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Q&A on why the CO alarm keep going off

Carbon monoxide CO alarm sound-off cause FAQs:

Questions & answers about why CO alarms sound off .

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FAQs on What Makes a CO Detector Alarm Sound

First Alert carbon monoxide CO alarm Model 605 0r 606 at InspectApedia.comThese questions and answers about what causes a carbon monoxide alarm (CO detector ) to sound or "go off" were posted originally at CO ALARM CAUSES. Please review that article.

IF YOU SUSPECT CARBON MONOXIDE POISONING GO INTO FRESH AIR IMMEDIATELY and get others out of the building, then call your fire department or emergency services for help.

Seek prompt advice from your doctor or health/safety experts if you have any reason to be concerned about exposure to toxic gases. Carbon monoxide poisoning can be fatal but exposure at lower limits can produce flu-like symptoms and headaches that are often mistaken for ordinary illness.

Carbon monoxide detector alarms may sound for a variety of reasons, but until you have diagnosed for sure why a particular alarm has sounded, you should assume that it has detected dangerous carbon monoxide indoors and you should follow the safety advice above.

On 2018-11-09 by (mod) - CO alarm seems to respond to new carpet off-gassing

Gary (and other readers)

The First Alert CO7 carbon monoxide detector manual includes this information about gas sensitivity:

CO Alarm is not formulated to detect CO levels below 30 ppm typically.

UL tested for false alarm resistance to Methane (500 ppm), Butane (300 ppm), Heptane (500 ppm), Ethyl Acetate (200 ppm), Isopropyl Alcohol (200 ppm) and Carbon Dioxide (5000 ppm). Values measure gas and vapor concentrations in parts per million.

That information tells you that your CO detector may sound an alarm when any of those gases is / are present at levels above the "false alarm resistance" data the company offers.

And from another source:

"Major interferents that can affect CO detectors are acetylene, dimethyl sulfide, ethyl alcohol, ethylene, hydrogen cyanide, hydrogen sulfide, isopropyl alcohol, mercaptan, methyl alcohol, propane, nitrogen dioxide, and sulfur dioxide." - source, Fire Engineering, 1996, http://www.fireengineering.com/articles/print/volume-149/issue-9/departments/letters-to-the-editor/other-gases-may-set-off-co-detectors.html

Watch out: it would be a possibly fatal mistake to ignore a CO detector alarm based on the assumption that it is "false".

While it's reasonable to wonder if the alarm is sounding in response to new materials (carpets, carpet padding, vinyl windows, paint, other off-gassing substances) and while it thus makes sense to also ventilate the home with fresh to speed that off-gassing process,

Watch out: DO NOT ignore the CO alarm sounding. There may also be an unsafe heating system combustion gas or CO gas leak (also such gases can come from a running vehicle like a car in a garage).

Below is an image of the First Alert CO detector you mentioned.

If you do not already have the instruction manual for your CO detector you can download it from this link:

There you will find additional details about how the alarm responds to various levels of CO in the air over time.

Excerpts:

CO Alarms are designed to alarm before there is an immediate life threat. Since you cannot see or smell CO, never assume it’s not present.

• An exposure to 100 ppm of CO for 20 minutes may not affect average, healthy adults, but after 4 hours the same level may cause headaches.

• An exposure to 400 ppm of CO may cause headaches in average, healthy adults after 35 minutes, but can cause death after 2 hours.

IMPORTANT

This CO Alarm measures exposure to CO over time. It alarms if CO levels are extremely high in a short period of time, or if CO levels reach a certain minimum over a long period of time.

The CO Alarm generally sounds an alarm before the onset of symptoms in average, healthy adults.

Why is this important? Because you need to be warned of a potential CO problem while you can still react in time.

In many reported cases of CO exposure, victims may be aware that they are not feeling well, but become disoriented and can no longer react well enough to exit the building or get help.

Also, young children and pets may be the first affected. The average healthy adult might not feel any symptoms when the CO Alarm sounds.

