reducing voltage to DDC pump

[Detrius]

I just recently expanded my loop by adding a 120.4 rad, a DDC 3.25 pump and a GPU block. This is in addition to an existing 2 year old D5 pump and 120.2 rad.

I added the second pump in series because I was concerned flow would be reduced with the new block/rad but most because I wanted some redundancy.

This new pump is loud. Probably not many db, but a high pitched sound. It runs at about 4500 RPM @ 12V. Reducing voltage reduces the pitch of the sound, but makes it louder. I have run the pump between 12V and about 8V (where it stalls) with less pitch to the sound but it gets increasingly noisy. I am using a fan controller to do this.

I have run the pump in my hand, so I can eliminate vibration resulting from installation.

Any ideas of how to tame the noise from this pump?

Its driving me crazy

 

[BugFreak]

I usually attach my pumps by putting a piece of thick velcro or rubber between the pump and chassis along with whatever hardware is used. I've always used D5 pumps so I can't say if it will help the DDC but it might be worth a shot. Also I'll leave it up to the pros to confirm but I would think the D5 alone would be enough for that whole setup.

 

[m0r7if3r]

Just to be clear, the noise is from the pump, not the vibration, right?

 

[Detrius]

Its not vibration. It makes the same sound mounted in the case as it makes running in my hand.

 

[RGE]

I ran ddc pump for 7 years and always ran my fans at 1100 rpms to drown out the high pitch sound, and my pump was decoupled with shoggy sandwich with tpe gel. I never found reducing volt with fan controller helped my ddc noise either.

When I decided to go quieter with 700 rpm fans, the only way I silenced the high pitch noise was switching to D5's with aftermarket metal tops.

yes the ddc have slightly more audible, higher pitch noise than D5's, not much to do once you have it decoupled. Either run fans louder, or use 2 D5's. The higher pitch ddc doesnt bother everyone, especially those with hearing loss in that range, or those that run fans at high enough speed.

 

[Detrius]

Is there any issue leaving the pump in the loop, but simply turnig it off. I seem to get ok enough flow from just the D5.

The DDC is installed in a resevoir that I would need to change if I take it out. I dont feel like taking it out and recutting the tubes, draining, filling, bleeding right now.

 

[RGE]

nope, non-functioning pump adds very little restriction, doesnt really affect flow much at all.

 

[Detrius]

rge, thanks for the advice and fast answer.

Awesome.

 

[GTXJackBauer]

Welcome to OCFs.

You should be good with the DDC off and the D5 running for now till you make your changes in the future. I myself have 2 MCP-35xs humming at 40% PWM (1.0 GPM). I don't hear the high pinch until I get them above say 50%-60%. I am used to them and personally have never heard a D5 before so I am not sure how much more quiet it is to a DDC but most folks that do will say the D5 is quieter than a DDC.

 

[m0r7if3r]

FWIW, running mismatched pumps may be a bad call anyways...

 

[bmaverick]

The DDC is installed in a resevoir that I would need to change if I take it out. I dont feel like taking it out and recutting the tubes, draining, filling, bleeding right now.

If the WCing loop is just straight water, the DDC pump will have noise. There are a few things to tone the dBa down and the pitch.

1. Burp out all the air. The DDC likes to entrap air and squeal like a piggy. When the air is out the cavitation is gone.

2. Add some PG (Propylene Glycol) to your loop. It acts as a lubricant to the DDC impeller to the white ceramic ball. It also breaks the water tension allowing those trapped bubbles in the pump to un-lodge free.

3. Do the PCB swap with the DIYINHK upgrade. Sure, you will need some minor soldering skills for 8 tiny wires from the coil to the new PCB to do. There are 5 or so youtube videos showing how easy this is done.

4. If you do take the pump out of the loop, take it apart. The impeller inside is plastic that rides on the white ceramic ball. It needs some 3in1 or 5W20 oil to revitalize the plastic. Do NOT use any cooking oil NOR any WD40 period. WD40 will ruin the embedded magnet inside the steel cup of the impeller. Cooking oils would allow microbes in your loop.

I've revitalized, repaired and rebuilt dozens of DDC pumps over the past 5 years. I have my DDC-1T (aka MCP350) running since 2003 nearly 24/7 on 7.5VDC @ 950mA via a wall-plug on the power backup strip. There is no noise over my two fans running at 625rpms.

If you are not interested in the tips above, it's still posted to others dealing with the noise and power issue of the DDC series.

 

[JeremyCT]

Interesting about the plastic and machine oil (3-in-one). Do you just put a dab in the plastic "cup", let it sit, then wipe out any excess? Normally there's fluid in that space so I'd imagine you'd want as little residual as possible.