First Alert CO400

First Alert CO400 Carbon Monoxide (CO) Detector User Manual

Model: CO400 | Brand: First Alert

Introduction

The First Alert CO400 Carbon Monoxide (CO) Detector is designed to provide continuous monitoring of carbon monoxide levels in your home, offering early warning of this odorless, colorless, and poisonous gas. Equipped with an advanced electrochemical sensor, this battery-operated alarm ensures protection even during power outages. Its user-friendly design allows for versatile placement, including an optional wall mount.

First Alert CO400 Carbon Monoxide Detector, front view

Front view of the First Alert CO400 Carbon Monoxide Detector, showing the test/silence button and First Alert logo.

Important Safety Information

Carbon monoxide (CO) is a highly toxic gas that can be produced by any fuel-burning appliance. It is invisible, odorless, and tasteless, making it extremely dangerous. CO alarms are crucial for detecting this poisonous gas and providing early warning to protect your family.

Two children playing on a window seat, with text 'Protect your family with advanced CO detection'

Image illustrating the importance of CO detection for family safety.

Official Product Video: Carbon Monoxide Alarms

This video provides an overview of First Alert Carbon Monoxide Alarms, including their types, placement recommendations, and essential safety tips. It highlights the importance of early detection and regular testing to ensure home safety.

Setup

Battery Installation

The First Alert CO400 operates on a 9V replaceable battery. To install or replace the battery:

  1. Locate the easy-access battery door on the back of the unit.
  2. Open the battery compartment.
  3. Insert a fresh 9V battery, ensuring correct polarity (+/-).
  4. Close the battery door securely.
Back of the First Alert CO400 detector showing the easy access battery door and a 9V battery

Rear view of the detector, highlighting the battery compartment and included 9V battery.

Placement

The CO400 detector is battery-operated, offering flexibility in placement without needing an outlet. It can be placed on a tabletop or mounted on a wall.

First Alert CO400 detector mounted on a wall next to a door

The CO400 detector mounted on a wall, demonstrating its battery-operated flexibility.

Diagram showing recommended placement of smoke and CO alarms in a house, including bedrooms, hallway, living room, kitchen, and basement

Diagram illustrating recommended placement of CO alarms throughout a typical home.

Operating Instructions

Normal Operation

Once the battery is installed, the CO400 will begin monitoring carbon monoxide levels. It is designed to provide continuous protection.

Testing the Alarm

Regular testing ensures your alarm is functioning correctly. Use the Test/Silence button to perform a test:

  1. Press and hold the Test/Silence button located on the front of the unit.
  2. The alarm should sound a loud 85-decibel horn, typically a sequence of 4 beeps, a pause, and then 4 beeps again.
  3. Release the button. The alarm should stop sounding.

If the alarm does not sound during the test, ensure fresh batteries are correctly installed and test again. If it still does not alarm, replace the unit immediately.

Close-up of the First Alert CO400 detector showing the Test & Silence Button

Detail of the Test & Silence button on the CO400 detector.

What to Do if the Alarm Sounds

If your carbon monoxide alarm sounds, it indicates the presence of CO. Follow these critical steps:

  1. Leave Immediately: Move to fresh air outdoors or open doors/windows to ventilate the area.
  2. Call Emergency Services: Once in fresh air, call 911 or your local emergency number.
  3. Do not re-enter the premises until emergency responders have cleared the area and confirmed it is safe.

Maintenance

Battery Replacement

The CO400 is powered by a 9V battery. An audible and visual low battery signal will alert you when it's time to replace the battery. It is recommended to replace batteries every six months, even if the low battery signal has not yet activated.

End-of-Life Signal

The detector is equipped with an end-of-life signal chirp, which indicates when it's time to replace the entire unit. The permanent sensor lasts up to 5 years. For optimal safety, replace your alarm every 5 to 10 years, depending on the manufacturer's instructions and the specific model's lifespan.

First Alert CO400 detector on a wall with text 'End-of-Life Warning Lets You Know When It's Time to Replace'

Visual representation of the end-of-life warning, indicating when to replace the unit.

Cleaning

To maintain optimal performance, gently vacuum the alarm cover once a month using the soft brush attachment of your vacuum cleaner. Do not paint the unit.

Troubleshooting

Understanding the different alarm signals can help you identify the issue quickly:

SignalMeaningAction
4 beeps and a pauseCarbon Monoxide detectedEvacuate immediately and call 911.
1 beep every minuteLow BatteryReplace the 9V battery.
5 beeps every minuteEnd of LifeReplace the entire CO detector unit.

Specifications

First Alert CO400 detector with dimensions labeled: 3.4in height, 1.5in depth, 5in width

Dimensions of the First Alert CO400 Carbon Monoxide Detector.

Warranty

The First Alert CO400 Carbon Monoxide Detector comes with a 5-Year Limited Warranty. Please refer to the included user manual for full warranty details and terms.

Support

For further assistance, technical support, or warranty claims, please contact First Alert customer service:

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