However, people with cardiac or respiratory problems, infants, unborn babies, pregnant mothers, or elderly people can be more quickly and severely affected by CO.

If you experience even mild symptoms of CO poisoning, consult your doctor immediately!

Standards: Underwriters Laboratories Inc. Single and Multiple Station carbon monoxide alarms UL2034.

According to Underwriters Laboratories Inc. UL2034, Section 1-1.2:

“Carbon monoxide alarms covered by these requirements are intended to respond to the presence of carbon monoxide from sources such as, but not limited to, exhaust from internal-combustion engines, abnormal operation of fuel-fired appliances, and fireplaces.

CO Alarms are intended to alarm at carbon monoxide levels below those that could cause a loss of ability to react to the dangers of Carbon Monoxide exposure.”

This CO Alarm monitors the air at the Alarm, and is designed to alarm before CO levels become life threatening. This allows you precious time to leave the house and correct the problem.

This is only possible if Alarms are located, installed, and maintained as described in this manual.

On 2018-11-09 by Anonymous

Thank you! This is a First Alert Model CO7 10. Electromechanical sensor.

On 2018-11-06 by (mod) - It's possible; most CO gas detectors may respond to more than the target gas.

It's possible; some gas detectors may respond to more than the target gas.

In particular some VOCs that may be off-gassed from new carpet or carpet padding (or drapes or new paint) can cause headaches and nausea and illnesses (some may actually be dangerous) and might also set off a CO alarm.

If your installers used glues or adhesives that can add to the VOC level indoors.

Fresh air ventilation and increased use of heating can speed the off-gassing process. But beware, some carpets can continue to off gas for several years.

For a more-scientific and reliable reply to your question we'd need to know the brand and model of your CO detector so that we can review its specifications that tell us just how specific and narrow is its range of response to various gases.

On 2018-11-06 by Gary G - wondering if the off-gasing of the carpet may have set off the CO detector

Installed a new carpet in a closed room yesterday containing our CO detector. Am wondering if the off-gasing of the carpet may have set off the CO detector last night. Has never happened before.

On 2018-10-10 by (mod) - CO detector responds to solvents in caulks & sealants, also some adhesives in other building materials, cabinets, flooring

Thanks for an interesting question. Obviously knowing so little about the situation I don't know what's causing your CO detector to sound off, but it's possible that the workmen were using an adhesive or caulk or sealant whose off-gassing was affecting the meters operation.

On 2018-10-09 by Sue H

Moved into a new house a week ago. Not heard a sound from the Carbon Monoxide detector.

Today we had workmen in replacing a velux window and every time they opened the front door for more than a couple of seconds the detector started beeping. It has never beeped when we've opened the door to go out, the only difference is that there was a space where the velux window was which is presumably creating a strong through wind. Can't understand why that would have an effect on it. The detector is on the first floor landing.

On 2018-08-15 by ALLEN JAGDFELD

Can a new asphalt driveway cause my co detector to go off. There is nothing running in my trailor.

On 2018-07-16 by andrew - oranges set of CO detector?

@Elaine,
I had two carbon monoxide detectors go off. I have a small house 5 rooms, one floor, easy to open front and back doors. I noticed a strong smell, like alcohol in the air. I checked everything inside and outside the house. Nothing the neighbors were doing indicated any reason for the detectors to sound.

Under my typewriter desk was a 5 pound bag of oranges in the mesh bag from the store. I looked at them through the bag and several were green and growing mold. This was the source of the smell. I have looked on the internet to no avail about oranges or rotting fruit setting off a detector.

I was going to call the fire dept to come by and take a look and smell but the detectors have stopped. Its a strange warning. The fruit is outside and on the lawn. Take warnings seriously.

On 2018-06-20 by (mod) - The amount of CO2 in the house was very high. The amount of CO2 in the house was very high.

First to be clear, you are almost certainly talking about CO - carbon monoxide - a dangerous, potentially fatal gas that's usually a product of combustion such as at a gas furnace or water heater - NOT CO2 (carbon dioxide) which is what you wrote. CO2 is a component of outdoor air and of our breath.

