Koolance PMP-500: Powerful, but LOUD

A Review On: Koolance Pump, PMP-500 G 1/4 BSP 16L/min, 6 to 12 VDC, Brushless DC Pump

Koolance Pump, PMP-500 G 1/4 BSP 16L/min, 6 to 12 VDC, Brushless DC Pump

Rated # 105 in Water Cooling
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Price paid: $79.95
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Pros: 4.2GPM, 24.6ft static head, Runs surprisingly cool

Cons: Loudest part in my computer, by far. Hefty power requirement makes powering/controlling pretty tricky.

For my system, I wanted to try something different. My case, a CaseLabs SM8, would have NO fans in it, with the only source of active cooling coming from an external MORA-3 with 9 Swiftech Helix 120mm. 90% of my fittings are 90 degree rotaries, which further restricts the flow. This meant a couple things:
  • My loop would be pretty long, running out of the case, to the radiator, and back inside.
  • Since my priority was minimizing sound output, I wanted to find a pump that would be powerful enough that I could pot out some of the power for quiet operation.

I've primarily used the D5 pump in the past, usually the 12V vario version. This pump ran dead silent, but even in my more conventional loops, it was somewhat lacking in the flow-rate and pressure departments.

Enter the PMP-500. The absurd amount of output this pump produces would surely mean that I could back the power off as far as I needed, to keep flow at a decent metric while limiting the noise. Boy was I wrong. First of all, the only way really to properly control the pump is with Koolance's 12/24V pump controller. The amount of current the pump requires to operate means you'd need a pretty beefed-up fan controller.

Once I got the power setup figured out, I filled my loop and fired the pump up. To my great pleasure, I was able to get roughly 1 GPM through the loop at around 25% voltage. But the NOISE, oh god the NOISE! I hoped there was just air in the loop that needed to be bled out, but after about a week of running the machine, the noise hadn't subsided. The main problem is that regardless of what speed you have the pump running at, the noise level did not fluctuate; the pitch just changed. In comparison, my 9 Helix fans running at 12V are completely inaudible when the pump is running.

On the plus side, I can increase the speed as much as I want, since it doesn't get any louder than it is at 25%.

  • Very complex or large loops, where noise is not an issue.
  • If noise is an issue, you may want to fab some sort of baffle box. The pump doesn't give off much heat externally. It just dumps it into the loop like a good boy.

  • Conventional loops where a more tame pump would suffice.
  • Builds where silence is a high priority.
  • You wouldn't mind spending a little extra to have two loops running lesser pumps, or a single loop with pumps in series.


Would this pump be able to push water through a Y adapter fork into two paths one to sli gpus and one to cpu separately? Thanks
That is with three rads of various restriction levels?