JP5878858B2 - Hot water storage water heater - Google Patents

Description

  The present invention relates to a hot water storage type water heater that boils hot water with a heating means and stores the hot water in a hot water storage tank.

  Conventionally, in this type of hot water storage type water heater, as shown in Patent Document 1, a hot water storage tank, a heat pump unit, a heating pipe connecting a lower portion of the hot water storage tank and an inlet of the heat pump unit, and an outlet of the heat pump unit And a heating return pipe connecting the upper part of the hot water storage tank, a heating branch pipe branched from the heating return pipe and connected to the lower part of the hot water storage tank, and a heating three-way valve provided at the branch point of the heating return pipe and the heating branch pipe In some cases, after the start of boiling, the heating three-way valve is switched from the heating branch pipe side to the heating return pipe side when the boiling temperature becomes a predetermined temperature or higher.

JP 2009-264617 A

  However, in such a conventional one, the heating three-way valve has a structure in which the outlet ports A and B are opened at the left and right ends of the T-shaped channel, and the inlet port C is opened at the lower end of the T-shape. Since it is common, if the heating three-way valve is assembled upside down, the heating return pipe on the hot water storage tank side should be connected to the outlet port A of the heating three-way valve. When the heating return pipe on the hot water storage tank side is connected to the outlet port B of the heating three-way valve to which the heating branch pipe should be connected, boiling is not normally performed and there is no means for detecting this. There was a problem.

  Therefore, in order to solve the above-described problems, the present invention provides a hot water storage tank for storing hot water for hot water supply, a hot water storage temperature sensor for detecting the temperature of hot water in the upper portion of the hot water storage tank, and a hot water storage tank in the hot water storage tank. A heating means for heating hot water, a heating forward pipe connecting the lower part of the hot water storage tank and the inlet of the heating means, a heating return pipe connecting the outlet of the heating means and the upper part of the hot water storage tank, and a branch from the heating return pipe A heating branch pipe connected to the lower part of the hot water storage tank, a heating circulation pump provided in the heating forward pipe for circulating hot water in the hot water storage tank to the heating means, an outlet port a, an outlet port b, and an inlet port c are provided. The outlet port a or one of the outlet port b and the inlet port c, and a valve motor for driving the valve body, and the outlet port a The heating return pipe on the hot water storage tank side, the outlet port b is heated by the heating branch pipe, the inlet port c is heated by the heating return pipe on the heating means side, and heated by the heating means. A boiling temperature sensor for detecting the temperature of hot water, and heating the hot water in the hot water storage tank by driving the heating means and the heating circulation pump, and at the start of boiling, the heating three-way valve In the hot water storage type hot water heater provided on the outlet port b side, and having a control means for driving the valve motor to switch the heating three-way valve to the outlet port a side when the boiling temperature sensor detects a predetermined temperature or higher, the control The means cannot confirm the temperature above a predetermined temperature with the hot water storage temperature sensor even though the heating three-way valve is switched to the outlet port a side after a certain time has elapsed since the start of boiling. Lever, switches the heating three-way valve to the outlet port b side, then confirms a predetermined temperature or higher by the hot water storage temperature sensor until the predetermined time elapses, and to determine the assembly opposite the heating three-way valve.

  Moreover, in Claim 2, in the thing of Claim 1, when the said control means judges that the said heating three-way valve is reversely assembled, it continues boiling in the state which switched the said heating three-way valve to the exit port b side. I did it.

  Moreover, in Claim 3, after the said control means judges that the said heating three-way valve was reversely assembled in the thing of Claim 1 or 2, the subsequent boiling is performed by the said heating three-way valve at the start of boiling. Is the outlet port a side, and the valve motor is driven to switch the heating three-way valve to the outlet port b side when the boiling temperature sensor detects a predetermined temperature or higher.

  Further, according to a fourth aspect of the present invention, in the first aspect, the control means uses the hot water storage temperature sensor to determine a predetermined value after the heating three-way valve is switched to the outlet port a side after a predetermined time has elapsed since the start of boiling. If the temperature cannot be confirmed, the heating three-way valve is switched to the outlet port b side. If the temperature does not exceed the predetermined temperature by the hot water storage temperature sensor even after a predetermined time has elapsed, it is determined that the heating means is reversely connected. I did it.

