On Fri, 23 Sep 2011 12:57:41 -0500, "
wrote:

On Fri, 23 Sep 2011 12:32:07 -0500, "Joe J" wrote:

Bought a house 6 months ago with all electric powered smoke detectors that
have a battery back-up. Sure enough, 3 AM, one starts chirping every 30
seconds. Really ****ed off the dog!

Seven detectors, so I changed the batteries in all of them, because the dog
said she didn't want another 3 AM wakeup call.

No manual, just wondering how long they last when they are AC wired? I know
battery only, they recommend once or twice a year, but what about AC
powered? I would think several years, no?

I've found it's still once a year with the AC wired units. It's not worth the
lost sleep trying to go longer.

Works for me. The batteries have an expiration date, do they last
three years?

I had a _3 AM wakeup call_ this past week. Wife gives me another
battery from her secret storage and I put it in. Still beeped.

New battery from the store fixed it.

Take a detector done, remove the battery, beeps more. Disconnected
from the AC power then another one started beeping.

And. Why do they only go off at 3 AM.....