat exchanger 3, a part of the tap water supplied from the water supply port 11 is mixed at the mixing valve 15 so as to reach the set temperature, and the hot water is supplied. The temperature of tap water is detected by a thermistor 16 and tap water is supplied from the hot water supply port 12 to a water faucet (not shown) connected to the hot water supply port 12, and is further intermittently provided downstream of the mixing valve 15. A water proportional valve 17 for preventing hot water temperature unevenness when hot water is supplied is provided.
An overpressure relief valve 18 is provided to release the pressure when the pressure inside the cylinder becomes abnormally high.

Reference numeral 19 denotes an anti-freezing heater attached to the hot water supply heat exchanger 3. The temperature of the hot water supply heat exchanger 3 detected by the heat exchange thermistor 20 provided in the hot water supply heat exchanger 3, and a water supply thermistor When the temperature of the water supply detected at 14 drops to a temperature at which freezing may occur, the water is supplied to heat the heat exchanger 3 for hot water supply, thereby preventing freezing from occurring in the hot water supply circuit 10. is there.

A bath circuit 21 includes an outgoing pipe 23 and a return pipe 24 connecting the bathtub 22 and the heat exchanger 4 for bath.
A bath thermistor 25 for detecting the temperature of bath water flowing into the bath heat exchanger 4 from the outgoing pipe 23 and the bath heat exchanger 4, and located in the bath circuit 21 between the outgoing pipe 23 and the bath heat exchanger 4. A self-priming circulating pump 26 for circulating bathtub water, and a running water switch 27 that is located between the bath heat exchanger 4 and the return pipe 24 and detects the bathtub water flow to prevent empty heating. It is a thing.

Reference numeral 28 denotes a control unit including a microcomputer 29 and various drive circuits 30, a power supply circuit 31, a memory 32, a timer 33, and the like. Hot water is supplied by setting a hot water switch (not shown) of an operation unit 34 such as a remote controller. In addition to performing the operation of heating and reheating the bath by setting the operation and other switches, when the above-described operation is not performed, or when the operation of the antifreeze switch (not shown) of the operation unit 34 is performed, the operation of the antifreeze operation is performed. At the time of setting, the hot water supply circuit 10 and the bath circuit 2
The anti-freezing control is performed so that 1 does not freeze.

When the hot water supply operation is performed, the operation unit 3
The amount of combustion by the burner 7 is determined in accordance with the set temperature 4 and the temperature detected by the hot water supply thermistor 16, and the amount of fuel supplied to the burner 7 and the amount of combustion air supplied by the blower 8 are adjusted based on the determined amount. The flow sensor 13 detects the flow of tap water generated in the hot water supply circuit 10 when the previously connected faucet is opened, thereby igniting the burner 7 to start combustion and closing the faucet. The flow sensor 13 detects the stoppage of water flow and extinguishes the burner 7.

When the bath is heated and reheated, the set temperature of the operation unit 34 and the bath thermistor 2 are set.
5, the amount of combustion by the burner 7 is determined in accordance with the detected temperature, and the amount of fuel supplied to the burner 7 and the amount of combustion air supplied by the blower 8 are adjusted based on the determined amount.
The flow of the bathtub water generated in the bath circuit 21 by the drive of the water is detected by the water switch 27, whereby the burner 7 is ignited and the combustion is started, and the detected temperature of the bath thermistor 25 reaches the set temperature of the operation unit 34. When it reaches, the burner 7 is extinguished.

In order to prevent freezing mainly in winter, when the hot-water supply operation, bath boiling and reheating operations are not performed, or when the anti-freezing operation is set, the hot-water supply circuit 10 performs heat exchange for hot-water supply. When the temperature detected by the heat exchange thermistor 20 attached to the heater 3 or the water supply thermistor 14 or the hot water supply thermistor 16 in the hot water supply circuit 10 decreases to a temperature at which freezing may occur, the hot water supply heat exchanger 3 is used to prevent freezing.
Energizes the anti-freezing heater 19 attached to the hot water supply circuit 1
0, heat exchange thermistor 20 or water supply thermistor 14
When the detected temperature of the hot water supply thermistor 16 rises to a temperature at which there is no risk of freezing, the energization of the antifreeze heater 19 is stopped.
If it is not possible to completely prevent the freezing of zero, the freezing is prevented by passing a small amount of tap water through the hot water supply circuit 10 with the hot water supply switch off.

In the bath circuit 21, when the temperature detected by the bath thermistor 25 drops to a temperature at which freezing may occur, a circulation pump 26 is driven to prevent freezing.
It circulates bath water in the bath circuit 21 and is shown in FIG.
This will be described according to the flowchart of FIG.