It's true that having multiple properly-located, tested, working CO detectors gives some protection for the building occupants, but

Watch out: NO, in my opinion it is absolutely not safe to stay in a home where high CO (Carbon Monoxide) was found and where the source of the problem has not yet been found and fixed.

Blowing out a home or bringing in fresh air after a high level of carbon MONOXIDE (CO) has been detected does absolutely nothing to find and fix the source of the carbon monoxide.

YOu need an onsite expert. This article may be helpful:

CARBON MONOXIDE INSPECTION https://inspectapedia.com/hazmat/Carbon_Monoxide_Inspection.php

On 2018-06-20 by Elaine

My daughters CO2 alarmed and she called the fire dept and gas company. The amount of CO2 in the house was very high. They checked everything and brought in blowers. They were unable to find the source. Is it safe for her and her family to stay there.

On 2018-06-20 by (mod) - is it safe to stay in a building where high CO was present and the cause has not been identified?

First to be clear, you are almost certainly talking about CO - carbon monoxide - a dangerous, potentially fatal gas that's usually a product of combustion such as at a gas furnace or water heater - NOT CO2 (carbon dioxide) which is what you wrote. CO2 is a component of outdoor air and of our breath.

It's true that having multiple properly-located, tested, working CO detectors gives some protection for the building occupants, but

NO, in my opinion it is not safe to stay in a home where high CO (Carbon Monoxide) was found and where the source of the problem has not yet been found and fixed.

Blowing out a home or bringing in fresh air after a high level of carbon MONOXIDE (CO) has been detected does absolutely nothing to find and fix the source of the carbon monoxide.

You need an onsite expert. This article may be helpful:

CARBON MONOXIDE INSPECTION

On 2018-06-20 by Elaine

My daughters CO2 alarmed and she called the fire dept and gas company. The amount of CO2 in the house was very high. They checked everything and brought in blowers. They were unable to find the source. Is it safe for her and her family to stay there.

On 2018-04-27 by (mod) - playing it safe with carbon monoxide alarms

Heather

Please understand that we cannot bet your life and health on an answer that would be a mere guess about a building where we have not a shred of information about the heating or other equipment that could be leaking dangerous CO.

CO detectors should sound specifically in response to Carbon Monoxide.

Check (or tell us) the brand and model of your CO detectors and we can help find the manufacturer's specifications and instructions. The manufacturer will generally tell you if the detector responds to other airborne chemicals besides CO.

On 2018-04-27 by Heather Mjelde

Just to let you know, I am using my daughters phone at the moment, so my contact info is actually hmjelde@gmail.com.

A family member of mine recently had a tree fall into her roof, which turned into a bigger can of worms after the asbestos popcorn ceiling then had to be removed. After all that was finished it came time to clean her very expensive wool carpeting.

Evidently there was a chemical reaction with the wool fibers and dry cleaning chemicals that caused the carbon monoxide detectors to sound in the basement after the drone fans were evenly distributed throughout the house all blowing downward onto the carpeting on the 2nd floor.

Once they started the co2 detectors in the basement started sounding. Could this just have been triggered by the air blowing into the all of the detectors perhaps or could she have been exposed to something dangerous? Thanks for any help in regards to this matter.

On 2018-01-22 by (mod) -

Sounds like a defective alarm if in fact it's body is quite hot - that's abnormal. I'd remove it and install a new model.

The "power source" ? should not be causing heat unless there's a wiring error.

Also some older CO detectors were considered too sensitive, giving enough false alarms that their design was later modified.

I'm not sure what LPS is

On 2018-01-21 by Susan

Ancient electric co detector plugged in a few days ago (never used before). It alarmed today, and was very warm to touch, as was the plug in jack.

Newer detector which has new batteries and tests functional has not gone off. I put it in the same room to compare. Could the heat caused by the power source or LPS sprayed downstairs from the electric co detector cause it to malfunction?

