JP3318260B2 - Valve control device in air conditioning system and valve control method in air conditioning system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve control device in an air conditioning system for performing air conditioning using a fan coil unit in a hotel, a hospital or the like, and a valve in an air conditioning system.
Control method .

[0002]

2. Description of the Related Art In a hotel, a hospital, or the like, air conditioning in a room is indispensable, and an air conditioning system that performs air conditioning in each room using a fan coil unit having a fan and a coil is employed. In this air conditioning system, cold or hot water generated by a cold source device installed outdoors is distributed to the coils of a plurality of fan coil units by piping, and a fan coil unit, a valve for controlling hot and cold water, etc. are provided for each room. Provided as a set. In the coil of the fan coil unit, cold water or hot water distributed from a cold heat source device is passed through a cold / hot water control valve, and heat exchange between the cold water or hot water and air is performed, and the cold air or hot air is passed through the fan coil. The cooling or heating of the room is performed by circulating the room with the fan of the unit. Indoor cooling is performed when cold water is distributed from the cold heat source device, and indoor heating is performed when hot water is distributed from the cold heat source device.

A controller is operated by a user to set conditions such as a room temperature, a fan flow rate of a fan coil unit, an operation mode, and the like. In an automatic mode, a controller controls a cold / hot water supply based on an input signal from a room temperature sensor for detecting a room temperature. The indoor temperature is automatically adjusted to the set temperature by controlling the opening of the control valve. Further, the controller rotates the fan of the fan coil unit at low speed, medium speed, and high speed in each of the low wind, medium wind, and strong wind modes.

[0004] A fan coil unit, piping, a valve for controlling hot and cold water, and the like are installed on the ceiling or wall of each room.
Japanese Patent Laying-Open No. 4-373005 discloses a valve opening remote control device for remotely operating a valve. JP 8
Japanese Patent Application Laid-Open No. 84649/1994 discloses a flow control unit for displaying the opening degree of a valve.

[0005]

In the above-mentioned air conditioning system, the valves for controlling the hot and cold water are installed on the ceiling and the wall of each room. The only option is to visually check the cold / hot water control valve installed on the ceiling, wall, etc., which makes maintenance difficult. In addition, when checking the operation of the cold / hot water control valve, the only way to check the operation of the cold / hot water control valve is to change the set temperature with the controller, or to warm or cool the room temperature sensor, and the maintenance is poor. . Further, if a malfunction of the cold / hot water control valve occurs during the normal operation, the malfunction of the cold / hot water control valve cannot be identified unless the operation of the cold / hot water control valve is confirmed as described above.

It is an object of the present invention to provide a valve control device in an air conditioning system in which the operation of a cold / hot water control valve can be easily checked in a maintenance mode, and the maintainability can be improved. And

According to the second aspect of the present invention, it is usually difficult for the user to open and close the cold / hot water control valve regardless of air conditioning, and the operation of the cold / hot water control valve can be easily confirmed in the maintenance mode. It is an object of the present invention to provide a valve control device for an air conditioning system that can improve the maintainability.

A third object of the present invention is to provide a valve control device for an air conditioning system which can easily confirm the operation of a cold / hot water control valve in a maintenance mode and can improve the maintainability. And

According to the fourth aspect of the present invention, the operation of the cold / hot water control valve can be easily confirmed in the maintenance mode, so that the maintainability can be improved. It is an object of the present invention to provide a valve control device in an air-conditioning system that can easily specify the occurrence of air-conditioning.

[0010]

Means for Solving the Problems In order to achieve the above object, the invention according to claim 1 performs a heat exchange between cold water or hot water distributed from a cold heat source device and air to bring cold or hot air into a room. A fan coil unit to be circulated, a valve for controlling cold / hot water control for controlling water distribution from the cold / hot source device to the fan coil unit, and a controller for controlling at least the valve for controlling cold / hot water, and a signal from the controller in the air conditioning system that operates based, setting a mode changeover switch capable of the controller to the maintenance mode, the normal non-maintenance mode
A room temperature up / down switch for raising and lowering the room temperature in a mode state, and in the maintenance mode, the controller
Raise room temperature in normal mode other than maintenance mode
The room temperature up / down switch to be lowered is a valve open / close switch.
The cold / hot water control valve is operated to open and close based on a valve open / close signal from a switch .

