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Freeze Sensor

Freeze Sensor

The freeze sensor from Hunter is used to control irrigation system operation during freezing temperatures. Use this freeze sensor in your home landscape to automatically turn OFF your irrigation system when it's close to freezing.

Part #: WS003

The Freeze Sensor from Hunter prevents irrigation when outdoor temperatures drop to near freezing by automatically stopping the controller program and keeping the valves closed. When the temperature rises above the set point, the Freeze Sensor resets the system to its regular program. Easy to install and easy to use, the Freeze Sensor can also be used in conjunction with other weather sensing devices to guarantee the optimum effectiveness of an irrigation control system in all kinds of weather.

Note: Use for landscape applications only - not for crop protection. A freeze sensor should only be used as part of a sound irrigation control system that includes regular visual system checks.

  • Dimensions: Sensor: 4 1/2" L
  • Electrical: 24VAC 6 amps
  • Parts Included : 25 ft. of #20 two conductor wire (direct burial and UV approved), two mounting screws and detailed instructions
  • Switch Rating : Closed above 3 C and open below 3 C (reverse switching model)
  • Temperature differential : +/- 1 C
  • Temperature set point : 37 F (3 C) +/- 2 C
  • UL listing : Class II Low Voltage (24 volt use only)
  • Can be used with other sensor devices
  • Double epoxy sealed sensing element aids the accuracy of temperature sensing
  • Simple to install and with no adjustment needed
  • Three year manufacturer’s warranty

Installation for Freeze Sensor

The correct placement of the Freeze Sensor is critical for accurate temperature sensing. It must be mounted out of direct sunlight, and where free outdoor air circulation is possible. Examples would be the north wall of a building or under eaves or overhangs.

The sensor housing is designed to provide the sensing element some amount of protection from direct or indirect radiation, while allowing air to move freely around it. This feature, along with the best possible placement, will allow the freeze sensor to respond at the correct temperature.

Using the screws provided, attach the sensor to the chosen surface. Run the extension wire to the controller. If an extension to the wire is needed, use wire no lighter than 20 AWG.


The sensor connects directly to the sensor terminal on the AC controller.

1.       Route the wires from the sensor up through the same opening used for valve wiring on the controller.

2.       Connect one of the sensor lead wires to the C terminal (common).

3.       Connect the other sensor lead wire to the valve’s common ground lead wire and connect the valve’s wires to the correct controller valve number terminals. If the valve common wire is connected to the controller common terminal disconnect it and connect it to the sensor. 

4.       The third wire, if available, is for a normally open lead; do not use.

If a rain sensor is already installed or is to be part of the installation (see the Figure below), the Freeze Sensor is to be wired in series with the Rain Sensor so that either (or both) devices can control the circuit.

Wiring the Freeze-Clik and Mini-Clik to Other Controllers