[SOLVED] Is it ok to place fans behind the radiator in pull?

[Harvygr8]

Hello , I have placed my fans like this build image

They are behind the radiator and the radiator come s in the front , also the fans are pulling air inside through the radiator into the case , is this configuration okay?
I’m worried that here’s gonna be more dust on the radiator since it’s the first thing that cool air will touch inside the case

Note that I don’t have any extra intake fans in front of the case

 

[R_1]

you are heating the system with heated exhaust from the CPU.
air get heated coming in through the RAD, the hot air get hotter over the GPU and VRM before being expelled out the rear.
reverse the fans on the RAD so you exhaust out the front. reverse the top and rear fans to draw in cool air. this way the radiator expels waste heat.

cool in/hot out

 

[Harvygr8]

you are heating the system with heated exhaust from the CPU.
air get heated coming in through the RAD, the hot air get hotter over the GPU and VRM before being expelled out the rear.
reverse the fans on the RAD so you exhaust out the front. reverse the top and rear fans to draw in cool air. this way the radiator expels waste heat.

cool in/hot out

But I have seen many people use this configuration , like the one in the image , is this configuration not ok? I mean every config has pro/cons right
Alternatively should I place fans in the front of the radiator in the same pull direction?

 

[Harvygr8]

Also rear fan is for exhaust right wouldn’t it Be “wierd” if I Use it for intake and radiator to exhaust heat?

 

[R_1]

rear fan is a fan, in or out. there are no rules. if you had a massive air cooler instead of the rad, the top and rear fans would be ideal as exhaust. they would draw in air from the bottom get hot and exhaust in the rear/top.
you have a big donkey water radiator. it will get hot and ideally it would be placed at the top of the system - where the fan is. intakes at front and rear will exhaust through the top radiator. heat rises naturally and this would take advantage of that.

as it assembled in the picture reversing the fans would be best. if you can move the rad to the top would be ideal
in through the rad and out the top rear is making the inside of the chassis an oven.

 

[britechguy]

A radiator has, as its very intent, the dissipation of heat. Air that blows over it picks up that heat.

It makes no sense to pull air IN over a radiator as all it does is heat up the inside of the case. Air should exhaust over a radiator in a computer setting. (And if you look at how laptops typically cool, that's exactly what happens on a much smaller scale and sans liquid).

The air that may already be somewhat heated inside the case is still more than cool enough to serve as the cooling stream over a radiator.

If circumstances could be ideal, there'd be a room temperature air intake for the radiator and the fans would be pushing it over the radiator and out. (Which is also what happens for a laptop, and it happens because the basic principle of cool in and warmer out applies when air goes over a radiator).

 

[EndEffeKt_24]

I would leave it be and test thermals.
A pull configuration has an advantage in noise levels in most cases. If your gpu or vrm temps are too high for your liking you can start to reverse airflow. But you will see thatwhile gpu temps might get some degrees better the cpu gets a little warmer.

 

[britechguy]

I would leave it be and test thermals

Which is probably the best advice yet.

Seeing how the system does "as is" is what should determine whether or not you change things up.

As far as I'm concerned, people generally get way over-anal about cooling. The "within normal limits" range for operating temperature has been steadily increasing over the decades, and what's "dead center" of that range for most modern processors would have made earlier era ones a pile of cinders.

You look at what your normal limits are and, when not under load, try to keep it below the median if possible. When under high load, and for extended periods, you had ought to expect temps to climb far up into the higher end of "within normal limits." 'Tis the nature of processor design these days. They can be pushed, and the designers intentionally push them, and they don't "fry themselves."

 

[rubix_1011]

It makes no sense to pull air IN over a radiator as all it does is heat up the inside of the case. Air should exhaust over a radiator in a computer setting.

This doesn't make sense. Airflow over a radiator is always necessary and fan orientation determines push vs. pull config. Neither push nor pull are correct, neither are incorrect - you only need to choose one.

Where the air goes and how hot it is depends on two things:

1. are you generating more thermal load than the cooler is designed to dissipate
2. you have poor airflow, allowing the 'warmer' air to pool and impact the ambient environment

In either scenario (1 or 2....or both), the choice of cooler and choice of chassis (and other case fans) determine the effectiveness of any cooler, air or liquid.

If you want to determine if the cooler is not sufficient or if airflow is insufficient, perform this simple test:

Remove the side panel of your case. Find a house fan or desk fan, turn it to the highest setting and direct air into the open case.

Note temps. If you see a difference of 5C+, you have an airflow problem; either case, fans or both.

If temps remain about the same (2-3C at most difference) then your airflow is likely OK. If the temps are still high, addressing the cooler is in order.

Please note - just because it is 'hot to a person' does not make it hot for a PC. Understand the operating thermal limits of your CPU and GPU...and do some Googling on what temperatures others see as well as compare to the reference specs on temperatures for the hardware.

 

[Paperdoc]

Lots of debate over whether a radiator should be part of air intake or exhaust. If it is intake, then the rest of the case gets warmer air than if the intake were just outside air. If it's exhaust, the case gets cooler air but the rad gets that air AFTER it has been warmed by the case contents. In the latter situation, one could argue that the pre-heated air inside the case is not hugely pre-heated, so the impact of this configuration on the rad system is small. But the real truth is, as some have said, you need to asses how well the system is doing its primary job - cooling the CPU with side-effects on case cooling - under your normal operating conditions. If it does that well and you have extra reserve cooling capacity for future workload increases, then it's fine the way it is.

I agree, push or pull really is NOT an issue. Most of these fans can work equally well no matter on which side the rad is.

