By Scott Gieseler · Published · Updated
If a carbon monoxide (CO) alarm sounds, get everyone outside to fresh air and call 911 from outside. Do not stay inside to test the alarm or find the source, and do not reenter until emergency responders say it is safe.
For routine checks when there is no emergency, follow your alarm’s manual for testing, placement, battery care and replacement. CO is colorless and odorless. Alarms warn of a hazard; they do not prevent CO or replace proper maintenance of fuel-burning equipment.
Why a Carbon Monoxide Detector Matters in Every Home
A carbon monoxide detector is designed to sound an alarm when it detects a potentially dangerous buildup of CO. This gas comes from incomplete fuel burning and can build up when fuel-burning appliances, furnaces, or fireplaces malfunction or are not vented properly.
The dangers of carbon monoxide exposure include:
- Headache or fatigue
- Nausea, dizziness, or confusion
- Shortness of breath and chest pain
- Loss of coordination or fainting
- In severe cases, unconsciousness or death
CO alarms add protection but do not replace correct installation, use, and professional maintenance of fuel-burning appliances. Install alarms on every level and outside sleeping areas, following each model’s instructions. If you suspect CO poisoning, get everyone outside immediately and call 911 from outside, even if no alarm has sounded.
Signs Your Detector May Not Be Working
A detector is crucial, but it needs to be maintained to keep your home safe. Watch for these warning signs:
- No alarm when testing – If the alarm does not respond as its manual describes during a routine test, follow the manufacturer’s troubleshooting and replacement instructions promptly.
- Expired unit – Replace the alarm at the age or replacement date specified by its manufacturer, or when its end-of-life signal occurs. Lifespans vary by model, including models rated for 10 years.
- Unexpected alarms or chirps – Do not assume a CO alarm is false. If the CO alarm sounds, leave immediately and call 911 from outside. Learn your model’s low-battery, fault, and end-of-life signals from its manual before an emergency; if you cannot tell whether a sound is a CO alarm, leave and call 911 from outside.
- Indicator lights – Check the meanings and expected light pattern in your model’s manual. A single light color does not establish that the alarm is working.
If the CO alarm sounds, leave immediately for fresh air and call 911 from outside; do not stay inside to troubleshoot or replace it. For a failed routine test or a confirmed maintenance signal, follow the manufacturer’s instructions promptly; replace an expired or end-of-life alarm.
How to Test Your Carbon Monoxide Detector
Use your alarm’s manual for the routine test schedule and procedure; some models require weekly testing:
- Press the test button – Follow the manual’s button sequence and expected sounds. A successful test does not establish that one alarm can be heard throughout the home.
- Check the indicator lights – Follow the test sequence and indicator meanings in the alarm’s manual; these differ by model.
- Use the manufacturer’s test procedure – Use only the test method specified for your model. Do not improvise a test with vehicle exhaust, a flame, or other CO sources.
- Test regularly – Set a reminder for the interval in your alarm’s manual.
Routine testing helps check alarm operation, but it does not guarantee protection at all times. CPSC notes that the test button checks circuitry, not sensor accuracy; replace the alarm when its manufacturer specifies.
Regular Maintenance Tips for Detectors
Follow your alarm’s maintenance instructions, including these checks:
- Replace the batteries – For models with replaceable batteries, use the battery type and replacement schedule in the manual, and act on a confirmed low-battery signal promptly. Sealed-battery alarms need whole-unit replacement when specified; do not open them to change the battery.
- Clean the detector – Use only the cleaning method and schedule specified in the manual. Avoid cleaning products or sprays that the manufacturer warns can damage the sensor.
- Replace old detectors – Follow the manufacturer’s replacement date and end-of-life instructions, even if the test button still sounds the alarm.
Routine care supports alarm operation, but it does not replace safe use and professional maintenance of fuel-burning equipment.
Common Mistakes to Avoid with CO Detectors
Even with installation, mistakes can reduce effectiveness:
- Wrong placement – Follow your model’s location and environmental limits. Do not dismiss a CO alarm as steam or a placement problem.
- Ignoring beeps – A CO alarm calls for immediate evacuation and a 911 call from outside. For a confirmed low-battery, fault, or end-of-life signal, follow your model’s instructions promptly. A battery change will not fix an expired alarm.
- Using just one detector – Install CO alarms on every level and outside each sleeping area, following the manufacturer’s instructions and applicable local requirements.
Correct placement and maintenance help your alarms work as intended; no alarm eliminates the need to respond to suspected CO exposure.
Best Detector Placement Guidelines
Detector placement is just one part of safety. Follow these guidelines along with your model’s instructions:
- Install CO alarms outside sleeping areas and follow the manual’s guidance for audibility and any additional alarms.
- Follow the manufacturer’s spacing instructions around fuel-burning appliances. CPSC does not recommend alarms in kitchens or directly above fuel-burning appliances.
- Ensure proper placement on each level of your home.
- Keep detectors away from open windows and vents that may interfere with readings.
Use alarms on every level and outside sleeping areas; check local requirements and the manufacturer’s placement instructions.
Professional Inspections and Installation
Follow the alarm manual for routine testing and cleaning. Qualified HVAC experts can inspect and service fuel-burning equipment:
- Inspect fuel-burning appliances for proper operation.
- Check furnace ventilation systems.
- Check chimneys and flues for blockages or disconnected venting.
- Correct identified appliance or venting problems before the equipment is used again.
Contact Tegridy Air about HVAC maintenance. For alarm-specific questions, consult the alarm manufacturer; during a CO emergency, call 911 from outside first.
What to Do if the Detector Sounds an Alarm
If a CO alarm sounds, or anyone has symptoms that may be caused by CO exposure, act immediately even if no alarm has sounded:
- Leave the home immediately and move to fresh air.
- Call 911 from outside and tell the dispatcher about any symptoms. Do not reenter until emergency responders say it is safe.
- Do not delay leaving to open windows, find the source, silence the alarm, or change batteries.
- After the emergency, have any appliance identified as the CO source serviced by a qualified technician before using it again.
Treat an unexpected CO alarm or suspected CO poisoning as an emergency. Do not wait for symptoms to worsen.
Conclusion
Tegridy Air: A CO alarm is one part of home safety. For routine alarm care:
- Test the detector using the procedure and schedule in its manual.
- Follow the manual’s battery instructions; sealed-battery models do not have user-replaceable batteries.
- Follow the manufacturer’s placement instructions and applicable local requirements.
- Replace the alarm when the manufacturer specifies or it signals end of life.
Use qualified professionals for fuel-burning appliance inspections and service.
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Safety references: CPSC CO-alarm guidance; Kidde testing and placement guidance; Kidde sealed-battery model example (C3010/C3010-D manual). Follow your own alarm’s manual for routine testing, cleaning, and replacement; model-specific instructions in these references do not apply to every alarm.