Fan Spins ONLY after being spun

[MrdcThMrlc]

Hello,

I recently bought a Noctua NF-P12 fan. I mounted it on my case (on the top) and it doesn't start spinning on it's own. After I give it the slighest of a spin ( I don't even need to make it spin, just touch it a little) it starts working normally. What's the problem here?
Thanks in advance!

 

[impsquared]

Some bearings don't work that well vertically. you can also try re-lubricating your fan (a few drops under the sticker).

 

[nukemaster]

If your board has fan Control(and the fan is connected to it), try to adjust it.

Many fans will not start if the voltage is too low.

Do not try to lubricate a new fan because it has a warranty for a reason(I am almost sure Noctua has the back sealed as well). I have personally run Noctua fans in both orientations without issues(so far). Many sleeve type bearings do not like being run horizontally(Top of bottom of the case. Some will be louder or have a shorter life.).

 

[photonboy]

Hi,
You need to adjust the motherboard FAN PROFILE to give it sufficient voltage to start.

It's a variable, PWM fan. I'm not sure if it will work with a 3-pin (voltage-only) source but if so that may be your problem.

Also, if you used the Low Noise Adapter you could be putting the voltage too low.

So...
If that doesn't help, then tell us EXACTLY how it's setup (motherboard name if plugged into motherboard, if not WHERE did you plug in the fan).

Again, I believe that fan needs:
a) PWM (4-pin) motherboard or fan controller, and
b) Motherboard fan Software must be setup properly (RPM vs Temperature).

Most motherboards have a BIOS/UEFI fan control software that you can use that may or may not do the job. If you use a Windows solution (see motherboard support site) such as Asus Thermal Radar then the UEFI solution kicks in first, then once Windows boots up the software you installed supersedes it.

*I have my top-rear fan assigned to the CPU sensor so as my CPU gets hotter my CPU and the top-rear fan also spin faster.

 

[MrdcThMrlc]

If your board has fan Control(and the fan is connected to it), try to adjust it.

Many fans will not start if the voltage is too low.

Do not try to lubricate a new fan because it has a warranty for a reason(I am almost sure Noctua has the back sealed as well). I have personally run Noctua fans in both orientations without issues(so far). Many sleeve type bearings do not like being run horizontally(Top of bottom of the case. Some will be louder or have a shorter life.).

Hi,
You need to adjust the motherboard FAN PROFILE to give it sufficient voltage to start.

It's a variable, PWM fan. I'm not sure if it will work with a 3-pin (voltage-only) source but if so that may be your problem.

Also, if you used the Low Noise Adapter you could be putting the voltage too low.

So...
If that doesn't help, then tell us EXACTLY how it's setup (motherboard name if plugged into motherboard, if not WHERE did you plug in the fan).

Again, I believe that fan needs:
a) PWM (4-pin) motherboard or fan controller, and
b) Motherboard fan Software must be setup properly (RPM vs Temperature).

Most motherboards have a BIOS/UEFI fan control software that you can use that may or may not do the job. If you use a Windows solution (see motherboard support site) such as Asus Thermal Radar then the UEFI solution kicks in first, then once Windows boots up the software you installed supersedes it.

*I have my top-rear fan assigned to the CPU sensor so as my CPU gets hotter my CPU and the top-rear fan also spin faster.

The mobo is an MSI Z97S SLI Krait Edition, and it's pluged into the system fan. In the mobo it's a 4-pin slot but the fan cable is a 3-pin one (I have one 3-pin cpu fan plugd also into a 4-pin slot and this problem doesn't happen). I use the MSI Command Center but I can't changed the speed of any fans there, except one of the CPU fan (the only one which as a 4-pin cable). I also tried changing speed in BIOS, but same thing. I can only change the speed of the one 4-pin CPU fan. The noctua fans, according to the manual, have 3 RPM modes, that are controlled by which cable adapter you use (all these adapters are 3-pin also). I'm using the slowest one, which is the Ultra-Low Noise, that runs at 600rpm.

