Why does the air conditioner display 'Preheat' or 'Defrost' during heating operation?

The 'Preheat' indicator appears because the air conditioner uses a hot start control to prevent cold air from being discharged at the beginning of heating operation. The 'Defrost' indicator appears when the outdoor temperature is too low, triggering a defrosting operation to maintain performance. Both are normal operating states for the heat pump model. (Page 16)