Kidde manufactures smoke alarms under the following brand names: Kidde, Firex, Nighthawk, Silhouette, CodeOne, Lifesaver and FireSentry. These units can be hardwired or battery-operated, and those that are hardwired usually have a backup battery. When a unit with a battery chirps, it's often because the battery needs replacing or the sensors are dirty. If the unit has a 10-year battery that can't be replaced, the chirping may mean that it's time to replace the unit.
Identifying the Sound
Before writing off the sound that your smoke alarm is making as merely annoying, it's important to make sure that it isn't actually sounding an alarm. Compare the sound the alarm is making with sound samples published on the Kidde website. The sounds occur in three modalities, which include a loud, continuous alarm, consistent chirping and intermittent chirping that occurs at random intervals. If the alarm is sounding, it's important to look carefully for signs of smoke or fire before troubleshooting the smoke detector -- the unit may simply be doing its job.
If the alarm sounds on a Kidde smoke detector and you see no signs of a fire, the cause could be smoke coming from the kitchen or even steam coming from the shower. Press the Hush button on the unit to silence it until the smoke or steam clears. In the absence of smoke or steam, check the circuit breaker -- it may have tripped, and a loss of power triggers the alarm. If the power is on, open the battery compartment and check the battery -- it may be installed incorrectly or dead. If the battery isn't replaceable, the alarm has probably reached the end of its life and needs to be replaced.
If your smoke alarm chirps consistently every 30 to 60 seconds, it may be because someone just pushed the Hush button to silence a false alarm. The unit chirps for seven minutes, then stops. If your smoke alarm has a replaceable battery, consistent chirping is a sign that the battery needs replacing; if the battery isn't replaceable, it's time to replace the unit. If you replace the battery and the unit still chirps while the red LED flashes, it's a sign that the unit is malfunctioning. Press the test button to reset the unit. If that doesn't work, replace it.
Chirping sounds that do not occur at regular intervals may occur as random clouds of smoke -- perhaps from cigarettes or steam -- waft through the unit. The sounds can also signify an improperly installed or worn battery. Open the battery cover, remove the battery and put it back in correctly -- if that doesn't work, try a new battery. Intermittent chirping can also signify a dirty sensing chamber. To clean the unit, turn the power off, take the unit down and blow out the chamber with compressed air. If the chirping is happening at more than one hardwired unit on the same circuit, the circuit may have a loose connection or may be experiencing voltage fluctuations.