First, the detected temperature X of the bath thermistor 25
However, the temperature in the bath circuit 21 is a temperature at which there is a possibility of freezing, and a predetermined temperature X ′ which is a temperature detected by the bath thermistor 25 when the bath thermistor 25 receives the influence of heat due to the combustion of the burner 7. Determine if it is low.
(S1)

In the present embodiment, the predetermined temperature X 'is set to 7 ° C., and when the detected temperature X of the bath thermistor 25 is lower than 7 ° C., the operation unit 34 is operated to set the freeze prevention mode. It is determined whether or not the hot water supply switch is turned off. (S2)

Accordingly, even if the bath thermistor 25 is affected by the heat generated by the combustion of the burner, the predetermined temperature X 'is set higher in consideration of this, so that the detected temperature of the bath thermistor is set to the actual bath temperature. Even when the temperature is higher than the temperature in the circuit, the anti-freezing control can be performed to prevent the bath circuit from freezing.

Then, the freeze prevention mode is set, or
When the hot water supply switch is turned off, the burner 7 does not burn, that is, the bath thermistor 25 disposed in the water heater body is not affected by the heat generated by the combustion of the burner 7. , As a normal setting,
The normal set values are set such that the set temperature A = a, the upper limit temperature B = b, the set time T = t, the lower limit temperature C = c, and the set operation time M = m. (S3) In this example, a = 4 ° C., b = 4 ° C., t = 10 minutes, c = −
The temperature was set at 5 ° C. and m = 1 minute.

When the antifreeze mode is not set and the hot water supply switch is on, the state in which the burner 7 may burn, that is, the effect of heat due to the combustion of the burner 7 is determined in the water heater main body. The bath thermistor 25 disposed at the position A may be subjected to the following corrections: the set temperature A = a ′, the upper limit temperature B = b ′, and the set time T.
= T ', lower limit temperature C = c', and set operation time M = m '. (S4) In this embodiment, a ′ = 7 ° C., b ′ = 7 ° C., t ′ = 5 minutes,
c ′ = − 3 ° C. and m ′ = 2 minutes.

Next, it is determined whether the detected temperature X of the bath thermistor 25 is lower than the set temperature A (S5). If the detected temperature X is lower than the set temperature A, it is determined that there is a possibility of freezing, and the timer 33 in the control unit 28 is started. . (S6)

Then, when the elapsed time of the timer 33 reaches (S7), the detected temperature X of the bath thermistor 25 at that time.
Is lower than the upper limit temperature B (S8). If it is higher than the upper limit temperature B, the process returns to (S1). If it is lower than the upper limit temperature B, it is further determined whether the detected temperature X of the bath thermistor 25 is higher than the lower limit temperature C. (S9)

In (S9), if the detected temperature X of the bath thermistor 25 is lower than the lower limit temperature C, the bath circuit 2
1 is frozen, and in this state the circulation pump 26
Is driven, it is determined that the circulation pump 26 is idle, and the process returns to (S1) without driving the circulation pump 26,
If the detected temperature X of the bath thermistor 25 is higher than the lower limit temperature C, it is determined that freezing has not yet occurred in the bath circuit 21, and the circulating pump 26 is driven to prevent freezing of the bath circuit 21 and at the same time the control unit. The timer 33 in 28 is started. (S10)

When the elapsed time of the timer 33 reaches the set operation time M (S11), the circulating pump 26 is stopped (S12), and the process returns to (S1).

Before the elapsed time of the timer 33 reaches the set time T in (S7), for example, if the burner 7 is ignited by the hot water supply operation and the combustion is performed, the influence of the heat due to the combustion of the burner 7 is taken into the bath. When the thermistor 25 receives the signal, it determines that the detected temperature X is not accurate (S13), and proceeds to (S10) to drive the circulation pump 26 to prevent the bath circuit 21 from freezing, and at the same time, the timer 33 in the control unit 28. Is to start.

As a result, the burner 7 burns before the elapsed time of the timer 33 reaches the set time T, and the heat causes the detected temperature X of the bath thermistor 25 to become higher than the actual temperature in the bath circuit 21. Also, when the burner 7 burns, the circulating pump 26 is driven to circulate the bath water in the bath circuit 21, so that freezing in the bath circuit 21 can be prevented.

