Introduction
The First Alert 9120B / SMI100-AC Hardwired Smoke Detector with Battery Backup is designed to provide reliable smoke detection and enhance home safety. This model features an ionization sensor for detecting fast-flaming fires and includes a 9-volt battery backup to ensure continuous operation during power outages. It is inter-connectable with up to 12 compatible smoke alarms and six other compatible devices, ensuring all alarms sound when smoke is detected by any unit in the series.
Key features include a single test/silence button for easy functionality checks and nuisance alarm silencing, and a perfect mount system with tamper-resistant locking brackets for straightforward installation.
Safety Information
WARNING: This smoke alarm will not operate if power is interrupted and battery is dead, disconnected, or improperly installed. Refer to the user's manual for complete installation and operating instructions. Constant use at high or low temperatures or high humidity may reduce battery life.
- Electrical Shock Hazard: Turn off power to the area where the smoke alarm is installed before removing the alarm from the mounting bracket. Failure to turn off power first may result in serious electrical shock, injury, or death.
- Ensure proper placement on every level of your home and in each bedroom for complete protection.
- Do not paint the smoke alarm. Paint can interfere with the sensor's ability to detect smoke.
Video: Learn about First Alert Hardwired Smoke Alarms and important safety considerations.
Package Contents
- First Alert BRK 9120B Hardwired Smoke Alarm with Battery Backup (3 units)
- 9-volt battery (3 units)
- Mounting brackets with hardware (3 sets)
- Dust cover (3 units)
- User's Manual
Image: Contents of the First Alert 9120B / SMI100-AC package, including the smoke alarm unit, mounting plate, wiring harness, and installation hardware.
Setup & Installation
Mounting Location
Install smoke alarms on every level of your home, including the basement, and in every bedroom. For optimal protection, place alarms in hallways, living rooms, and kitchens. Avoid placing alarms near windows, doors, or areas with high airflow that could interfere with smoke detection.
Image: Recommended placement diagram for smoke alarms, carbon monoxide alarms, and fire extinguishers within a typical home layout.
Wiring and Mounting
This hardwired smoke alarm connects directly to your home's electrical system. Ensure the power to the circuit is turned OFF at the breaker box before beginning installation. The unit comes with a wiring harness (black, white, and orange wires) that connects to your existing electrical box. The mounting bracket offers multiple mounting locations for easy alignment.
- Turn off power at the main fuse or circuit breaker.
- Connect the wiring harness to your household wiring (black to live, white to neutral, orange to interconnect for multiple alarms).
- Secure the mounting bracket to the electrical box using the provided screws.
- Insert the 9-volt battery into the battery compartment on the back of the smoke alarm.
- Align the smoke alarm with the mounting bracket and twist clockwise until it locks securely into place. The tamper-resistant locking brackets help prevent unauthorized removal.
- Remove the battery activation tab (if present) to activate the battery backup.
- Turn on power at the main fuse or circuit breaker.
Image: Underside of the smoke detector, highlighting the wiring connection and mounting mechanism.
Operating Instructions
Normal Operation
During normal operation, the green LED indicator will flash every 60 seconds, indicating that the alarm is receiving power and functioning correctly. The ionization sensor is designed to detect smoke from fast-flaming fires.
Test/Silence Button
The large test/silence button on the front of the alarm allows you to test the unit's functionality or silence a non-threatening alarm or low battery warning.
- To Test: Press and hold the test/silence button until the alarm sounds. The alarm will emit a loud, piercing sound. Release the button to stop the alarm.
- To Silence: If a nuisance alarm occurs (e.g., from cooking smoke), press the test/silence button to temporarily silence the alarm for several minutes. The alarm will automatically reset after the silence period.
Alarm Signals
- Smoke Alarm: 3 beeps, repeating.
- Low Battery Warning: 1 chirp every minute. Replace battery.
- Malfunction: 5 chirps per minute. Replace alarm.
- End of Life: 5 chirps per minute. Replace alarm.
Image: Top view of the smoke detector, highlighting the test/silence button and power indicator light.
Maintenance
Regular Testing
Test your smoke alarm weekly by pressing the test/silence button. This ensures the unit is functioning correctly.
Cleaning
Clean your smoke alarm monthly to remove dust and debris that could interfere with its operation. Use a soft brush attachment on your vacuum cleaner to gently clean the vents and cover. Do not use water, cleaners, or solvents.
Battery Replacement
The 9-volt battery backup should be replaced annually, or immediately when the alarm chirps once every minute. To replace the battery, twist the alarm counter-clockwise from the mounting bracket, open the battery compartment, replace the old battery with a new 9-volt battery, and reattach the alarm.
Alarm Replacement
Smoke alarms have a limited lifespan. This unit is designed for 10 years of service. Replace the entire smoke alarm unit 10 years after the installation date, regardless of whether it appears to be functioning. The manufactured date is printed on the back of the alarm.
Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Alarm chirps once every minute | Low battery | Replace 9-volt battery. |
| Alarm chirps five times every minute | Malfunction or End of Life | Replace the entire smoke alarm unit. |
| Alarm sounds without visible smoke/fire | Nuisance alarm (e.g., cooking smoke, steam, high humidity, dust) | Press the test/silence button. Move to fresh air if necessary. Clean the alarm. Relocate if nuisance alarms persist. |
| Alarm does not sound during test | No power, dead battery, or malfunction | Check power connection. Replace battery. If issue persists, replace alarm. |
Specifications
- Brand: First Alert
- Model Number: BRK 9120B-3
- Power Source: Hardwired (120-Volt AC) with 9-Volt Battery Backup
- Sensor Type: Ionization
- Color: White
- Product Dimensions: 1.9"D x 5.6"W x 5.6"H
- Item Weight: 0.6 Pounds
- Inter-connectable: Yes, with up to 12 compatible smoke alarms and 6 compatible devices.
- Alarm Loudness: 85 decibels
- Certifications: UL Listed
Warranty and Support
The First Alert 9120B / SMI100-AC Smoke Detector comes with a 10-year limited warranty, reflecting its quality and durability. For warranty claims, technical support, or any questions regarding your product, please contact First Alert customer service.
- Customer Service: 1-800-323-9005
- Website: www.firstalert.com
