Battery-operated smoke detectors detect smoke from a fire. When they detect smoke they begin to emit a loud warning alarm. When the battery is low the alarm begins chirping every 30 seconds to indicate a new battery is needed. Sometimes the chirping may continue even after the battery is replaced. Or it may occur randomly for no apparent reason. A few steps can be taken to try and troubleshoot this chirping.
Remove the battery. Re-install the battery and put the smoke detector cover back on. If the beep continues, proceed to Step 2.
Locate the "Test" button. On some smoke detectors this may be labeled as "Reset." Press and hold the button for a few seconds. A tone will emit. Release the button. Wait a few minutes. If the chirp occurs again proceed to Step 3.
Remove the smoke detector cover or battery compartment door and remove the battery. Press and hold down the "Test" or "Reset" button for a few seconds. This will drain any remaining electrical current in the detector. Replace the battery and wait a few minutes. If the chirp continues proceed to Step 4.
Remove the battery and hold the compressed air can upright. Remove the smoke detector cover and hold the can a few inches from the detector. Press the nozzle down and spray out any dust in the detector.
Remove the battery and replace with a fresh battery. Verify that the "positive" and "negative" terminals line up to the matching "+" and "-" icons in the battery compartment. Close the cover or compartment door. Press the "Test" button once to ensure the smoke detector is getting power.
It is important to replace defective smoke detectors as soon as possible. If the smoke detector continues to emit chirps or does not make a sound when "test" is pressed, even after all troubleshooting, the detector needs to be replaced. If you have any doubt of the functionality of a fire alarm, have it replaced immediately.
Do not hold the canned air nozzle too close to the components of the smoke detector as the force of the air could damage the sensitive components.