2 chassis fan connected but 3 fans

Cash425 · Oct 24, 2016

Hello I have a corsair air 740 case that comes with 3 fans. On my motherboard(asus x99 a2) there are only 2 chassis fan connecters. How do I fix this. I don't know what fans the corsair air 740 has and I heard there are 3 pin or 4 pin but I don't understand which is which. What do I need to buy specifically for my motherboard and case?
I appreciate the help.
Thanks, Kyle

boosted1g · Oct 24, 2016

3pin had 3 pins on the plug coming form the fan, and 4pin has 4, simple as that.

You can get a fan to molex adpter to power the fan off of the power supply,
you can get a Y cable to power 2 fans off 1 mothboard header.
or you can get a fan controller for all 3 fans.

Cash425 · Oct 24, 2016

Okay great thanks for your help. Now how do I know if it's a 4 pin or 3 pin on the case? I don't have the case yet it's coming in the mail. I think the fan is a corsair af140l. Now can you link me a 2 y splitter cause I don't want it on the psu and I don't want a fan controller.
Thanks

boosted1g · Oct 24, 2016

The pins are from the fan itself to the motherboard.

Most motherboards will have a 4 pin header to support 3 and 4 pin fans.
So a 4pin Y will give you full support for both 3 pin and 4 pin fans:
https://www.amazon.com/PWM-Y-Splitter-Cable-Adapter/dp/B002OFP6QW/ref=sr_1_7?ie=UTF8&qid=1477344327&sr=8-7&keywords=4+pin+y+fan+cable

Cash425 · Oct 24, 2016

Thanks. This is for a pwm fan, and I think the corsair af140l only runs at 1 speed of 1000rpm. Will this still work for that type of fan?

boosted1g · Oct 24, 2016

Yes, these will support a 4pin or 3pin fan, the cable is just that, some pieces of copper, the cable itself does not care if only 3 of the 4 pins are populated.

Your motherboard will detect that it is a 3 pin fan and work accordingly.

Cash425 · Oct 24, 2016

Ok so pwm y cable doesn't matter whether the fan only runs at one speed of 1000 rpm or a variable speed, correct?

boosted1g · Oct 24, 2016

Correct, the Y cable will support 3pin and 4pin fans. Now you cant put 1 4pin and 1 3pin in the Y cable, but 2 3 pin or 2 4 pin are just fine.

Cash425 · Oct 24, 2016

Okay perfect because there both the same 2 fans with the case.
Awesome thanks.
Now since you seem to know so much about fans I'll ask you one other question.

I also bought a corsair h100i v2 liquid CPU cooler. I know there are two fan connectors and one water pump header on the pump. My motherboard has the pump header. A CPU fan connector and one opt CPU fan connector for a total of 2. Now for the h100i v2 with the 3 connectors I'm assuming I can plug the water pump header into the slot on the motherboard but the 2 water pump fans connect to the 2 CPU connectors. Is that correct?

boosted1g · Oct 24, 2016

Ok, should have said about the h100i in the first place.

The cooler has a 4 fan hub built into it, and its own Y cables. You plug the 2 fans into the fan hub with the included Y cable.
The cooler then has a Sata style power connector and 3 pin fan cable you need to plug in. Sata power goes to any open one from PSU, and teh 3 pin plugs into your CPU fan header on motherboard.

http://www.corsair.com/en-us/blog/2013/february/how-to-install-the-hydro-series-h100i-cpu-cooler

Cash425 · Oct 24, 2016

I'm a little confused. Do I need to buy the splitter then? The 2 fans in the front is what I would buy the splitter for but I'm confused about the h100i v2. Does it have its own fan controller hub? I'm confused. I thought the h100i only had 3 cables. One water pump and two CPU which I why I would plug the h100i coolers into the two CPU slots

boosted1g · Oct 24, 2016

EDITED:

No you do not need to buy anything, just follow the instructions in that link.

The cooler has its own 4 fan hub built into it, and comes with its own Y cables.

Whether you are installing the radiator at top or at front that will eliminate one of the 3 fans in your case.

If installing at top, you can wire the back fan to the hub instead of the motherboard. You will have to remove the top fan from the case because your radiator will mount there.
If installing in front then connect your back/top fans to motherboard and if your case even allows you to keep the front fan and mount the radiator then you can plug that fan into the cooler's hub, and then plug your back/top fans into motherboard:

Cash425 · Oct 24, 2016

I have two fans in the front and one in the back. And the radiator (h100i v2) would have two fans on the top so a total 5 fans. Now how would I connect those to my motherboard? You sure I don't need any y cable? What do I do with the 2 CPU fan headers?

boosted1g · Oct 24, 2016

Ok, sorry i assumed your case had the typical 1 bottom, 1 top, 1 front fan configuration.

So for your case:
Use one of the Y cables from your cooler for the front fans to connect to 1 motherboard header, and connect the back to the other header.

Cash425 · Oct 24, 2016

Ok perfect now I understand you

boosted1g · Oct 24, 2016

The cooler connects to the primary motherboard CPU header and it uses that signal (which tells it how fast to run) to feed the output of the (up to 4) fans plugged into the integrated hub.

So doing it this way is better over just plugging the fans directly into the motherboard as you can power 4 fans with the hub (vs only 2 with the motherboard) and it makes for better cable management.

Cash425 · Oct 24, 2016

So just to make sure I got this right. There is one connection that goes from the CPU header on the motherboard to the cooler. That breaks off into 4 fan connectors. 2 can be used for the cooler fans and the other two can be used for the 2 front fans. Is that correct?

Cash425 · Oct 24, 2016

Basically could I do it my way cause that's the way I understand. Have a splitter for the front 2 fans going into the chassis fan on the motherboard. Have the 1 back fan do the same, using both chassis fan slots. Then for the cooler, I have the 2 fans run into both CPU headers and one run into the pump header. Will that work the way it is. That seems the least confusing. The cable management isn't a big deal.

boosted1g · Oct 24, 2016

I would not advise that!

I dont know if the cooler will like being connected without being connected the motherboard CPU header. The best way to hook it up is as per the OEMs instructions. The other bennifit is that Corsair includes software that allows better automatic and manual control of the fans.

So you have 3 fans on the case, 2 fans on the cooler, and 2 Y cables that come with the cooler:
Plug cooler into CPU header
Plug your 2 cooler fans into Y cable and into cooler
Plug your 2 front fans into a Y cable and into your motherboard fan header
Plug your 1 back fan into the other motherboard fan header

Your front intake fans should not be connected to the fan hub of a top mount radiator because they should be drawing in more air then your CPU radiator fans do.

Cash425 · Oct 24, 2016

oh I see that makes sense. So I only need to plug the cooler into the one CPU header and the 2 cooler fans plug into the coolers onboard splitter. Then the 2 front fans goes into a splitter into the motherboard and the back fan does right into the motherboard. Is that correct?

boosted1g · Oct 25, 2016

Correct

2 chassis fan connected but 3 fans

Honorable

Titan

Honorable

Titan

Honorable

Titan

Honorable

Titan

Honorable

Titan

Honorable

Titan

Honorable

Titan

Honorable

Titan

Honorable

Honorable

Titan

Honorable

Titan

Share this page