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Carrier Error Code 79: Compressor / inverter fault (failed start) (AC)

Updated · by Aurora Star Tech Inc.

Carrier error code 79 on a air conditioner means: Compressor / inverter fault (failed start). It is also called Carrier diagnostic code 79.

Medium severityAir ConditionerAlso Heat PumpCarrier Infinity 19VS 24VNA9

Homeowner? What Carrier code 79 means for you

Check, then call Your air conditioner is reporting: Compressor / inverter fault (failed start). This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.

Safe things you can check yourself

  • Check the thermostat: right mode (Heat or Cool), set a few degrees past room temperature, and fresh batteries if it uses them.
  • Check both breakers and the outdoor disconnect box beside the outdoor unit; all should be ON.
  • Look at the air filter. If it is grey and clogged, replace it; a blocked filter causes many shutdowns.
  • Keep about 2 feet around the outdoor unit clear of leaves, grass and debris.
  • If you see ice on the pipes or the indoor coil, turn the system off and run only the fan for a few hours, then call a technician.
  • Try one reset: turn the power off for 30 seconds, then back on. If the code comes back, stop resetting and call a technician.

Call (647) 657-2977Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Carrier error code 79 mean?

Amber STATUS light flashes 79. The compressor failed to start. The system retries; after 5 occurrences it becomes code 88. Type: Local; reset: Automatic retry.

Applies to: Carrier Infinity 19VS variable speed air conditioner 24VNA9 (AOC control + inverter)

Common causes of Carrier code 79

  • Compressor fails to start
Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

Carrier models that use code 79

24VNA924VNA91324VNA92424VNA92524VNA93624VNA93724VNA94824VNA94924VNA960

Other Carrier AC codes

CodeMeaning
72Suction over temperature (event)
73Contactor shorted
74Discharge temperature lockout
75Maximum power mode - temperature
76Fan inverter lockout
77Maximum power mode - compressor current
81Low stage thermal lockout
82Suction over temperature lockout
83Low pressure lockout (4 hours)
84High pressure lockout (4 hours)
86Fan inverter current lockout
88Compressor / inverter lockout

All Carrier Air Conditioner error codes →

Carrier code 79: homeowner questions

What does Carrier code 79 mean?

Compressor / inverter fault (failed start). Amber STATUS light flashes 79. The compressor failed to start. The system retries; after 5 occurrences it becomes code 88. Type: Local; reset: Automatic retry.

Is it safe to keep using my air conditioner with code 79?

It depends on the cause. This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.

Can I reset Carrier code 79 myself?

You can try one reset (power off for 30 seconds, then on). If Carrier code 79 comes back, the cause is still there and a licensed technician should check it.

Who can fix Carrier code 79 near me?

Aurora Star Tech Inc. repairs Carrier air conditioners in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.

Homeowner help: AC Running But Not Cooling: What to Check

Troubleshooting guides

Source: Carrier 25VNA8 / 24VNA9 Service Manual, Table 6 Fault Code Actions, p.23. Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.

Emergency HVAC Service

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