According to a second aspect of the present invention, in the valve control device for an air conditioning system according to the first aspect, the controller normally hides the mode changeover switch and removes the mode changeover switch by a special operation. It has a cover to be exposed.

According to a third aspect of the present invention, in the valve control device of the air conditioning system according to the first or second aspect, the display means for displaying the open / close state of the cold / hot water control valve when the maintenance mode is set by the mode changeover switch. It is provided.

According to a fourth aspect of the present invention, there is provided a fan coil unit for exchanging heat between cold water or hot water distributed from a cold heat source device and air to circulate cool air or hot air indoors, A cold / hot water control valve that controls water distribution to the fan coil unit, and a controller that controls at least the cold / hot water control valve, in a valve control method for an air conditioning system that operates based on a signal from the controller, The controller is set to a maintenance mode, and when the maintenance mode is set, the cold / hot water control valve is opened / closed based on a signal from an operating means.

[0014]

FIG. 1 shows a circuit configuration of an embodiment of the present invention, and FIG. 2 shows an arrangement of components in this embodiment. This embodiment is an embodiment of a valve control device in an air conditioning system that performs air conditioning using a fan coil unit in a hotel, a hospital, or the like. The valve control device is provided for each room 1 in a hotel, a hospital, and the like. It is an embodiment in the case of a formula. Cooling and heat source equipment and a host are arranged in the center of a hotel, a hospital, or the like. The coil 3 of the fan coil unit 2 in the valve control device of each room 1 has a fully open / fully closed limit switch as a cold / hot water control valve. The pipes 5, 6 are connected to the pipes 5, 6 via the direction valve 4, and the pipes 5, 6 are connected to the above-mentioned cold heat source equipment.

The fan coil unit 2 has a coil 3 and a fan 7, and has a two-way valve 4 with a fully open / fully closed limit switch.
Includes a fully open limit switch for detecting the fully open state of the two-way valve 4 and a fully closed limit switch for detecting the fully closed state of the two-way valve 4. In this valve control device, a fan coil unit 2, a cold / hot water control valve 4, and a power unit 9 are installed on a ceiling 8 of a room 1, and a room temperature controller 12
Is installed in the room 1. An opening / closing valve 10 is provided so as to be manually closed at the time of maintenance.

The power unit 9 has a power supply 13, a controller interface (I / F) 14, a valve drive output unit 15, a valve status input unit 16, and a fan drive output unit 17.
Valve drive output section 1 5, is fed to the fan drive output unit 17. The room temperature controller 12 includes a microcomputer (CPU) 18 as a control unit, a power unit I /
F19, a liquid crystal display 20 as a display unit, a key switch 21 as an operation unit, a temperature sensor 22 for detecting a temperature in the room 1, a mode for setting and canceling a maintenance mode.
And a communication I / F 23 for communicating with the external host.

FIG. 3 shows the room temperature controller 12. The liquid crystal display 20, the operation state of the present embodiment (cooling, heating, blowing) and a display unit 24 for displaying, the display or the fan 7 of the air volume of the opening and closing operation of the hot and cold water control valve 4 (weak wind, paralytic , Strong wind)
Display section 25 for displaying the display, display section 2 for displaying the set room temperature
6, a display unit 27 for displaying room temperature, and a display unit 28 for displaying an automatic mode for automatically controlling the temperature in the room 1, and the display units 25, 26, and 27 are open / close states of the cold / hot water control valve 4. It is also used for display.

A key switch 21 is a run / stop key 29 for switching between an operation mode and a stop mode according to the present embodiment, and an air flow rate of the fan 7 by cyclically switching an automatic mode, a low air blowing mode, a blowing mode, and a high air blowing mode. , An up key 31 for raising the room temperature, and a down key 32 for lowering the room temperature. The up key 31 is for moving the cold / hot water control valve 4 in the opening direction. Down key 32
Also serves as a valve closing switch for moving the cold / hot water control valve 4 in the closing direction. The liquid crystal display 20 is a liquid crystal display 2
The cover 34 is provided so as to be openable and closable with respect to the main body 0, and the cover 34 is usually closed with screws 35.

