Question AIO fans need help to start spinning

[Orangepistachio]

New prebuilt PC 1mo old. Noticed AIO fans were not spinning when under load, and system fcrashed once likely due to CPU overheat (radiator was hot). Sometimes one AIO fan turns on, sometimes the other, sometimes both, and sometimes neither. Fan curves are never set to 0. If I flick it with my finger like in the video, the fans will kick in but looks like the back spins slower than the front.

Specs:
Ryzen 7800x3d
Gigabyte B650M C V-2:
AIO Cooler: ?cyberpower stock cooler
3 front fans connected to sys_fan1 via daisy chain splitter.
2 AIO fans and back fan connected to sys_fan2 via daisy chain splitter. AIO pump connected to cpu_fan

View: https://youtube.com/shorts/QWREKBHQGDM?si=L9JmdFGmuO_bNZ5z

 

[drivinfast247]

Buy a better cooler or set fans to 100%.

 

[Paperdoc]

There is a much better way to connect your AIO system that will give you proper control of the rad fans. Right now they are being controlled according to a temperature sensor on the mobo. They SHOULD be controlled by the sensor inside the CPU chip, and that is done ONLY when you connect the rad fans to the CPU_FAN header.

How to do that? You will use a small "trick" of pump design and you will need to buy a simple fan SPLITTER like this

https://www.amazon.com/Gavemi-Splitter-Computer-Cooling-Splitter/dp/B0CRQXX21W/ref=sr_1_10?crid=2ZAVR0W60EDBX&dib=eyJ2IjoiMSJ9.RIe0_ceToDT3fDg7nh4HA9t2OSw7wwyUL3ouhfDVUbYBWvmAsjV6AhDa3Jafj3Wv0FPl8cKmi-Eqad0iWcyR5aF4ntmWRXONFNuTzHDSdUTtB6SBYciL_5MCBvjoS6qMs30w7er88yP7uTcmdgkzGxCpiLaXBCFUyiyxDy8k8mMLJIuLPP9gxJ9eclLmvXBWAvVSU8QmQx29qbenC0-kgpnjr4MncySCHktouZPlR4g.aaleK4hWqN_h_tJ8B7zLZsePz7RxoCGcuTraK4X2Q5w&dib_tag=se&keywords=fan+splitter&qid=1721014683&sprefix=fan+splitter,aps,102&sr=8-10&th=1

That's a 2-pack (you need only 1) of 4-pin Splitters with THREE outputs. NOTE that this device has one input "arm" with a female connector to go to the CPU_FAN header and three male outputs for pump and fans and NO other connections. Do NOT buy a HUB - it would have similar "arms" but ALSO a third type that must plug into a SATA power output connector from the PSU.

NOTE in the Splitter that only ONE of the male outputs has all FOUR pins in it. You MUST plug the PUMP into that output so that its speed signal is sent back to the header. Plug the two rad fans into the other two.

If you do not have it yet, get the BIOS Setup manual for that mobo here

https://download.gigabyte.com/FileL...e_0104.pdf?v=cfbe0375700835184b0adf38304d004b

Once the Splitter is installed, you should go into BIOS Setup immediately on start-up. See the manual on p. 2 to get in there, then press F6 to get to the Smart Fan menu - see p. 6. On this screen at upper left select the CPU_FAN header. Set up options this way;


Fan Speed Control Normal
Fan / Pump Control Mode to PWM, not to Auto or Voltage
Fan / Pump Stop to DISabled so it never stops
Fan / Pump Fail Warning to ENabled so you WILL get a warning if the pump ever fails

When all are done, use Esc back to Main Menu, then F10 to reach the Exit Menu (p. 25) There choose Save and Exit Setup to save your settings and reboot.

When you connect those items this way, here is what happens. Power and control of the Pump and both rad fans is done by the CPU_FAN header using as its guide the temp sensor inside the CPU chip. Of these three, only the PUMP can report its speed to the header so you can "see" it; the two fans' speeds will never be seen anywhere but they will be controlled automatically by the header. The header ALSO will monitor the speed signal from the pump for NO signal indicating pump failure. If that ever happens you will get a prominent warning on your screen and likely in a short time the system will shut down your system to prevent overheating of the CPU due to NO cooling. In the AIO system, the critical item to monitor for such failure is the pump, not the rad fans. But since the fans' speed cannot be monitored for failure, from time to time YOU should just look and verify they both are working.

