Connect 4 wire fans in parallel

greenhouse · Jan 22, 2009, 03:33 PM

My 3 wire case fan is always running at high speed and is very noisy while my cpu fan is nice and quiet.

Can I connect two 4 wire fans to the motherboad fan connector in parallel?

Later edit:
I have replaced the 3 wire case fan with a four wire one.

MRCL · Jan 22, 2009, 03:37 PM

You mean, operate two fans on one motherboard plug, am I correct?

PVTCaboose1337 · Jan 22, 2009, 03:37 PM

Are you replacing the noisy one with two less noisy ones? I don't understand.

But yes, as long as the fans are not really amp hungry, you should be fine putting them in parallel.

greenhouse · Jan 22, 2009, 03:42 PM

Yes, you are correct MRCL.

Zanga · Jan 22, 2009, 03:44 PM

4 pin coolers are PWM (Pulse-width modulation) controlled. You cant connect two coolers together as the speed signal / phase and the pulse speed control will mix, thus making the both spin to fast, nor at all, or damage the MB controller.

Later edit:

You can still solve the problem. PWM coolers without sense and control spin at the maximum rpm given by it's power supply. On the case fan remove the speed sense and pwm control wire and leave only the power supply and ground. The MB controller will "see" only the cpu cooler and control it's speed, but you tied the second cooler to it, so both coolers will run at controlled speed.

You still should check whats the maximum current allowed by the MB and whats the maximum combined power draw of the two coolers.

Later edit 2:

Pin Function & Wire Color
1 GND Black
2 12 V Yellow
3 Sense Green
4 Control Blue

AsRock · Jan 22, 2009, 04:04 PM

Quote:

Originally Posted by greenhouse

My 3 wire case fan is always running at high speed and is very noisy while my cpu fan is nice and quiet.

Can I connect two 4 wire fans to the motherboad fan connector in parallel?

Plug the 3 pin fan in to another 3 pin connector on the mobo also check in the bios for some kind of control for the fan.

Not all fan connections have the option to control them. Try checking your manual.

greenhouse · Jan 22, 2009, 04:05 PM

Excellent response Zanga. Thanks.

If I understand you correctly, on the second fan I connect only pins 1 & 2.

Zanga · Jan 22, 2009, 04:12 PM

Yes correct, use only pin 1 and 2 and connect them to the same wires on the CPU cooler, but check first what's the current rating of the fans.

greenhouse · Jan 22, 2009, 04:26 PM

Hi Zanga.

I just tried it connecting only pins 1 & 2. One or both of the fans went to high speed.
Same result connecting pins 1, 2, & 3.

What did seem to work was connecting pins 1, 2, & 4 and leaving pin 3 unconnected on the case fan.

Zanga · Jan 22, 2009, 04:31 PM

Just forgot that the power supply stays constant @ 12V. Having the sense off is ok. Now both fans receive 12V, Cpu fan reports speed and MB signals to both to adjust speed.

greenhouse · Jan 22, 2009, 04:36 PM

OK. Thanks. Nice and quiet now.

Jan 22, 2009, 03:33 PM	#1
greenhouse Join Date: Nov 2008 Posts: 68 (0.04/day) Thanks: 14 Thanked 2 Times in 2 Posts	Connect 4 wire fans in parallel My 3 wire case fan is always running at high speed and is very noisy while my cpu fan is nice and quiet. Can I connect two 4 wire fans to the motherboad fan connector in parallel? Later edit: I have replaced the 3 wire case fan with a four wire one. Last edited by greenhouse; Jan 22, 2009 at 04:30 PM.

Jan 22, 2009, 03:37 PM	#2
MRCL Join Date: May 2008 Location: Switzerland, Heart of Europe Posts: 3,798 (2.06/day) Thanks: 340 Thanked 862 Times in 705 Posts System Specs	You mean, operate two fans on one motherboard plug, am I correct? __________________ [I.R.A.] FBi I wouldnt buy toilet paper from MSI as it may be missing the preforations

System Name:	Fractality 1.0
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Memory:	4GB Mushkin DDR3
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Hard Disk:	OCZ Vertex 64GB + 180GB SSD / Samsung F1 1000GB HDD
Optical Drive:	LiteON DVD writer
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Sound Card:	onboard
PSU:	Corsair HX750W modular, sadly only stock sleeving
Software:	Win 7 64bit

Jan 22, 2009, 03:37 PM	#3
PVTCaboose1337 Graphical Hacker Join Date: Feb 2006 Location: San Antonio, Texas Posts: 7,478 (2.78/day) Thanks: 798 Thanked 1,174 Times in 834 Posts System Specs	Are you replacing the noisy one with two less noisy ones? I don't understand. But yes, as long as the fans are not really amp hungry, you should be fine putting them in parallel. __________________ CPU-Z validation sig pics temporarily blocked

System Name:	Whim
Processor:	Intel Core i5 2500k @ 4.4ghz
Motherboard:	Gigabyte P67A-D3-B3
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Video Card:	Gigabyte GTX 670 2gb
Hard Disk:	WD 640gb Black (Main), WD 2tb Black (Secondary)
Optical Drive:	LG DVD-RW Drive
CRT/LCD Model:	Asus VE228 and Samsung 2053BW
Case:	Cooler Master 430 Elite
Sound Card:	Onboard > PA2V2 Amp > Senn 595's
PSU:	Seasonic 650w
Software:	Windows 7 Ultimate (Tweaked)

Jan 22, 2009, 03:42 PM	#4
greenhouse Join Date: Nov 2008 Posts: 68 (0.04/day) Thanks: 14 Thanked 2 Times in 2 Posts	Yes, you are correct MRCL.

