I have 2 mains-powered Smoke Detectors in my house that make a regular ‘chirp’ if the backup batteries are low.
I’ve replaced the batteries in both with brand new Duracells, checked the main circuit breaker isn’t tripped, and I’ve vacuum-cleaned the sensors, as I’ve heard that can confuse the little buggers.
Any suggestion, pilgrims?
(Plan B may involve a large hammer, extreme violence and a misguided sense of my superiority over inanimate household fixtures)
Are they strictly smoke detectors or combo smoke/CO2 detectors? Maybe your CO2 levels are up…
AFAIK, just smoke.
Good question, but if they were tripped I’m assuming they’d make an alarm sound, not just the low battery ‘chirp’ sound every few minutes.
How old are they? IIRC correctly, some detectors have a life expectancy after which they should be replaced, and some beep when this date is reached.
I did not know this.
Hmm. House is 7 years old - I’d have thunk they’d be good for longer than that but I’ll check. Thanks
Is your house on fire? (You didn’t mention this either to confirm or rule out).
If it’s the type that depend on beta or alpha radiation from an installed source being blocked by smoke to work, it could be that enough half-lives have passed that the source needs replacing.
Probably not a user serviceable part in this here Era of Terror (pronounce it so it rhymes… like Dora the Explorer).
Edit: Am-241 has a half-life over 400 years.
A make and model of detector would be helpful.
Good call!
I knew it would be something obvious
I am lead technician for a small fire alarm company. Most often, the periodic “chirp” from a home type smoke detector is due to a bad battery, but sometimes, the detectors just go bad. They are rather inexpensive and easy to replace.
They’re putting lead in fire alarms now? When will the madness stop?!
If it keeps up after you extinguish the blaze, could you (after appropriate electrical precautions) disconnect one detector from the other? If one is going bad, then I would think that procedure may help to identify which one that is.
You might want to power down the whole system, replace the batteries, and then start it up again. Kinda like rebooting.
Worked for me.
Also, the ‘chirping’ sounded like it was coming from detector 1 and 2, but just like a cricket’s chirp, it was deceiving me, and I had to circle back and replace another battery, as it wasn’t the detector I thought it was.
That’s what I did. Will try again and note the make and model details
Welcome to the SDMB, Sub Judice.
I’m sorry, but I just get this little grin thinking that the little chirping noise has been going on for a couple of days now. Surprised you haven’t shot the damn things yet.
It got bloody close! 
Another whoosh with the vacuum cleaner did the trick.
Mine beeped semi-regularly all-day, everyday for about a year. The only thing I learned is how amazing my ears are at getting used to it and ignoring it.
Now that I put two and two together, this detector was near my furnace (perhaps it’s a CO2/gas detector?) in comparison to my smoke alarm in the hall, so maybe I should get that checked out. At least I haven’t died yet!
Missed it by 4 hours! Yup, dust is the most common problem after batteries. Using the furniture brush will generally do the trick.
As Phoebe learned on Friends, that plan B idea doesn’t always pan out very well.
(youtube link)