CRS320 PSU fan speed over 5k at 20C

Hi!

I have recently booted up a new CRS320-8P-8B-4S+ which currently is sitting in a rather cold room (below 15C) with 1 PoE-cam connected (802.3at) and it has OK fan speed on all internal fans (750-1100rpm) besides the psu1-fan which is running stable at 5400-5500rpm, even though it is at 20C.

 0  poe-out-consumption  2.1          W   
 1  cpu-temperature      38           C   
 2  fan1-speed           720          RPM 
 3  fan2-speed           1020         RPM 
 4  fan3-speed           750          RPM 
 5  board-temperature1   22           C   
 6  board-temperature2   12           C   
 7  poe-out1-voltage     54.7         V   
 8  psu1-state           ok               
 9  psu2-state           not-present      
10  psu1-power           17           W   
11  psu1-temperature     20           C   
12  psu1-fan-speed       5480         RPM 
13  psu1-input-voltage   241          V

There are no SFP-modules inserted into the unit. The switch is running ROS 7.18.2.

Is this really normal? I cannot see why it would need to be running that fast when there is no need for it, is it possible to affect this? I’ve read on this forum, and other places, regarding high-RPM fans but I haven’t seen anything related to the PSU-fans specifically.

Cheers

This is normal behavior. For most PSU fans ~5k RPM is their minimal operating speed. These are low-resistance fans designed to spin fast with low noise and low power consumption