Jan 22, 2009, 03:44 PM	#5
Zanga Join Date: Sep 2008 Posts: 76 (0.04/day) Thanks: 9 Thanked 11 Times in 10 Posts System Specs	4 pin coolers are PWM (Pulse-width modulation) controlled. You cant connect two coolers together as the speed signal / phase and the pulse speed control will mix, thus making the both spin to fast, nor at all, or damage the MB controller. Later edit: You can still solve the problem. PWM coolers without sense and control spin at the maximum rpm given by it's power supply. On the case fan remove the speed sense and pwm control wire and leave only the power supply and ground. The MB controller will "see" only the cpu cooler and control it's speed, but you tied the second cooler to it, so both coolers will run at controlled speed. You still should check whats the maximum current allowed by the MB and whats the maximum combined power draw of the two coolers. Later edit 2: Pin Function & Wire Color 1 GND Black 2 12 V Yellow 3 Sense Green 4 Control Blue Last edited by Zanga; Jan 22, 2009 at 03:57 PM.

Processor:	Q6600 @ stock speed
Motherboard:	Asus P5K-PRO
Cooling:	Fresh air
Memory:	Buffalo 4 GB DDR-II 800 mhz
Video Card:	Asus EAH4850 + Akasa Neo Vortexx
Hard Disk:	2 SATA RAID 0 arrays (2x80 + 2x80)
Optical Drive:	Asus DRW-1604P-D
CRT/LCD Model:	22" Wide TFT + 21" CRT
Case:	Custom twin tower
Sound Card:	Audigy SE @ XFi
PSU:	Dual PSU mod (410 + 460W)
Software:	Vista x64

System Name:	weeeeeeeeeeeeeeeeeee
Processor:	i5 2500k \ i7 3770k
Motherboard:	ASRock Z68 Extreme3 Gen3 \ ASRock Z77 Extreme 4
Cooling:	Gemini II S524 \ XIGMATEK Gaia SD1283 with Couger 1500 RPM fans\ ZM-MFC2
Memory:	Samsung 1600 16GB \ Samsung 1600 16GB
Video Card:	XFX HD6770 \ XFX 6970 w/Prolima MK-13 ( With modded 5870 VRM hrstsink )
Hard Disk:	2x intel ssd x25 G2 80GB \ OCZ Solid 3+2 Corsair Force GT's 120GB (Use HDD's for backups only
Optical Drive:	LiteOn DVD 163 \ TEAC exturnal DVD drive
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Case:	ARK Black HTPC 400BA \ None
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PSU:	CoolMax CXI-600B\ PC Power & Cooling Silencer 750 Quad
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Jan 22, 2009, 04:05 PM	#7
greenhouse Join Date: Nov 2008 Posts: 68 (0.04/day) Thanks: 14 Thanked 2 Times in 2 Posts	Excellent response Zanga. Thanks. If I understand you correctly, on the second fan I connect only pins 1 & 2.

Jan 22, 2009, 04:12 PM	#8
Zanga Join Date: Sep 2008 Posts: 76 (0.04/day) Thanks: 9 Thanked 11 Times in 10 Posts System Specs	Yes correct, use only pin 1 and 2 and connect them to the same wires on the CPU cooler, but check first what's the current rating of the fans.

Jan 22, 2009, 04:26 PM	#9
greenhouse Join Date: Nov 2008 Posts: 68 (0.04/day) Thanks: 14 Thanked 2 Times in 2 Posts	Hi Zanga. I just tried it connecting only pins 1 & 2. One or both of the fans went to high speed. Same result connecting pins 1, 2, & 3. What did seem to work was connecting pins 1, 2, & 4 and leaving pin 3 unconnected on the case fan. Last edited by greenhouse; Jan 22, 2009 at 04:32 PM.

Jan 22, 2009, 04:31 PM	#10
Zanga Join Date: Sep 2008 Posts: 76 (0.04/day) Thanks: 9 Thanked 11 Times in 10 Posts System Specs	Just forgot that the power supply stays constant @ 12V. Having the sense off is ok. Now both fans receive 12V, Cpu fan reports speed and MB signals to both to adjust speed.

Jan 22, 2009, 04:36 PM	#11
greenhouse Join Date: Nov 2008 Posts: 68 (0.04/day) Thanks: 14 Thanked 2 Times in 2 Posts	OK. Thanks. Nice and quiet now.

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