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How can water shut off be controlled using the Ajax security system


In addition to theft and fire protection, the Ajax security system can prevent site flooding attributed to pipe breaks or failures of plumbing fixtures. In order to implement the anti-flood system, you will need a LeaksProtect, water leakage detector, a compatible electric valve as well as a WallSwitch or Relay. Thus, the relay enables shutting off the water supply not only in the case of alarms, but also automatically when the security system is armed or disarmed as well as manually via the application.


⚠️ Only a qualified electrician can implement installation of the WallSwitch and the Relay! Regardless of the type of electrical circuit that accommodates the device.


The relay is used to open and close electrical circuits and can be used to control the power supply of electrical appliances.
  • Relay — is a low-current remote control relay with a voltage-free “dry contact”.
  • WallSwitch — is a PCB relay for remote control of power featuring an electric power meter.
Both devices are remotely controlled via the Ajax application. The application allows you to set up automatic closing and/or opening of the relay contacts when changing the armed state and using the “night mode”.

Choosing an electric valve to shut off the water


The electric valve opens and shuts off water supply when it receives an electrical signal. When choosing an electric valve, pay attention to the following parameters:

  • Pipe diameter and threaded connection type of the fitting.
  • Valve type. Valves are either normally closed or normally open. There are also special electric valves with two stable states that alternate when a DC pulse is applied.
Normally closed valves are usually used. They shut off water when external power is lost. Normally open valves remain open when power is lost.


  • Power supply voltage. Electric valves operate at different DC and AC voltages: 230 V АС, 24 V AC, 24 V DC, 12 V DC, etc.
  • Manual control. The rotating mechanism provides manual control of the electric valve similar to a common tap. This allows you to shut off the water even if the phone is not available.
  • The number of control inputs — one or two control inputs or controlled by polarity inversion of the electrical signal at the input.

In order to implement the water shut off system based on the Ajax system, it is recommended to use normally closed valves with one control input — no coupling relays are required to connect the valves of this type. If you use pulse valves, the Ajax application will not know the valve state: open or closed. The Relay uses electric valves operating at 12/24 V, the WallSwitch — 230 V.

The valve should have two power supply sources: the main power source (electricity grid) of the site and backup from the battery. In this case, you will be able to shut off the water even if the building is disconnected. It is easier and cheaper to provide 12/24 V backup power supply rather than 230 V.

Ajax anti-flood system


The system based on the electric valve, the Ajax Hub, the WallSwitch/Relay and the LeaksProtect flood detector protects against flooding allowing you to shut off the water supply when leakage is detected.

The Ajax update planned for Q3 2019 will add the feasibility of automatic closure of the electric valve when the detector senses a water leak.


Layout diagram of the Relay connection to a 12/24 V electromagnetic valve


⚠️ During mounting and operating, follow the general electrical safety rules when using electrical appliances as well as the requirements of electrical safety laws and regulations.

When power is lost, the Relay contacts remain in the open state. After the external power is restored, the Relay contacts restore their initial state.

Connection to the electric valve featuring one control input


👆🏻 In order to implement connection according to the diagram, it is necessary to provide a 12/24 V external power source!


The Relay and the electric valve can be powered from a single power supply source. When mounting the device, do not allow any moisture to penetrate the Relay or the site of cable connections.



  1. Connect the power supply source to the power terminals of the Relay.
  2. Connect the “positive” contact terminal of the power source to one of the relay contact terminals, and the “positive” contact (control input) of the electromagnetic valve — to the other Relay contact terminal.
  3. Connect the “negative” contact terminal of the electromagnetic valve to the “negative” contact terminal of the power source.

Such connection ensures closing of the electromagnetic valve using the Relay.

Valve examples:


  • PIE T20-S2-B
  • CONVA A20-T25-S2-C
  • Ebowan 12 V DC

Operation of the 12/24 V DC electromagnetic valve featuring one control input

Relay set up


  1. Go to the Devices tab.
  2. Go to the Relay menu, then to Settings and select Bistable operation mode, and set the Initial state of contact terminalsNormally open.

Operation of the electric valve in the Ajax application


Click the switch in the Relay line — the state of the relay contact terminals will change to the opposite.



When the Relay contact terminals are closed, the electric valve receives power and opens. When opened, the electric valve remains unpowered and the water is shut off.

