A malfunctioning smoke detector is not only noisy, but also unable to do its very important job of alerting you to a fire. Silencing a beeping smoke detector and restoring it to working order is relatively easy. No special skills or tools are needed, although you may need to purchase a replacement smoke detector if the beep refuses to be silenced.
Go to the fuse box and find the fuse or circuit breaker that controls the electricity in the area where your smoke detector is located. This information is typically on the inside of the fuse box cover. Remove the fuse or trip the circuit breaker to cut the power to the smoke detector.
Replace the battery backup in the smoke detector. A battery backup supply that is running low on power can cause a smoke detector to beep continuously. Take off the smoke detector's cover plate. This may require turning the cover plate counterclockwise or removing the screws from the cover plate, using a Phillips screwdriver. Take out the battery backup. Replace it with the same kind of battery that you just removed. Close the cover plate. Press the "Test" button once to sound the alarm. This will confirm that the battery has been properly connected to the alarm and cause the electronics to stop reporting otherwise by beeping.
Reset the smoke detector by pressing the reset button at the bottom or side of the detector. Hold the button in until the alarm sounds. Release the button and wait for the alarm to stop sounding.