CO Detector 3 Beeps

We thought it was the nearby smoke detector that went off today.  Three loud beeps, repeated every 30 seconds or so.  So I quickly removed the battery from the smoke detector on the ceiling in the hall by standing on a chair.  Still 3 beeps but not from the smoke detector!

Five feet away, nearer the floor, was the "First Choice" Carbon Monoxide (CO) detector.
I unplugged it and still heard the loud (85 decibel) 3 beeps, but it wasn't coming from that detector.

Several feet away (it's a split level home) there is another CO detector, so I unplugged that.
At least I had the correct detector as it now issued 3 beeps in my hand, so I took both CO detectors out to the garage, pressing Silence on their panels.

My head hurt from hearing the high decibel BEEPS!

Quickly reviewing First Choice's printed instructions on the unit, only 4 Beeps indicated "remove to fresh air, and call 911".  The instruction continued:  3 Beeps:  Trouble. 

Huh?
Trouble with what?  The detector?  Was it malfunctioning?
That could be a very dangerous guess (if the detector was working well), so I read further.
1 Beep meant the battery needed replacing.  5 Beeps meant the unit's end of life (it's guaranteed for a five year life).

But what the heck does 3 Beeps "Trouble" refer to?

Ah...finally found it in the online user's manual:



So, a malfunction of the detector.
Whew...

But we went down to the basement to look at the woodstove...just in case!
No idea what we thought we would find by looking at the stove, but we did nevertheless.


Time to buy a new CO detector, although these units haven't been installed for five years yet.

Potential emergency averted, the cold weather reminds me of a graphic I received via email:

Yes, it's been cold, although we didn't get as cold as those folks above.

I don't recall which morning it was, but BRRRRRR here's our temp last week.  And the temperature had dropped to 17.4 inside early that morning! 

Brrrrrr!

My ears are still ringing from the 85 decibel alarm.

Hibernation...