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Old 06-14-2011, 12:33 AM
malkavia malkavia is offline
Join Date: Nov 2000
Location: Phoenix
Posts: 2,215
What on earth is my carbon monoxide detector doing?!(Possibly need answer quick)

Tonight our carbon monoxide tester started beeping--4 beeps every 5 seconds. A quick Google search turns up bad news, this is the actual carbon monoxide detected alert. EEEE!!

So I grab it and go outside to the front yard. Guess what? It still beeps outside. So I move it further from the house, hit the reset button. Wait. Silence. Silence. BEEP BEEP BEEP BEEP. Five seconds elapse. BEEP BEEP BEEP BEEP!

Is my whole neighborhood a death trap?!

No one in the house feels sick. We don't have a fireplace, we aren't running the heater, which is the only gas appliance in the house. We do also have a gas hot water heater, but it is stored in a separate work shed accessible from the backyard.

Appliances running include:
Central Air Conditioner (just changed the air filters on this)
Washing Machine
Recently used the electric oven to bake a chicken
Ceiling fans
Television and other assorted electronics

I feel weird about calling 9-1-1 and evacuating everyone if the alarm also goes off outside too. Anyone have any experience with a detector on the fritz?

Should we evacuate anyway? And what on earth could possibly be emitting such high concentrations of carbon monoxide that the alarm goes off when its outside too?
Old 06-14-2011, 12:45 AM
Absolute Absolute is offline
Join Date: Apr 2000
Location: In flight
Posts: 4,080
Before calling in the National Guard, have you tried changing the battery?

If that's not it - CO detectors do not respond instantly to changes in concentration. It is somewhat expected that, if the alarm were set off inside, it would not immediately cease when you take it outside.

Does this one have a digital readout of the concentration? What model is it?

Last edited by Absolute; 06-14-2011 at 12:50 AM.
Old 06-14-2011, 12:57 AM
malkavia malkavia is offline
Join Date: Nov 2000
Location: Phoenix
Posts: 2,215
Oof. I forgot to mention that I did change the batteries, yes.

I took it outside and hit the test/reset button and it's been quiet ever since, even though I brought it back in and sat it on the (electric and not in use) fireplace. It's a NightHawk Kidde, fairly similar to this guy.

I've been reading that you're not supposed to place it in a kitchen or near a heated appliance, which may be the problem. It's a 2008 model and we've had it in the kitchen since 2009.

I'm watching it carefully, it's been about 7 minutes and it's just flashing the green button every 30 seconds or so to tell us it's active. How. Weird. I'm not quite ready to close the doors yet though.

ETA: No digital read-out, but the one I pick up tomorrow will be!

Last edited by malkavia; 06-14-2011 at 12:58 AM.
Old 06-14-2011, 01:19 AM
Absolute Absolute is offline
Join Date: Apr 2000
Location: In flight
Posts: 4,080
Newer CO detectors (like the one you have) have much lower false positive rates than older models. Nevertheless, they can still be affected by fumes from cooking, cleaning products, high humidity, and other factors.

The fact that it is not going off now is unsurprising, given that you have probably been ventilating the house for the past hour. Detectors can be set off by a high level of CO, or a low level of CO sustained over a long period (see the chart at the bottom of this page: If the latter is the case, ventilation could easily have reduced the CO concentration below the threshold level very quickly, and it might take several hours for it to alarm again.

I would suggest turning off all centralized ventilation equipment in your house (AC or heat), opening all the windows, use fans in windows where possible to draw fresh air in overnight, and placing the detector near where you are sleeping. Buy another detector tomorrow, close all the windows, and see what happens.

You are right to be concerned about this. CO poisoning is very dangerous while you are asleep, as you cannot recognize the onset of symptoms, and might not wake up until the cognitive impairment is severe.

That said, this does seem a bit odd, given that you don't have any equipment running in your house that would be expected to produce CO. Does your heater have a pilot light or anything? Anyone in your house a smoker?
Old 06-14-2011, 01:55 AM
malkavia malkavia is offline
Join Date: Nov 2000
Location: Phoenix
Posts: 2,215
I do have an outdoor smoker in the house. I decided to run up to Walmart and get a detector with a digital readout on it so that I can sleep soundly. It's got a readout of 0 right now, so I feel a little better. I shut both doors and am going to monitor it to see if the number changes at all between now and bedtime.

Thank you for your input, I'll let you know what happens.


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