Huge temperature drops from flipping switch into vertical orientation?

[Dalis]

Hi all – I've been reading reports of how overly hot switches cool down dramatically if you flip them into a vertical orientation. Typically it's a 10+° C drop for a device that was running in the 60s or 70s. Ubiquiti example here.

Have you observed this? What explains the drop in temps? With those overheating Ubiquiti POE switches I don't think they have any vents on the sides. If you prop them up such that one of the sides is now on top, I don't understand why it would change the thermal situation.

The heated air wants to rise, but without vents on top, or on the sides which become the top, I don't see how the heat escapes. It would make a lot of sense to design devices with a vertical orientation and top vents, with heatsinks aligned for vertical airflow, but that's not the Ubiquiti design. What gives?

Thanks.

 

[pcmoore]

Without knowing anything about the switch in question, could it be a simple matter of when you reorient the switch the temperature sensor is now positioned *below* the main heat source such that the hot air doesn't come into as much contact with the sensor?

 

[J--]

I'm betting some people moved it out of the rack too to run it vertically.