Pump fan (3pin) reporting 0 rpm in BIOS

[tacchan23]

I am using this Motherboard and AIO cooler:
ID-Cooling Zoomflow 240
- the 2 PWM radiator fans (4pin) are connected trough splitter cable to a PWM connector on the motherboard;
- the Pump (3pin) is connected to another PWM connector on the motherboard;
- the Pump SATA cable is connected to PSU
- the cooler doesn't have USB connector or his own Application to control fans and RGB lights.

MSI MPG Z390 Gaming Edge AC
-when connecting a 3pin Fan to the PWM connector, the fan speed will always be at 100%

I really have almost zero knowledge about this kind of stuff, so maybe my questions are stupid^^
I am wondering why the BIOS report 0 rpm for the Pump (temps are fine under 40 C so I assume the Pump is working fine).
The AIO manual, states "IF you connect the pump 3pin to motherboard, make sure you set 12V for it)" so it seems to not be even required to connect this cable? What's the purpose of the 3pin pump cable then?

Thanks

 

[mwryder55]

Normally the pump on an AIO is connected to the CPU fan connector. Is one of your radiator fans connected to that connector?

 

[tacchan23]

The Motherboard has 2 PWM connectors labeled as CPU_FAN and PUMP_FAN. (they seem to be identical other than the name)
The 2 PWM radiator fans are connected to CPU_FAN while the 3pin pump is connected to PUMP_FAN.

 

[mwryder55]

If you swap the headers do you get the same reading for the pump? Also, if you use a program like HWMonitor does it show zero for the pump?

 

[tacchan23]

If I swap Pump and Radiator Fans connectors, the Pump still reads 0 rpm (while the radiator fans report the correct speed).
HWMonitor and similar apps show zero rpm for the pump too.

Sorry if it's a stupid question and after trying to google a lot I am even more confused... in general, can a 3 pin fan report its speed to the motherboard PWM connector?
If I connect the Pump to a DC connector, it shows about 20000 rpm (whatever voltage I set)

 

[RememberThe5th]

PUMP is not meant to be controlled. it has to run 100% of time, soo connect it to chassis fan and set to 100/max (or to dedicated pump header).
The fans of aio connect to the cpu fan header soo it is automatically controlled by mobo.

For instance my antec 1250 didnt show pump speed.

 

[tacchan23]

PUMP is not meant to be controlled. it has to run 100% of time, soo connect it to chassis fan and set to 100/max (or to dedicated pump header).
The fans of aio connect to the cpu fan header soo it is automatically controlled by mobo.

For instance my antec 1250 didnt show pump speed.

Yes, the AIO manual says that the Pump has to run at full speed.
Just I wonder why it reports 0 rpm and if it's normal to not report the Pump speed... then why this 3 pin connector is even needed? The Pump SATA cable is directly connected to PSU so this should be already enough to run the pump at full speed.

 

[RememberThe5th]

Others also reported that they couldnt see the rpm.
http://www.tomshardware.co.uk/answers/id-3663804/cpu-overheating-aio-pump-working.html