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Lennox Furnace ⚠️ Use With Caution

Lennox Furnace Error Code 242

Lennox Furnace error code 242: Draft pressure switch failed closed.

Last reviewed: Last updated:

Methodology: We combine OEM HVAC documentation with field repair patterns, then review for safety-first troubleshooting.

Sources: HVAC manufacturer documentation, installation/service manuals, and technician-reported repair patterns.

Limits: Guidance is informational and may not match every model-year or revision. Confirm with the official manual and diagnostics before replacing parts. For safety-critical or electrical work, use a qualified technician.

Is it safe?
⚠️ Use with caution
Stop using until the cause is identified. Check your owner's manual for model-specific guidance.
Can I fix it?
Technician Recommended
Tools: Multimeter, Screwdriver set
Repair cost
DIY: Varies
Pro: $100–$500
⏱ 30–120 min

What Does Error Code 242 Mean?

Lennox Furnace error code 242: Draft pressure switch failed closed.

Part that typically fails: See description above

Stop using until the cause is identified. Check your owner's manual for model-specific guidance.

Symptoms You May Notice

Troubleshooting Steps

  1. 1 Check your owner's manual for model-specific guidance on error code reset procedures
  2. 2 Contact a licensed HVAC technician — refrigerant handling requires EPA 608 certification
  3. 3 If the error persists after reset and basic checks, contact a qualified technician
🛠️ Tools needed: Multimeter, Screwdriver set · Time: 30–120 min
⚡ Quick tip: Always try a full power reset first — turn the unit off at the breaker, wait 30 seconds, restore power.

Frequently Asked Questions

What does Lennox Furnace error code 242 mean? ▼
Error code 242 on a Lennox gas furnace indicates: Draft pressure switch failed closed. The unit has detected this condition and has limited or stopped operation to prevent further damage.
How do I fix Lennox Furnace error code 242? ▼
Start by powering the unit off for 30 seconds and restarting. If error 242 returns, the underlying cause (draft pressure switch failed closed) needs to be addressed. Check wiring connections and filters first before replacing components.
Is Lennox error code 242 serious? ▼
It depends on the root cause. Some 242 errors resolve with a reset. Others indicate a failed component that requires professional repair. Don't continue operating with this error — it can lead to further damage.

More Lennox Furnace Error Codes

All Lennox furnace codes → All Lennox HVAC codes →

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