The safety checks that protect your family, not just your furnace
Most furnace maintenance articles talk about efficiency, comfort, and saving money.
This one talks about keeping people safe.
Carbon monoxide (CO) incidents almost never happen because a furnace was “cheap” or “old.” They happen because combustion safety was ignored—blocked airflow, neglected venting, or missing detectors.
I’ve walked into homes where everything looked fine… but one overlooked detail could’ve turned deadly.
80,000 BTU 96% AFUE Upflow/Horizontal Single Stage Goodman Gas Furnace - GR9S960803BN
This guide covers the non-negotiable safety maintenance every homeowner with a gas furnace needs to understand—clearly, calmly, and without fear tactics.
🧠 Why Combustion Safety Deserves Its Own Guide
Gas furnaces work by controlled combustion. That means:
-
Fire
-
Exhaust gases
-
Oxygen intake
-
Safety controls working together
When any one of those fails, the system is supposed to shut down.
When safety devices are missing, bypassed, or ignored—that’s when people get hurt.
According to the CDC, carbon monoxide causes over 400 unintentional deaths and 20,000 ER visits per year in the U.S.
🔗 https://www.cdc.gov/carbon-monoxide/about/index.html
Most of those incidents are preventable.
☠️ What Carbon Monoxide Is (And Why You Can’t Detect It Yourself)
Carbon monoxide is:
-
Colorless
-
Odorless
-
Tasteless
You will not smell it.
You will not see it.
You will feel symptoms only after exposure has already begun.
Early CO Symptoms
-
Headache
-
Dizziness
-
Fatigue
-
Nausea
Severe Exposure
-
Confusion
-
Loss of consciousness
-
Death
That’s why CO safety relies on prevention and detection, not human senses.
🔔 Step 1: Carbon Monoxide Detectors (Non-Negotiable)
If I could mandate one thing, it would be this.
✔️ Where CO Detectors Must Be Installed
-
Outside all sleeping areas
-
On every level of the home
-
Near (but not directly above) the furnace room
✔️ Maintenance Rules
-
Test monthly
-
Replace batteries yearly
-
Replace units every 5–10 years (check manufacturer date)
The Consumer Product Safety Commission strongly recommends CO detectors in all homes with fuel-burning appliances.
🔗 https://www.cpsc.gov/safety-education/safety-guides/carbon-monoxide
No detector = no warning.
🔥 Step 2: Combustion Air — The Most Overlooked Safety Factor
Your furnace needs oxygen to burn fuel safely.
What Combustion Air Is
-
Fresh air drawn into the furnace
-
Used to burn gas completely
-
Prevents backdrafting and incomplete combustion
What Happens Without It
-
Yellow flames
-
Soot buildup
-
CO production
-
Furnace shutdown—or worse
Modern homes are tightly sealed. That makes combustion air more important than ever.
🌬️ Step 3: Keep Combustion Air Open & Unrestricted
✔️ Check For These Common Blockages
-
Storage boxes near the furnace
-
Insulation blocking air openings
-
Plastic covers over intake grilles
-
Laundry room clutter
❌ What Not to Do
-
Seal furnace rooms tightly
-
Store chemicals or paint near the furnace
-
Close combustion air vents to “stop drafts”
Combustion air openings exist for a reason—blocking them is dangerous.
The EPA confirms that inadequate combustion air is a leading cause of indoor air quality hazards.
https://www.epa.gov/indoor-air-quality-iaq/what-are-combustion-products
🧱 Step 4: Venting & Exhaust Pipes (Where CO Leaves the Home)
Exhaust systems must work perfectly—every time.
✔️ What to Inspect Visually
-
Vent pipes securely connected
-
No corrosion, rust flakes, or gaps
-
Proper slope (for high-efficiency PVC systems)
-
Outdoor terminations clear of snow, leaves, nests
⚠️ Red Flags
-
Rust around vent joints
-
Disconnected sections
-
Condensation dripping where it shouldn’t
Blocked or leaking vents can send exhaust gases back into the home.
🔍 Step 5: Flame Appearance Tells a Safety Story
You don’t need tools to spot warning signs.
✔️ Normal Flame
-
Steady
-
Blue
-
Even across burners
❌ Unsafe Flame
-
Yellow or orange
-
Flickering wildly
-
Lifting off burners
These indicate combustion problems that can increase CO production.
If flames look wrong, stop troubleshooting and call a professional.
💧 Step 6: Moisture & Condensate Management (High-Efficiency Furnaces)
High-efficiency furnaces create condensation as part of normal operation.
Why This Matters
-
Blocked drains affect pressure switches
-
Moisture buildup affects combustion safety
-
Standing water can corrode components
✔️ What to Check
-
Clear drain lines
-
No algae or slime
-
No standing water in the furnace base
The EPA warns that unmanaged HVAC moisture contributes to corrosion and unsafe operating conditions.
https://www.epa.gov/indoor-air-quality-iaq/moisture-control-guidance-building-design-construction-and-maintenance-0
🔌 Step 7: Never Bypass Safety Switches (Ever)
I need to say this plainly:
If a furnace safety switch trips, it’s doing its job.
Common Safety Devices
-
Pressure switches
-
Limit switches
-
Flame sensors
Dangerous DIY Mistakes
-
Jumping switches
-
Taping down sensors
-
Resetting repeatedly without fixing the cause
Bypassing safeties turns a controlled system into a hazard.
🐭 Step 8: Rodents & Combustion Safety
This one surprises people.
How Pests Create CO Risk
-
Chewing wiring
-
Blocking vents with nests
-
Dislodging drain tubing
Prevention Tips
-
Keep furnace area clean
-
Seal gaps
-
Avoid cardboard storage
The CPSC identifies rodent-damaged wiring as a common household safety issue.
🔗 https://www.cpsc.gov/safety-education/safety-guides/home
📅 Step 9: Annual Professional Combustion Check
There’s no DIY substitute for this.
What Pros Check
-
Combustion efficiency
-
Draft and venting
-
Gas pressure
-
CO levels at startup and steady-state
Manufacturers recommend annual inspections to ensure safe operation and warranty compliance.
Goodman safety & warranty guidance:
https://www.goodmanmfg.com/warranty-information
❌ Common Safety Myths That Get People Hurt
Let’s shut these down:
❌ “I’d smell carbon monoxide”
❌ “New furnaces don’t make CO”
❌ “If it’s running, it’s safe”
❌ “CO detectors are optional”
None of these are true.
💰 Safety Maintenance vs. Emergency Consequences
| Ignored Item | Possible Outcome |
|---|---|
| No CO detectors | No warning |
| Blocked combustion air | CO production |
| Poor venting | Backdrafting |
| Bypassed safeties | Serious injury |
Safety maintenance isn’t expensive—but ignoring it can be.
🧾 Tony’s Non-Negotiable Safety Rules
Here’s what I live by:
-
CO detectors everywhere they’re required
-
Never block combustion air
-
Never bypass safety switches
-
Annual professional inspection
If you follow just those four rules, you dramatically reduce risk.
🏁 Final Word from Tony
Comfort and efficiency are nice.
Safety is essential.
Your furnace is safe when it’s clean, properly vented, given enough air to breathe, and monitored with working CO detectors.
Do the checks. Respect the warnings. And never ignore combustion safety.
That’s not being paranoid—that’s being responsible.
Buy this on Amazon at: https://amzn.to/48HGh2g
In the next topic we will know more about: The Ultimate Seasonal Maintenance Checklist for Your Goodman 96% AFUE Furnace
