Honeywell 5816—Battery Replacement
When it is time to replace the battery in your Honeywell 5816 door/window sensor, you will see an alert on your system panel.
Follow the instructions below to replace your battery and clear the alert from your system. The Honeywell 5816 sensor requires a CR123A 3-volt lithium battery, which can be purchased at your local hardware, mass retailer, or battery store.
1. Press the end latch to remove the cover.
2. Remove and replace the CR123A 3-volt lithium battery.
3. Return the cover to the sensor, starting with the side opposite the latch, pressing closed until the latch snaps into place.
4. Check if the low battery status has cleared.