On 2017-11-07 4 by (mod) - mis-wired electrical circuit problems ?

VInce

But here's another possibility: if the CO detectors are a type that plug into a 120VAC circuit (as well as having a backup battery) and the problem occurs only at one CO detector mounting site, that circuit may be defective, mis-wired, or may have lost power.

CO detectors normally chirp to indicate a power problem while an actual alarm is unmistakable in volume and sound.

Let me know what else you can see or find.

On 2017-11-07 by (mod) - other causes of chirping CO alarm

Vince,

WATCH OUT: first we have to rule out a possible carbon monoxide problem. A mistake on your part can mean you or other occupants of the home die from CO poisoning.

Here is what Kidde, a manufacturer of CO detectors says describing the chirps that a CO detector may make:

When the carbon monoxide (CO) alarm senses a dangerous level of carbon monoxide, the unit will emit a loud alarm pattern. The alarm pattern is four short beeps – followed by five seconds of silence – followed by four short beeps.*

If you are hearing an alarm pattern you need to get people out of the home and call for help.

If there is no CO ALARM pattern then the cause of chirping is might be one of these:

1. low battery power. A bad battery OR a bad battery connection, or a battery not fully inserted, or a battery door not fully shut can also cause this.

2. the alarm is at the end of its useful life and needs to be replaced

3. the alarm is malfunctioning - this could be dirt and dust or cigarette smoke deposits on the alarm sensor. If cleaning according to your alarm's manufacturer's instructions doesn't cure the problem you should replace the entire unit.

4. Local environment conditions can cause alarm chirping: steam from a shower, condensation, exposure to high temperature (over 100 degF) such as in a covered-over electrical box on a hot ceiling below a hot attic; high air flow such as directing a fan at an alarm can also cause it to sound.

Dead animals, building materials, paints, glues, new carpets and other gases or off-gassing might set off a CO alarm, depending on the specific gases present and the concentration of gases in air at the location of the alarm.

5. Need for manual alarm reset: for an alarm that connects to a 120VAC circuit you may need to reset its alarm by removing all power, holding the reset button 15 seconds or longer, then restoring battery ( and electrical connections if it's a 120VAC unit)

I don't and can't (by e-text) have enough information to diagnose this CO alarm problem.

On 2017-11-07 by Vince

I have 2 different CO detectors, no matter which one I put at the end of the mobile home that has the furnace, I get a single CHIRP every 3 or 4 minutes.

Both detectors have new batteries in them, they are 2 different brands and neither is that old and we are not even using the heat yet..

This always seems to start at 2 or 3 in the morning, never during the daytime. I will get up and swap the detectors and which ever one is at that end of the house will chirp.

On 2017-11-04 by Sue - Can a dead mouse smell set off co2 alarm?

Can a dead mouse smell set off co2 alarm?

On 2017-08-16 by B.J.

I just came home and the blue light was on and the alarm was ringing on my carbon monoxide and natural gas alarm , I do not smell any gas and can't find anything wrong. Battery was changed about 3 months ago'.any reason to worry?

On 2017-04-10 1 by (mod) - Faeces do not emit carbon monoxide.

Faeces do not emit carbon monoxide. But high levels of methane (over 500 ppm) from sewage may set off an alarm.

On 2017-04-10 14 by Grace

Can extremely foul smelling poop cause the CO2 alarm to go off.

On 2017-03-22 by (mod) -

Possibly, since the exhaust may indeed contain carbon monoxide. I suggest photos too.

On 2017-03-22 by Linda

My neighbor has a rusty old pickup that belches smoke and horrible smells that seem to hang in the air. Even with all my windows closed I get light headed. Would a co detector alarm go off from this? I want to have some kind of tangible proof before I approach him.

On 2017-02-23 by (mod) - Depending on the level, methane from a sewage spill may set off some CO alarms.

Seems unlikely, Joan. A CO detector responds to carbon monxide - we wouldn't expect to find that in sewage;

But it might. Depending on the level, methane may set off some CO alarms.

