I would suspect every detector on the premises as the culprit. Your detectors are interconnected and what affects one, affects all. Dust and insects can trigger detectors, small spiders especially. First, I would blow out every detector to hopefully remove dust and insects. I have never damaged a detector using even as much as 50 PSI on the air hose from a portable compressor.

Is there an attic above the ceiling? Maybe an extra smoke detector in there or something approximately above the smoke detector that is making the beeping. If this is in a hallway, you still have smoke detectors in the bedrooms and they are still interconnected.
Hank

I had a similar problem. The problem detector was a wired/battery backup unit. Initially we thought the batteries were dead, but after replacing batteries we continued to get an intermittant beep.

I blew on the detector thinking some dust had gotten on the sensor and that didn't help. When I removed just the detector, I did still get "sympathy" beeps from other interwired detectors. But when I removed the entire unit leaving just the wires the "sympathy" beeping stopped.

We figured it was a bad unit and replaced it with another wired detector and have had no problems.

(I still have the one we removed and did try blowing on it to clean it out, but if that is the problem, I'm evidently not a big enought blowhard. We still have it and will try blowing it out with the air compressor despite the instructions not to do that. If that works, it seems I have an extra everything else, might as well add this to the pile.)

So it could well be the other detectors, or one in the attic if you have one.

I meant to mention, when detectors do pass their 'use by' date, their failure mode is low-battery beeping, which will continue even if you change the battery. The life seems to be five years as far as I know....some battery units are now being supplied with a 'lifetime' battery - battery goes, time to change the unit.

Slovat:

We had the same problem and after cutting an opening in the drywall, we found a battery operated unit between the studs, beeping away with a low battery. Totally missed it when doing the drywalling.

It could be your carbon monoxide detector! After spending all morning on a ladder changing batteries in smoke detectors I realized it was the monoxide detector plugged into the wall right below one of the alarms. It was not the steady "get to fresh air" beep but rather the chirping (which sounds exactly like a smoke alarm) that signals the unit is going bad.

I have read all the details written here, but nothing works. I was told the batteries are good for 10 years; it's been four. Come to find out the batteries are good but the chirping still goes on. It is in the bedroom and hallway alarms. Once in awhile the beeping goes away for a few hours only to return. I cannot afford the cost of an electrician. Any other ideas? Thank you.

I FOUND IT ANNOYING WHEN EVERYONE WOULD TELL ME TO CHANGE THE BATTERY, WHEN I HAD THIS PROBLEM (AS IF I HADN'T THOUGHT OF IT). AS IT TURNS OUT, SINCE MY ALARM WAS HARD-WIRED AND BATTERY OPERATED, I HAD TO FLIP THE POWER SWITCH ON THE CIRCUIT BREAKER TO GET THE BEEPING TO STOP - IT DID THE TRICK!!!

Slovatt, did you ever resolve this issue? I am having the SAME exact issue and have tried cleaning the unit, replacing ALL with new batteries, I even went as far as taking a working unit from another property and switching them out only to have the problem pick up where it left off. Will call manufacturer on Monday to see what they recommend.

Wright602, EVERY house we have bought and lived in eventually had detector issues. As was mentioned above, look on the backside of the detector for expiration date. I've gotten to where I just replace them all if the date is close. Something that people do to make wiring easier is pull off the foam insulation on the back of their detectors. BAD idea. Without the insulation sealing it off, moisture, dust and bugs from the attic make their way into the detector as air WILL flow through any hole in the ceiling envelope. This will eventually make the detector false trigger. Everyone should make sure their detectors are functioning properly as they save lives. They will always go off when a fire is still small enough to give everyone time to get out and to call the fire department. Just read the paper for the stories about fire tragedies and notice how many say 'house did not have working smoke detectors'.

Did you ever find out what was beeping in the ceiling? Was there another smoke alarm up there? I found this page while looking for how to change the battery in my smoke alarm. I found a link that shows pictures of the battery removal process that may help the next person looking for the answer.

Here is a link that might be useful: How to remove a smoke alarm battery

I have wired smokes and CO alarms. They beep when the batteries died. I changed them and a couple of weeks later they were beeping again. Damn Lowe's Utilitech batteries. Half the brick of 9V's were dead in the box. NEVER FREAKING AGAIN.

hi ronnatalie,

I will never buy anything made by Utilitech again.
Total junk.

I have a modular home. It has one wired/battery backup smoke detector and two battery-only detectors. The wired one started chirping, so I replaced the battery and it continued to chirp. I removed it entirely from the wall, and something behind the box continues to chirp. This is crazy -- I don't want to have to tear out drywall to see if there is anything behind there but what else could it be? This isn't the first time a battery has been replaced but it didn't continue chirping with no detector connected before either.

Based on my primitive knowledge of electrical code, there should not be anything electrical sealed inside a wall in such a way that it's inaccessible, except for the wiring itself. No devices or junction boxes. That's not much help but whatever is in there probably should not be.