  According to claim 1 of the present invention, it is possible to reliably detect that the piping corresponding to the outlet port of the heating three-way valve is erroneously assembled in reverse.

  Further, according to the second and third aspects, after the reverse assembly of the heating three-way valve is detected, the control means can change the control direction of the heating three-way valve and boil up as usual.

  Further, according to the fourth aspect, it is possible to discriminate between the reverse assembly of the heating three-way valve and the reverse connection in which the inlet and outlet of the heating means are connected in reverse, and subsequent measures are facilitated.

Schematic configuration diagram of one embodiment of the present invention Flow chart for explaining the operation of the same embodiment Schematic configuration diagram of the reverse assembly state of the heated three-way valve Diagram showing correspondence between piping connected to outlet port of heating three-way valve Schematic configuration diagram of reverse connection of heating means

Next, a hot water storage type water heater according to an embodiment of the present invention will be described with reference to the drawings.
1 is a hot water storage tank unit having a hot water storage tank 2 for storing hot water for hot water supply, 3 is a heat pump unit as a heating means for heating hot water in the hot water storage tank 2, 4 is a hot water tap, 5 is a display unit 5a and a plurality of It is a water heater remote controller having an operation switch 5b. The volume of the hot water storage tank 2 is about 150L to 550L.

  6 is a water supply pipe for supplying city water to the bottom of the hot water storage tank 2, 7 is a hot water discharge pipe for discharging water from the upper part of the hot water storage tank 2, 8 is a water supply bypass pipe branched from the water supply pipe 6, and 9 is hot water from the hot water supply pipe 7. And a hot water supply mixing valve 10 for mixing water from the water supply bypass pipe 8 to a desired temperature, and 10 is a hot water supply pipe for leading the hot water mixed by the hot water supply mixing valve 9 to the external hot water tap 4.

  Reference numeral 11 denotes a pressure reducing valve that is provided in the water supply pipe 6 at the most upstream position in the case of the hot water storage tank unit 1, and 12 is an overpressure relief valve that relieves the overpressure in the hot water storage tank 2.

  Reference numeral 13 denotes a hot water supply temperature sensor that is provided in the middle of the hot water supply pipe 10 and detects the hot water supply temperature, and 14 is a hot water supply flow rate sensor that is provided in the middle of the hot water supply pipe 10 and detects the hot water supply flow rate.

  The heat pump unit 3 includes a compressor 15 that compresses the refrigerant, a refrigerant water heat exchanger 16 that exchanges heat between the compressed high-temperature refrigerant and hot water from the hot water storage tank 2, and the refrigerant that has dissipated heat in the refrigerant water heat exchanger 16. An expansion valve 17 that decompresses the refrigerant, an evaporator 18 that evaporates the low-temperature and low-pressure refrigerant, a refrigeration cycle pipe 19 that annularly connects the compressor 15, the refrigerant water heat exchanger 16, the expansion valve 17, and the evaporator 18, and evaporation A blower 20 that blows outside air serving as a heat source to the cooler 18 and a heating circulation pump 21 that supplies hot water from the hot water storage tank 2 to the water side of the refrigerant water heat exchanger 16 are provided.

  22 is a heating forward pipe connecting the lower part of the hot water storage tank 2 and the water side inlet of the refrigerant water heat exchanger 16 of the heat pump unit 3, and 23 is the water side outlet of the refrigerant water heat exchanger 16 of the heat pump unit 3 and the upper part of the hot water tank 2. The heating return pipe 24 is connected to the lower part of the hot water storage tank 2 via the water supply pipe 6 and is branched from the middle of the heating return pipe 23, and 25 is a branching position of the heating return pipe 23 and the heating branch pipe 24. Is a heating three-way valve. The heating branch pipe 24 may be directly connected to the lower part of the hot water storage tank 2.

  Here, the heating three-way valve 25 has a body 25a having outlet ports a and b at the left and right ends of the T-shaped flow path and an inlet port c at the lower end of the T-shape, and is disposed in the body 25a. A ball valve 25b as a valve body that has a letter-shaped flow path and communicates one of the outlet port a or the outlet port b and the inlet port c, and a valve motor 25c that rotates the ball valve 25b. The port c is connected to the heating return pipe 23 on the heat pump unit 3 side, the outlet port a is connected to the heating return pipe 23 on the hot water storage tank 2 side, and the outlet port b is connected to the heating branch pipe 24.