The mode changeover switch 33 for setting and canceling the maintenance mode is hidden from the outside when the cover 34 is closed and becomes invisible. The serviceman removes the screw 35 and opens the cover 34. By performing a special operation, it can be exposed and turned on / off. The liquid crystal display 20 is configured to perform display regardless of whether the cover 34 is opened or closed, and the key switches 30 to 32 are configured to be operable regardless of whether the cover 34 is opened or closed. A small hole may be formed in the cover 34 above the switch 33, and the switch 33 may be operated by inserting a rod through the small hole. In this case, it is not necessary to remove the cover 34. In this case, the switch 33 is normally hidden, and can be operated by a rod by a special operation of inserting a specific rod from a small hole of the cover 34, so that the switch 33 is exposed as an operable switch. It is included in the present invention.

The cold / hot water control valve 4 is driven by a valve drive output unit 15, and the fan 7 is driven by a fan drive output unit 17.
Driven by The CPU 18 includes a key switch 21,
The input signal from the room temperature sensor 22 is taken in, and the input signals from the fully open limit switch and the fully closed limit switch in the two-way valve 4 with the fully open / fully closed limit switch as a cold / hot water control valve are set as open status and closed status. Status input unit 16, controller I
/ F14, via the power unit I / F19, the power unit I / F19 and the controller I / F.
The control unit 14 controls the valve drive output unit 15 and the fan drive output unit 17 and controls the liquid crystal display 20.

Each time the user presses the run / stop key 29, the operation mode and the stop mode of this embodiment are alternately switched and set. The CPU 18 has a run / stop key 2
The operation mode and the stop mode are alternately switched and set every time an input signal is input from the power unit 9 and the power unit I / F 19 and the controller I / F 14 when the operation mode is set.
Via the valve drive output unit 15 and the fan drive output unit 1
7 is controlled to perform the operation of the present embodiment. CPU1
8 is a power unit I / F 19 when the stop mode is set.
The controller also controls the valve drive output unit 15 and the fan drive output unit 17 via the controller I / F 14 to completely close the cold / hot water control valve 4 and stop the fan 7.

Each time the user presses the ventilation switching key 30, the automatic mode, the ventilation mode, the ventilation mode, and the ventilation mode are switched and set cyclically. CP
U18 cyclically switches and sets an automatic mode, a low air blowing mode, a low air blowing mode, and a high air blowing mode according to an input signal from the air blowing switching key 30, and when the high air blowing mode is set, the power unit I / F 19 and the controller I / F.
The fan drive output unit 17 is controlled via the
Is rotated at a high speed, so that the blowing of the fan 7 is increased.

The CPU 18 controls the fan drive output section 17 via the power unit I / F 19 and the controller I / F 14 to rotate the fan 7 at a medium speed when the air blowing mode is set, so that the air flow of the fan 7 is set to the medium level. age,
At the time of setting the low air blowing mode, the fan drive output unit 17 is connected via the power unit I / F 19 and the controller I / F 14.
Is controlled to rotate the fan 7 at a low speed, thereby weakening the ventilation of the fan 7. When the automatic mode is set, the CPU 18 compares the current room temperature detected by the room temperature sensor 22 with the set room temperature based on the input signal from the room temperature sensor 22,
Based on the comparison result, the valve drive output unit 15 is controlled via the power unit I / F 19 and the controller I / F 14 to control the opening of the cold / hot water control valve 4 so that the current temperature becomes the set room temperature. The temperature inside is controlled to the set room temperature.

In the operation mode, the CPU 18 displays the current room temperature on the display unit 27 of the liquid crystal display 20 according to the input signal from the room temperature sensor 22, and the air volume of the fan 7 (weak wind,
The display unit 25 displays the operating state (cooling, heating,
Is displayed on the display unit 24. Also, the CPU 18
, During operation mode, to display the set room temperature in the display unit 26, the automatic mode is set is displayed on the display unit 28 that the automatic mode. In the operation mode, the CPU 18 raises the set room temperature in units of, for example, 0.5 ° C. by an input signal from the up switch 31 and the down switch 32
The set room temperature is changed by lowering the set room temperature by, for example, a unit of 0.5 ° C. in response to an input signal from the controller.

