QS5210-840—Battery Replacement

When it is time to replace the battery in your Qolsys QS5210-840, you will see an alert on your system panel, as well as a notification in the Brinks Home™ Mobile App.

Follow the instructions below to replace your battery and clear the alert from your system. The QS5210-840 carbon monoxide detector requires a CR123A 3-volt lithium battery, which can be purchased at your local hardware, mass retailer, or battery store. You may also order these online here or at your preferred online retailer.


Once you've replaced the batteries, the error on your panel should clear within one hour. If you would like to clear the error manually, click here.


Step-by-Step Instructions

1. Twist sensor counter-clockwise to remove from base.

001 - QS5210-840 Open


2. Remove and replace the CR123A 3-volt lithium battery.

002 QS5210-840 Battery


3. Align over the baseplate, and twist the sensor clockwise to reinstall.

003 - QS5210-840 Close


4. Check if the low battery status has cleared or go to the following link for further instructions on clearing the error from the panel memory: IQ Panel 2 - System Sensor Status.