Hello,
in the product description, it says
The unit has dual redundant power supplies and passive cooling case, so it’s completely silent - for hot environments two redundant fans will automatically keep the system cool if needed.
.
At which Temperature (internal?, Ambient?) will these fans be turned on?
Is this documented anywhere?
Can this be set?
Can this be entirely disabled, as I want to keep the device fanless at all times?
Thank you for Answers
Hi,
with the current RouterOS version the threshold seems to be fixed at 40C. If the CPU or any SFP temperature reaches this mark the fan will kick in until the temperature is lower again.
I would love to have an option to change this threshold, but it seems to be impossible right now.
I have one of these switches running under living room conditions and even at idle the switch reaches this temperature. The result is a running fan every 1-2 minutes for 30 seconds 
An older RouterOS version did not have this threshold at 40C and the switch was running fanless at around 42C under same conditions.
Mikrotik, please add an option to set the fan starting temperature and a bigger hysteresis.
Thank you for your answer.
Thats a shame, I also would have liked this device if it would perform fanless most of the time.
Perhaps someone vom MikroTik can explain, if there are upcoming changes to enable our request 