HVACopediaCarrier · Air conditioner
83 Low pressure lockout (4 hours)
What the control is telling you
Amber STATUS light flashes 83. Suction pressure dropped below the no-operation level 3 times (elevated from code 32). 4-hour lockout. Type: System malfunction; reset: 4 hours.
Applies to: Carrier Infinity 19VS variable speed air conditioner 24VNA9 (AOC control + inverter)
Likely causes
- Service valve left closed
- Undercharged system
- Indoor airflow too low or off / iced coil
- Restriction in circuits or tubing
- Restricted filter drier
- Expansion device restriction (TXV on short line sets under 15 ft)
Test and repair steps
- Make sure both service valves are fully open.
- Cooling check subcooling in Charging Mode (or the subcooling chart on the control box door) and adjust charge (add charge if low).
- Check the indoor coil, filter and blower; de-ice if needed.
- Check for a temperature drop across the filter drier and replace it if restricted.
- Troubleshoot the TXV; repair any tubing restriction.
Save it for the next call
Star this code in the HVACopedia app and keep the whole library on your phone for jobs with no signal.
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.