  Reference numeral 26 denotes an incoming water temperature sensor that detects the temperature of hot water flowing into the refrigerant water heat exchanger 16 from the heating forward pipe 22, and reference numeral 27 denotes a boiling point that detects the temperature of hot water flowing from the refrigerant water heat exchanger 16 to the heating return pipe 23. A plurality of temperature sensors 28 a to d are hot water storage temperature sensors provided on the upper and lower sides of the hot water storage tank 2.

  29 is supplied with detection values of the hot water temperature sensor 13, the hot water flow rate sensor 14, and the hot water storage temperature sensors 28a to 28d, and controls the operation of the hot water mixing valve 9 and the heating three-way valve 25, and the hot water remote controller 5 and necessary information. It is the hot water storage control means connected so that transmission / reception is possible.

  30 is inputted with detection values of the incoming water temperature sensor 26 and the boiling temperature sensor 27, and controls the operation of the compressor 15, the expansion valve 17, the blower 20, and the heating circulation pump 21, and the hot water storage control means 29 and necessary information. It is the heating control means connected so that transmission / reception was possible.

  Here, the hot water storage control means 29 and the heating control means 30 serve as the control means 31 that exchanges necessary information with each other and controls the operation of the hot water storage type hot water heater in cooperation with each other.

  The control means 31 stores in advance a program for controlling the operation of the hot water storage type hot water heater, and also has a calculation, comparison, clock function, and a rewritable storage means 32 that retains the memory even when the power is turned off. In the storage means 32, the correspondence relationship between the heating return pipe 23 and the heating branch pipe 24 on the hot water storage tank 2 side connected to the outlet ports a and b of the heating three-way valve 25 is shown in FIG. In the default state (normal state), the outlet port a corresponds to the heating return pipe 23 (hereinafter referred to as the boiling side) on the hot water storage tank 2 side, and the outlet port b corresponds to the heating branch pipe 24 (hereinafter referred to as the branch side). ).

Next, the boiling operation will be described based on the flowchart of FIG.
When a start request for the boiling operation is generated at the start time of the midnight time zone when the power unit price is cheap, the control unit 31 refers to the correspondence relationship of the storage unit 32 (here, the correspondence relationship of FIG. 4A). Then, the valve motor 25c of the heating three-way valve 25 is driven so that the ball valve 25b of the heating three-way valve 25 faces the outlet port b on the branch side (step S2).

  Next, the control means 31 drives the heating circulation pump 21 (step S3), drives the compressor 15, the expansion valve 17, and the blower 20 to drive the heat pump unit 3 (step S4). The water taken out through the heating forward pipe 22 is boiled by the heat pump unit 3 and returned to the lower part of the hot water storage tank 2 through the heating branch pipe 24 during the rising period of the heat pump unit 3 so that low and medium temperature hot water is supplied. It does not return to the upper part of the hot water storage tank 2.

  Then, when the heat pump unit 3 rises to a state where it can exhibit a sufficient heating capacity and detects that the boiling temperature sensor 27 has reached a predetermined temperature (45 ° C. here) or higher (Y in step S5), the control means 31 Drives the valve motor 25c of the heating three-way valve 25 so that the ball valve 25b of the heating three-way valve 25 faces the outlet port a on the heating side (step S6).

  In step S5, if the boiling temperature sensor 27 cannot detect a predetermined temperature or higher even after a certain time (for example, 2 hours) has elapsed since the start of boiling, circulation including the heat pump unit 3 or the heating circulation pump 21 is performed. If there is an abnormality in the route, an error is stopped (not shown).

  When a certain time (here, 1 hour) has elapsed since the switching of the heating three-way valve 25 in step S6 (Y in step S7), the control means 31 confirms the detection value of the uppermost hot water storage temperature sensor 28a, and the heat pump unit 3 It is determined whether or not the boiling water is higher than a predetermined temperature (here, 50 ° C.) indicating that the hot water is being stored from the upper part of the hot water storage tank 2. If the above is confirmed (Y in step S8), the process proceeds to the next step.

