on arrival found downflow unit running at medium speed on heat putting out a 30° temperature split. Switched the fan and the heat terminals so that heat is now on the low speed and fan is on medium low speed. Temperature split is now 42° which is warmer and still within range of the temperature split. System is working correctly at this time with a good temperature split and clients are happy with this change. Let the clients know that cooling unfortunately cannot be change from the high speed and the fan will still be loud when running the cooling. If need to change we may be able to bring the fan down to medium high but for now left the way it is.