Press and hold the smoke detector test button
Listen for the alarm sound
Replace the battery if the sound is weak, intermittent, or absent
Remove the detector from its mounting bracket if needed
Open the battery compartment
Take out the old battery
Insert a new battery of the correct type and orientation
Close the battery compartment
Reattach the detector to the mounting bracket
Press the test button again to confirm proper operation
Replace the battery immediately if the low-battery chirp continues