I've read some fire department accounts of combustible gases setting off some CO monitors - specifically acetylene.

So methane in sewage might set off some CO or other alarm types depending on their alarm. That's because gas-sensitive alarms are not exactly specific to just the one gas for which they're designed. Gases comprised of similarly-sized or shaped molecules, for example, can, depending on their concentration, cause interference.

"Major interferents that can affect CO detectors are acetylene, dimethyl sulfide, ethyl alcohol, ethylene, hydrogen cyanide, hydrogen sulfide, isopropyl alcohol, mercaptan, methyl alcohol, propane, nitrogen dioxide, and sulfur dioxide." - source, Fire Engineering, 1996, http://www.fireengineering.com/articles/print/volume-149/issue-9/departments/letters-to-the-editor/other-gases-may-set-off-co-detectors.html

On 2017-02-23 01:36:00.378423 by joan

can a toilet overflow cause fire and carbon monoxide detector go off?

On 2016-04-12 12:59:32.730685 by (mod) -

Cristel, as Kidde, an alarm manufacturer explains,

In 2009, Underwriters Laboratories (UL), began requiring an end-of-life warning to alert homeowners when their carbon monoxide alarm has reached the end of its useful life.

On your alarm the end of life (or low battery) alarm may include a beep, chirp (3 chirps), or blinking light.

To know for sure what the light means on your particular CO alarm we'd need to know the brand and model.

On 2016-04-09 10:12:36.412573 by Cristel

My alarm light is red should it be the color ?

On 2016-04-01 02:07:42.722534 by (mod) -

Big,

Dust has been recognized as a contamination factor that interferes with the operation of some types of smoke detectors. I think that the dust problem depends on the technology being used to build the sensor.

Can you provide me with a research citation that documents the problem with CO2 detection?

On 2016-04-01 00:12:37.885802 by bighatnohorse

High levels of pollen and micro dust will make the CO alarm false.

On 2015-11-09 21:24:20.705373 by (mod) - CO Detector Locations To Avoid

Not that explicitly: the number of CO alarm installation location mistakes that we could make is near infinite. So the instructions may be more general like:

The following are excepted from a Kiddie CO alarm installation guide

CO Detector Locations To Avoid

IMPORTANT: Improper location can affect the sensitive electronic com- ponents in this alarm. To avoid causing damage to the unit, to provide optimum performance, and to prevent unnecessary nuisance alarms:

• Do not install in kitchens, garages or furnace rooms that may expose the sensor to substances that could damage or contaminate it. 


• Do not install in areas where the temperature is colder than 40°F (4.4°C) or hotter than 100°F (37.8°C) such as crawl spaces, attics, porches and garages. 


• Do not install within 5 ft. of heating or cooking appliances. (Kidde recommends 15 ft. to prevent nuisance alarms). 


• Do not install near vents, flues, chimneys or any forced/unforced air ventilation openings. 


• Do not install near ceiling fans, doors, windows or areas directly exposed to the weather. 


• Do not install in dead air spaces, such as peaks of vaulted ceilings or gabled roofs, where CO may not reach the sensor in time to provide early warning. 


• Do not install this unit near deep-cell large batteries. Large batteries have emissions that can cause the alarm to perform at less than optimum performance. 


• Do not obstruct the vents located on the alarm. Do not place the alarm where drapes, furniture or other objects block the flow of air to the vents.

On 2015-11-08 20:05:02.943904 by Anonymous

is there a ruling that co alarms not be placed to close to air diffusers

On 2015-09-20 19:08:19.267559 by (mod) -

Thanks NHFB we've merged your remarks into the article above.

Question:

I just bought a carbon monoxide detector about a month ago and when I came home today it was chirping and displayed LB for low battery. I was wondering if the alarm could of went off while I was at work and drained the battery and that's why it was chirping. - Jona 2/8/2012

Reply:

Jona, chirping from a CO alarm means that it needs a new battery. The chirp is a signal, not a cause, of low battery problems.