Automatic operation of the electric valve


Ajax allows you to automatically change the state of relay contact terminals when arming and disarming the security system as well as turning the Night Mode on and off.

Select the response to the disarming/arming in the relay settings as shown in the screenshot:



When the security system is armed, the valve will close. When the security system is disarmed — it will open.

In order to open/shut off the water supply when using the night mode, enable the React to night mode option.

Connection to the electric valve featuring two control inputs


👆🏻 In order to implement connection according to the diagram, it is necessary to provide a 12/24 V external power source and a SPDT-type coupling relay (12/24 V)!


Relay, coupling relay, and electric valve can be powered from a single power source. When mounting the device, do not allow any moisture to penetrate the Relay, coupling relay, or the site of cable connections.



  1. Connect the power supply source to the power terminals of the Relay.
  2. Connect the “positive” contact terminal of the power source to one of the Relay contact terminals, and the “positive” contact terminal of the coupling relay — to the other Relay contact terminal.
  3. Connect the “negative” contact terminal of the electromagnetic valve (common contact) and the “negative” contact terminal of the coupling relay to the “negative” contact terminal of the power source.
  4. Connect the “COM” contact terminal of the coupling relay to the “positive” contact terminal of the power source.
  5. Connect the “NC” contact terminal of the coupling relay to the control opening input of the electric valve, and the “NO” contact terminal — to the closing input.

Such connection ensures closing of the electromagnetic valve using the Relay.

Valve examples:

  • Neptun Bugatti PRO 12 V (Neptun)

Operation of the 12/24 V DC electromagnetic valve featuring two control inputs

Relay set up


  1. Go to the Devices tab.
  2. Go to the Relay menu, then to Settings and select Bistable operation mode, and set the Initial state of contact terminalsNormally closed.

Operation of the electric valve in the Ajax application


Click the switch in the Relay line — the state of the relay contact terminals will change to the opposite.



When contacts close, the valve closes; when contacts open, the valve opens.

Automatic operation of the electric valve


Ajax allows you to automatically change the state of relay contact terminals when arming and disarming the security system as well as turning the Night Mode on and off.

Select the response to the disarming/arming in the relay settings as shown in the screenshot:



When the security system is armed, the valve closes. When the security system is disarmed, the valve opens.

In order to open/shut off the water supply when using the night mode, enable the React to night mode option.

Connection to electric valve featuring “polarity inversion” control input


👆🏻 In order to implement connection according to the diagram, it is necessary to provide a 12/24 V external power supply source and a DPDT-type coupling relay (12/24 V)!


Relay, coupling relay, and electric valve can be powered from a single power source. When mounting the device, do not allow any moisture to penetrate the Relay, coupling relay, or the site of cable connections.



  1. Connect the power supply source to the power terminals of the Relay.
  2. Connect the “positive” contact terminal of the power source to one of the Relay contact terminals, and the “positive” contact terminal of the coupling relay — to the other Relay contact terminal.
  3. Connect the “NO” contact terminal of the first relay to the “positive” contact terminal, and the “NO” contact terminal — to the “negative” contact terminal of the power source.
  4. Connect the “NO” contact terminal of the second relay to the “negative” contact terminal, and the “NO” contact terminal — to the “positive” contact terminal of the power source.
  5. Connect the “COM” contact terminal of the first coupling relay to the first control input, and the “COM” contact terminal of the second relay — to the second control input of the electric valve.
  6. Connect the “negative” contact terminal of the coupling relay to the “negative” contact terminal of the power source.
  7. Connect the “NC” contact terminal of the coupling relay to the first control input, and the “NO” contact terminal — to the second control input.

Such connection ensures operation of the coupling relay that supplies power of variable polarity to the electric valve control inputs using the Relay. The polarity of the input voltage determines the electric valve state: open or closed.

Valve examples:

  • COVNA A20-T15-S2-C
  • CVX-15N

Operation of the 12/24 V DC electromagnetic valve featuring polarity inversion control

Relay set up

  1. Go to the Devices tab.
  2. Go to the Relay menu, then to Settings and select Bistable operation mode, and set the Initial state of contact terminalsNormally closed.

Operation of the electric valve in the Ajax application

Click the switch in the Relay line — the state of the relay contact terminals will change to the opposite.


When contacts close, the valve closes; when contacts open, the valve opens.

