I found this thread searching for a switch with enough POE and SFP+ ports and so far these are awesome and many thanks to
@fohdeesha for this thread.
So I thought I would post my fan experiences in trying to quiet down the ICX7250-24P switches. In my quest to mount the switch on my desk I found
nothing I tried from SAN ACE, Delta, SUNON, FXOCONN would get quiet enough once the switch booted up and set themselves without lots of coil whine to speed-1. I also found that by putting in slower spinning fans to quiet the system they also did not have enough static pressure to pull the air through the switch and it overheated or ran way to hot.
For the final solution I then opted to use 3 Noctua(NF-A4x20 FLX) quiet fans pulling the air out and one generic fan pushing air in directly over the switch controller heatsink and this seemed to solve the heat/noise issue in my case. I am only running 1 actual POE device currently with a handfull of fiber/ethernet connections and the temps have been stable around 41C(MGMT) and 49C(PSU).
Here is what I did in detail to my switches maybe it will help someone else
Cover modifications:
I cut a 60mm hole just over the controller heatsink for the 60x15mm fan (there is only 18mm clearance betwen the cover and heatsink). for the 4 holes i used the fan guard to estimate the hole placements.
Here you can see I cut out the existing vents holes to allow the most air flow and try to eliminate any turbulance noise. Then the 3rd hole (internal mount is already there) I used a 40mm hole saw to cut that out but I think I could have used a 38mm hole saw just fine.
I also put in a panel jack for the fan power so that I can use an external power supply that is adjustable that way I can adjust the fan speed/noise to my likeling. You can see that I had to cut a hole large enough for the jack to clear but I was a little off so i used a dremel to ream it out

.
Wiring:
here you can see the panel jack wiring into the fan splitter which is 1 to 3 splitter. i just cut off an old fan plug then spliced it to the panel jack cables.
This next part is a little more complicated so opted to purchase some fan plugs/pins and crimped my own wires. I also had to use Two 3 wire fan extensions.
From the splitter to the fan extension wires you can see from the pics you have to make sure you wire the voltage directly to the fans then run the speed sensor wire to the motherboard. You also need to make sure that the ground from your fan power is tied to the motherboard and your fans othwise your fan speed will not be seen at the switch motherboard.
Since this was a generic fan and a little more noisy than the rest of the Noctua used a Noctua Y cable and a Noctua low noise cable I had from other fans to match the noise output of all 3 Noctua fans.
here is everything tucked away before putting it all back together.
After running it over night here is my temps and sound

. The PSU is higher than I like but I might adress that later and maybe just put another 60mm fan there as well. The sound was taken right at the switch and then less than 3 feet away where my keyboard is and since my sound meter only goes down to 30db min it did not register.

