D5T STRONG - Voltage

[jack_l2]

I have the non-vario version. I read on the reviews that this pump does not operate below 4000 RPM. At which voltage will it spin at 4000 RPM, is it 8v or more?

At 7v it wont start spinning.

[jack_l2]

5900 RPM at 12v should land 4000 RPM at 8 volts, guess that makes sense. In other words each volt increase should make the pump 500 RPM faster, up to 12v

[DazMode]

I think slow down d5 pump is waste of time. Unlike DDC, you cannot hear it at any speed.

[bungwirez]

non-vario version should be set it and forget it.
unless you've got a super short loop, and a really small tube rez,
creating there's way too much turbulence with pump on max,
then maybe I would consider tuning it down a notch.
but I really think you would be hard pressed to design such loop.

[jack_l2]

I think slow down d5 pump is waste of time. Unlike DDC, you cannot hear it at any speed.

My goal is a 80-100% quiet PC. In other words, almost no difference between powering it on or off.

I changed the 140mm fan on the BeQuiet PSU to a Noctua 140mm fan. For the radiator fans, I used 120mm Noctua NSF and NSP series fans. At this point I can only hear the pump. I ordered sound blocking material, waiting for it by mail. That and lowering the voltage should make the PC truly whisper quiet.

[gdesmo]

Like Daz said, almost no difference. You will hear your fans first for sure, would bet 85-90 % of us here have some sort of D5. D stands for dead reliable and deathly silent !

[bungwirez]

well, if you can only hear the pump thats pretty good... or there's still some cavitation/air in your loop?

[jack_l2]

system is well bled, just the noise of the pump's motor. Not loud, but its the constant humming / whining noise coming from it that is annoying

[bungwirez]

I suggest headphones

[Grinder]

I don't understand why you bought a D5 strong. You need a 12 to 24V converter to actually run it at full speed, which you wouldn't want anyway due to the noise. And at 12V it is only equivalent to a D5 vario at setting 4. A D5 PWM might have been a better choice, as you could have run it off your CPU PWM header, and it is capable of full D5 vario setting 5 speed or much lower without directly changing the voltage to it. Hmm, I suppose that you might have been planning ahead for your fan controller purchase, and wanted something that WAS controllable with voltage...

It may run at 7V once you get it started. Most high end fan controllers allow for a higher start up voltage before settling down to the speed you have set.

[DazMode]

Any whining noise suggest air trapped in pump.

[jack_l2]

I don't understand why you bought a D5 strong. You need a 12 to 24V converter to actually run it at full speed, which you wouldn't want anyway due to the noise. And at 12V it is only equivalent to a D5 vario at setting 4. A D5 PWM might have been a better choice, as you could have run it off your CPU PWM header, and it is capable of full D5 vario setting 5 speed or much lower without directly changing the voltage to it. Hmm, I suppose that you might have been planning ahead for your fan controller purchase, and wanted something that WAS controllable with voltage...

It may run at 7V once you get it started. Most high end fan controllers allow for a higher start up voltage before settling down to the speed you have set.

I found out about the D5 PWM after purchasing, and to return it, pay restocking fee, shipping, etc, I will lose half the value of the pump, so I kept it.

I think what will work best is the accoustic blocking material I will try.

Again, my goal is to make the PC completely silent, not so much about performance or high flow rate of the pump.

[Grinder]

Make sure you have something on your mount to dampen the vibration, if you don't already. That can cause a lot of the noise. And as Daz points out, trapped air make it noisier. Acoustic blocking sounds like a fine idea as well.

[jack_l2]

Any whining noise suggest air trapped in pump.

Any way to know there is air stuck in the pump itself besides the noise? I dont see or hear any air bubble going through, and the system been running for a while now.

The motor of the pump itself has noise, which is what I am referring to as "whining", but in reality it is that "mmmmmmm" noise the motor makes, which is normal.

The pump is rated at around +- 35 db, and that is mostly from the motor itself, really.