Lennox AC Error Code 421
EEV failure — the electronic expansion valve is not functioning properly.
⚠️ Symptoms You'll Notice
- • Weak or no cooling
- • System cycles off
- • AC won't maintain temperature
- • Compressor protection
What Causes Error Code 421?
🔧 DIY Troubleshooting Steps
- 1 Check that both supply and return lines are present
- 2 Feel temperature difference between lines
- 3 Verify system is getting power
- 4 Reset the system
📞 When to Call a Professional
EEV repair or replacement requires professional service.
Estimated repair cost in Albuquerque: $300–$800
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Frequently Asked Questions
What does Lennox Air Conditioner error code 421 mean? ▼
EEV failure — the electronic expansion valve is not functioning properly.
How much does it cost to fix error code 421 in Albuquerque? ▼
Typical repair costs in Albuquerque for Lennox Air Conditioner error code 421 range from $300–$800. EEV repair or replacement requires professional service.
Can I fix Lennox error code 421 myself? ▼
Some basic troubleshooting is safe to try: Check that both supply and return lines are present. Feel temperature difference between lines. EEV repair or replacement requires professional service.
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