Learn how to install or replace a battery in the Visonic MCT-340 SMA door or window sensor.
What you'll need
- Xfinity Home
- MCT-340 SMA door or window sensor
- One CR2032 battery
- Double-sided tape (optional)
Difficulty
Medium
Do you need a battery?
Make sure you have batteries before you proceed. Visit your nearest retail store that sells batteries or click the button below to order your replacement battery kit.
Call us at 1-800-XFINITY if you receive a low battery alert within 30 days of device installation.
Install the battery
Before proceeding, make sure that your system is disarmed. Working on devices while the system is armed can generate false alarms.
Did you know? You may want to have some double-sided tape on hand if you need to remove your sensor from the wall to install a battery. Use the tape to reattach your sensor if its existing adhesive fails to hold it in place.
Help protect our environment: Please properly recycle your discarded batteries. For your convenience, batteries are accepted for recycling at various locations. Check call2recycle.org or call 1-800-8-BATTERY (1-800-8-228-8379) to find a recycling location near you.
Is this your sensor? Make sure that your sensor looks like the one in the image below. If it does, you're in the right place to find out how to install a battery in your sensor.
Did you see? There is a mark located on the side of the sensor (see arrow above) that shows the recommended side to use when matching up the sensor with the magnet. The same mark is found on the magnet for easy alignment.
- Locate the small horizontal raised lines in the shape of a pyramid on the sensor.
- Place your thumb or finger on the horizontal lines and push or pull toward the end of the sensor.
- The cover will slide down a short distance, allowing you to pull the cover off the sensor.
- After removing the cover you may receive a tamper alert from your system.
- The tamper alert warns you when the cover of your device is open and will clear once the battery is replaced and the cover is reattached.
- Be sure not to press down on the tamper (small black switch to the right of the battery) when inserting the battery as this will reset the sensor to the factory settings.
- Take a look. If a battery is already present, remove it by using your fingertip to gently pull one end of the battery up until the battery is loose and you can pull it free from the slot.
- Insert the CR2032 battery by placing it flat against the prongs in the battery compartment with the negative (-) side facing down. The battery should fit inside the battery cradle.
- Align the small tabs on the cover with the slots in the track on the sensor's body and press the cover down onto the sensor.
- Use your thumb or finger to slide the cover towards the other end of the sensor until it snaps into place.
- When the battery is inserted correctly and the cover is reattached, the red light on the front of the sensor will light up.
- If you're replacing the battery, confirm that the low battery alert has resolved and the sensor appears on your list of connected devices in your touchscreen or the Xfinity Home app.
- Test the sensor to confirm that it is working correctly.
Additional information
Visit our Online Support Center to find common solutions.
The easiest way to activate, manage, and troubleshoot your Xfinity experience is with the Xfinity app! Get 24/7 real-time support, pay your bill, view plan details, get outage updates, and more. Download the free Xfinity app, or scan the QR code with your smartphone.
Need additional support? Ask Xfinity Assistant.