This all works by using an oddity of the pump. It is designed electrically just like an older -3-pin fan, so when provided with power and control signals intended for a 4-pin modern fan it cannot slow down - it always runs full speed. That is exactly what the AIO system wants. ALL control of CPU cooling is done by varying the speeds of only the rad fans.

When using a Splitter to connect more than one fan to a header, one must check the max current consumed by each item connected. In this case with no specifications provided we can make educated guesses. Those rad fans are common types that consume 0.10 to 0.25 A max per fan. A common Pump can consume 0.2 to 0.5 A. The total is certainly less than 1 A. The manual say the max capacity for its CPU_FAN header is 2.0 A, so we have NO problem there.

This should ensure that your AIO system functions properly with the pump running full speed always, the two rad fans never stopping but changing their speeds according to CPU temperture, and failure monitoring of the pump in place.

 

[Orangepistachio]

There is a much better way to connect your AIO system that will give you proper control of the rad fans. Right now they are being controlled according to a temperature sensor on the mobo. They SHOULD be controlled by the sensor inside the CPU chip, and that is done ONLY when you connect the rad fans to the CPU_FAN header.

How to do that? You will use a small "trick" of pump design and you will need to buy a simple fan SPLITTER like this

https://www.amazon.com/Gavemi-Splitter-Computer-Cooling-Splitter/dp/B0CRQXX21W/ref=sr_1_10?crid=2ZAVR0W60EDBX&dib=eyJ2IjoiMSJ9.RIe0_ceToDT3fDg7nh4HA9t2OSw7wwyUL3ouhfDVUbYBWvmAsjV6AhDa3Jafj3Wv0FPl8cKmi-Eqad0iWcyR5aF4ntmWRXONFNuTzHDSdUTtB6SBYciL_5MCBvjoS6qMs30w7er88yP7uTcmdgkzGxCpiLaXBCFUyiyxDy8k8mMLJIuLPP9gxJ9eclLmvXBWAvVSU8QmQx29qbenC0-kgpnjr4MncySCHktouZPlR4g.aaleK4hWqN_h_tJ8B7zLZsePz7RxoCGcuTraK4X2Q5w&dib_tag=se&keywords=fan+splitter&qid=1721014683&sprefix=fan+splitter,aps,102&sr=8-10&th=1

That's a 2-pack (you need only 1) of 4-pin Splitters with THREE outputs. NOTE that this device has one input "arm" with a female connector to go to the CPU_FAN header and three male outputs for pump and fans and NO other connections. Do NOT buy a HUB - it would have similar "arms" but ALSO a third type that must plug into a SATA power output connector from the PSU.

NOTE in the Splitter that only ONE of the male outputs has all FOUR pins in it. You MUST plug the PUMP into that output so that its speed signal is sent back to the header. Plug the two rad fans into the other two.

If you do not have it yet, get the BIOS Setup manual for that mobo here

https://download.gigabyte.com/FileL...e_0104.pdf?v=cfbe0375700835184b0adf38304d004b

Once the Splitter is installed, you should go into BIOS Setup immediately on start-up. See the manual on p. 2 to get in there, then press F6 to get to the Smart Fan menu - see p. 6. On this screen at upper left select the CPU_FAN header. Set up options this way;


Fan Speed Control Normal
Fan / Pump Control Mode to PWM, not to Auto or Voltage
Fan / Pump Stop to DISabled so it never stops
Fan / Pump Fail Warning to ENabled so you WILL get a warning if the pump ever fails

When all are done, use Esc back to Main Menu, then F10 to reach the Exit Menu (p. 25) There choose Save and Exit Setup to save your settings and reboot.

When you connect those items this way, here is what happens. Power and control of the Pump and both rad fans is done by the CPU_FAN header using as its guide the temp sensor inside the CPU chip. Of these three, only the PUMP can report its speed to the header so you can "see" it; the two fans' speeds will never be seen anywhere but they will be controlled automatically by the header. The header ALSO will monitor the speed signal from the pump for NO signal indicating pump failure. If that ever happens you will get a prominent warning on your screen and likely in a short time the system will shut down your system to prevent overheating of the CPU due to NO cooling. In the AIO system, the critical item to monitor for such failure is the pump, not the rad fans. But since the fans' speed cannot be monitored for failure, from time to time YOU should just look and verify they both are working.