In this embodiment, the set temperature A and the upper limit temperature B are set to the same temperature. However, the present invention is not limited to this. The upper limit temperature B is set lower than the set temperature A or the temperature A is set higher than the upper limit temperature B. May be set higher. Further, in order to prevent freezing of the hot water supply circuit 10, a second correction set value may be provided in consideration of the influence of heat due to energization of the freeze prevention heater 19, and in this case, the elapsed time of the timer 33 is set in (S7). When the anti-freezing heater 19 is energized before the time T is reached, the bath thermistor 25 receives the influence of heat from the anti-freezing heater 19, and determines that the detected temperature X is not accurate (S13), (S10). Alternatively, the circulation pump 26 may be driven to prevent freezing.

[0030]

As described above, the present invention provides a bath circuit provided with a circulating pump and a bath thermistor for detecting the temperature of bath water while returning from the bath to the bath through the bath heat exchanger. A water heater with a reheating function having a control unit that operates a circulating pump based on the detected temperature of the thermistor to prevent freezing, wherein the control unit has a timer, and the timer is used when the detected temperature of the bath thermistor is equal to or lower than a predetermined temperature. When the detected temperature when the elapsed time of the timer elapses a predetermined time is equal to or lower than the upper limit temperature which is a temperature at which freezing may occur and higher than the lower limit temperature which is a temperature at which freezing has already occurred, the circulation pump Is operated for the set operation time to prevent freezing, and keeps the circulation pump stopped when the temperature is below the lower limit temperature, and drives the circulation pump even if the bath circuit does not freeze. It is capable not to perform unnecessary freeze prevention operation called.

When the detected temperature of the bath thermistor is lower than the lower limit temperature, it is determined that freezing has already occurred in the bath circuit, and the circulation pump is not driven. Therefore, the detected temperature of the bath thermistor is lower than the set temperature. If the temperature suddenly drops from the time to the elapse of the set time and the bath circuit freezes, the circulation pump will not be driven in that state, and the circulation pump will not operate due to idling when the bath circuit freezes. Damage can be prevented.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a water heater with a reheating function provided with an embodiment of the present invention.

FIG. 2 is a block diagram of the same.

FIG. 3 is a flowchart showing control for preventing freezing of the bath circuit.

[Explanation of symbols]

 Reference Signs List 4 heat exchanger for bath 21 bath circuit 22 bathtub 25 bath thermistor 26 circulation pump 28 control unit 33 timer

Claims (3)

[Claims] A bath circuit provided with a circulation pump and a bath thermistor for detecting the temperature of bath water on the way from the bath to the bath again through the bath heat exchanger, and a circulation pump based on the detected temperature of the bath thermistor. A water heater with a reheating function provided with a control unit that operates to prevent freezing, wherein the control unit has a timer, and when the detected temperature of the bath thermistor is equal to or lower than a predetermined temperature, the timer is started, and the elapsed time of the timer is elapsed. When the detected temperature when the predetermined time has elapsed is equal to or lower than the upper limit temperature which is a temperature at which there is a possibility of freezing and higher than the lower limit temperature which is a temperature at which freezing has already occurred, the circulation pump is operated for the set operation time to perform freezing. A water heater with a reheating function, which prevents heat and keeps the circulation pump stopped when the temperature is below the lower limit temperature. 2. A bath circuit provided with a circulating pump and a bath thermistor for detecting the temperature of bath water on the way from the bath tub to the bath tub and back to the bath tub again, and from a water supply port through the hot water supply heat exchanger. A reheating function including a hot water supply circuit leading to a hot water supply port, a combustion unit for heating the bath heat exchanger and the hot water supply heat exchanger, an operation unit having a hot water supply operation switch, and a control unit having a timer. In the attached water heater, the control unit includes:
When the detected temperature of the bath thermistor is lower than the predetermined temperature, it is further determined whether the detected temperature is lower than the set temperature which is lower than the predetermined temperature, and when the detected temperature is lower than the set temperature, the timer is started and the elapsed time of the timer is set. When the detected temperature when the time has elapsed is equal to or lower than the upper limit temperature at which there is a possibility of freezing and higher than the lower limit temperature at which freezing occurs, the circulation pump is operated for the set operation time to prevent the bath circuit from freezing. When the temperature is equal to or lower than the lower limit temperature, the circulation pump is kept stopped, and the set values of the set temperature, set time, upper limit temperature, set operation time, and lower limit temperature are set so that the detected temperature of the bath thermistor is equal to or lower than a predetermined temperature. A hot water heater with a reheating function, wherein a normal set value is set when the hot water supply operation switch is off and a correction set value is set when the hot water supply operation switch is on. 3. The control unit immediately activates the circulation pump for a set operation time when the combustion unit burns during a period from a time when a detected temperature of the bath thermistor falls below a set temperature to a time when a set time elapses. 3. The water heater with reheating function according to claim 2, wherein the bath circuit is prevented from freezing.