When your furnace or water heater suddenly stops working, the issue often traces back to a failed draft inducer motor—the small, powerful fan that helps push combustion gases safely out of your HVAC system. If it fails, your system may shut down entirely as a protective measure.
Draft inducer motors play a critical safety and performance role in your furnace or water heater. Left unchecked, a failing motor can lead to:
- Carbon monoxide buildup
- System lockouts during freezing weather
- Higher energy bills from struggling motors
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Expensive emergency service calls
Read our Blog: How to Install A Furnace Blower Motor
We see a lot of motor failures, and here are the top 5 reasons that come into our motor shop and some tips on how you can troubleshoot the issue:
1. Worn-Out Bearings
🔍 Problem: Continuous use during heating seasons wears down internal bearings, causing noise, inefficiency, and eventual failure.
🧩 Detailed Symptoms:
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Loud Screeching or Grinding: This indicates metal-on-metal contact where lubrication has broken down.
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Motor Struggles to Start: Bearings may seize or add friction that the motor can't overcome.
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Vibration or Shaking: Worn bearings throw the shaft off balance, causing excessive vibration.
🛠️ Why It Happens:
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High Heat & Friction: Bearings are the most stressed components in any rotating motor.
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Dust, Pet Hair, Lint: These contaminants build up in furnace closets and utility spaces, infiltrating the motor housing.
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Poor Filtration: Older homes or neglected filters accelerate dust accumulation and bearing wear.
✅ Solutions:
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Replace the Motor: Once bearings fail, replacing the motor is typically more cost-effective than rebuilding.
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Choose Sealed Bearings: Look for motors with sealed, permanently lubricated ball bearings like those from Century, US Motors, or Fasco.
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Upgrade for Durability: Many newer Fasco motors offer enhanced designs to withstand harsh conditions, especially in regions where furnaces run constantly.
2. Electrical Failure
🔍 Problem: Surges, short circuits, or aging capacitors can fry your motor’s windings or electronics.
🧩 Detailed Symptoms:
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Motor Doesn’t Turn On: A dead or unresponsive inducer often points to a loss of power.
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Circuit Breaker Trips Repeatedly: Indicates a short inside the motor or incorrect amperage draw.
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Burnt Smell or Smoke: Usually means the windings have shorted internally or the capacitor has blown.
🛠️ Why It Happens:
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Power Surges/Outages: Lightning or grid disruptions can damage sensitive motor components.
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Worn Capacitors: These degrade over time, causing insufficient startup torque or erratic function.
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Voltage Mismatch: Older homes or DIY installations may supply the wrong voltage or phase.
✅ Solutions:
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Test with a Multimeter: Check line voltage and resistance across motor terminals.
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Inspect the Capacitor: PSC motors like many Fasco models rely on capacitors to start.
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Replace as Needed: Brands like Genteq offer quality capacitors often bundled with draft inducer motor kits.
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Match Voltage & Phase Exactly: Confirm motor specs align with your system before installation.
💡 Pro Tip: Many electrical failures are mistaken for mechanical issues—always check power first!
3. Blocked or Dirty Venting
🔍 Problem: Obstructions in your exhaust pipe or flue system cause excessive strain on the draft inducer motor, leading to overheating or shutdown.
🧩 Detailed Symptoms:
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System Shuts Down Mid-Cycle: The draft pressure switch can’t confirm proper airflow.
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Motor Runs but Heat Doesn’t Start: The safety system prevents operation without sufficient draft.
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Weak or No Airflow from Vent: Indicates blockage or back pressure.
🛠️ Why It Happens:
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Debris in the Vent Line: Birds, rodents, and even insects often nest in exterior exhaust vents.
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Soot or Moisture Buildup: Especially in older or oil-fired systems.
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Lack of Seasonal Maintenance: Most homeowners never inspect their flue until there’s a problem.
✅ Solutions:
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Clean the Venting Thoroughly: Use a camera scope or snake to confirm it’s clear.
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Install a Bird Screen: Prevent future animal blockages.
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Upgrade to Motors for High Resistance: Brands like Marathon or Baldor offer motors built for higher static pressure environments, often with reinforced impellers and added cooling features.
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Add Maintenance to Fall Checklist: Especially in homes with trees, chimney caps, or shared exhaust stacks.
4. Incorrect Motor Replacement
🔍 Problem: Swapping your old motor with a generic or non-matching replacement can lead to poor airflow, excess noise, or even damage to your heating system.
🧩 Detailed Symptoms:
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Motor Doesn’t Trigger Furnace Start: It may be underpowered or lack proper airflow output.
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Unusual Noises or Vibrations: Sign of poor fit, shaft misalignment, or unbalanced blower wheels.
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Improper Mounting: If the bracket or holes don’t line up, vibration or unsafe operation may occur.
🛠️ Why It Happens:
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RPM Mismatch: Too high or too low can prevent the pressure switch from working.
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Mounting Differences: Each system has specific flange styles and footprint requirements.
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Wrong Shaft Length or Diameter: This affects blower alignment and airflow consistency.
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Improper Voltage/Phase: Using a 115V motor in a 230V system, or vice versa, can damage the board.
✅ Solutions:
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Use OEM Parts Whenever Possible: Fasco offers exact-fit replacements for major HVAC brands like Carrier, Trane, Rheem, and Lennox.
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Shop by Model Number: Use Square One’s Master Product Search Tool to find perfect matches.
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Include Photos for Accuracy: A snapshot of your motor’s label helps our team match specs precisely.
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Brands Like Leeson and US Motors provide in-depth spec sheets and durable commercial-grade motors with tight tolerances for performance.
5. Motor Age & Long-Term Wear
🔍 Problem: Even in ideal conditions, motors degrade over time. After 10+ years, performance drops sharply.
🧩 Detailed Symptoms:
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Unexplained Shutdowns or Restarts: Windings may have deteriorated or insulation has failed.
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Persistent Motor Noise: Internal components lose alignment or lubrication.
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System Still Struggles Despite Clean Filters & Vents: Indicates motor is past its prime.
🛠️ Why It Happens:
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Wear & Tear: Bearings, shafts, windings, and insulation break down with age.
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Higher Amp Draw: Older motors draw more current, increasing electric bills.
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Lack of Modern Features: No thermal cutoff, no vibration dampening, outdated efficiency.
✅ Solutions:
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Proactive Replacement Saves Money: Don’t wait for total failure.
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Upgrade to Fasco or Baldor Motors: Today’s models include thermal protection, balanced rotors, improved airflow, and UL/CSA certifications.
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Improve Efficiency & Safety: Newer motors are quieter, cooler, and more energy-efficient.
Where to Buy Draft Inducer Motors
Benefits of Shopping at Square One Electric Motors & Pumps:
Fasco Draft Inducer Motors (OEM and universal fit)
Models from Century, Baldor, Leeson, Marathon, and US Motors
Fast U.S. shipping from multiple warehouses
Live customer support with motor specialists
All motors include manufacturer warranties
🛒 Browse All Draft Inducer Motors Now »
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📚 More Resources from Our Tech Tips Blog
📈 How to Install A Furnace Blower Motor