 

[Paperdoc]

The three SYS_FAN headers on your mobo may have 4 pins, but they actually appear (according to the labels on p. 1-22 of it manual) to be operating in Voltage Control Mode only, which is exactly what is needed to power and control 3-pin fans. HOWEVER, you have caused your own problem.

Those "cable adapters" that come with your fans are NOT supposed to be used when you connect them to a mobo header that automatically control a fan's speed. They are used only when you connect the fans directly to a fixed 12 VDC supply from the PSU and have no other way to control the fan's speed. Each adapter is a small resistor that reduces the voltage going to the fan, so using them with a fixed 12 VDC supply allows you to reduce their speed. BUT you are connecting your fans to mobo SYS_FAN headers and they control the speed of their fans by reducing the voltage sent out. By using those adapters in addition to the reduced voltage from the mobo header, you are supplying those fans with a voltage so low that at least one of them cannot start up without help.

Remove all of those those "low noise" adapters from the leads to your fans. See your manual, p. 3-28. For each of your fans (3 SYS_FANs and the CPU_FAN), ensure that they are set to use the "Smart Fan Mode". Then for each, ensure that the "All Set Default" choice has been chosen. When done, back out of BIOS Setup and don't forget to SAVE and EXIT. What the mobo fan headers will do when set this way is to check constantly the temperatures measured by two sensors (one inside the CPU chip, and one on the mobo) and adjust their respective fans' speeds to make sure the actual temperatures are what they should be. If your system is running cool, it will slow the fans down and they will be quieter; if temperatures rise, the fans will speed up. You do NOT want to defeat all that by forcing the fans to be slow and quiet all the time, because then you are preventing proper cooling of your system.

I'm confused about your CPU cooling fans. You seem to say you have one 4-pin fan on the CPU plugged into the mobo CPU_FAN header, PLUS a second fan - this one 3-pin type - cooling the CPU and plugged into a "4-pin slot" you don't identify. Is that correct? Your CPU_FAN headers DO use PWM Mode for control (and only that mode I think), so each can control a 4-pin fan properly. But if you connect a 3-pin fan to such a header (in your case, either CPU_FAN1 or 2) there is no speed control - that 3-pin fan can only run at full speed all the time. So, do you have a 3-pin fan plugged into one of those CPU_FANn headers? If you do, I expect that fan's speed is NOT ever going to be less than full speed. If that is the case, this is the ONE place where you could afford to use one of those "Low Noise Adapters" in the cable to that 3-pin fan, since it is receiving a fixed 12 VDC supply from a mobo header that is trying to use PWM Mode to control a 4-pin fan that isn't.

 

[MrdcThMrlc]

The three SYS_FAN headers on your mobo may have 4 pins, but they actually appear (according to the labels on p. 1-22 of it manual) to be operating in Voltage Control Mode only, which is exactly what is needed to power and control 3-pin fans. HOWEVER, you have caused your own problem.

Those "cable adapters" that come with your fans are NOT supposed to be used when you connect them to a mobo header that automatically control a fan's speed. They are used only when you connect the fans directly to a fixed 12 VDC supply from the PSU and have no other way to control the fan's speed. Each adapter is a small resistor that reduces the voltage going to the fan, so using them with a fixed 12 VDC supply allows you to reduce their speed. BUT you are connecting your fans to mobo SYS_FAN headers and they control the speed of their fans by reducing the voltage sent out. By using those adapters in addition to the reduced voltage from the mobo header, you are supplying those fans with a voltage so low that at least one of them cannot start up without help.

Remove all of those those "low noise" adapters from the leads to your fans. See your manual, p. 3-28. For each of your fans (3 SYS_FANs and the CPU_FAN), ensure that they are set to use the "Smart Fan Mode". Then for each, ensure that the "All Set Default" choice has been chosen. When done, back out of BIOS Setup and don't forget to SAVE and EXIT. What the mobo fan headers will do when set this way is to check constantly the temperatures measured by two sensors (one inside the CPU chip, and one on the mobo) and adjust their respective fans' speeds to make sure the actual temperatures are what they should be. If your system is running cool, it will slow the fans down and they will be quieter; if temperatures rise, the fans will speed up. You do NOT want to defeat all that by forcing the fans to be slow and quiet all the time, because then you are preventing proper cooling of your system.