OP, your original concern has been largely ignored - dust accumulation in the rad fins. I agree that IS a concern. But it should be dealt with reasonably exactly as you would with ANY intake fan system - dust filters ahead of the fans. You ALWAYS should have dust filters (usually simple sheets of open-cell polyurethane foam) mounted on the intake (fresh air) side, and you must remove and clean them, then re-install from time to time. With a rad at this position, I would recommend that, at the same time you remove and clean the dust filters, you use a vacuum briefly to suck air and dust back out of the front of the rad that is temporarily exposed.

 

[rubix_1011]

Lots of debate over whether a radiator should be part of air intake or exhaust. If it is intake, then the rest of the case gets warmer air than if the intake were just outside air. If it's exhaust, the case gets cooler air bu the rad gets that air AFTER it has been warmed by the case contents. In the latter situation, one could argue that the pre-heated air inside the case is not hugely pre-heated, so the impact of this configuration on the rad system is small. But the real truth is, as some have said, you need to asses how well the system is doing its primary job - cooling the CPU with side-effects on case cooling - under your normal operating conditions. If it does that well and you have extra reserve cooling capacity for future workload increases, then it's fine the way it is.

What you are discussing, at its fundamental core, is general case airflow, not the cooler or where it is mounted. If case airflow is good and quality, cool air is circulated well through the chassis, where the heat exchanger is mounted or blowing to/from is irrelevant. Cool air is cool air, hot air is hot air. If air is allowed to 'get hot enough' then this still isn't a cooler issue, it's an airflow issue.

OP, your original concern has been largely ignored - dust accumulation in the rad fins. I agree that IS a concern. But it should be dealt with reasonably exactly as you would with ANY intake fan system - dust filters ahead of the fans. You ALWAYS should have dust filters (usually simple sheets of open-cell polyurethane foam) mounted on the intake (fresh air) side, and you must remove and clean them, then re-install from time to time. With a rad at this position, I would recommend that, at the same time you remove and clean the dust filters, you use a vacuum briefly to suck air and dust back out of the front of the rad that is temporarily exposed.

Agreed. Be certain to avoid static build up from vacuum cleaners...they are notorious for this and can permanently damage PC components if static discharge hits them.

 

[britechguy]

What you are discussing, at its fundamental core, is general case airflow, not the cooler or where it is mounted.

You're really splitting hairs here. I agree with your overall statement, completely, but common sense dictates that, ideally, one would not be drawing air into a closed space over a radiator if one wants to maximize cooling potential for the other bits in the system.

By drawing air over a heat dissipating device and into an enclosed case, no matter what other fans you have, you will end up with a warmer "in case" situation than if the airflow over the radiator is exhausted.

It may make no practical difference, which is why the "test it out" advice is good advice. But from a pure design and engineering perspective you don't want to be pre-heating air that's going to be drawn in to the case if you can avoid that (and if it makes any difference). There are lots of suboptimal configurations that work just fine, but that doesn't make them "not suboptimal."

 

[rubix_1011]

A radiator should rarely discharge heat warmer than slightly warm-to-the-hand when a CPU is running at load. If it is warmer than this, you have inadequate cooling capacity for the CPU (or component) being cooled. It means heat soak is occurring and the cooler is unable to balance the thermal load being absorbed with dissipated thermal load.

So, selection of radiator for wattage to be dissipated is still more important than which direction the air flows over the radiator or inside/outside a case.

 

[extreme_noob]

Your config is fine.
The air pushed out of the rad will only be slightly warmer and shouldn't really affect GPU temps as much as air cooling depends more on airflow than the actual temperature of that air (One example of this is how stock coolers cool motherboard VRMs with hot air.)

 

[Karadjgne]

Radiators are not aircooler heatsinks. There's a huge difference there. With a rad, it's all about the coolant temp, which is absolutely not the same thing as cpu or gpu temps. Just because the cpu is 50°C, does not mean you will see 50°C at the radiator. With a radiator it's a constant battle with ambient temps, either case ambient for exhaust mounted rads or outside ambient for intake rads.

With 50°C cpu, 23°C outside ambient on an intake mounted rad, you'd be looking at 32-35°C coolant. That's all. That's what the fans are blowing into the case. Not the 50°C cpu.

Inside the case, ambient temps with an air cooler, exhaust mount rad, or basically any setup generally run 6-12°C above outside ambient, simply due to heat from various sources like Northbridge chipset, ram, gpu, Sata controller chipsets etc. So with a 23°C outside ambient, you can easily expect case temps to run @ 29-35°C.

Adding 32-35°C air from an intake radiator to case temps that already run 29-35°C doesn't make a damn bit of difference. You aren't magically dumping excessive hot air into the case, heating everything up.

It honestly changes nothing to any real measurable degree.

 

[britechguy]

It honestly changes nothing to any real measurable degree

And this I accept entirely. There are often so many factors, subtle factors, involved where real world variables cancel each other out, just different ones for different configurations, that the net result is the same.

This is way more about getting an acceptable end result than a so-called ideal configuration (which truly doesn't exist in this situation).

 

[Harvygr8]

Wow thanks for your inputs guys,So with my current configuration(radiators intake, and top and rear exhaust) I am experiencing pretty good temps of about 65-70c under full load so should I keep this configuration or not?

 

[britechguy]

Keep it. 70 degrees C under full load if it holds relatively steady is "cold" under those conditions. It's not much above "just warm" to begin with.

 

[Paperdoc]

Agreed, keep it. And thanks for Best Answer.