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MEDIUM URGENCY

Carrier Code 42 - Inducer Motor Speed Out of Range

Code 42 (4 short + 2 long flashes)

Inducer motor speed outside valid range.

Brand: Carrier (Also covers Bryant, Payne)  |  Equipment: Gas Furnace

What This Code Means

Code 42 on Carrier (Bryant, Payne) means the draft inducer motor is running too slow, too fast, or not at all. Usually inducer failure or capacitor.

Likely Causes (Ranked)

Most common

Failed inducer motor

What: Bearings worn or windings burned out.

How to check: Listen at startup - should run smoothly.

Fix: Replace inducer assembly.

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Common

Failed inducer capacitor

What: If model has separate inducer capacitor, weak cap = slow inducer.

How to check: Test with meter.

Fix: Replace capacitor.

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Less common

Restricted exhaust

What: Blocked vent creates back pressure affecting motor speed.

How to check: Inspect outdoor exhaust.

Fix: Clear blockage.

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Diagnostic Steps

  1. Cut power
  2. Listen for inducer at heat call
  3. Test inducer capacitor if present
  4. Replace inducer if seized
  5. Check exhaust vent

Frequently Asked Questions

Cost to replace Carrier inducer?
Inducer assembly typically \$150-350. Labor adds 1-2 hours.
Same on Bryant/Payne?
Yes.
DIY?
Inducer replacement is moderate difficulty - 2-3 hours, basic tools.

Related Carrier Codes

Carrier Error Code 31Carrier Error Code 23

Related Symptoms

Furnace Not IgnitingFurnace Blowing Cold Air

Need More Help?

Try our interactive symptom diagnostic tool or browse Carrier parts.

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