If the Power light near the bottom of your Irritrol Rain Sensor is blinking, you have a power issue. This most often means the battery needs to be replaced in your sensor. 

To change the battery in your sensor:

1) Removed the bottom cover of the sensor by pressing down on the thumb-release lever on the side of the unit. Carefully slide the circuit board out. 

2) Remove the battery cover and replace the two 3V CR2032 batteries. Install with the positive side of the batteries facing up. 

3) Reassemble unit in reverse order.