Automatic operation of the electric valve


Ajax allows you to automatically change the state of relay contact terminals when arming and disarming the security system as well as turning the Night Mode on and off.

Select the React to the disarming/arming in the relay settings as shown in the screenshot:



When the security system is armed, the valve closes. When the security system is disarmed, the valve opens.

In order to open/shut off the water supply when using the night mode, enable the React to night mode option.

Layout diagram of the WallSwitch connection to a 230 V AC electromagnetic valve


⚠️ During mounting and operating, follow the general electrical safety rules when using electrical appliances as well as the requirements of electrical safety laws and regulations.


Connection to the 230 V AC electric valve featuring one control input


👆🏻 In order to implement connection according to the diagram, it is necessary to provide a 230 V external power supply source!


WallSwitch and electric valve can be powered from a single power supply source. When mounting the device, do not allow any moisture to penetrate the WallSwitch or the site of cable connections.



  1. Connect the power supply source to the power terminals of the WallSwitch observing the polarity.
  2. Connect the “N” output terminal (neutral) of the WallSwitch to the “N” contact terminal of the electric valve.
  3. Connect the “L” output terminal (phase) of the WallSwitch to the control input of the electric valve.
  4. Connect the “L” contact terminal of the electric valve to the 230 V phase of the power source.  
  5. Ground the “PE” contact terminal of the electric valve.

Such connection ensures the closing of the electromagnetic valve using the WallSwitch. When the WallSwitch contacts close, the valve closes. When they open, the valve opens.

Some valves enable selection of the normal state: open or closed when control input is closed.

Valve examples:

  • ESBE MBA 100 series
  • Neptun HC220V
  • 2W-160-15C

Operation of the 230 V AC electromagnetic valves featuring one control input


No additional WallSwitch set up via the application is required.

Click the switch in the WallSwitch line — the state of the relay contacts will change to the opposite.


When the WallSwitch contacts are closed, the electric valve is supplied with power and it closes. When contacts are opened, the control input is cut off and the electric valve opens.

Automatic operation of the electric valve


Ajax allows you to automatically change the state of relay contact terminals when arming and disarming the security system as well as turning the Night Mode on and off.

Select the response to the disarming/arming in the relay settings as shown in the screenshot:



When the security system is armed, the valve closes. When the security system is disarmed, the valve opens.

In order to open/shut off the water supply when using the night mode, enable the React to night mode option.

Connection to the 230 V AC electric valve featuring two control inputs


👆🏻 In order to implement connection according to the diagram, it is necessary to provide a 230 V external power supply source and a SPDT-type coupling relay (230 V)!


WallSwitch, coupling relay, and electric valve can be powered from a single power source. When mounting the device, do not allow any moisture to penetrate the WallSwitch, coupling relay or the site of cable connections.



  1. Connect the power supply source to the power terminals of the WallSwitch observing the polarity.
  2. Connect the “N” output terminal (neutral) of the WallSwitch to the “N” terminal of the coupling relay, and the “L” terminal (phase) of the WallSwitch — to the “L” contact terminal of the coupling relay.
  3. Connect the “COM” contact terminal of the coupling relay to the “L” contact terminal of the power source.
  4. Connect the “NC” contact terminal of the coupling relay to the control opening input of the electric valve, and the “NC” contact terminal — to the closing input.
  5. Connect the “N” contact terminal (neutral) of the electric valve to the “N” contact terminal of the power source and ground the “PE” contact of the electric valve.

Such connection ensures the closing of the electromagnetic valve using the WallSwitch.

Valve examples:

  • Neptun Bugatti Pro 220 V

Operation of the 230 V AC electromagnetic valves featuring two control inputs


No additional WallSwitch set up via the application is required.

Click the switch in the WallSwitch line — the state of the relay contacts will change to the opposite.


When the WallSwitch contacts are closed, the electric valve is supplied with power and it closes. When contacts are opened, the control input is cut off and the electric valve opens.

Automatic operation of the electric valve

Ajax allows you to automatically change the state of relay contact terminals when arming and disarming the security system as well as turning the Night Mode on and off.

Select the response to the disarming/arming in the relay settings as shown in the screenshot:


When the security system is armed, the valve closes. When the security system is disarmed, the valve opens.

In order to open/shut off the water supply when using the night mode, enable the Response to the night mode option.

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