Lennox HVAC Error Code E27: How to Fix It

Medium 30-60 minutes Medium Severity Verified June 2026
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Error Code
E27
Brand
Lennox
Product Type
hvac
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
30-60 minutes
Error code E27 on your Lennox HVAC system indicates a fault with the zone damper actuator. This means one of the dampers in your zoning system is not operating correctly, which can lead to uneven heating or cooling. Most fixes involve checking wiring, resetting the actuator, or replacing a faulty component.
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Tools You'll Need

How to Fix Error Code E27

  1. Turn Off Power to the System

    Always turn off power before working on HVAC equipment.

  2. Identify the Faulty Zone

  3. Inspect Damper Actuator Wiring

    Be cautious not to touch live terminals even with power off; capacitors may hold charge.

  4. Reset the Actuator

  5. Test the Actuator Manually

    Use proper multimeter safety. Do not probe live circuits without training.

  6. Replace the Damper Actuator (if needed)

    Ensure replacement actuator matches voltage and torque specifications for your system.

  7. Clear the Error Code

Parts You May Need

Zone Damper Actuator
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Zone Damper Actuator
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Zone Damper Actuator
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Zone Damper Actuator
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When to Call a Professional

If you are uncomfortable working with electrical components, or if the error persists after replacing the actuator, call a professional HVAC technician. Persistent E27 may indicate a zone control board failure or complex wiring issue.

Frequently Asked Questions

What does Lennox error code E27 mean?
Error code E27 indicates a zone damper actuator fault. The HVAC system has detected that one of the zone dampers is not operating correctly.
Can I reset Lennox error code E27 myself?
Yes, you can try resetting by turning off power to the system for 30 seconds, then turning it back on. Some dampers have a manual reset button. If the error returns, further troubleshooting is needed.
How do I know which zone damper is faulty?
The error code often displays the zone number on the thermostat or zone panel. If not, check each actuator for visible damage or test with a multimeter.
Is it safe to replace a damper actuator myself?
With the power off, replacing an actuator is safe for DIYers with basic electrical knowledge. Always turn off the breaker and follow safety precautions.
How much does a replacement damper actuator cost?
Replacement actuators for Lennox systems typically cost $30 to $80, depending on the model.

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