Computers & Electronics

Help on Push and Pull Radiator Fan setup and Case fan setup

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  • Jan 21st, 2018 11:31 am
Deal Addict
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Jan 29, 2005
2093 posts
585 upvotes
Mississauga

Help on Push and Pull Radiator Fan setup and Case fan setup

So I have setup this build, but am running in a dilemma on how to go about connecting the fans. The phanteks evolv case has an intake region at the bottom of the case and exhaust region at the top the case. I have the cooler master ml120l radiator in the bottom region which was in a pull configuration with the included 120mm fan. I have now decided to add a phanteks 120mm fan to push air into the radiator. There is also a cooler master masterfan 120 pro fan on the side of the case that pulls air in to the case and in the same region as the rad. I have one exhaust fan at the top of the case and is the same cooler master master fan 120 pro. The motherboard has 3 fan headers, one is the cpu fan header, one is a chassis fan/ water pump header and the last one is a chassis fan header. My plan is to use a fan splitter and connect the included cooler master radiator (pull) fan and the phanteks (push) fan to the cpu header. The water pump will be connected to the chassis fan/water pump header. The 2 cooler master masterfan 120 pro fans (one intake and the other exhaust) again through a fan splitter to the second chassis fan header. Are the connection fine? Also the phanteks fan is a 3pin, while the included radiator fan is a 4pin would that be alright?
2 replies
Deal Expert
Mar 23, 2004
35606 posts
18999 upvotes
Ideally you want the same fans on both sides of the rad, running in sync at the same speeds. That way they're always working together. Different fans are going to have different RPMs, different airflow/pressure, and not really ideal to use in push-pull. Adding insult to injury one is PWM and the other is not. To use a PWM fan with PWM control you hold the voltage at 100% and send a PWM signal to vary the speed; you can obviously also control the speed with voltage but this defeats the purpose of having a 4-pin fan to begin with. The 3-pin fan you will only be able to control with voltage, so if you connect both these fans together the only way you'll control the speed on both is to use voltage and NOT PWM. So you'd have to set this manually otherwise the board will auto-detect a PWM fan and use 100% voltage meaning the 3-pin fan will always be at 100%. Even controlling both, if you're doing so with the same voltage they're going to have different RPM at a given voltage and the start/stop point may be different as well. I.e. at a certain voltage one may stop spinning altogether while the other is still turning.

In short? Use two identical fans on the rad if you want to do push-pull. Keep in mind push-pull will only get you a degree or two cooler, though granted you may be able to run lower speeds for the same cooling performance (however two fans also make more noise than one). If not using the same fans, I'd say just use one fan.
Deal Addict
User avatar
Jan 29, 2005
2093 posts
585 upvotes
Mississauga
Thanks for the advice. I will definitely follow what you have suggested and for the time being I will take the push fan out of the equation for now till I get the exact model as the pull fan. Alot of people who have own the case suggest the push and pull helps this case a lot. Also as you have mentioned and so have the same people have suggested, running them at lower rpm to achieve the same as result as a single fan run at a higher rpm helps with the noise level. So I’m I good with the header connections I have mentioned in my orig post? Or do I need to change which fans are connected to which headers? Thanks again
ES_Revenge wrote: Ideally you want the same fans on both sides of the rad, running in sync at the same speeds. That way they're always working together. Different fans are going to have different RPMs, different airflow/pressure, and not really ideal to use in push-pull. Adding insult to injury one is PWM and the other is not. To use a PWM fan with PWM control you hold the voltage at 100% and send a PWM signal to vary the speed; you can obviously also control the speed with voltage but this defeats the purpose of having a 4-pin fan to begin with. The 3-pin fan you will only be able to control with voltage, so if you connect both these fans together the only way you'll control the speed on both is to use voltage and NOT PWM. So you'd have to set this manually otherwise the board will auto-detect a PWM fan and use 100% voltage meaning the 3-pin fan will always be at 100%. Even controlling both, if you're doing so with the same voltage they're going to have different RPM at a given voltage and the start/stop point may be different as well. I.e. at a certain voltage one may stop spinning altogether while the other is still turning.

In short? Use two identical fans on the rad if you want to do push-pull. Keep in mind push-pull will only get you a degree or two cooler, though granted you may be able to run lower speeds for the same cooling performance (however two fans also make more noise than one). If not using the same fans, I'd say just use one fan.

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