I'm confused about your CPU cooling fans. You seem to say you have one 4-pin fan on the CPU plugged into the mobo CPU_FAN header, PLUS a second fan - this one 3-pin type - cooling the CPU and plugged into a "4-pin slot" you don't identify. Is that correct? Your CPU_FAN headers DO use PWM Mode for control (and only that mode I think), so each can control a 4-pin fan properly. But if you connect a 3-pin fan to such a header (in your case, either CPU_FAN1 or 2) there is no speed control - that 3-pin fan can only run at full speed all the time. So, do you have a 3-pin fan plugged into one of those CPU_FANn headers? If you do, I expect that fan's speed is NOT ever going to be less than full speed. If that is the case, this is the ONE place where you could afford to use one of those "Low Noise Adapters" in the cable to that 3-pin fan, since it is receiving a fixed 12 VDC supply from a mobo header that is trying to use PWM Mode to control a 4-pin fan that isn't.

You are correct! I removed the low-noise adapter and it's working as usual! Is it better to have it connected directly to the PSU with the low-noise adapter or leave it like this and control the fans via Command center and/or let it do the smart mode control?
When it comes to my second CPU fan, it's connected to a 4-pin CPU_FAN2 slot. I can control all fans now via the Command center now except this fan. So there isn't any way I can control this fan via software or smart mode? Is it smarter to just plug-in this second CPU fan into a system fan header instead and let it be controled by the smart mode?

 

[Paperdoc]

For all your case fans and for the main 4-pin CPU cooling fan, I believe it is best to connect to the mobo appropriate headers and let its automatic control system do the job for you. Command Center may allow you to customize what that control system does for each fan. However, unless you know you need something special, the default settings may be based on more detailed knowledge of the cooling needs than you have yourself.

The issue with your second CPU cooling fan is that it is a 3-pin design connected to a CPU_FAN2 header that can only use PWM Mode for control. That mode cannot control any 3-pin fan, so it will always run at full speed. There are three things you can do about that: (a) replace the fan with a 4-pin model that CAN be controlled in that manner; (b) buy an adapter and connect it instead to a PSU power output (either 4-pin Molex or SATA power), which also will run it at full speed all the time; or, (c) leave it plugged into the CPU_FAN2 header which cannot control it, but use one or two of the Low Noise Adapters to reduce its speed to some fixed lower speed (it still won't be under automatic control, but it will run slower with less noise and less cooling for your CPU).

 

[MrdcThMrlc]

For all your case fans and for the main 4-pin CPU cooling fan, I believe it is best to connect to the mobo appropriate headers and let its automatic control system do the job for you. Command Center may allow you to customize what that control system does for each fan. However, unless you know you need something special, the default settings may be based on more detailed knowledge of the cooling needs than you have yourself.

The issue with your second CPU cooling fan is that it is a 3-pin design connected to a CPU_FAN2 header that can only use PWM Mode for control. That mode cannot control any 3-pin fan, so it will always run at full speed. There are three things you can do about that: (a) replace the fan with a 4-pin model that CAN be controlled in that manner; (b) buy an adapter and connect it instead to a PSU power output (either 4-pin Molex or SATA power), which also will run it at full speed all the time; or, (c) leave it plugged into the CPU_FAN2 header which cannot control it, but use one or two of the Low Noise Adapters to reduce its speed to some fixed lower speed (it still won't be under automatic control, but it will run slower with less noise and less cooling for your CPU).

Thank you very much! I will used a Low-noise adapter to keep it at a reasonable rpm at all times!

 

[Paperdoc]

You're welcome, and thanks for Best Solution.