Rain/Freeze Sensor Troubleshooting

In this article, we will go over some troubleshooting steps for both our wired and our wireless Rain/Freeze Sensors.

Hard Wired Rain Sensors

When a hard wired sensor is connected to a timer it can be tested on most timers by turning the sprinklers on manually from the timer. Push the “test stem” down that sticks out of the top of the rain sensor and the water should turn off. When you release the test stem the water will turn on again. If the water doesn’t turn off make sure that the rain sensor switch is switched to on/active if the timer has a rain sensor switch and the jumper wire was removed from the rain sensor terminals. If water still doesn’t turn off there are some Hydro-Rain and Toro timers that the manual on overrides the rain sensor. Turn the timer on manually and press the rain sensor “test stem” down to see if the water turns off. If you cannot confirm that the rain sensor is working using this method, try the following steps.

If you cannot confirm that the rain sensor is working while connected to a timer you can use an ohmmeter to test it. Disconnect the rain sensor from the timer. Put one ohmmeter probe on each wire going to the rain sensor. You may show a few ohms on the meter but it should be close to zero. Push the “test stem” on top of the rain sensor down and you should now have an infinite reading (open circuit). If you get the above ohm readings the rain sensor is good.

Wireless Rain Sensors

If your wireless rain sensor not working, then these steps should help. Turn on a sprinkler zone manually and push the “test stem” down on the sensor transmitter. Two things should happen. The “active sensor” LED should light up and the water should turn off. If this doesn’t happen, check the sensor switch on the timer to make sure it is in the on/active position. Verify that the jumper wire was removed from the sensor terminals. If either condition was not correct try the manual test again. If sensor still doesn’t turn the water off turn the timer on manually and press the “test stem” down to see if the water turns off. The manual operation on some timers overrides the rain sensor.

If the active sensor light did not come on press the large white button “manual override” down and the “sensor override” and “active sensor” LEDs should light up. They should turn off when the manual override button is pushed again. If they don’t light up, either the sensor is bad or the 24 vac is not connected correctly. Assume the 24 vac is not corrected correctly and get detailed information on the connection. If you have a voltmeter, then measure the voltage across the two points where the red wires from the rain sensor are connected. You should have about 24 to 28 vac at that point. Be sure that the two red wires are not twisted together and connected to one terminal on the timer.

If the test above passes, then push the “test stem” on the transmitter down and the “active sensor” LED should come on. If the “active sensor” LED comes on use an ohmmeter to measure between the white and yellow wire on the rain sensor. When the “active sensor” LED is on you should have an infinite ohm reading (open circuit). When the “active sensor” LED is off you should have a very low (near zero) ohm reading (closed circuit). You can also turn on a sprinkler zone manually and see if it goes off when the “test stem” is pushed down.

If the “active sensor” LED does not come on, do the “Verify Communications between the Transmitter and Receiver” on page 11 of the User’s Manual. Make sure that batteries in the transmitter are good/new and that the “low battery” LED is not on. If the “active sensor” LED does not come on after this test is completed there is a problem with the rain sensor. If the “active sensor” LED comes on when the “test stem” is pushed down the rain sensor is working. Turn on a sprinkler zone manually and confirm that they turn off when the “test stem” is pushed down.

If these steps did not help with getting your Rain/Freeze sensor working, then please click  here to reach out to our Customer Care Team.