HELP! Chassis fan running at a crazy rpm

[aceslinger]

HELLO GUYS

I have just completed my first PC build and i have noticed that one of my chassis fans spins at an rpm of 19640 for a split second and then it fluctuates between 1000 and 2000 rpm at idle. My other fan stays at around an rpm of 1100.Is the fan faulty? And is 1100 rpm too high for idle anyway?
i have the s340 case.

Thanks in advance

Update:

Thanks Nine Layer Nige and Plumboby, i really do appreciate the reply's.

The fan connectors on the mobo are 4 pin, and the fans are 3 pins.
i have the asus z170 extreme4 mobo and i have the fans connected to slot 1 and 3. i tried connecting the fans to different slots but it was the same.

Update:

I have managed to change the fan speed manually using open hardware monitor. One the fan is running at 600 rpm and the other is 500 rpm. The large fluctuations have stopped as far i can tell and the CPU (I5 6600K) temperature is around 24-25 degrees.
The system temperature is 27 degrees, is this normal? And have i affected the motherboards ability to regulate the CPU and GPU temperatures by manually changing the fan speeds? will the fan speeds increase in accordance with increasing load or will they same at the set speed?

Thanks for all your help again )

Update:

*sigh* It reverts back to its old ways upon restarting the PC. Open Hardware monitor doesn't save the changes. Are there any other software's that control fan speed?

 

[Nine Layer Nige]

19640 rpm !! a case fan would rip itself to shreds at 19640 rpm
Where on the mobo do the fans plug into , as in, how many pins on the connectors ?
1100 rpm is too fast for idle. Should be more like 100rpm

 

[Plumboby]

faulty fans be the issue i have had that issue before

 

[aceslinger]

faulty fans be the issue i have had that issue before

Thanks for the reply
Did you have the s340 case aswell? if so, did you replace both of your fans?

 

[aceslinger]

19640 rpm !! a case fan would rip itself to shreds at 19640 rpm
Where on the mobo do the fans plug into , as in, how many pins on the connectors ?
1100 rpm is too fast for idle. Should be more like 100rpm

Thanks for the reply
is my motherboard the problem? or the fans?or the cables?

 

[Nine Layer Nige]

Page 93 Chapter 4.6 of your user manual seems to indicate some fan settings that solve your problem

 

[aceslinger]

Page 93 Chapter 4.6 of your user manual seems to indicate some fan settings that solve your problem

which settings are you referring to? When i alternate between the different fan modes nothing changes. It is currently on quiet and it sounds exactly the same as standard.

 

[Nine Layer Nige]

Seems that you need fans with 4 pins connections

 

[aceslinger]

Seems that you need fans with 4 pins connections

Speedfan has managed to solve the problem

Thanks for all the help