What the code means
1 Flash: Fan ON delay modified
The Carrier 48FC IGC board LED alarm-code table indicates the fan ON delay has been modified.
Troubleshooting code
Carrier® WeatherMaker® - 7.5 Ton Packaged Rooftop Gas Heat & Electric Cool Unit High Heat (208/230-3-60) 1 Flash troubleshooting
Fan ON delay modified. Use this page to document the issue and prepare for service. GreenFlow should handle diagnosis for electrical, refrigerant, lockout, or recurring conditions.
Safe checks before calling
- Confirm the thermostat or controller is powered, set correctly, and calling for heating or cooling.
- Check filters, return-air grilles, supply registers, and visible airflow paths that can be reached without opening equipment panels.
- Look for visible outdoor-unit or rooftop obstructions, debris, snow, ice, or blocked clearances from a safe location only.
- Take photos of the displayed code or LED pattern, equipment nameplate, thermostat or controller, and the surrounding equipment area before scheduling service.
When to stop and call GreenFlow
Call GreenFlow if the code repeats, the unit is locked out, heating or cooling is not restored, there is flame, gas, electrical, refrigerant, pressure, compressor, fan-motor, rooftop-access, or warranty-related concern, or any troubleshooting would require opening equipment panels.
Share the visible code, model and serial number if available, photos, current symptoms, and whether the issue affects heating, cooling, or both.
1 Flash questions
What does 1 Flash mean on a Carrier® WeatherMaker® - 7.5 Ton Packaged Rooftop Gas Heat & Electric Cool Unit High Heat (208/230-3-60)?
The Carrier 48FC IGC board LED alarm-code table indicates the fan ON delay has been modified.
What should I safely check before scheduling service?
Confirm thermostat or controller status, check filters and visible airflow restrictions, look for outdoor-unit or rooftop obstructions from a safe location, and take photos of the code or LED pattern and nameplate. Do not open electrical, gas, refrigerant, or rooftop control compartments.
When should GreenFlow handle this code?
Call GreenFlow if the code repeats, the unit is locked out, heating or cooling is not restored, there is flame, gas, electrical, refrigerant, pressure, compressor, fan-motor, rooftop-access, or warranty-related concern, or any troubleshooting would require opening equipment panels.
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