The Carbon Monoxide Detector went off. Three times, about 3 hours apart. It made for a rough night sleep.
The first time, we heard one beep. I brought the attic one down to the second floor and moved the second floor one to a different spot. It was about 11 pm.
The second time, we heard two beeps. It was around 1:30. I was a bit disoriented, and jumped up immediately. I stepped on T while jumping out of bed. It sounds worse than it was.
I took batteries out of the "first" one and moved a third from the basement to our bedroom. The second and third detectors both have readouts, which were zero. I noticed that the heater in the bathroom was giving off some kind of gas, most likely steam (It is steam heat). I turned it off.
The third time was around 5:30. We heard one beep (Not from the bedroom one) and called the fire department. They just left telling us we had really low levels, especially with it being winter and the house closed up. No danger.
I replaced the batteries in all alarms about a week after Daylight Savings time, so that shouldn't be the problem.
These are the detectors I have. I think the Model KN-COPP-B. It was nice to find the docs right on the web site. Over the weekend, we'll probably buy a CO detector (or two) from a competing brand. One for the first floor and one to keep on the bedroom floor.