Principal Parts of a Carbon Monoxide FCD3N Detector

Test and Silence Button

• The dual purpose test and silence button appears near the front of the carbon monoxide detector. First Alert recommends that the detector be checked on a weekly basis by pressing the test button and listening for the alarm. Should the alarm sound due to a malfunction, pressing this button will silence the noise temporarily.

Battery Light

• The First Alert FCD3N detector will not operate without a properly connected 9-volt battery. The green battery light will blink and you will hear a chirping sound when installing a new battery. When in working condition, the battery light will continue to flash every 30 seconds. When the battery runs low, a chirping noise will accompany the green flashing light as a reminder to change the battery.

Service Light

• The service light flashes yellow and a chirping sound will occur every 30 seconds when the First Alert carbon monoxide detector needs replacing.

Carbon Monoxide Alarm Light

• The red alarm light will flash rapidly and the alarm will sound continuously when the unit detects a dangerous level of carbon monoxide.

Interior Alarm Parts

• The interior of the FCD3N model includes the alarm horn, carbon monoxide sensors and the malfunction warning sensors.