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Carrier · Air conditioner

79 Compressor / inverter fault (failed start)

Medium severity Carrier Infinity 19VS 24VNA9

What the control is telling you

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)

Likely causes

  • Compressor fails to start

Test and repair steps

  1. Let the system retry; if it repeats, troubleshoot as code 88.

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Source: Carrier 25VNA8 / 24VNA9 Service Manual, Table 6 Fault Code Actions, p.23. Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.