besides the obvious, what can give off CO

11 years ago

Hi! My mother has a 7-year old carbon monoxide detector (the kind that plugs into a regular AC receptacle) with a battery back-up that's located in the basement, in the furnace room. The furnace is oil, but right now the AC is running and not the oil burner. So far it seemed to work properly, but last Saturday I was helping her cleaning the upstairs bathroom, and when I came down into the furnace room, I noticed the CO detector showing a value of 47 ppm on the display. I attributed it to the products I used in the bathroom (bleach, VIM and Comet cleansing powder), opened the window in the furnace room and the display quickly dropped back to 0. However, last night I was at her place for a supper and sleep-over, when I noticed the CO detector showing a value of 48 ppm on the display. I saw a bag of onions at the foot of the detector, so I thought something from the onions fooled the sensor, I moved the bag to another room and went to bed.

This morning, the detector was reading 58 ppm. We called the fire department who sent out a crew. Firefighters took readings in different areas of the house as well as outside, and said that they didn't detect any CO and said her detector more than likely is faulty and should be replaced.

Out of curiosity, I brought the detector to my house where the display has quickly dropped down to 0. Back into my mother's house, it took 5 minutes for the display to come back up to 58 ppm. It also seems to be higher in the kitchen than where it was previously, in the basement's furnace room.

She didn't use the oil burner nor the fireplace, neither of us smoke and we didn't burn anything on the cooktop. Besides the obvious malfunctioning fuel-burning appliance, smoking, etc, what can emit carbon monoxide? I know that buying a new unit would quickly confirm or not the theory of the false positives, but I am skeptical and I know how deadly and dangerous CO is, so I don't want to put my mother at risk.

Sorry for my long post, and thanks for helping me solve this mystery.

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Comments (10)

brickeyee
11 years ago
Anything that burns fuel using a flame can produce CO.
live_wire_oak
11 years ago
Pilot lights on furnaces or older gas ranges can produce carbon monoxide if they are burning faultily. You don't have to be using the appliance for the pilot to be lit. Or, do you have a gas water heater? That would be a primary suspect as you will be using hot water even if you don't cook or use heat.
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w0lley32
Original Author
11 years ago
Thanks for your replies. However, as I indicated in my post, the only devices that burn fuel in the house are the oil furnace and wood fireplace, which haven't been used since around early April. Every heat-producing device in the house is electric. However, the air handler of the furnace was in use with the central AC. Could it be a bad motor? The house was built in the early 70's, so it's far from airtight. Could the CO be coming from the outside?
w0lley32
Original Author
11 years ago
I just re-read the replies, and when I read Brickeyee's post I thought to myself: But that's why I find it so strange, because I know that nothing is burning in the house!

On second thought, could a fire be starting behind the walls, without any other signs? I know for sure that no lights are flickering (they're all incandescent and almost every circuit in the house has at least 1), there are no receptacles that are humming or hot to the touch, and everything in the house performs as it should. I also mapped all circuits in the house when I was a kid as part of a scouts project, and that map is still taped to the breaker panel door, so I am 99,999% sure that no circuit is overloaded. Also, I know what an arcing electrical connexion smells and that smell is not present, or at least I can't smell it, nor do I smell anything abnormal in or outside the house. Could the CO detector be intermittent, and it happened to "function properly" when I brought it to my house? Thanks.
bus_driver
11 years ago
7 years is well beyond the replacement interval that most manufacturers specify for CO detectors. I think the unit is faulty.
mike_kaiser_gw
11 years ago
The fire department is out and their equipment registers zero and the professionals suggest replacing your detector. Why would you just not do that?
w0lley32
Original Author
11 years ago
Thanks to all! I am going to replace the unit, no doubt about that, but because the unit seems to be functioning normally at my house, I wanted some insights in case the new unit also registers CO.
jaansu
11 years ago
As a PhD chemist, there is little that might produce CO in your home beyond certain exotic chemicals I doubt you store. Read the reviews, buy a good CO monitor and why not test it side by side with your older one. If you see parallel readings, then you have a mystery since the coincidence would be too great. Is it possible some strong EMF field nearby could influence the readings? And while opening the windows, you moved the detector in the field to cause a deviation? But these things are cheap, but a new one.
steve_in
11 years ago
We had a similar situation. We had painted much of our basement with BIN (shellac based primer). CO detector registered high. Fire department came out and couldn't figure out what was causing it. For whatever reason, the fumes of the paint drying caused the detector to go off. In our case, the Fire Department's detector registered a reading also. They had never seen anything like it. After airing the house out for a night with all windows open, the reading went down. When painting after that with BIN, the readings went up. I can't recall, but I think the fumes ruined the detector and caused it to be ultra sensitive to some chemical in the air.
brickeyee
11 years ago
If you are really worried, even items with open electric heating elements can burn debris that gets on the element.

Shellac uses alcohol as the solvent, and it might very well fool a CO detector.