How to connect my case fans properly?

[felix.fainshtein]

Hello
I'm having a real hard time figuring out the fan system on my case and will appreciate some guidance.

Disclaimer!!! I have very little knowledge connector types, port types, ect..and will try to explain what's going on inside my case as well as I can.

I have an antec GX505 steel window case, and I can't get the 3 fans that come with the case to work. From each of those fans is a cable with 3 holes at it's end.
I have an asus h-270 pro mobo with 4 fan ports:
cpu_fan - the cpu fan is already connected to it and working.
cha1_fan
cha2_fan
aio_pump

In addition, I have a switch on top of my case that can be set to HI, STOP or LOW. The visibility of things connected to this switch is very limited, but it looks like there are a bunch of cables that are connected to it:
1. A cable that has 4 rather large silver pins (Molex?) and can connect to the mobo once I use ANOTHER cable that has 4 rather large holes on one end and a 4 pin slot head on the other end to connect to one of the mobo fan ports.
2. A cable that has 3 connection points on it (REAR FAN, TOP FAN, TOP FAN) where each of the cables coming out of the fans can connect to. Each such point seems to have 2 pins on it.

How am I supposed to connect the fans? Each fan directly to a different port? Or, as I am given to understand, I can connect all 3 fans to the cable described above, connect it's other end (using the additional cable) to the mobo and so all 3 fans should work on the same port (kind of like a net of fans with a single connection point, is this correct?). If both are possible, what is the difference between the 2 methods and what should I do in the BIOS program regarding the fans so that all works well?
I have tried connecting all fans individualy to the 3 ports and they all work, but I couldn't get any of them to work when trying to connect them all to the same port.

Thanks a lot!!!!

 

[clutchc]

You are suppose to connect the Molex cable from the fan controller to any Molex from the PSU. That powers the fan controller. You then connect the 3 x fan cables to their matching connectors also coming from the fan controller. (They may be already connected) That way the built-in fan controller will power the 3 fans at low or high speed. Or off.

 

[felix.fainshtein]

You are suppose to connect the Molex cable from the fan controller to any Molex from the PSU. That powers the fan controller. You then connect the 3 x fan cables to their matching connectors also coming from the fan controller. (They may be already connected) That way the built-in fan controller will power the 3 fans at low or high speed. Or off.

So the molex from the fan controller shouldn't connect to the mobo using the addition cable that can connect to the molex from one end, and to the mobo from the other end? (4 pin).

Also, which connection is better? All fans to a the controller or each fan to his own port? And do I need to adjust something in the BIOS? Sorry for all the questions haha..

 

[Paperdoc]

That's right. The adapter unit you talk about is normally used to convert a PSU Molex power output to a different connector such as a 4-pin fan connector.

The three fans in your case may have only two wires from them, each ending in only three holes, right? And they obviously can connect to the case's fan controller module via its three-output cable. Such a fan controller module VERY often is powered by a male 4-pin Molex connector, which is what you describe as cable #1. It must plug into a female connector of the same type that is on the wires coming out of the PSU. It does NOT ever connect to any motherboard header.

This system will allow you to control the speed of your case fans manually, and thus it is up to you to monitor system temperatures from time to time to get used to what speed to set those fans to keep the system cool enough. With that fan system the motherboard can NOT do any control of the fans, nor can it display the speeds of those fans.

There MAY be a way to have the motherboard do automatic control of those case fans. "Automatic control" means that the motherboard constantly checks the temperature inside your case (using a sensor on the mobo) and alters the fan speeds for you to keep the temperature where is should be, no matter what workload you are doing. IF you want to achieve that there are a few pieces of information we need, and maybe a few items you will need.

