A rain sensor that does not stop scheduled watering may be dry, bypassed, incorrectly wired, incompatible with the controller, poorly located, or defective. Smart weather adjustment and a physical rain shutoff sensor are also different features.
Confirm enough rain reached the sensor
The sensor must be exposed to rainfall but not direct sprinkler spray. Roof overhangs, dense foliage, and gutters can keep it dry. Many cork-disc sensors require enough rainfall to swell the discs before they open the control circuit.
Check controller status
- Set the sensor switch to Active rather than Bypass.
- Confirm the relevant program or stations are not configured to ignore the sensor.
- Look for sensor, rain-delay, or communication indicators.
- For a wireless model, check battery and receiver status.
Test the sensor safely
Follow the manufacturer’s manual. Many mechanical sensors have a test spindle: while a manual cycle is running, pressing it should stop irrigation. If the controller responds, wiring and logic may be working and the problem may be exposure or adjustment.
Inspect wiring and jumpers
A factory jumper usually occupies the sensor terminals when no sensor is installed. It generally must be removed when a compatible normally closed sensor is connected. Loose splices, staples through insulation, corrosion, and wrong terminal placement can keep the circuit from changing state.
Smart controller confusion
Weather-based seasonal adjustment may change future runtime without cancelling a schedule immediately after rain. Use the controller’s rain delay or compatible physical sensor if immediate shutoff is required.
When replacement is reasonable
If location, settings, wiring, battery, compatibility, and the manual test are all correct but the circuit never changes, the sensor or receiver may have failed. Match the replacement’s contact type and compatibility to the controller.
Turn off controller power before changing wiring and follow local electrical rules.
Related guides
Not sure where to start? Open the Irrigation Troubleshooter.
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