AIO Pump - 3-pin connection

[jeocho54]

Hi,

I am using a MSI b350 pc mate motherboard (https://asset.msi.com/global/picture/image/feature/mb/Z270/AM4/B350PCMATE/msi-b350_pc_mate-tuning-hero.png) on an am4 socket with a Coolermaster masterliquid ml240r aio cooler and I have a 2 cables running from my pump. One is a 4-pin RGB connection which I already plugged in but the other is a 3-pin connection that connects to the motherboard powering the pump itself. Where would I connect this 3-pin connection for the pump because I don't have an a 3-pin connection anywhere on my motherboard, or a CPU_OPT header.

Help would be appreciated

 

[volkgren]

I wish I had bought an AiO when I wanted one so I would know for sure what to tell you. But I do know 3-pin fan connectors plug in to 4-pin fan headers and work just fine, just line the slot up on the connectors.

 

[jeocho54]

But which 4-pin header do I plug it into? I've already got the fans that are mounted onto my 240 radiator for my AIO plugged into the 4-pin CPU_FAN1 header at the top of the motherboard near the ram slots (Reference to where everything on the motherboard is here: https://asset.msi.com/global/picture/image/feature/mb/Z270/AM4/B350PCMATE/msi-b350_pc_mate-tuning-hero.png) so at this stage what would I do?

 

[drea.drechsler]

But which 4-pin header do I plug it into? I've already got the fans that are mounted onto my 240 radiator for my AIO plugged into the 4-pin CPU_FAN1 header at the top of the motherboard near the ram slots (Reference to where everything on the motherboard is here: https://asset.msi.com/global/picture/image/feature/mb/Z270/AM4/B350PCMATE/msi-b350_pc_mate-tuning-hero.png) so at this stage what would I do?

To be honest, it kind of depends. First thing to know is most pumps are DC controlled anyway, not PWM, hence the three pin connector. Like Jeocho says, you can plug it onto a 4 pin PWM header (just observe the key-way) and it will still work, usually at 100%/full speed if it's set to PWM mode. But a pump on an AIO should run at 100%, 12V, full speed anyways. This is because it is (or should be) so quiet it doesn't matter and it assures instant cooling when the processor starts working hard. So this fact gives you many choices.

Using an appropriate adapter you could connect it directly to one of the unused drive connections directly from the power supply. If you've no other controllable headers this leaves the CPU fan header free which should then be used to control the radiator fans. The only bad thing about that approach is it doesn't monitor pump RPM which is good to use for setting an alarm should it stop, assuming your BIOS has that feature.

Most modern BIOS will refuse to turn on if they don't detect an operable fan on the CPU header. So if monitoring the pump is important then use the CPU fan header for the pump but keep it at 100% and put the radiator fans on another header that's controllable. Fans on an AIO are usually noisy at 100% so you will want them on a profile.

You could put the pump on an uncontrollable header that reports RPM but the BIOS probably won't monitor that header and refuse to start if the pump fails.

If you don't have another controllable fan header (many boards don't) then you may have to get an after market fan controller so you can keep radiator and chassis fans at reasonable levels.

Lastly, you can get really gimicky: leave the pump connected direct to the power supply but swap the RPM monitor wire from the pump connector into the radiator fan connector (just remove that wire and tie it back) and let the CPU header monitor RPM on the pump but power and control the radiator fans.

 

[jeocho54]

Is the "CPU fan header" you're talking about the one near the top right of the motherboard, slightly on the left to the ramslots? If so then don't bother answering that part

So, just to clarify... I should plug my 3-pin pump cable to my "CPU fan header" and my radiator fans to "SYS_FAN1"? And sorry to bring this up now but what do I do with my PUMP FAN1 header on the very top right of my motherboard?

Thanks.

 

[CountMike]

Pump on that cooler should be connected to any fan header that can be set to work without regulation as pump needs to run full speed all the time. Since there's already "PUMP FAN1" header, connect it there and make nonadjustable. Radiator fans to CPU_Fan of course.

 

[JMaiuri]

I am having the exact same issue. The problem arises that the three pin pump connector is a moulded connector that will absolutely not fit onto any four pin headers. You would have to cut that connection apart and put N actual four pin connector on the pump cable.