In the operation mode, the CPU 18 detects an abnormality in the memory for storing the set room temperature and the like, an abnormality in the room temperature sensor 22,
It is checked whether an abnormality has occurred in the cold / hot water control valve 4. If the memory abnormality, the room temperature sensor 22 abnormality, or the cold / hot water control valve 4 abnormality occurs, the power unit I / F 19 and the controller are immediately checked. The valve drive output unit 15 and the fan drive output unit 17 are controlled via the I / F 14 to completely close the cold / hot water control valve 4 to stop the fan 7, and at the same time, the liquid crystal display 20 displays an error corresponding to the abnormality. Display an error by displaying the code.
In this case, the CPU 18 determines that a memory abnormality has occurred due to the occurrence of a sum check error in the initial writing of the memory when the power is turned on, and determines that an abnormality has occurred in the room temperature sensor 22 when the output of the room temperature sensor 22 exceeds a normal range. Deemed,
Even if the cold / hot water control valve 4 exceeds a predetermined operation time, if the fully open signal and the fully closed signal are not input from the fully open limit switch and the fully closed limit switch, it is regarded that the cold / hot water control valve 4 has failed.

In the case where a host for centrally managing the air conditioning system is provided at the center, the host is provided with the communication I / F 23.
Sends a run / stop signal to the CPU 18 via the
18 to perform the operation / stop of the present embodiment,
A signal for selectively setting the low air blowing mode, the low air blowing mode, and the high air blowing mode is transmitted to the CPU 18 via the communication I / F 23, and the automatic mode, the low air blowing mode, the mid air blowing mode, and the high air blowing mode are selectively transmitted to the CPU 18. To be set. further,
The host transmits a signal for changing the set room temperature to the CPU 18 via the communication I / F 23 to cause the CPU 18 to change the set room temperature, and reads the current room temperature, the set room temperature, and the like from the CPU 18 via the communication I / F 23.

FIG. 4 shows an operation flow of this embodiment. C
The PU 18 performs a stop mode process such as stopping the fan 7 by fully closing the cold / hot water control valve 4 as described above if not in the operation mode, and the cold / hot water control valve 4 as described above if it is in the operation mode. , The fan 7 and the liquid crystal display 20 are controlled to perform normal operation mode processing such as driving the present embodiment.

The CPU 18 alternately sets and releases the maintenance mode each time an input signal is input from the mode switch 33. When the maintenance mode is set, the CPU 18 checks whether or not the valve open switch is pressed and turned on by an input signal from an up key 31 as a valve open switch. Valve drive output unit 1 via I / F 19 and controller I / F 14
5 to move the cold / hot water control valve 4 in the opening direction,
A display output during valve operation is output to the display unit 25 of the liquid crystal display 20, and when the cold / hot water control valve 4 is fully opened, the display unit 2
The OP is displayed at 6 (see FIG. 5).

When the maintenance mode is set, the CPU 18 operates a down key 32 as a valve closing switch.
It is checked whether or not the valve close switch has been pressed and turned on by the input signal from the controller. When the valve close switch has been pressed and turned on, the valve drive output unit 15 is output via the power unit I / F 19 and the controller I / F 14. The liquid crystal display 2 is controlled by moving the cold / hot water control valve 4 in the closing direction.
A display output during valve operation is output to the display unit 25 of 0, and when the cold / hot water control valve 4 is fully closed, CL is displayed on the display unit 27 (see FIG. 5). Further, the CPU 18 sets the up key 31 and the down key 3
If 2 is not pressed, the current state of the cold / hot water control valve 4 is displayed on the display unit 26 of the liquid crystal display 20.

FIG. 6 shows a part of another embodiment of the present invention. In this embodiment, the piping system is a four- tube switching system,
In the above embodiment, three-way valves 38 and 39 are used instead of the two-way valve 4 as the cold / hot water control valve. Both ends of the coil 3 of the fan coil unit (FCU) 2 are connected to a cold water pipe 40 and a hot water pipe 41 via three-way valves 38 and 39, respectively, and the pipes 40 and 41 are connected to the cold heat source equipment. . The three-way valves 38 and 39 are driven by the valve drive output unit 15 to operate the fan coil unit (FC).
U) The coil 3 of 2 is switched and connected to the cold water pipe 40 and the hot water pipe 41.