First, the wires from the fans end in a connector with three holes, so it's female. It MAY be a standard connector for 3-pin fans. 3-pin fans have THREE wires coming from them to the connector - do yours? A standard fan connector has two ridges along one side of it to form a groove down that side. If you look at the 4-pin CHA_FAN headers (two of them) on your mobo, you will see a plastic tongue sticking up beside the first three pins. So a standard 3-pin connector on the end of a fan's wires can plug into those first three pins so that the groove fits over that tongue; the fourth pin is not used. So, do your fans' connectors plug into a mobo header that way? If yes, what you have likely are "standard" 3-pin fans that CAN be controlled by the mobo.

IF you want to do this, the fans will NOT be connected to that case fan controller module at all, and that module will not need a connection to a Molex power output from the PSU. Consider also the length of the fan wires - can they reach to the mobo headers?

If all that says yes, there's still another matter - you have 3 fans but only two CHA_FAN headers. The solution is you need one SPLITTER, like this

https://www.newegg.com/Product/Product.aspx?Item=N82E16812423161&cm_re=coboc_fan_splitter-_-12-423-161-_-Product

You will note that this item is actually for a 4-pin fan system, but you can use it for 3-pin fans, too. Look closely and you will see it has two types of arms. One arm has a female connector that must plug into a mobo CHA_FAN header. The two other arms end in male connectors (with pins) and you plug two fans into them. The Splitter has NO other arm types. Do not buy a HUB. A Hub is different because it also has a third arm type that connects to a power output from the PSU, and you cannot use that with this fan system.

Just an FYI: if you can connect fans to mobo headers, the mobo can show you the speeds of the fans. BUT when you use a Splitter to connect two fans to a single CHA_FAN header, only ONE of those fans' speeds will be shown, and the other ignored. That is not a problem for using these devices.

In your case, OP, I'd suggest using the Splitter to connect both front fans to one CHA_FAN header, and then plug the third fan (at the rear) into the other CHA_FAN header. Do not use the AIO_PUMP header. Of course, the cooling fan for your CPU will be plugged into the CPU_FAN header.

Now, last step(s). Your mobo's CHA_FAN headers each can be configured in BIOS Setup for use either with 3-pin (DC Mode) fans or with 4-pin (PWM Mode) fans. You must set both of those headers to DC Mode in order for them to control your 3-pin fans properly. So, if you want to do this change, post back here for details on how to do that last step. It's not hard.

 

[felix.fainshtein]

That's right. The adapter unit you talk about is normally used to convert a PSU Molex power output to a different connector such as a 4-pin fan connector.

The three fans in your case may have only two wires from them, each ending in only three holes, right? And they obviously can connect to the case's fan controller module via its three-output cable. Such a fan controller module VERY often is powered by a male 4-pin Molex connector, which is what you describe as cable #1. It must plug into a female connector of the same type that is on the wires coming out of the PSU. It does NOT ever connect to any motherboard header.

This system will allow you to control the speed of your case fans manually, and thus it is up to you to monitor system temperatures from time to time to get used to what speed to set those fans to keep the system cool enough. With that fan system the motherboard can NOT do any control of the fans, nor can it display the speeds of those fans.

There MAY be a way to have the motherboard do automatic control of those case fans. "Automatic control" means that the motherboard constantly checks the temperature inside your case (using a sensor on the mobo) and alters the fan speeds for you to keep the temperature where is should be, no matter what workload you are doing. IF you want to achieve that there are a few pieces of information we need, and maybe a few items you will need.

First, the wires from the fans end in a connector with three holes, so it's female. It MAY be a standard connector for 3-pin fans. 3-pin fans have THREE wires coming from them to the connector - do yours? A standard fan connector has two ridges along one side of it to form a groove down that side. If you look at the 4-pin CHA_FAN headers (two of them) on your mobo, you will see a plastic tongue sticking up beside the first three pins. So a standard 3-pin connector on the end of a fan's wires can plug into those first three pins so that the groove fits over that tongue; the fourth pin is not used. So, do your fans' connectors plug into a mobo header that way? If yes, what you have likely are "standard" 3-pin fans that CAN be controlled by the mobo.