  And if the control means 31 confirms that the hot water more than the target hot water storage amount was stored in the hot water storage tank 2 based on the detected value of the hot water temperature sensors 28a-d (Y in step S9), the compressor 15, the expansion The heat pump unit 3 is stopped by stopping the valve 17 and the blower 20 (step S10), the heating circulation pump 21 is stopped (step S11), and the outlet port b where the ball valve 25b of the heating three-way valve 25 is on the branch side is opened. The valve motor 25c of the heating three-way valve 25 is driven so as to face (step S12), and the boiling operation is finished.

  On the other hand, as shown in FIG. 3, the outlet port a is connected to the heating branch pipe 24 and the outlet port b is connected to the heating return pipe 23 on the hot water storage tank 2 side by making a mistake in the front and back of the heating three-way valve 25. The operation will be described. In a state where the control means 31 does not know that the heating three-way valve 25 is in the reverse assembly state, the default correspondence relationship of the storage means 32 (FIG. 4A) is referred to in step S1. Then, the valve motor 25c of the heating three-way valve 25 is driven so that the ball valve 25b of the heating three-way valve 25 faces the outlet port b (step S2).

  The control means 31 drives the heating circulation pump 21 (step S3), and drives the compressor 15, the expansion valve 17, and the blower 20 to drive the heat pump unit 3 (step S4).

  At this time, the control means 31 controls the heating three-way valve 25 by recognizing that the outlet port b is on the branch side. However, since the outlet port b is on the boiling side in the reverse assembly state, the hot water storage tank 2 The water taken out from the lower part of the hot water through the heating pipe 22 is boiled by the heat pump unit 3 and returned to the upper part of the hot water storage tank 2 through the heating return pipe 23.

  Then, when the heat pump unit 3 rises to a state where it can exhibit a sufficient heating capacity and detects that the boiling temperature sensor 27 has reached a predetermined temperature (45 ° C. here) or higher (Y in step S5), the control means 31 Drives the valve motor 25c of the heating three-way valve 25 so that the ball valve 25b of the heating three-way valve 25 faces the outlet port a (step S6).

  At this time, the control means 31 controls the heating three-way valve 25 by recognizing that the outlet port a is on the boiling side. However, since the outlet port a is actually on the branch side in the reverse assembly state, the heat pump unit 3 The hot water boiled in is returned to the lower part of the hot water storage tank 2 via the heating branch pipe 24, and a fixed time (here, 1 hour) has elapsed since the switching of the heating three-way valve 25 in step S6 (step 1). Even if the control means 31 confirms the detection value of the uppermost hot water storage temperature sensor 28a, the predetermined temperature indicating that the hot water boiled by the heat pump unit 3 is stored from the upper part of the hot water storage tank 2 (S7: Y) Here, it is confirmed that the temperature does not exceed 50 ° C. (N in step S7), and the process proceeds to step S13.

  In step S13, the control means 31 drives the valve motor 25c of the heating three-way valve 25 so that the ball valve 25b of the heating three-way valve 25 faces the outlet port b. Thereby, since the ball valve 25b of the heating three-way valve 25 faces the heating return pipe 23 on the hot water storage tank 2 side, the hot water boiled by the heat pump unit 3 is stored from the upper part of the hot water storage tank 2.

  When a predetermined time (here, 1 hour) has elapsed since the switching of the heating three-way valve 25 in step S13 (Y in step S14), the control means 31 confirms the detection value of the uppermost hot water storage temperature sensor 28a, and the heat pump unit. 3 determines whether the hot water boiled in 3 is higher than a predetermined temperature (in this case, 50 ° C.) indicating that the hot water is stored from the upper part of the hot water storage tank 2, and if it is determined that it is higher than the predetermined temperature (Y in step S15) ), It is determined that the heating three-way valve 25 is reversely assembled (step S16), and an error code is displayed by displaying an error code indicating that the heating three-way valve 25 is reversely assembled on the display unit 5a of the water heater remote controller 5 ( Step S17).

  In this way, it is possible to reliably detect that the pipes corresponding to the outlet ports a and b of the heating three-way valve 25 are erroneously assembled in reverse.

  While the error is being notified, the control means 31 is associated with the heating return pipe 23 and the heating branch pipe 24 on the hot water storage tank 2 side connected to the outlet ports a and b of the heating three-way valve 25 stored in the storage means 32. As shown in FIG. 4B, the stored content is rewritten with the boiling side corresponding to the outlet port b and the branch side corresponding to the outlet port a (step S18).

