Why Does My Smoke Alarm Beep or Chirp?

It’s likely one of three things:

  1. Bad backup battery – A weak battery in a smoke alarm will cause the smoke alarm to “chirp” around once every minute to let you know that a replacement is needed. Please Note: The battery issue will only create a chirp. It will NOT send this signal through to your service.
  2. Dirt/dust on sensors – While less likely, depending on placement, general air quality, etc., dust and or dirt can find its way into your smoke detector. This can cause your detector to chirp and also create false alarms. If you’ve had your alarm go off at times when it shouldn’t have, that could also indicate you have dust/dirt build-up in your smoke/CO detector.
  3. Old or defective unit – your detector is not meant to last forever. If it’s time to get a new one, or multiple ones (they are generally rated for the same lifespan. This is to say that if you have one go down, the others purchased at or around the same time, will likely break down soon as well. I mention this as it is generally cheaper to replace all your detectors at the same time.

First, locate the unit in question. Sometimes you will have to wait on the chirp (quite often more than once) and triangulate the sound to figure out which unit is having trouble.

Found it? Great. Let’s move on to…

Troubleshooting:

First Thing, Check Your Reset Button…

Once the unit in question is found, find the reset button on the smoke/CO detector. It’s usually found on the face cover but not always…

Hold the button for about 15 or 20 seconds and then release (BTW: this should probably be done weekly according to most instructions).

Wait a couple of minutes and listen for the chirping noise again

If the chirping stops, then your problem is solved for the time being. But, if the chirping continues, you have another issue…

IMPORTANT:

Manufacturer Time Stamp Shows: 2006AUG14

Before we move on: At this point, it is most advisable to find out how old your smoke/CO detector might be. Take your detector down and look on the back of the unit for the manufacturing date. If you find the date stamp and the date is more than 10 years old, you should replace the unit. If you don’t find a date stamp, then you should also replace the unit (better safe than sorry).
Remember that smoke detectors are important to keeping you and your family safe. And, the detector in question is not meant to last a lifetime. Replacing them is a matter of general home maintenance and personal safety.



A hard-wired smoke detector usually chirps due to one of three problems:

In order of probability:

  1. A dead backup battery

  2. Dust/dirt inside the unit

  3. Malfunctioning/defective or old unit

We’ll start with the most likely,

Dead backup battery:

Most hard-wired smoke detectors come with a 9-volt backup battery that’s supposed to “back up” your electricity if you experience an outage. If that battery is weak, your detector will alert you.

Solution: Replace the battery
To replace the battery in your hard-wired smoke detector, follow these steps:

Turn off power to your wired smoke detector at the circuit box

Find the battery cover panel on the detector. Remove the old battery and replace it with a new one

Press the “test” button and listen for a beep. If you hear a tone, then your detector is working. If the chirping persists later, then the battery is not your issue.


Next: Dust/dirt inside your unit:

Depending on placement, general air quality, etc., dust and or dirt will find its way into your smoke detector. This can cause your detector to chirp and also create false alarms. If you’ve had your alarm go off at times when it shouldn’t have, that could also indicate you have dust/dirt build-up in your smoke/CO detector.

To Clean your detector:

Turn off power to your wired smoke detector at the circuit box
Take the unit down off the ceiling or wall.

Remove the face of the detector and the backup battery.

Use a vacuum hose or a small brush to clean out all of the dust.

IMPORTANT: Do not ever use water or any liquid inside of the detector. Electronics do not generally respond well to moisture.

Replace the battery and the face cover of the detector.

listen for the chirping sound. If you still have a chirp, you may have a malfunctioning or an old detector…


Next: Malfunctioning/old detector

As explained above, your detector is not meant to last forever. If it’s time to get a new one, or multiple ones (they are generally rated for the same lifespan. This is to say that if you have one go down, the others purchased at or around the same time, will likely break down soon as well. I mention this as it is generally cheaper to replace all your detectors at the same time.

If your smoke detector is relatively new, it might still be under warranty. Check with the manufacturer to see if they might send you a replacement.

Best of Luck. Be Safe.

Berk

Berk

Berk is a Home Improvement Contractor with many years of experience in every area of household maintenance and improvement.

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