PSU fan running at max speed all the time

[ghunt81]

I have an HP Z240 that I have not used in over a year, I recently got it back out and set it up. Only change I made was I added a 1 TB HDD from another computer as a slave.

Since the first time starting it up after doing this, all the fans on it are running all the time. I don't know if they are all running at max speed but the PSU fan definitely is- I downloaded HP Performance Advisor and it shows my PSU fan running at a constant 3800 RPM. All temps look normal, CPU is 30°C, chassis temp is 20°C.

I updated the BIOS and it did not fix it- what is the issue? Did adding the other HDD cause this?

[DGroves]

while i own both z240 versions (SFF/Tower) i'm not near them at this time so it's possible i'm wrong

but i suspect they use a ambient air temp sensor somewhere that has failed

or a fan is no longer running or running slowly

in the z8x0 and z6x0 systems the sensor was in the main power on off cable

however these z240 systems may have it located in the power supply itself

you can check the bios to see if it shows the aiment air temp and if 0 that's your problem

use the  HP performance advisor it should show this sensor

https://www.hp.com/us-en/workstations/performance-advisor.html

3rd party apps like aida64 will also show this sensor

check the service guide for help

https://h10032.www1.hp.com/ctg/Manual/c04897695.pdf

[ghunt81]

So I have looked at the BIOS previously and was unable to find anything useful in the BIOS. Do you know where it would be listed in the BIOS?

HP performance advisor shows a chassis air temp, but I do not see an ambient air temperature or sensor listed anywhere in the sensors. Chassis temp shows as 19°C currently.

Maybe I just need to replace the power supply and see if that helps.

[DGroves]

think about it, chassis temp = ambient temp in other words the air inside the chassis is the ambient temp got it?

the case fan will also spin up if the cpu temp is high

[ghunt81]

OK so, if the chassis air temp is reading normal and the CPU is only showing around 30°C, then what do I need to do?

[DGroves]

CHECK/REPLACE THE CMOS BATTERY some motherboards act strange when the cmos battery has failed or is low

[ghunt81]

Bought a refurbished power supply for $25 and that fixed the problem 👍