To anyone with a CW-3000, I just made a modification to mine that is going to be my favorite yet! The fan on the 110 VAC model runs on 110 VAC, so it’s quite simple to install a fan control knob.
I found this one on Amazon and it was super simple to drill a hole through the front of the unit, the control knob comes with double sided mounting pads and a nut and washer to hold it in place, so just a 5/16" drill bit was all that was needed there.
The wiring involved cutting the black wire right before it goes into the fan. I added just under two feet of 16 AWG stranded wire to each side that I just cut (using solder and heat shrink tubing, but a wire nut and electrical tape is probably sufficient here). On the new loose ends, use 1/4" female spade connectors to make it ready for a simple plug into the new fan control knob.
So far it’s working great! I have it turned off with a close eye on the coolant temperature. I deal with industrial liquid cooled pumps at work and I believe that there is enough liquid volume in the tank, plus the other heat loss avenues of uninsulated tubing and the radiator, that the noisy fan is far overkill for a CNC setup like this. I am leaving it turned off, but since it’s on a dial, I can adjust the fan speed if needed based on coolant temperature. Anything less than full blast is going to be quieter than before.