Is your smoke alarm chirping or beeping? This always seems to occur in the middle of the night in my house. Here are the steps to follow to stop the incessant beeping!

Smoke Alarm Beeps Every 30 Seconds

If your smoke alarms are like mine, when the battery starts to run low, they chirp approximately every 30 seconds. It is incredibly annoying and usually happens at the worst possible time (2 am). These alarms have a low/missing battery monitor circuit that causes the alarm to “chirp” every 30-40 seconds for a minimum of 7 days when the battery gets low! Usually replacing the battery will fix the problem.

Note: It is not necessary to disconnect the alarm from the AC power when replacing the battery, though be forewarned, that it may beep or chirp while you are replacing it!

Steps to Reset a Fire Alarm

  1. Determine which smoke alarm is going off.
  2. Open the hatch and remove the old battery.
  3. Insert a new 9 volt battery.
  4. If the problem persists, remove the smoke alarm from the receptacle.
  5. Use a vacuum cleaner or “canned air” to blow out the smoke alarm.
  6. Remove the battery and press and hold the reset button for about 30 seconds.
  7. If it’s still not working, replace the smoke alarm (recommended every 10 years).

The following contains details for these steps, including pictures.

Detailed Instructions for Resetting a Fire Alarm

Step 1: Determine which smoke alarm is going off.

Have someone stand under each one to determine which one is actually sounding.

Step 2: Open the hatch and remove the old battery.

Most smoke alarms have a hatch that slides open. Slide it open, push the battery towards its terminals, and pull the back out.

smoke-detector-battery-hatch-open

Step 3: Insert a new 9 volt battery.

Put the new battery in. Look inside the battery hatch to make sure you have the (+) and (-) in the right way.

I usually buy a pack of 9 volt batteries from Amazon.

Hint: The hexagonal terminal is the (-), and the round terminal is the (+).

Replacing-battery-in-a-smoke-Detector-9v

That should fix the problem. But…if it doesn’t, continue to the next step.

Step 4: Remove the smoke alarm from the receptacle.

Many smoke detectors attach to the receptacle by a twist lock. Untwist the alarm by turning counter-clockwise.

twist-smoke-detector-to-remove

The smoke detector will now be dangling by the wiring harness.

smoke-alarm-dangling-from-wire-harness

Disconnect the wiring harness by pressing the 2 tabs on the sides and lifting up on the big flat tab.

back-of-smoke-detector-with-plug

Pull the plug off.

unplugging-smoke-alarm

Step 5: Use a vacuum cleaner or “canned air” to blow out the smoke alarm.

Sometimes small insects such as bugs or spiders can cause the sensor in the smoke alarm to go off (disgusting…). Use a vacuum or some other method to blow out any dust, cobwebs, or dead bugs.

Smoke-detector-removed-from-receptacle

Step 6: Remove the battery and press and hold the reset button for about 30 seconds.

Sometimes the smoke alarm just needs to be reset. To do this, with the smoke detector unplugged, remove the battery. Press and hold the reset button for about 30 seconds or so to reset it. Then put the battery back in, plug it back in, and see if it is working okay.

back-of-smoke-alarm-pins

Step 7: If it’s still not working, replace the smoke alarm.

If the smoke alarm is still beeping intermittently, it may be time to replace it. It is generally recommended to replace your smoke alarms every 10 years or so.

Here is the link to the smoke alarm shown in this post:

Kidde 21026063 AC Hardwired Smoke Detector Alarm with 9V Back up and Front Load Battery Door

And a link to the batteries for purchase:

9 Volt Batteries

I hope this helped solve your problem; thanks for reading practicalmechanic.com!