Originally Posted by NZDaz
HdC = Maximum fan speed, use to scale large fan down. Represented in percentage.
So there are 2 factors that control your fan output.
1. The CFM of your fan (10 or 50)
2. The value of HdC (0000-0100, this is expressed in a percentage so that means it can only be a number from 0 all the way to 100)
Example: If you have a 10CFM fan and you set your HdC value to 0025 then;
10CFM * 25% = 2.5CFM will be your max fan output.