  And if the control means 31 confirms that the hot water more than the target hot water storage amount was stored in the hot water storage tank 2 based on the detected value of the hot water temperature sensors 28a-d (Y in step S9), the compressor 15, the expansion The valve 17 and the blower 20 are stopped to stop the heat pump unit 3 (step S10), and the heating circulation pump 21 is stopped (step S11).

  Next, the control means 31 drives the valve motor 25c of the heating three-way valve 25 so that the ball valve 25b of the heating three-way valve 25 faces the outlet port a on the branch side based on the correspondence relationship of the storage means 32 that has been rewritten and stored. (Step S12), and the boiling operation is finished. Note that the error code display on the water heater remote controller 5 is erased simultaneously with the end of the boiling operation.

  At the time of boiling after the next time, the boiling operation is performed according to the operation of step S1 to step S12 based on the correspondence relationship (FIG. 4B) of the storage means 32 rewritten and stored, and the heating three-way valve 25 is reversed. Even if assembled, it can be heated as usual.

  In this way, after the reverse assembly of the heating three-way valve 25 is detected, the control means 31 can continue the boiling by changing the control direction of the heating three-way valve 25. Can do.

  Here, as a cause of N in step S8, in addition to the reverse assembly of the heating three-way valve 25, the reverse connection of the heat pump unit 3 is conceivable, but the reverse connection of the heat pump unit 3 and the reverse assembly of the heating three-way valve 25 are considered. The determination will be described. Note that the reverse connection of the heat pump unit 3 means a state in which the inlet side of the heat pump unit 3 is connected to the heating return pipe 23 and the outlet side is connected to the heating forward pipe 22 as shown in FIG.

  When the heat pump unit 3 is reversely connected, the hot water taken out from the upper part or the lower part of the hot water tank 2 is boiled and returned to the lower part of the hot water tank 2 depending on the direction of the heating three-way valve 25. Since the reverse connection state is not recognized, the same operation as normal is performed from step S1 to step S7.

  However, since the hot water boiled by the heat pump unit 3 flows into the lower part of the hot water storage tank 2, the temperature in the hot water storage tank 2 rises only slowly as a whole, and the temperature of the upper part of the hot water storage tank 2 is increased in step S8. It is determined that the temperature is equal to or lower than the predetermined temperature, and the process proceeds to step S13.

  In step S13, the control means 31 drives the valve motor 25c of the heating three-way valve 25 so that the ball valve 25b of the heating three-way valve 25 faces the outlet port b in order to determine reverse assembly of the heating three-way valve 25. Since the situation where the heated water returns from the lower part of the hot water storage tank 2 does not change, even if the temperature of the upper part of the hot water storage tank 2 is confirmed after waiting for a predetermined time in step S14, it remains below the predetermined temperature. N.

  The control means 31 determines that it is not reverse assembly of the heating three-way valve 25 but reverse connection of the heat pump unit 3 by becoming N in step S15 (step S19), and the water heater remote controller 5 is connected to the reverse of the heat pump unit 3. Error notification is performed by displaying an error code indicating that the connection is established on the display unit 5a (step S20).

  And the control means 31 stops the compressor 15, the expansion valve 17, and the air blower 20, stops the heat pump unit 3 (step S21), stops the heating circulation pump 21 (step S22), and sets the heating three-way valve 25. The valve motor 25c of the heating three-way valve 25 is driven so that the ball valve 25b faces the outlet port b on the branch side (step S23), and the boiling operation ends in error.

  And if an installer etc. recognizes the end of an error by reverse connection of heat pump unit 3, an abnormal state can be canceled by reconstructing heat pump unit 3 so that it may return to a normal connection state.

  In addition, in the reverse assembly state of the heating three-way valve 25 and when the reverse connection state of the heat pump unit 3 is overlapped, the reverse connection of the heat pump unit 3 is determined first, and after re-working in a normal state, the heating is performed. The reverse assembly state of the three-way valve 25 is determined.

  In this way, the reverse assembly of the heating three-way valve 25 and the reverse connection of the heat pump unit 3 can be clearly discriminated, so that the reverse assembly of the heating three-way valve 25 capable of normal boiling operation by control measures is boiling. The heating operation can be continued, and the reverse connection of the heat pump unit 3 where normal boiling operation cannot be performed by control measures can be terminated by an error, and the subsequent measures are facilitated.