At the time of cooling operation, the CPU 18 compares the output value of the temperature sensor 22 with the set value, and controls the valve drive output unit 15 via the power unit I / F 19 and the controller I / F 14 based on the result, and the fan coil unit. The coil 3 of the (FCU) 2 is connected to the chilled water pipe 40, and the chilled water generated by the chilled heat source device is cooled by the chilled water pipe 40.
Fan coil unit (FC) via three-way valves 38 and 39
U) The cooling of the inside of the chamber 1 is performed through the coil 3 of 2 as described above.

During the heating operation, the CPU 18 compares the output value of the temperature sensor 22 with the set value, and controls the valve drive output unit 15 via the power unit I / F 19 and the controller I / F 14 based on the result, thereby controlling the fan coil unit. The coil 3 of the (FCU) 2 is connected to the heating pipe 41, and the hot water generated by the cold heat source equipment is connected to the hot water pipe 41,
Fan coil unit (FC) via three-way valves 38 and 39
U) The heating of the inside of the room 1 is performed as described above by passing through the coil 3 of 2. When the output value of the temperature sensor 22 matches the set value, the CPU 18 determines that the three-way valves 38 and 39
To the closed position.

FIG. 7 shows a part of another embodiment of the present invention. In this embodiment, the piping system is a four-pipe system.
Two-way valves 4a, 4b with two fully open / fully closed limit switches
Is used. Both ends of the coil 3 of the fan coil unit (FCU) 2 are connected to a cold water pipe 40 via a two-way valve 4a, and connected to a hot water pipe 41 via a two-way valve 4b. 41 is connected to the cold heat source device. 2-way valve 4a with fully open / fully closed limit switch,
4b is driven by the valve drive output unit 15, and the CPU 1
8 is a two-way valve 4a, 4b with a fully open / fully closed limit switch
The input signals from the fully open limit switch and the fully closed limit switch in the valve status input unit 16, the controller I / F 14,
The data is taken in via the power unit I / F19.

When the cooling mode is set, the CPU 18 controls the valve drive output unit 15 via the power unit I / F 19 and the controller I / F 14 to connect the coil 3 of the fan coil unit (FCU) 2 to the cold water pipe 40, The chilled water generated by the chilled heat source equipment is chilled water piping 40,
Fan coil unit (FCU) 2 via two-way valve 4a
The cooling of the inside of the chamber 1 is performed as described above.

When the heating mode is set, the CPU 18 controls the valve drive output unit 15 via the power unit I / F 19 and the controller I / F 14 to connect the coil 3 of the fan coil unit (FCU) 2 to the heating pipe 41, Hot water generated by the cold heat source device is a hot water pipe 41,
Fan coil unit (FCU) 2 via two-way valve 4b
To heat the interior of the chamber 1 as described above.

Each of the above embodiments is an embodiment of the invention according to claim 1, and performs heat exchange between cold water or hot water distributed from a cold heat source device and air to circulate cool air or warm air indoors. A fan coil unit 2; cold / hot water control valves 4, 4a, 4b, 38, 39 for controlling water distribution from the cold / hot source device to the fan coil unit 2, and at least the cold / hot water control valves 4, 4a, 4b , 38, 39
And an air conditioning system that operates on the basis of a signal from the controller 12, and is provided with the controller 12 and is normally hidden and is exposed by a special operation. The maintenance mode can be set. The controller 12 includes an up key 3 serving as an operating means when the maintenance mode is set by the mode switch 33.
1. Since the cold / hot water control valves 4, 4a, 4b, 38, and 39 are opened / closed based on a signal from the down key 32, the operation of each cold / hot water control valve is checked when the operation of the cold / hot water control valve is confirmed. This eliminates the need to visually check the cold / hot water control valve itself installed on the ceiling, wall, or the like, thereby improving maintainability. Further, when checking the operation of the cold / hot water control valve, it is not necessary to change the set temperature by the controller, or to warm or cool the room temperature sensor to check the operation of the cold / hot water control valve. , 32 for the cold and hot water control valves 4, 4a, 4
b, 38, and 39 are forcibly opened and closed, and the operation of the cold / hot water control valve can be confirmed, so that the maintainability can be improved.