IF you want to do this, the fans will NOT be connected to that case fan controller module at all, and that module will not need a connection to a Molex power output from the PSU. Consider also the length of the fan wires - can they reach to the mobo headers?

If all that says yes, there's still another matter - you have 3 fans but only two CHA_FAN headers. The solution is you need one SPLITTER, like this

https://www.newegg.com/Product/Product.aspx?Item=N82E16812423161&cm_re=coboc_fan_splitter-_-12-423-161-_-Product

You will note that this item is actually for a 4-pin fan system, but you can use it for 3-pin fans, too. Look closely and you will see it has two types of arms. One arm has a female connector that must plug into a mobo CHA_FAN header. The two other arms end in male connectors (with pins) and you plug two fans into them. The Splitter has NO other arm types. Do not buy a HUB. A Hub is different because it also has a third arm type that connects to a power output from the PSU, and you cannot use that with this fan system.

Just an FYI: if you can connect fans to mobo headers, the mobo can show you the speeds of the fans. BUT when you use a Splitter to connect two fans to a single CHA_FAN header, only ONE of those fans' speeds will be shown, and the other ignored. That is not a problem for using these devices.

In your case, OP, I'd suggest using the Splitter to connect both front fans to one CHA_FAN header, and then plug the third fan (at the rear) into the other CHA_FAN header. Do not use the AIO_PUMP header. Of course, the cooling fan for your CPU will be plugged into the CPU_FAN header.

Now, last step(s). Your mobo's CHA_FAN headers each can be configured in BIOS Setup for use either with 3-pin (DC Mode) fans or with 4-pin (PWM Mode) fans. You must set both of those headers to DC Mode in order for them to control your 3-pin fans properly. So, if you want to do this change, post back here for details on how to do that last step. It's not hard.

Thank you so much for this detailed and comprehensive reply!! It answered questions for me even before I asked them!
This was really helpful and advanced me a lot. So...
regarding the fan controller - I did what you said, disconnected the Molex from the mobo and connected it directly to the PSU and now all 3 fans work like a charm, and the controller as well. So now that this more 'primitive' system works, I want to turn on the mobo system. Each of my fans indeed has 3 wires coming from them that end in a connector with 3 holes, which I WAS able to connect to the mobo headers.
I connected one fan to the AIO_PUMP as well despite what you said and the fan is actually turning (so now all 3 fans are connected directly and are ALL working), so do you mind telling me why I can't/shouldn't do so? Won't this make all 3 of my fans work without the splitter?

As you said in your last paragraph, I want to set the headers in my BIOS to control the fans, so can you please elaborate?

 

[Paperdoc]

Glad to hear you have confirmed that all those fans CAN be used as "standard" 3-pin units.

RE-examining the manual for your mobo, I may have made a mistake regarding the AIO_FAN header. I thought I had read that it could not do any control. But now I see its pinout labels say it can, and the mobo's web page says that all those headers use automatic detection of the fan type connected, and will adjust themselves to that.

For details of configuring, get your mobo's manual. Start with Section 2.2 on p. 2-6, where it tells you how to get into BIOS Setup. It says to push the "Del" key early during the POST process right after you switch on. I often find that does not quite work, because the system may not be "looking" at the keyboard just at that moment. So I hold down the "Del" key until the opening screen of BIOS Setup appears. Usually that will be in EZ Mode (see p. s-7), where you can click on the box "QFan Control" at bottom center. But it MIGHT be in Advanced Mode (p. 2-8), in which case you can see at top center that you should use the "F6" button to enter QFan Control.

