Carbon Monoxide & Boiler Safety

What Is Carbon Monoxide and How Is It Produced?

Carbon monoxide is produced when any fuel — natural gas, propane, oil, wood — burns incompletely. In a properly functioning boiler, combustion is nearly complete and CO levels are minimal (typically <50 ppm in the flue, undetectable in living space).

• Normal combustion: Blue flame, CO <50 ppm in flue, CO₂ 8-10%, O₂ 3-6%. Safe operation.
• Incomplete combustion: Yellow/orange flame, CO >100 ppm (can exceed 1,000+ ppm), soot production. Dangerous — indicates a problem requiring immediate professional attention.
• Common causes of incomplete combustion: Cracked heat exchanger, blocked flue or air intake, dirty burner, incorrect gas pressure, failing gas valve, inadequate combustion air supply.

CO Detector Requirements for BC Homes

BC law and the National Building Code require CO detectors in homes with fuel-burning appliances or attached garages. Here's what you need:

• Required locations: Outside each sleeping area (within 5 meters of bedroom doors) — at minimum one per floor with bedrooms
• Recommended additional locations: One on every floor, including the basement. One near (but not directly above) the boiler or gas appliance.
• Placement: Wall-mounted at eye level or ceiling-mounted per manufacturer instructions. CO mixes evenly with air (unlike smoke, which rises), so placement is less height-sensitive.
• Replacement: CO detectors expire. Replace the entire unit every 7-10 years (check the manufacture date on the back). Test monthly with the test button.
• Combination smoke/CO detectors: Acceptable, but ensure it's a photoelectric smoke sensor (not ionization) for fewer false alarms from cooking.

CO Poisoning Symptoms — Know the Warning Signs

CO poisoning symptoms are often mistaken for the flu — but unlike the flu, they improve when you leave the house and worsen when you return. If multiple family members have the same symptoms, CO is a strong suspect.

• Mild exposure: Headache, fatigue, dizziness, nausea — often described as 'flu-like' symptoms
• Moderate exposure: Severe headache, confusion, vomiting, shortness of breath
• Severe exposure: Loss of consciousness, seizures, cardiac arrest — can be fatal within minutes at very high concentrations
• Key differentiator from flu: Symptoms improve when away from home and worsen when back. Multiple people or pets affected simultaneously. No fever.
• Children, elderly, and people with heart/respiratory conditions are more susceptible to CO effects at lower concentrations.

Emergency Response: If Your CO Detector Alarms

Every second counts. Follow these steps immediately:

• 1. GET EVERYONE OUT immediately — don't stop to investigate, don't open windows, just leave
• 2. CALL 911 from outside the house — do not re-enter
• 3. Do NOT re-enter until the fire department clears your home
• 4. Call us to inspect your boiler before operating it again — even if the fire department resets the detector
• 5. If anyone has symptoms, seek medical attention immediately — CO poisoning can have delayed neurological effects
• IMPORTANT: If your CO detector alarms and then stops when you ventilate the house, the CO didn't disappear — you just diluted it temporarily. The source is still there. Get the boiler inspected.

Preventing CO from Your Boiler — Annual Safety Inspection

The single most effective prevention is annual professional boiler maintenance with combustion analysis. During every boiler service, we:

• Measure CO levels in the flue gas at both low-fire and high-fire using a calibrated analyzer
• Test ambient CO near the boiler and in living spaces
• Inspect the heat exchanger for cracks, corrosion, or soot that could leak CO into the living space
• Check flue and venting integrity — no leaks, corrosion, or blockages
• Verify combustion air supply is adequate and unobstructed
• Test all safety controls — high-limit, rollout, and blocked vent switches
• Document all readings in your written service report

Frequently Asked Questions