My carbon monoxide detector keep beep. Why? It's been beep since I got home yesterday afternoon. I demonstrably don't...

It's been beep since I got home yesterday afternoon. I demonstrably don't have any carbon monoxide within my house, because i would have notice in times past 26 hours (still opened window and turned off fry to be on safe side). I've even unplugged the detector from the ceiling, but some piece in the electric wiring in the ceiling keep beeping. It's driving me and my dog insane. Any one know to win it to stop?
How do I dry out my firewood?
Answers:    Your battery could be dated and need a alien one. The detector itself could be too old and obligation replacing. Try changing the battery-operated first and see if that helps. If not, buy a modern one.
What get your window and conservatory window dirty?
get another carbon monoxide detector.. if it beep too, then you better attain out of the house until the problem is taken care of..