STEP 3: Build a fan speed control
If you have full control over your brewery room build, instead of building a fan speed control box consider using an industrial KBWC-15K fan control from KB Electronics installed directly in the wall beside the control panel.
No separate (external) fan speed control box is therefore required and this step may be skipped.
When plugged in, the Vortex fan turns at full speed. This is perfect for evacuating heat and moisture from the brewery during the full wort boil, but overkill when we're heating strike water, mashing, or cleaning up. During those times we want the fan to run at a lower speed to only remove the excess heat from the brewery. To control the fan speed we use a Lutron quiet 3-speed fan switch in a simple box we built.
Regular light dimmers cannot be used as they reduce power by simply chopping up the AC sine wave which causes the fan to issue an annoying buzz whenever it is run at anything less than 100%. Fan speed controls are not the same as light dimmers: Most fan speed controls have built in noise reducing circuitry to avoid fan 'hum' (the word 'quiet' or 'silent' is often used in the product name).
Install the Lutron quiet 3-speed fan switch together with a Decora 120VAC/15A NEMA 5-15R 2-pole 3-wire duplex receptacle in a weatherproof 2-gang outlet box. An 18AWG universal power cord (IEC320C13) is used to supply power. A 1/2" strain relief cord connector is used at the entry point to the 2-gang outlet box. It is held in place permanently with JB Weld. A Decora strap with .406" hole is used to cover up the rotary fan control. A 2-gang Decora cover is used to cover the 2-gang outlet box.
The fan speed control box is then plugged into a standard 120V/15A receptacle and the fan is plugged into the speed control box.
Fan control wiring diagram:
Components inside the 2-gang outlet box: