No, not that, though we HAVE been eating a lot of beans around here since we got the slow cooker.
Our carbon monoxide detector went off today. We’re not sure why, and to confuse matters further, it said it was in Test Mode… yet it said it had seen (when? now?) 287ppm. The furnace, hot water heater, and oven were all going. I’m scheduling a check for all of the gas appliances, since we haven’t had them checked in more than a year– in fact, more than 2 years. The time just slips away.
The alarm is not going off now. By the end of today we will have several new CO detectors in the house, a mix of the battery-powered type and the house-current type. I’ve learned a number of things in the past few hours which surprised me, including things I was Just Plain Wrong about. Fortunately, not Dead Wrong. If the situation were different, though, my lack of correct information might have been fatal. So, let me share, just in case you know some of the same wrong things.
What to do first. If you’re like most people, including us, the first thing you do is go to the alarm and see what’s up, then start looking for the problem. No. Not even remotely correct. The FIRST THING you do is LEAVE THE HOUSE. Period. No questions. Grab all family members and pets and get out. Only then do you think about what to do next and make a plan of action. 
Why? Because in case your alarm went off only in the cumulative exposure fuzzy-headed stage, you may already be at risk of going to the next level of CO poisoning. It can be abrupt, and you could go from ‘mostly fine’ to ‘I can’t think and need to just sit down for a moment’ without any real warning. If it turns out to be that bad, you might never stand up again.
The next thing that everybody does is start opening up windows ‘just in case’. Apparently that’s also wrong. Instead, you should, theoretically, call the fire department, your appliance repair person, or your utility company and actually have them do a check. If you’re like most of us, you’re probably not going to do that, you’re going to change the battery in the thing instead (you did write the date of the last change on the battery with a sharpie, yes?) and if it goes off again, then you’re going to think about calling someone.
At least get folks out of the house first, and don’t go opening all the windows yet. “Many CO alarm calls have been classified as ‘false alarms’ because the homeowner has ventilated the home and turned off the equipment before firemen or technicians can measure the CO levels and find the source.” 
Another ‘everybody knows’ pseudo-fact is as long as you don’t have a skull-splitting headache, you’re okay. NOT! What most folks don’t know, and I sure didn’t, is that low levels of exposure commonly cause flu-like symptoms, including sniffling, red eyes, tiredness, nausea, mild headache. At medium levels of exposure, the ones that could tip suddenly depending on your physiology, that’s where you get symptoms like “severe throbbing headache, drowsiness, confusion, fast heart rate.” 
If you tend to be sniffly and tired at home in the evenings or weekends, but feel better at work or out of the house, well, that could be a lot of things from needing to clean the ducts to vacuuming to dust mites. But it could also be low-level CO exposure, so add that to your list. Get yourself a CO detector that measures continual exposure and make sure you get your appliances checked annually.
Speaking of which, as long as the flame is blue, not orange we tend to think it’s ok. Leaky ducting can cause CO exposure even when the flame adjustment is ok, so don’t rule it out just because the flame looks right. Get somebody with a sniffer to confirm your in-house levels.
The CO detector should be in your bedroom, right? Maybe one of those little plug-in ones? Well, partially. Ideally, the CO detector should be either on the ceiling or about 5 feet off the ground, since CO is generally lighter than room air. I was unpleasantly shocked to find out that the only CO detector in our place was actually in the 2nd bedroom, which Mike uses as a workroom. Why? We don’t remember. Well, that will change by this evening!
We also tend to think that as long as the ‘test’ button works, the alarm works. Wrong, alas. Apparently very few CO or smoke detectors actually test the detector, rather than the audible alert. Pressing the ‘test’ button tests the NOISE circuit, not the detector, in the vast majority of detectors.
We purchased our detector when we moved in, almost 5 years ago. We assumed it was good ‘forever’ as long as we changed the batteries. Nope. The mechanisms they use to detect CO differ, and many of the small battery-powered ones use a colored disk that they monitor for changes, rather than more direct chemical means. Multiple sources say that most CO detectors have a 5-year lifespan but some may be valid for only a couple of years. Either way, we need to replace ours.
What kind should you get? Here in the States, I quote Underwriters’ Labs: Rather than looking for specific features, look for the UL Mark with the adjacent phrase “Single Station Carbon Monoxide Alarm.” 
Why? Because it’s required to have a silence button and to re-alarm within 6 minutes if the condition persists. Many detectors will just happily shut up and not go off again if you silence them. Low batteries can cause an alarm to go off, so if one does go off, after you think it’s safe (remember the first part of this article) then you can change the batteries and see if it goes off AGAIN.
There’s so much more, but that’s a good start. Don’t freak out, but take part of an afternoon and put some safety in the bank for you and your family. Have a safe n happy new year!
 Incredibly detailed and helpful info from our Canadian buddies: http://www.cmhc-schl.gc.ca/en/co/maho/yohoyohe/inaiqu/inaiqu_002.cfm