Question:

why don't manufacturers of smoke alarms make them easier to read, instead of beige raised lettering on a beige background ? hard to replace battery when you cannot read directions - PoliceFan123 8/21/2012

Reply:

Police: I agree that some embossed plastic instructions are hard to read. I suspect the underlying reason that these notes are not made in a different color combines an aesthetic opinion (for lettering on exposed surfaces) along with a wish to keep the product cost low as possible.

Here's a tip: before installing your next CO alarm or smoke detector, if you want to make its plastic embossed indicators, arrows, or instructions easier to read in the future, try just touching the raised lettering or symbols with a magic marker.

Question: what causes a periodic beep or chirp from my carbon monoxide alarm?

(Mar 22, 2013) Laura said:
My Carbon Monoxide detector made a long beep sound and then stopped. Then several hours later it did it again. Has it detected Carbon Monoxide, or is it malfunctioning? How do I know what the alarm is supposed to sound like?

(Jan 29, 2014) Anthony Tran said:
My 1 year old electric Kidde Carbon Monoxide Alarm beeping every ten seconds. I do not smell any thing. What should I do?

Reply:

Laura,

An intermittent beep from a CO or smoke detector often means that the battery is failing. Try replacing the battery.

Anthony,

try changing the battery

Question: CO detector sounding blamed on solar system

(May 21, 2014) Anonymous said:
1. I just got a carbon monoxide detector and place it in a corner on the wall not far from our solar batteries.[our electricity is solar.] We charged the batteries via the outdoor generator, and then took off the cover to add water to them as we do monthly. After about 15 minutes the detector went off. I pushed the silent button and I called our solar installer and he said that will happen after one charges them, and especially after you take off the cover, and that it is nothing to worry about.

Comment, please?

2. And after I silence it, will the detector continue to let me know if it detects monoxide again?

Reply:

Anon,

We both need to do some research to understand why a battery system would be producing carbon monoxide.

Some oblique mention is in

Larminie, James, and John Lowry. Front Matter. John Wiley & Sons, Ltd, 2003.

Sun, Bianting, and M. Skyllas-Kazacos. "Modification of graphite electrode materials for vanadium redox flow battery application—I. Thermal treatment." Electrochimica Acta 37, no. 7 (1992): 1253-1260.

Check the specs on your CO detector; generally they are designed to work again after silencing.

Question: CO detector goes off as soon as we plug it in

(Feb 16, 2015) Phoenix said:
My CO detector goes off right when we plug it in. We use a wood stove to heat downstairs and a space heater upstairs. Should we be worried about this or is it malfunctioning?

Reply:

Phoenix

It is normal for most carbon monoxide detector and smoke alarms to sound briefly or to even emit spoken words (some models shout "FIRE") when the alarm batteries are replaced or the alarm is first plugged-in. This is a diagnostic test to confirm that the unit is working.

But if the alarm keeps sounding after that initial check then something is wrong and your building could be unsafe.

Question: Can an oil fired radiator cause my alarm to sound?

(Apr 25, 2015) M. Mahoney said:
Can an oil fired radiator cause my alarm to sound?

Reply:

MM\

What alarm? Smoke alarm? If so, I'd be looking for smoke, or a fire. If an electrically operated heating device were causing a short circuit or electrical fire that could indeed trip a smoke alarm.

In normal operation? Carbon monoxide alarms? That's the topic of the article above.

Oil fired radiator? I don't know what that is. If you mean that you have an oil fired heating boiler, it is possible, but not easy, to release carbon monoxide into a building from oil fired heating equipment.

In any case if your CO alarm is sounding you MUST TREAT IT SERIOUSLY as a LIFE SAFETY HAZARD WARNING.

Question: can cat litter or animal waste make a CO detector alarm sound?

21 July 2015 Norm said:
My detector is about 3 feet above a cat litter box. Can a dirty litter box (lots of urine)set the alarm off ?

Reply:

Not that I can imagine. I've not found references citing that cat pee or poop emits carbon monoxide.


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