🔧 R-32 Gas Furnaces Are Reliable—But Nothing’s Perfect
Hey there, Mike here.
Let’s be real: R-32 gas furnaces are built solid. They’re efficient, eco-friendly, and don’t guzzle gas like the old clunkers did. But just like any machine, they can act up—especially if they haven’t been cleaned or tuned in a while.
Today I’m breaking down the most common problems I’ve seen in the field, along with no-nonsense tips for fixing them (or at least knowing when to call for help).
🛑 1. Short Cycling
What’s happening:
Your furnace keeps turning on and off every few minutes.
What causes it:
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Dirty air filter
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Thermostat issues
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Furnace overheating due to restricted airflow
Fix it like Mike:
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Swap in a new MERV-rated air filter (check monthly!)
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Make sure thermostat wires are secure and it’s properly calibrated
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Have your HVAC tech check for blocked return vents or undersized ductwork
🔥 2. No Heat or Low Heat
What’s happening:
Furnace runs, but it’s blowing lukewarm air—or nothing at all.
What causes it:
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Pilot light or ignition failure
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Gas valve problems
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Clogged burners
Fix it like Mike:
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Make sure the thermostat is set to "heat" and above room temp
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Check for a flashing error code on the control board
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If the igniter is cracked, it’ll need replacing
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For deeper fixes, a licensed HVAC tech can test the gas pressure and flame sensor
More help? Check Energy.gov’s Furnace Troubleshooting Guide
💨 3. Weak Airflow
What’s happening:
Your vents are barely pushing out air.
What causes it:
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Dirty blower fan
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Clogged evaporator coil (yes, even in winter)
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Failing blower motor
Fix it like Mike:
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Clean or replace the air filter (again, always start here)
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Inspect ductwork for kinks or damage
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Schedule a coil and blower wheel cleaning
Want to DIY clean your blower? Here’s a how-to from Family Handyman
🔥 4. Furnace Smells Bad
What’s happening:
That rotten egg, burning plastic, or musty basement smell when the heat kicks on.
What causes it:
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Dust burning off
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Electrical problems
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Mold in the ducts
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Natural gas leak (only if it smells like sulfur)
Fix it like Mike:
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If it’s musty or dusty, run the fan on "ON" mode for a few hours and open windows
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For burning or sulfur smells—shut it off and call your gas provider immediately
For more on gas safety, see National Fire Protection Association’s furnace tips
⚠️ 5. Furnace Turns On, Then Shuts Down Quickly
What’s happening:
You hear it start up—but it shuts off before heating anything.
What causes it:
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Flame sensor isn’t detecting ignition
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Pressure switch failure
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Blocked exhaust flue or condensate drain
Fix it like Mike:
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Pull and clean the flame sensor with steel wool
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Check for water backing up in the condensate drain
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Make sure the flue pipe outside isn’t clogged with leaves or snow
🔁 6. Your Furnace Is Too Noisy
What’s happening:
Thumping, whining, or rattling that wasn’t there last week.
What causes it:
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Loose panels or ductwork
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Blower motor bearings
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Dirty burners
Fix it like Mike:
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Tighten panel screws and duct joints
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Lube the blower motor (if yours isn’t sealed)
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Schedule an annual inspection before the cold hits
Pro tip: ASHRAE’s residential HVAC noise guide has industry-level insights for those curious.
✅ Mike’s Final Tips for Furnace Fixes
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Change your air filter monthly during heavy heating use. It’s cheap insurance.
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Don’t ignore weird noises or smells. Small issues snowball into big repairs.
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Do a preseason tune-up every fall. Keeps things running safely and smoothly.
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Match your furnace to your square footage. Oversized units can cycle too fast.
If your R-32 gas furnace is acting up and you’re not sure what to do, reach out to us at The Furnace Outlet. We’ll help you troubleshoot or match you with a newer, high-efficiency replacement that fits your home and your budget.
Stay warm and stay smart,
– Mike
In the next topic read about: Best R-32 Gas Furnaces for Older Homes: Mike’s Picks for Comfort & Efficiency
