Recessed Door and Window Sensors | NorthStar Home Support

How to replace the battery in a Honeywell Recessed Door/Window Sensor

Locate the sensor that has a low battery by verifying the zone number, and location of that sensor on the alarm panel.
Place the alarm panel in Walk Test mode.
Go to the sensor on the door.

Using a flatblade screwdriver, open the sensor by turning it counterclockwise using the screwdriver. Once it comes loose, remove it from the sensor.

Pull the sensor out of the housing. (Use sharp-nose pliers if you cannot reach it)

Remove the old battery from the sensor, by pulling it straight up out of the battery tray.
Now that the battery has been removed from the sensor, replace it with a new AAA battery.
Pay close attention to the orientation of the battery in the battery tray. The battery will have a positive side, and a negative side, and the battery tray will have the proper orientation marked.

Once the battery has been replaced, you will need to replace the sensor inside the housing, push the sensor back into the housing making sure it is installed in the same direction it was installed to start.

Install the lid of the sensor back in its place making sure that the tabs line up properly, then secure it by using your screwdriver to turn the lid clockwise securing it in place.
Now that the lid of the sensor is properly secured onto the sensor, we will want to reboot the panel.
Once the panel has been rebooted, test the sensor by opening the sensor that was affected. If no Low Battery returns, the sensor has been fixed. If the Low Battery returns, the sensor may need to be replaced, at this point contact our Tech Support department.