Each of the above embodiments is an embodiment of the invention according to claim 2, and in the valve control device for an air conditioning system according to claim 1, the controller 1
2, the mode changeover switch 33 is normally hidden, and is removed by a special operation.
The cover 34 for exposing the cold water control valve is normally difficult for the user to open and close the cold / hot water control valve regardless of the air conditioning. The operation of the water control valve can be easily checked, and the maintainability can be improved.

Further, each of the above embodiments is an embodiment of the invention according to claim 3, and in the valve control device for an air conditioning system according to claim 1 or 2, when the maintenance mode is set by the mode switching switch 33, Since the display units 26 and 27 of the liquid crystal display 20 are provided as display means for displaying the open / close states of the cold / hot water control valves 4, 4a, 4b, 38 and 39, the operation of the cold / hot water control valves in the maintenance mode is performed. It can be easily checked indoors, and the maintainability can be improved.

Further, each of the above embodiments is an embodiment of the invention according to claim 4, and in the valve control device for an air conditioning system according to claim 1, 2, or 3, the controller 12 is provided in a mode other than the maintenance mode. In the normal mode, the cold / hot water control valves 4, 4a, 4b, 38, 39
The operation of the chilled / hot water control valve can be checked easily in the maintenance mode because the operation of the chilled / hot water control valve can be easily checked in the maintenance mode. Can be easily identified.

[0040]

As described above, according to the first aspect of the present invention, the operation of the cold / hot water control valve can be easily confirmed in the maintenance mode with the above configuration, and the maintenance property can be improved. .

According to the second aspect of the present invention, it is usually difficult for the user to open and close the cold / hot water control valve regardless of air conditioning, and the operation of the cold / hot water control valve in the maintenance mode is normally difficult. It can be easily checked, and the maintainability can be improved.

According to the third aspect of the present invention, the operation of the cold / hot water control valve can be easily checked in the maintenance mode with the above configuration, and the maintenance property can be improved.

[0043]

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a circuit configuration according to an embodiment of the present invention.

FIG. 2 is a sectional view showing an arrangement of each component in the embodiment.

FIG. 3 is a plan view, a side view, and a front view showing the controller of the embodiment.

FIG. 4 is a flowchart showing an operation flow of the embodiment.

FIG. 5 is a view for explaining an operation state display of the cold / hot water control valve in the embodiment.

FIG. 6 is a piping diagram showing a part of another embodiment of the present invention.

FIG. 7 is a piping diagram showing a part of another embodiment of the present invention.

[Explanation of symbols]

2 fan coil unit 4, 4a, 4b, 38, 39 for hot and cold water control valve 12 controller 33 a mode switching switch 34 cover 20 liquid crystal display 26, 27 display unit

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F24F 11/02 102

Claims (4)

(57) [Claims] 1. A fan coil unit for circulating cold air or warm air in a room by exchanging heat between cold water or hot water supplied from a cold heat source device and air, and distributing water from the cold heat source device to the fan coil unit. and hot and cold water control valve for controlling the, and a controller for controlling at least the cold hot water control valve, in the air conditioning system that operates based on a signal from the controller, the controller can set the maintenance mode Mode switch and normal mode other than maintenance mode
And a room temperature up and down switch for raising and lowering the room temperature, maintainer
When in the maintenance mode, the controller
Above and below room temperature in normal mode other than mode
The lower switch is a valve open / close switch .
A valve control device for an air conditioning system, wherein the valve for controlling cold / hot water performs an opening / closing operation based on a valve opening / closing signal. 2. The valve control device according to claim 1, wherein the controller includes a cover that normally hides the mode changeover switch and is removed by a special operation to expose the mode changeover switch. A valve control device for an air conditioning system, comprising: 3. The valve control device according to claim 1, further comprising display means for displaying the open / close state of the cold / hot water control valve when the maintenance mode is set by the mode changeover switch. Control device in the air conditioning system to be used. 4. Cold water or hot water distributed from a cold heat source device.
Exchanges heat with air to circulate cold or warm air indoors.
Fan coil unit, and the fan from the cold heat source device.
Cooling / heating water control bar that controls water distribution to the fan coil unit
A valve for controlling at least the cold / hot water control valve.
And a controller based on a signal from the controller.
Valve control method in an air-conditioning system
Stomach, set the controller to the maintenance mode
When the maintenance mode is set,
Perform the opening / closing operation of the cold / hot water control valve based on the
Valve control in air conditioning system characterized by
Method.