[SOLVED] Liquid Cooler - Pump Fan Control

[mmtoller]

Hey!

Recently I got a Cooler Master Liquid Cooler ML240L V2 ARGB and it is attached to MOBO MSI Maz Z490 Tomahawk.
In BIOS > Hardware Monitoring Menu, the CPU Fan (4-Pin PWM Connector - obviously) is set to Smart Fan Mode ON by default. So far so good.
My question is related to the PUMP FUN settings... it is a 3-pin connector (DC) and the Smart Fan Mode is OFF by default, and the FAN Speed in both BIOS and WINDOWS is 2400 rpm. When I set the Smart Fan Mode ON, then the sliders of Temp/RPM shows up, and then, the PUMP FAN speed goes to ZERO in BIOS. I didn't tested it with that setup further on windows log on, because i am afraid of some damage - yeah, I am ignorant on this subject. Maybe the RPM would increase automatically... IDK.

Should I leave the Smart Fan Mode OFF by default? I am not expert in this subject and I don't want to set anything manually... but I am looking for a stable configuration, with performance, low temps, etc.

Thx!

 

[Lutfij]

Happy New Year!

Might I ask what BIOS version you're on for your motherboard at this moment of time? Also, does the behavior you explained happen with the other fan headers on your motherboard(outside of the PUMP_FAN header)? I own the same AIO and I've manually set the fan speeds, the pump been running as is without any adjustments.

 

[mmtoller]

BIOS Ver E7C80IMS.1CO - 06/11/2022 and yes, the System Fans are working fine.
Acctualy I don't know if there is a real problem with the fan. To be honest, I am just looking for a efficient setup.

Minutes ago I execute some tests and observations on PUMP Fan screen:

1st step - Smart Fan Mode Off
Speed ~2400rpm
CPU Temp 31ºC/87ºF (steady)

2nd step - Smart Fan Mode On
Speed 0rpm
After a couple minutes, CPU Temp reached 48ºC/118ºF.
When the CPU reached ~55ºC/131ºF, the fan started to spin fast and the temps got back to around 35ºC/95ºF.
After that, the fan stoped again and the temps started to rise again to ~55ºC/131ºF and the cycle repeat over and over again.

My main question is, should I set the PUMP FAN to Dynamic and submit/give in the CPU to these temps changes or should I set the PUMP Fan to Static, to have steady rpm and a steady temp? Important to mention, this tests were made on BIOS only, only, and off course, a practically idle system.

Here some screenshots
https://1drv.ms/u/s!Ai3L2ceG05PKoEM-JwuqzImwTGWC?e=IZYRgd

Sorry for any english mistake or anything that could disturb the reading comprehension.

 

[candymancan]

Keep smart fan mode on, you dont want your pump to sit at 0% and let the water sitting still and get warm inside the block "it wont hurt it" but i believe it should always be flowing even a little. Set it to manual if you can actually and adjust the sliders or graph to the temps and % you want the "fan" aka pump to run at.. Like for me i on my 5800x 3d and x570 board i set the OPT fan " which is where my pump is connected" to run at 40% at 38c, which is about 1000 rpm "quiet and barely runs" and once my cpu gets to 70c i set it to run 100%. This also curves meaning itll go to say 60% at 55 then 70% at 60c and so forth.

This way the system is quiet as my thermaltake ring fans are also set to this, so my fans and pump run off the same profile.. So theyre at 1000rpm with the pump, and once the cpu hits 70c it jumps to 1700 rpm for the fans and like 3200 for the pump.. "max speeds" I did this because my 5800x 3d gets to 80-90c gaming and my case gets really warm inside with it set to "quiet" mode.. aka 50%.. changing this profile manually allowed everything to run 100% at 70c, and now my cpu stays around there

 

[mmtoller]

Yeah buddy, I decided to use the smart fan mode ON for the pump fan, but some adjustments on the sliders were needed. Anything below 40% of fan voltage wasn't doing the fan to spin. So, for the pump fan the first of four stages is a bit higher than the first stage for the CPU fan, the other 3 are equal... the same % speed for the same temperature.
The case fans are set to the default values.

I'll observe the temps for the next days.

PS: I´ve read in some forums that coolermaster recommends full speed (12 volts) for pump fan, no matter of the cpu and system temps.

 

[Paperdoc]

This is something NOT mentioned often in AIO instructions, and I don't understand why it is omitted. When you connect a PUMP to a fan header that header should NOT be set to "Auto" detect the fan type.

A 3-pin fan connected to a header using the new 4-pin PMW Mode of speed control will always run full speed. To get its speed under control you have to set the header to the older Voltage Control Mode, (aka DC Mode). Many mobo fan headers now have those two Mode settings plus a third called "Auto". In that Mode, when the system starts up it starts the fan at full speed in PWM Mode, then tries to reduce the speed with the PWM signal. If that does NOT reduce the fan speed, it assumes it must be an older 3-pin fan and changes to Voltage Control Mode and thereafter sends out reduced Voltage to the fan for speed control.

In most AIO systems the PUMP is designed to run full speed all the time, and control of cooling is done solely by changing the rad FAN speeds. So they use a "trick" of this fan type situation. The PUMP is wired just like a 3-pin fan, so IF that is plugged into a header using the new PWM Mode, it will run full speed all the time, as intended. BUT if you leave that header in "Auto" detect mode, it WILL find out that it has a 3-pin "fan" (actually, a pump) connected and WILL switch to the older Voltage Control Mode so it can slow that pump down. That is exactly what you do NOT want!! You NEED to set that header (where the PUMP is attached) to PWM Mode, even though the connection to it has 3 pins.

On your mobo, you have both a CPU_FAN header and a PUMP_FAN1 header. With your AIO system the PUMP should be plugged into the PUMP_FAN1 header and it MUST be set to PWM Mode, NOT to DC. IF there is an option for that header to set for either Pump or Fan use, set it to PUMP. Do NOT try to set its speed to anything less than full speed. The two rad FANS should be connect (via the Splitter supplied) to the CPU_FAN header and that header also should be set to PWM Mode because the fans are PWM type. That header WILL alter those fans' speeds according to the CPU's internal temperature.

 

[mmtoller]

Hey Paperdoc, thanks for your reply!

Yeah, after some readings I've decided to set the PUMP "FAN" fom dynamic (smart fan mode, with sliders stuff) to steady speed (full), desabling the smart fan mode.
Something in your statement is intriguing me, because the PUMP "FAN" is set as DC, not PWM and even so it's running 2400rpm all the way, independent of CPU temp. Considering this, is really necessary to set to PWM to reach the same result?

 

[Paperdoc]

Well, setting to PWM Mode means that the pump itself can NOT respond to ANY attempt to reduce its speed, since it cannot accept or use the PWM signal. Thus it can only operate at full speed since its power supply from Pin #2 will always be 12 VDC in that MODE. On the other hand, irrespective of which MODE you set for that header, IF you set it to NOT control speed automatically and send out a constant FULL speed signal, the pump certainly will run full speed.

 

[mmtoller]

Right! Well, for safety, I will set ir to PWM in BIOS. Thank you so much!

Have a great upcoming weekend!

 

[Paperdoc]

You're welcome, and thanks for Best Solution.