Learn how to install or replace a battery in the Visonic MCT-427 SMA smoke detector.
What you'll need
- Xfinity Home
- MCT-427 SMA smoke detector
- One CR123A battery
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 and in test mode. Working on devices while the system is armed can generate false alarms.
Did you know? Removing batteries without putting the system in test mode could trigger an alarm, dispatch police or fire assistance, and may result in a fine for a false alarm.
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 (1-800-822-8837) to find a recycling location near you.
Is this your smoke detector? Make sure that your smoke detector 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 smoke detector.
To install batteries:
- Put your system in test mode.
- If you have removed the smoke detector from the wall or ceiling, turn the smoke detector body counterclockwise until the cover tabs are free from the slots holding the detector in place.
- If the device is still attached to the wall or ceiling, hold the top of the smoke detector and turn it counterclockwise until it stops.
- The cover will remain attached once you've pulled the detector away.
- Locate the battery compartment cover on the top of the smoke detector and use your finger to lift the cover.
- 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 (red square) 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. Then, you can pull it free from the slot.
- Place one CR123A battery into the slot with the negative (-) end of the battery on top of the red spring located next to the negative (-) battery placement indicator on the outside of the compartment.
- Press the positive (+) end of the battery into the slot next to the positive (+) battery placement indicator.
- When the battery is inserted correctly, the smoke detector will emit a short beeping sound.
- If you're replacing the battery, confirm that the low battery alert has resolved and the detector appears on your list of connected devices in your touchscreen, Subscriber Portal or the Xfinity Home app.
- Close the battery compartment cover by pushing it down with your finger until it snaps into place.
- Align the tabs on the cover with the slots on the body of the smoke detector.
- Turn the cover clockwise until it snaps into place. If you have removed the smoke detector from the wall or ceiling, remount the device.
- Did you know? You should take the opportunity to clean the sensor when you have the smoke detector removed from its mount.
- Clean the front and back of the smoke detector with a dry or damp (water only) cloth.
Additional information
Visit our Online Support Center to find common solutions.
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