1. Introduction and Overview
The Kidde KN-COPP-3 Carbon Monoxide Detector is designed to protect your home and family from the dangers of poisonous carbon monoxide (CO) gas. Utilizing advanced electrochemical sensor technology, this detector provides continuous monitoring and alerts you with an 85-decibel alarm when CO is detected. It features a digital LED display that shows CO levels in parts per million (PPM) and updates every 15 seconds. The unit operates by plugging into a standard 120V AC power outlet and includes a 9-volt alkaline battery for backup power during outages. Key features include Peak Level Memory, which records the highest CO level detected, and a Smart-Hush button to temporarily silence nuisance alarms.

Figure 1: Front view of the Kidde KN-COPP-3 Carbon Monoxide Detector with digital display.
- Easy Installation: Simply plug into a standard 120V outlet.
- 9-volt Battery Backup: Ensures continuous protection during power outages.
- Digital LED Display: Shows real-time carbon monoxide levels.
- 85-Decibel Alarm: Provides a loud alert when CO is detected.
- Peak Level Memory: Records the highest CO concentration.
- Smart-Hush Button: Temporarily silences the alarm for convenience.
2. Setup
The Kidde KN-COPP-3 Carbon Monoxide Detector offers flexible installation options for optimal placement in your home.
2.1. Unpacking and Initial Setup
Carefully remove the detector from its packaging. Locate the included 9-volt alkaline battery. Open the battery compartment on the back of the unit and connect the battery, ensuring correct polarity. The unit will perform a self-test upon battery insertion.

Figure 2: Installing the 9-volt backup battery into the detector's compartment.
2.2. Placement Options
The detector can be installed in three ways:
- Direct Plug-in: Plug the unit directly into any standard 120V AC wall outlet. The plug can be rotated to accommodate vertical or horizontal outlets, ensuring the unit remains upright.
- Tabletop Placement: Use the included 6-foot extension cord to place the detector on a table or shelf. This allows for optimal positioning away from direct heat sources or vents.
- Wall-Mount: For permanent installation, the unit can be mounted to a wall using the provided mounting hardware. Ensure the chosen location is within reach of a 120V AC outlet.

Figure 3: Rear view of the detector illustrating the removable AC adapter and keyholes for wall mounting.
For optimal safety, install a carbon monoxide detector on every level of your home, especially near sleeping areas. Avoid placing detectors within 15 feet of cooking or heating appliances to prevent false alarms.

Figure 4: Recommended placement guide for carbon monoxide detectors in a home layout.
3. Operating Instructions
Once installed and powered, the Kidde KN-COPP-3 operates continuously to monitor CO levels.
3.1. Digital LED Display
The digital display continuously shows the level of carbon monoxide the sensor is detecting in parts per million (PPM). This reading updates every 15 seconds. A blinking dot in the lower right-hand corner indicates normal operation.

Figure 5: The digital LED display showing a reading of "0" PPM, indicating no carbon monoxide detected.
3.2. Alarm Operation
If unhealthy levels of carbon monoxide are detected, the alarm will emit four quick audible beats every five seconds. The digital display will show the detected CO level. The alarm will continue until CO levels decrease or the Test/Reset button is pressed.
3.3. Peak Level Memory
Press the "Peak Level" button to view the highest CO concentration recorded by the alarm since it was last reset or unplugged. This feature is useful for understanding past exposure levels.
3.4. Smart-Hush Button
The "Test/Reset" button also functions as a Smart-Hush button. Pressing it will temporarily silence the alarm for approximately 8 minutes. This is useful for silencing nuisance alarms caused by temporary conditions like cooking fumes or shower steam. The alarm will reactivate if CO levels remain high or increase.

Figure 6: A user pressing the Test/Reset button, which also functions as the Smart-Hush button.
4. Maintenance
Regular maintenance ensures the continued reliability of your carbon monoxide detector.
- Weekly Testing: Press and hold the "Test/Reset" button for a few seconds until the alarm sounds. This verifies the unit's electronic circuitry and horn are working.
- Battery Replacement: The 9-volt backup battery should be replaced annually, or immediately if the unit indicates a low battery warning (usually a chirp or specific display message).
- Cleaning: Gently vacuum or wipe the exterior of the detector with a soft, damp cloth at least once a month to remove dust and debris that could obstruct the sensor. Do not use cleaning solvents or sprays.
- Unit Replacement: Carbon monoxide detectors have a limited lifespan. The Kidde KN-COPP-3 has a 7-year life. Replace the unit after 7 years from the date of manufacture (found on the back of the unit) or immediately if it indicates an end-of-life warning.
5. Troubleshooting
If your carbon monoxide detector is not functioning as expected, refer to the following common issues:
| Problem | Possible Cause | Solution |
|---|---|---|
| Alarm sounds frequently without apparent CO. | Nuisance alarm due to cooking fumes, high humidity, or proximity to combustion sources. | Press the Smart-Hush button. Relocate the unit if nuisance alarms persist. Ensure proper ventilation. |
| Unit chirps periodically. | Low battery. | Replace the 9-volt battery immediately. |
| Digital display shows "Lb" or "End". | "Lb" indicates low battery. "End" indicates end of unit life. | For "Lb", replace battery. For "End", replace the entire CO detector unit. |
| No display or unit is unresponsive. | No power or dead battery. | Ensure unit is properly plugged into a live outlet. Check and replace the 9-volt battery. |
If issues persist after attempting these solutions, contact Kidde customer support for further assistance.
6. Specifications
| Feature | Detail |
|---|---|
| Brand | Kidde |
| Model Number | KN-COPP-3 |
| Power Source | Plug In (120 Volts AC) with 9-Volt Battery Backup |
| Sensor Type | Electrochemical |
| Alarm Loudness | 85-decibel |
| Product Dimensions | 1.75"D x 3.75"W x 6.06"H |
| Item Weight | 1.08 pounds |
| Operating Humidity | 5% to 95% relative humidity, non-condensing |
| Certifications | UL Certified (Meets UL 2034, UL217, NFPA72, NFPA101, FHA, HUD requirements) |
| Warranty | 10-Year Limited Manufacturer's Warranty |
7. Warranty and Support
The Kidde KN-COPP-3 Carbon Monoxide Detector comes with a 10-Year Limited Manufacturer's Warranty, ensuring peace of mind regarding its quality and performance.
For detailed warranty information, troubleshooting, or technical support, please refer to the official documentation:
You can also visit the official Kidde website or contact their customer service for further assistance.





