Carrier HVAC Error Code 16: How to Fix Low Pressure Switch Lockout

Medium 30-60 minutes Medium Severity Verified June 2026
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Error Code
16
Brand
Carrier
Product Type
hvac
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
30-60 minutes
Carrier HVAC error code 16 indicates a low pressure switch lockout, meaning the system detected abnormally low refrigerant pressure and shut down to protect the compressor. This is a medium-severity issue that can be caused by low refrigerant, a clogged filter, or a faulty switch. Follow these steps to diagnose and fix the problem.
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Tools You'll Need

How to Fix Error Code 16

  1. Turn Off Power and Inspect Air Filters

    Always turn off power before accessing the HVAC unit.

  2. Check for Visible Refrigerant Leaks

    Refrigerant is hazardous. Do not attempt to handle it yourself.

  3. Reset the System

  4. Test the Low Pressure Switch

    Be careful not to damage wires or connectors.

  5. Measure Refrigerant Pressure

    Only do this if you are trained; otherwise, call a technician.

  6. Replace the Low Pressure Switch (If Faulty)

    Refrigerant recovery requires EPA certification. Call a pro if unsure.

Parts You May Need

Low pressure switch
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Air filter
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Low pressure switch
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Air filter
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Low pressure switch
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Air filter
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Low pressure switch
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Air filter
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When to Call a Professional

If you find a refrigerant leak, need to recharge the system, or the error persists after replacing the switch, call an HVAC technician. Handling refrigerant requires EPA certification.

Frequently Asked Questions

What does Carrier error code 16 mean?
It means the low pressure switch opened due to low refrigerant pressure, causing a lockout to protect the compressor.
Can I reset Carrier error 16 myself?
Yes, by turning off the system for 5 minutes and restoring power. But if the error returns, there's an underlying issue.
What are the common causes of error 16?
Common causes include low refrigerant (leak), dirty air filter, restricted airflow, or a faulty low pressure switch.
Is it safe to continue using the AC with error 16?
No. The system is locked out to prevent damage. Continuing to use it could damage the compressor.
Do I need a professional to fix error 16?
If you suspect a refrigerant leak or need to recharge, yes. Basic checks like filter replacement and reset are DIY.

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