  Here, the reverse assembly state of the heating three-way valve 25 can be normally heated only by reversing the relationship between the outlet ports a and b and the connection destination with that in the normal state. It is inherently desirable to return it, and when it is returned to the normal assembly state, the correspondence relationship of the storage means 32 that has been rewritten and stored once in a reverse state by a specific operation of the operation switch 5b of the water heater remote controller 5 (see FIG. 4 (B)) may be returned to the default correspondence (FIG. 4A).

  The present invention is not limited to the above-described embodiment, but can be modified without changing the gist of the invention. The heating means is not limited to the heat pump type, and the electric heater type. It is also possible to use a waste heat recovery device of a heating means or a cogeneration system.

  Moreover, the start timing of the fixed time count in step S7 is not only the switching timing of the heating three-way valve 25 in step S6, but also starts boiling on the precondition that the switching operation of the heating three-way valve 25 in step S6 is performed. The time may be counted from this timing, and the temperature determination is performed after a predetermined time has elapsed in step S8 and step S15, but the temperature exceeds the determination temperature until the predetermined time elapses. It is also possible to determine whether or not it has become.

2 Hot water storage tank 3 Heat pump unit (heating means)
21 Heating circulation pump 22 Heating forward pipe 23 Heating return pipe 24 Heating branch pipe 25 Heating three-way valve 25b Ball valve (valve element)
25c Valve motor 28a Hot water storage temperature sensor 31 Control means

Claims (4)

A hot water storage tank for storing hot water for hot water supply,
A hot water storage temperature sensor for detecting the temperature of hot water in the upper part of the hot water storage tank;
Heating means for heating hot water in the hot water storage tank;
A heating forward pipe connecting the lower part of the hot water storage tank and the heating means inlet;
A heating return pipe connecting the outlet of the heating means and the upper part of the hot water storage tank;
A heating branch pipe branched from the heating return pipe and connected to the lower part of the hot water storage tank;
A heating circulation pump that is provided in the heating forward pipe and circulates hot water in a hot water storage tank to the heating means;
A body having an outlet port a, an outlet port b, and an inlet port c; a valve body that communicates one of the outlet port a or the outlet port b and the inlet port c; and a valve motor that drives the valve body The heating port is connected to the heating return pipe on the hot water storage tank side, the outlet port b is connected to the heating branch pipe, and the inlet port c is connected to the heating return pipe on the heating means side. A valve,
A boiling temperature sensor for detecting the temperature of hot water boiled by the heating means;
The heating means and the heating circulation pump are driven to perform boiling to heat the hot water in the hot water storage tank, and at the start of boiling, the heating three-way valve is set to the outlet port b side, and the boiling temperature sensor is set to a predetermined value. In a hot water storage type hot water heater provided with a control means for driving the valve motor to switch the heating three-way valve to the outlet port a side when a temperature is detected or higher,
If the control means cannot confirm the predetermined temperature or higher by the hot water storage temperature sensor after the heating three-way valve is switched to the outlet port a side after a certain time has elapsed from the start of boiling, the control means exits the heating three-way valve. The hot water storage type hot water supply apparatus is characterized in that it is determined that the heating three-way valve is reversely assembled when the temperature is confirmed by the hot water storage temperature sensor until the predetermined time elapses after switching to the port b side. 2. The hot water storage device according to claim 1, wherein when the control means determines that the heating three-way valve is reversely assembled, boiling is continued in a state where the heating three-way valve is switched to the outlet port b side. Type water heater. After the control means determines that the heating three-way valve is reversely assembled, the subsequent boiling is performed when the heating three-way valve is set to the outlet port a side at the start of boiling, and the boiling temperature sensor is equal to or higher than a predetermined temperature. 3. The hot water storage type hot water heater according to claim 1, wherein the valve motor is driven so as to switch the heating three-way valve to the outlet port b side when the detection is detected. If the control means cannot confirm the predetermined temperature or higher by the hot water storage temperature sensor after the heating three-way valve is switched to the outlet port a side after a certain time has elapsed from the start of boiling, the control means exits the heating three-way valve. 2. The hot water storage according to claim 1, wherein if the temperature of the hot water storage sensor is not confirmed to be higher than a predetermined temperature even after a predetermined time has passed after switching to the port b side, it is determined that the heating means is reversely connected. Type water heater.

Images