It keeps beeping every half hour or so, and when I go look at it, the CO peak level is zero. It’s plugged into the wall, so it’s not a battery issue. It has been a bit chilly, and our furnace is about 30 years old, so if the furnace is giving out CO, I’d really like to know about it (without, you know, dying and stuff).
Any ideas?
Low battery, maybe? That’s what happened with our smoke detector.
(Oops, meant to clarify. It may still have a battery even if its hard wired. Our SD did and was.)
Call the fire department. They will send someone out to check levels.
My CO detectors, also primarially powered by AC, have battery backups. They will beep when the battery gets low. If it is reading 0, I’d try the battery first. If it still beeps, call the fire department.
Enjoy,
Steven
I think all y’all are right about the battery - I unplugged it to move it, and the lights stayed on. Funny how soon you forget about something like putting a battery in a CO detector (and we haven’t even had this detector all that long). 
I have to go change a battery now.
Definitely a possibility. Some models of CO detectors have a replaceable cartridge with a battery and the actual CO sensor, which needs to be replaced periodically, even if the battery is good. The beeping may be its way of reminding you. What brand and model is it?
It is a Kidde single station carbon monoxide alarm.
Consider yourself lucky it didn’t happen at 4:00 AM after a night of, uh, imbibing…we once had the battery go down in one of our smoke alarms at that time.
How can I describe the joy of searching for the new batteries, going down to the garage, getting the ladder, schlepping it upstairs and downstairs, and changing all six of the smoke alarm batteries in the middle of the night? One of the smoke alarms is on the high, vaulted ceiling where you have to stand on the second from the top rung of the ladder…try doing that sober, let alone when you are, uh, tired…
I can only imagine. You know, we have vaulted ceilings all over our main floor, and it never occurred to me until now to be grateful that the smoke detector isn’t at the top of one of these.
Word. The instrumentation that we carry on our trucks is of high quality and is periodically recalibrated with a known cal gas to ensure accuracy. Having an aging furnace regularly inspected to verify that the heat exchanger isn’t cracked is a wise practice, also.
Can you still breath? If not, you might be dying.