1. Introduction
The Kidde KN-COSM-XTR-BA is a battery-powered combination smoke and carbon monoxide (CO) alarm designed to provide early warning of both fire and carbon monoxide hazards. This device utilizes both ionization and electrochemical sensor technologies to detect invisible fire particles and poisonous carbon monoxide gas. It features voice alerts, LED indicators, and a test/hush button for user convenience and safety.
2. Safety Information
Please read and understand all instructions before installing and operating this alarm. Keep this manual for future reference. This alarm is designed for residential use. It is not intended for use in non-residential buildings or for commercial or industrial applications. Regular testing and maintenance are crucial for proper operation.
WARNING:
- This alarm will not work without batteries. Ensure batteries are correctly installed and replaced as needed.
- Do not paint the alarm. Paint can clog the sensing chambers and prevent the alarm from operating properly.
- Do not place the alarm in areas with high humidity, extreme temperatures, or near cooking appliances to avoid nuisance alarms.
3. Setup and Installation
3.1 Package Contents
- Kidde KN-COSM-XTR-BA Combination Smoke & CO Alarm
- Two (2) AA batteries
- Mounting hardware (screws and anchors)
- User Manual
3.2 Battery Installation
- Slide the battery compartment door open.
- Insert the two (2) AA batteries, matching the positive (+) and negative (-) terminals correctly.
- Close the battery compartment door securely. The alarm will chirp and the green LED will flash to indicate proper installation.

Figure 1: Battery compartment open, showing AA batteries. Ensure correct polarity when inserting batteries.
3.3 Mounting the Alarm
- Select an appropriate location (see Section 7: Placement Guidelines).
- Use the provided mounting bracket as a template to mark two screw holes on the ceiling or wall.
- Drill pilot holes and insert the plastic anchors if mounting into drywall or plaster.
- Attach the mounting bracket using the provided screws.
- Align the alarm with the mounting bracket and twist clockwise until it locks into place.

Figure 2: Mounting plate for secure installation. This plate attaches to the ceiling or wall before the alarm unit is twisted onto it.
3.4 Initial Test
After installation, press and hold the Test/Hush button for a few seconds. The alarm will sound a series of beeps and voice announcements (e.g., "Fire! Fire!", "Warning! Carbon Monoxide!"). This confirms the unit is functioning correctly.
4. Operating the Alarm
4.1 Normal Operation
During normal operation, the green LED will flash approximately once every 30-60 seconds, indicating the alarm is receiving power and functioning properly.
4.2 Alarm Conditions and Voice Alerts
The alarm provides distinct audible and voice alerts for different hazards:
- Smoke/Fire Alarm: Three long beeps followed by the voice announcement "Fire! Fire!". The red LED will flash in unison.
- Carbon Monoxide (CO) Alarm: Four quick beeps followed by the voice announcement "Warning! Carbon Monoxide!". The red LED will flash in unison.
- Low Battery Warning: A single chirp approximately every 60 seconds, accompanied by the voice announcement "Low Battery!". The green LED will flash twice per second.
Video 1: This video demonstrates the voice alerts and LED indicators for fire, carbon monoxide, and low battery conditions on the Kidde Intelligent Alarm. It shows the alarm sounding and announcing the specific hazard, providing a clear example of its operational features.
4.3 Hush Feature
The Hush feature temporarily silences the alarm for approximately 8-9 minutes. This is useful for nuisance alarms caused by cooking or steam. To activate, press the Test/Hush button during an alarm. The green LED will flash twice per second to indicate the Hush mode is active. The alarm will automatically reset after the Hush period or if smoke/CO levels remain high.
4.4 Test/Reset Button
The large button on the front of the alarm serves two functions:
- Test: Press and hold to test the alarm's functionality.
- Reset/Hush: Press briefly to silence a nuisance alarm or reset the alarm after a hazard has cleared.
5. Maintenance
5.1 Regular Testing
Test the alarm weekly by pressing and holding the Test/Hush button until the alarm sounds. This ensures the electronic circuitry, horn, and battery are working.
5.2 Battery Replacement
Replace batteries when the alarm announces "Low Battery!" and chirps every 60 seconds. Use only specified AA alkaline batteries. Refer to Section 3.2 for battery installation steps.
5.3 Cleaning
Clean the alarm regularly to prevent dust and debris from interfering with its operation. Use a soft brush attachment on your vacuum cleaner to gently remove dust from the alarm's vents. Do not use cleaning solvents or spray directly onto the alarm.
5.4 End-of-Life Warning
The alarm has a 10-year operational life. After 10 years from the date of manufacture, the alarm will indicate its end-of-life by chirping twice every 30 seconds. Replace the alarm immediately when this occurs.
6. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Alarm chirps every 60 seconds with "Low Battery!" voice alert. | Low battery. | Replace batteries immediately (see Section 5.2). |
| Alarm sounds with "Fire! Fire!" or "Warning! Carbon Monoxide!" voice alert. | Presence of smoke or carbon monoxide. | Follow emergency procedures. If it's a nuisance alarm, use the Hush feature (see Section 4.3). |
| Alarm chirps twice every 30 seconds. | End-of-life warning. | Replace the alarm unit immediately (see Section 5.4). |
| Alarm does not sound during test. | Dead batteries, incorrect battery installation, or unit malfunction. | Check/replace batteries. Ensure correct polarity. If problem persists, replace the unit. |
7. Placement Guidelines
Proper placement of your smoke and carbon monoxide alarm is critical for effective protection. Follow these general guidelines:
- Install at least one alarm on every level of your home, including basements and attics.
- For smoke detection, install alarms inside every bedroom and outside each sleeping area.
- For carbon monoxide detection, install alarms on every level and in sleeping areas.
- Avoid placing alarms near windows, doors, or vents where drafts could interfere with detection.
- Keep alarms at least 20 feet away from cooking appliances to minimize nuisance alarms.

Figure 3: Home Safety Product Placement Guide. This diagram illustrates optimal locations for various safety devices within a typical home layout.
7.1 Potential Sources of Carbon Monoxide
Be aware of common sources of carbon monoxide in and around your home:
- Vehicles left running in an attached garage.
- Portable generators.
- Corroded or disconnected water heater vent pipes.
- Portable kerosene or gas heaters.
- Loose or broken vent pipes from furnaces.
- Improperly installed kitchen ranges or vents.
- Operating a grill indoors or in a garage.
- Gas or wood-burning fireplaces.

Figure 4: Potential Sources of Carbon Monoxide. Understanding these sources helps in preventing CO buildup.
8. Specifications
- Model: KN-COSM-XTR-BA
- Power Source: 2 AA batteries (included)
- Sensor Type: Ionization (smoke), Electrochemical (CO)
- Alarm Loudness: 85 decibels
- Product Dimensions: 1.8"D x 5.6"W x 5.6"H
- Item Weight: 0.16 ounces
- Operating Humidity: 10% to 85% relative humidity, non-condensing
- Upper Temperature Rating: 100 Degrees Fahrenheit
- Certifications: UL Certified
9. Warranty and Support
9.1 Warranty
This Kidde alarm comes with a 10-year limited warranty. For warranty claims or detailed information, please refer to the warranty card included in the product packaging or contact Kidde customer support.
9.2 Customer Support
For technical assistance, troubleshooting, or any questions regarding your Kidde KN-COSM-XTR-BA alarm, please contact Kidde customer support. Contact information can typically be found on the product packaging or the official Kidde website.





