How do I program the VFD for two-speed fan operation?

For the SmartVFD HVAC (HVFDSDxxxxxx), set the low speed fan at parameter P1.8 or P3.3.1 during setup, and configure high speed at P3.3.12. For Compact or HVAC2 models, set low speed at P3.1 and high speed at P3.5. When the thermostat calls for ventilation or first stage cooling, the fan runs at minimum frequency (lower speed), and for heating or second stage cooling, it runs at preset frequency 1 (higher speed).