Rheem HVAC Error Code 16: How to Fix It

Medium 45-90 minutes Medium Severity Verified June 2026
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Error Code
16
Brand
Rheem
Product Type
hvac
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
45-90 minutes
Rheem HVAC error code 16 indicates that the system's compressor is not running, which means your air conditioner or heat pump cannot properly cool or heat your home. This error is typically triggered by electrical faults, a failed capacitor, refrigerant issues, or a seized compressor motor. Addressing this promptly is important because running the system without a working compressor can cause additional damage to related components.
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Tools You'll Need

How to Fix Error Code 16

  1. Turn Off the System and Check the Thermostat

    Do not attempt to restart the system repeatedly if the compressor is failing — this can burn out the motor windings.

  2. Reset the System at the Breaker Panel

    If the breaker trips again immediately after resetting, do not reset it a second time. A repeatedly tripping breaker indicates a serious electrical fault requiring a licensed technician.

  3. Inspect the Outdoor Disconnect Box

    Turn off the main HVAC breaker at the panel before touching the disconnect box or fuses. Even with the disconnect removed, capacitors in the unit can hold a dangerous electrical charge.

  4. Check and Test the Run Capacitor

    Capacitors store high-voltage electricity even when power is off. Always discharge the capacitor by carefully shorting its terminals with an insulated-handle screwdriver before touching it. Failure to do so can result in severe electrical shock.

  5. Inspect the Contactor in the Outdoor Unit

    Keep power fully off at both the disconnect and the breaker while inspecting the contactor.

  6. Check for Ice Buildup or Blocked Airflow

    Never use sharp tools or heat guns to speed up the thawing process on a frozen coil, as this can damage the coil fins.

  7. Listen and Observe the Compressor at Startup

    If the compressor makes grinding or clanking sounds, shut off power immediately. A seized compressor requires professional evaluation and likely full compressor or system replacement.

  8. Check Low-Voltage Control Wiring

    Turn off power at the thermostat and breaker before touching control wiring.

Parts You May Need

Run Capacitor
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Contactor
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Hard Start Kit
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Disconnect Fuses
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Air Filter
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Run Capacitor
Check Price on Amazon
Contactor
Check Price on Amazon
Hard Start Kit
Check Price on Amazon
Disconnect Fuses
Check Price on Amazon
Air Filter
Check Price on Amazon
Run Capacitor
Check Price on Amazon
Contactor
Check Price on Amazon
Hard Start Kit
Check Price on Amazon
Disconnect Fuses
Check Price on Amazon
Air Filter
Check Price on Amazon
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When to Call a Professional

You should call a licensed HVAC technician if: the breaker trips repeatedly after resetting; the capacitor and contactor appear fine but the compressor still won't run; you hear humming, grinding, or clunking from the compressor; the system shows signs of refrigerant issues such as ice on the lines or warm air despite the compressor running; you are not comfortable working with high-voltage electrical components; or the compressor is mechanically seized. Compressor replacement, refrigerant handling, and complex electrical diagnostics require EPA-certified and licensed professionals and should never be attempted as DIY repairs.

Frequently Asked Questions

What does Rheem error code 16 mean?
Rheem error code 16 means the system has detected that the compressor is not running. This can be caused by a blown fuse, failed run capacitor, bad contactor, tripped breaker, low refrigerant, or a mechanically failed compressor motor.
Can I reset Rheem error code 16 myself?
Yes, you can attempt a reset by turning off the system at the thermostat, switching the breaker off for 30 seconds, and then restoring power. However, if the error returns, there is an underlying issue that needs to be diagnosed and repaired before the code will clear permanently.
How much does it cost to fix a Rheem HVAC compressor not running?
Costs vary widely by cause. A run capacitor replacement typically costs $150–$300 with labor. A contactor replacement runs $100–$250. A hard-start kit is $100–$200 installed. If the compressor itself has failed, replacement costs range from $800–$2,500 or more depending on system size and whether it is under warranty.
Why does my Rheem AC run but not cool the house?
If the outdoor fan is spinning but you are not getting cold air, the compressor may not be running even if the rest of the system appears active. Check whether the compressor is making any sound. A silent compressor while the fan runs is a classic sign of a failed capacitor, bad contactor, or seized compressor motor.
Is a failed capacitor the most common cause of Rheem error code 16?
Yes, a failed run capacitor is one of the most common causes of a non-running compressor on Rheem HVAC systems. Capacitors degrade over time — especially in hot climates — and are a frequent wear item. They are relatively affordable and straightforward for a technician to replace, making them the first component to inspect when troubleshooting error code 16.

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