This all works by using an oddity of the pump. It is designed electrically just like an older -3-pin fan, so when provided with power and control signals intended for a 4-pin modern fan it cannot slow down - it always runs full speed. That is exactly what the AIO system wants. ALL control of CPU cooling is done by varying the speeds of only the rad fans.

When using a Splitter to connect more than one fan to a header, one must check the max current consumed by each item connected. In this case with no specifications provided we can make educated guesses. Those rad fans are common types that consume 0.10 to 0.25 A max per fan. A common Pump can consume 0.2 to 0.5 A. The total is certainly less than 1 A. The manual say the max capacity for its CPU_FAN header is 2.0 A, so we have NO problem there.

This should ensure that your AIO system functions properly with the pump running full speed always, the two rad fans never stopping but changing their speeds according to CPU temperture, and failure monitoring of the pump in place.

Thank you so much for your reply! I got the fan splitter and configured it as suggested; the pump fan connector I have is only 3 pin, but I plugged this into the single 4 pin male connector anyways, and the 2 rad fans into the 3 pin spots. I unfortunately am having the same issue - sometimes one fan will start spinning, sometimes the other, sometimes neither and sometimes both. I can see it trying to start when I boot, but it usually won't continue spinning until I give it a flick. I don't believe this is a software issue, because the Gigabyte fan software in BIOS (and the corresponding program in windows) detects the fans spinning at a certain RPM, however upon physical inspection they are in fact not moving. I removed the actual fan blade from the bearing and re-inserted, but no luck. They seem to spin very freely when I spin them with power off... The machine is still under warranty so I will likely have to send in my PC to try and have them fix it or hopefully replace the fans entirely unless you have other suggestions.

 

[Zerk2012]

Thank you so much for your reply! I got the fan splitter and configured it as suggested; the pump fan connector I have is only 3 pin, but I plugged this into the single 4 pin male connector anyways, and the 2 rad fans into the 3 pin spots. I unfortunately am having the same issue - sometimes one fan will start spinning, sometimes the other, sometimes neither and sometimes both. I can see it trying to start when I boot, but it usually won't continue spinning until I give it a flick. I don't believe this is a software issue, because the Gigabyte fan software in BIOS (and the corresponding program in windows) detects the fans spinning at a certain RPM, however upon physical inspection they are in fact not moving. I removed the actual fan blade from the bearing and re-inserted, but no luck. They seem to spin very freely when I spin them with power off... The machine is still under warranty so I will likely have to send in my PC to try and have them fix it or hopefully replace the fans entirely unless you have other suggestions.

Return the PC it's not your problem.
Put it back like it was and give them the crap back.
I would probably ask for a full refund and find a reputable seller or build your own.
A prebuilt PC should be fully tested and stress tested yours was neither.

 

[Paperdoc]

OP, re-check the details of how I recommended you configure the options for the CPU_FAN header. What you describe MAY be faulty fans. But it also MAY be that they are being sent a too-slow speed signal, and that should NOT happen if you really have the header set to the Normal default fan curve.

 

[NOR1NCO]

The fan is defective, and the problem is a damaged startup capacitor inside. I suggest returning it to the seller. The reason is that the fan should work as long as it's connected to 12V and GND, regardless of whether there's a PWM signal or not.

 

[Paperdoc]

^ That's a reasonable idea. What is puzzling is that BOTH rad fans do exactly the same thing! That is why I said to verify the type of signal sent out by the CPU_FAN header as determined by its Fan Speed Control configuration setting.

OP, you report that you can see a fan speed in BIOS even though it is not spinning. If you connected it as I said with the rad fans AND the Pump connected to CPU_FAN via a Splitter, then you can "see" in BIOS the speed of ONLY the PUMP. You will NOT see the RAD FAN speeds anywhere! This is because, as I recommended, you connected the PUMP to the ONLY Splitter output that HAS a pin in the #3 position to carry back the speed signal. The two rad fans have no way to send their speed signal anywhere.

 

[Orangepistachio]

@Paperdoc correction, yes I confused which fans it was showing the RPM for - the ones that I see and can configure are the system fans. Regardless, computer is being sent back.

Thank you all again for your help.

 

[Paperdoc]

Good luck! I hope this gets resolved well.