In the QFAN screens you need to check (maybe change) three items for EACH of the two SYS_FAN headers AND for the AIO_PUMP header. First, ensure that its Profile is set to "Standard" so that it will use its pre-programmed settings for how to control the fans. Then I believe each has a place to select which temperature sensor is used to guide the fans on it. That may be set by default to the CPU's internal sensor. Make sure it is changed to the Motherboard temp sensor for all three of these. Finally, check what control Mode it is using. The manual does not show that screen, but usually on ASUS BIOS's the Mode choice will be "Automatic", "PWM Mode", or "DC Mode". I suggest you set all three headers to DC Mode because you know you are using 3-pin fans. When you're done, use the "F7" key to return to the EZ Mode Menu. There, click at top right on the EXIT choice (see p. 2-11). On the Exit screen, choose "Save Changes and Reset" and confirm. Your system will save your new settings and reboot. setting the AIO_PUMP header the same as the CHA_FAN headers should make it control its fan just like the others.

From now on if you watch closely, at boot time all the fans will start up at full speed for just a few seconds, just to be SURE they start. Then as the POST process finishes and it gets real temperature readings from the sensors, the fans will be slowed down to the slow speeds suitable for a cool system that has not generated much heat yet. As you work, their speeds will change.

 

[felix.fainshtein]

Glad to hear you have confirmed that all those fans CAN be used as "standard" 3-pin units.

RE-examining the manual for your mobo, I may have made a mistake regarding the AIO_FAN header. I thought I had read that it could not do any control. But now I see its pinout labels say it can, and the mobo's web page says that all those headers use automatic detection of the fan type connected, and will adjust themselves to that.

For details of configuring, get your mobo's manual. Start with Section 2.2 on p. 2-6, where it tells you how to get into BIOS Setup. It says to push the "Del" key early during the POST process right after you switch on. I often find that does not quite work, because the system may not be "looking" at the keyboard just at that moment. So I hold down the "Del" key until the opening screen of BIOS Setup appears. Usually that will be in EZ Mode (see p. s-7), where you can click on the box "QFan Control" at bottom center. But it MIGHT be in Advanced Mode (p. 2-8), in which case you can see at top center that you should use the "F6" button to enter QFan Control.

In the QFAN screens you need to check (maybe change) three items for EACH of the two SYS_FAN headers AND for the AIO_PUMP header. First, ensure that its Profile is set to "Standard" so that it will use its pre-programmed settings for how to control the fans. Then I believe each has a place to select which temperature sensor is used to guide the fans on it. That may be set by default to the CPU's internal sensor. Make sure it is changed to the Motherboard temp sensor for all three of these. Finally, check what control Mode it is using. The manual does not show that screen, but usually on ASUS BIOS's the Mode choice will be "Automatic", "PWM Mode", or "DC Mode". I suggest you set all three headers to DC Mode because you know you are using 3-pin fans. When you're done, use the "F7" key to return to the EZ Mode Menu. There, click at top right on the EXIT choice (see p. 2-11). On the Exit screen, choose "Save Changes and Reset" and confirm. Your system will save your new settings and reboot. setting the AIO_PUMP header the same as the CHA_FAN headers should make it control its fan just like the others.

From now on if you watch closely, at boot time all the fans will start up at full speed for just a few seconds, just to be SURE they start. Then as the POST process finishes and it gets real temperature readings from the sensors, the fans will be slowed down to the slow speeds suitable for a cool system that has not generated much heat yet. As you work, their speeds will change.

Okay, I think everything works
I did as you said and indeed all 3 fans were on AUTO mode by default and I see their speeds are adjusted as needed =]
Just one last question - the cpu's cooler-fan which I connected to the CPU__FAN header is default set to "PWM" and not "DC", is this okay?

 

[Paperdoc]

Very likely that is OK, but you can do two checks. This is because most CPU cooler systems today use 4-pin PWM type fans, whereas many case makers save a little money by installing 3-pin fans instead of 4-pin ones. First and simplest: look at the wires in the cable from the CPU cooling fan to its header. If there are 4 wires ending in a female connector with 4 holes, it is a 4-pin fan and SHOULD be used with a header that employs PWM Mode for control. Second check is to observe that CPU cooler at start-up and then during changing workloads. If it does actually change its speed, then it is just fine with PWM Mode. The only "red flag" would be if it starts up at full speed and always stays that way.

 

[Paperdoc]

Thanks for Best Solution.