BRK CO5120BNA Carbon Monoxide Alarm, 120V Hardwired w/ Battery Backup
MFR Part #:CO5120BN
- Alarm Type :Latching
- Power Source :120 VAC/9 VDC Battery
- Audible Alert :85 dB at 10 ft
- Sensor Type :Electrochemical
- Humidity Rating :0.95
- Color :White
First Alert® Carbon Monoxide Alarm, 3rd Generation, 120 VAC/VDC, Electrochemical/Photoelectric Sensor, Hardwired Power Source, 85 dB Alert, White
The BRK CO5120BNA carbon monoxide alarm is a 120V hardwired detector with battery backup, designed for residential and multi-unit installations. It uses an electrochemical sensor with a 10-year service life and supports interconnection with other compatible alarms.
Step-by-Step DIY Installation
You don’t need specialty tools or an electrician for this upgrade. Follow these simple steps to secure your home in under 15 minutes:
- Power Down: Turn off the power at your home's breaker panel for the alarm circuit.
- Remove Old Unit: Twist your old alarm counter-clockwise and unplug the wiring harness.
- Check the Bracket: If you’re replacing an older BRK model, the bracket might already be a match. If not, swap it out using a standard screwdriver—the keyhole slots make this effortless.
- Quick-Connect: Plug the new "Quick-Connect" wiring harness into the back of your CO5120BNA.
- Mount & Locked: Twist the unit onto the bracket. Use the optional locking pin if you want to prevent tampering.
- Activate & Test: Slide the 9V battery into the side-load compartment (no need to take the unit down!) and press the Test/Silence button. Once you hear the 85dB beep, you’re protected.
- First Alert® CO5120BN 3rd Generation Carbon Monoxide Alarm, Electrochemical/Photoelectric Sensor, Hardwired, 85 dB
Electrochemical CO Sensor (10-year life) → Provides accurate carbon monoxide detection with long-term reliability
120V AC hardwired with 9V battery backup → Ensures continuous protection during power outages
Interconnect capability (up to 18 devices) → Enables whole-property alerting when one alarm detects CO
85 dB alarm horn → Delivers clear, audible alerts across rooms and floors
Intelligent Sensing Technology → Reduces nuisance alarms for more dependable operation
Latching alarm indicator → Identifies which unit triggered the alarm in interconnected systems
End-of-life signal (10-year) → Notifies when replacement is required, preventing unnoticed device aging
Test/Silence button with low-battery silence → Simplifies testing and temporarily silences nuisance or low battery alerts
Self-diagnostic function → Alerts users to malfunctions via audible warning patterns
Quick-Connect wiring harness → Speeds up installation and reduces wiring complexity
Specification
Details
Model
CO5120BN
Power Source
120V AC, 60Hz (hardwired)
Battery Backup
9V alkaline battery
Sensor Type
Electrochemical
Sensor Life
10 years
Alarm Output
85 dB at 10 ft
CO Detection Thresholds
70 PPM (60–240 min), 150 PPM (10–50 min), 400 PPM (4–15 min)
Low-Level Detection
Does not alarm below 30 PPM
Operating Temperature
40°F to 100°F (4°C to 38°C)
Humidity Range
10% to 95% RH
Interconnection
Up to 18 units (max 12 smoke alarms)
Dimensions
5.4 in diameter x 1.9 in height
Weight
6.4 oz
Indicators
LED status indicators (power, alarm, latching)
Alarm Reset
Automatic when CO clears
Standards & Listings
UL2034, NFPA 720, ICC, CSFM compliant
Residential homes → Hardwired CO detection with backup power for continuous safety
Multi-family housing → Interconnected system alerts across units or floors
Hotels, dormitories, and institutional buildings → Suitable for sleeping areas requiring code compliance
New construction or retrofits → Quick-connect installation and contractor-friendly features
Compatible with:
- BRK and First Alert interconnectable smoke, CO, and heat alarms
- Standard 120V AC electrical systems (with junction box installation)
System limits:
- Maximum of 18 interconnected devices
- Up to 12 smoke alarms within the network
What type of sensor does the BRK CO5120BNA carbon monoxide alarm use?
It uses an electrochemical carbon monoxide sensor, designed for precise detection and a 10-year service life.
Can this alarm function during a power outage?
Yes. It is hardwired to 120V AC power and includes a 9V battery backup to maintain operation during outages.
How many units can be interconnected?
Up to 18 compatible alarms can be interconnected, including a maximum of 12 smoke alarms.
Does the alarm detect low levels of carbon monoxide?
No. The unit is calibrated not to alarm below 30 PPM and follows defined time thresholds for higher concentrations.
How do I know when the alarm needs replacement?
The unit provides an end-of-life signal after approximately 10 years, indicating it should be replaced.
What is the "Latching Alarm Indicator"?
If you have multiple alarms interconnected and one goes off while you're out, the "Latching" feature flashes the LED on the unit that first detected the gas. You’ll know exactly where the leak started.
How often do I need to change the battery?
The 9V backup battery should be replaced once a year. Thanks to the Side-Load Battery Drawer, you can swap it in seconds without ever removing the alarm from your ceiling.
Does it detect smoke too?
No, this is a dedicated Carbon Monoxide alarm. For full protection, we recommend pairing it with a BRK Hardwired Smoke Alarm in an interconnected system.