Alphacool Dual DC-LT Res and Pumps

L

leejc73

New member
Don't know if anyone else has bought this setup yet, but thought I would give a couple of thoughts on it since mine arrived yesterday and I've spent a few hours testing it.

First thoughts were that it appeared to be well put together, then I fitted the pumps/filled it and powered it on and the noise was horrific!!!

I loosened the pumps off to see if this reduced noise to no effect so then decided to drain it and see if I could find a reason for the excessive noise. First thing I noticed was what I initially thought was a grease sitting in all the machined parts of the pump housings, only thing is it's not grease, it's excess glue that's been left when they've sandwiched the additional plate on the front between the main body/pump housing. I cleared all of this out and reassembled. It appeared quieter but there wasn't much in it. So I started looking at the actual design of the pump housing and the problem that's become apparent to me is the location of the return and pump intake. They are just too close.
The res bay is meant to be used in a horizontal position, but if you do that then you have to completely top out the res in a perfectly horizontal position and remove ALL air from the system, the turbulance that the returned water produces agitates the smallest bit of air in the system which throws it back through the pump, making it sound like it's eating a bag of pebbles.
I turned the res to the vertical with the return at the bottom and i've now got what I would consider an acceptable level of pump hum. Sure they aren't the quietest things to start with, but the design of the res hasn't improved things at all.
I would go so far as to advise not using the alphacool dual pump res, and go for one of the top feed res's if you want it to be as quiet as possible.

Anyone else noticed the glue floating around inside these pump housings? It was all over the external seam as well.

Cheers
Lee
 
Hi Mate,
Yeah I've got a DDC 18w on an XSPC res and a XSPC RASA 750. They both made noise during the bleed process, this one just won't stop making noise unless there is 0 air at all in the system or it's rotated through 90 degrees.
Kind of makes a mockery of the 100/75/Min markings on the front of the bay when it will only run at anything approaching acceptable noise levels with it at 100% and with the fill port slightly sunk into the body of the res, actually getting it full with 0 air bubbles isn't an easy task. Think it could be improved considerably with a baffle between the return port and the pump inlet and getting rid of the recess on the fill port.
Just my opinion though.
 
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I used one of these when building my mates PC.

We had so so many problems with them, for various reason. One was actually getting the pumps in. The rubber rings would not go in the right place which made it a massive pain. Also the lack of instructions made it even more annoying as we were only provided with 4 screws in total - 2 sets of different sizes to mount 2 identical pumps.

After a good 3 days of fiddling we finally got it to work at an acceptable level.

I think as the people who will be buying the res will also be buying at least one of the pumps - probably 2, it'd have been better for us if the pumps came pre-installed into the res. This would allow for a slightly different design, and would most likely lead to an overall better product
 
I got 4 screws the same size for the pumps, and then 2 longer ones holding the blanking plate on. It came with rubber seals on the pumps and 2 extras with the holed lugs on with the res for mounting. I haven't had the leak issue's I've seen other people mention but from looking closely at mine I think i've got variant 2, as there seems to be some extra machining done on the pump housing (they were suffering with impeller contact problems on the first batch apparently)

I would have thought they might have modeled it pre production and noticed the turbulance on the return port being fed straight back into the feed port, could have so easily been solved with a bit of a acrylic running half the length of the res between return/feed ports.
 
I'd quite like to know what difference it makes having 2 of the pumps.

I'm considering doing a GPU only loop in the future, so having 1 of the pumps with the res top seems a better idea to me than going for the drive bay res.

I'm thinking 1 would be fine for gpu only
 
I've got a pair, I haven't done a flow test though to find out what it will push through lph wise.
One thing I did notice though is don't believe you have redundancy with a pair of pumps with this setup because you don't.
If one pump fails (I can't remember which, I'll have another play later and report back I think it's the one nearest the feed port) but it essentially stops all flow through the loop as the second pump doesn't have the kahoonas to overcome the resistance created by the stalled device.

Just something to bear in mind.
 
We did have an issue like that. a bit of end tubing I think managed to get caught in the loop and stopped the first pump.
It did still push the water around, but temps rocketed.

If I do get round to doing the gpu loop, I'll have a big think about what I'm gunna use. I can imagine the single pump with the top res being good on its own, and far easier to fit together.
 
It would have been my choice knowing what I now know, but I'm just a little concerned about single pump flow rates, and the fact you've not got any built in feedback, which is really a minor niggle.
I would be interested to see a pair of these in a single loop with top feed res's on both, as I think it would considerably reduce the noise and produce a fair flow rate, but for the cost you're looking at you're into DDC/D5 territory and I don't think there is anything to touch those 2 pumps at the minute.
 
Agreed, sorry mixing terms.
I'm going to do a head height test on this later on and find out what the difference is between single and dual pumps.
 
http://www.review-center.de/wasserkuehlung/444-david-gegen-goliath-alphacool-dc-lt-vs-laing-d5.html

That is the only review of these out.

Also, to echo the OP, the pumps are pretty nice (though I had a flange break off on one with putting barely any pressure at all on it), but the dual DC-LT res in specific is horribly designed.

Basically, you can not fill up the res all of the way since the fill port is recessed. This wouldn't normally be an issue, but the inlet and outlet channel to the pumps are located right next to each other. What this does is cause a wave pattern in the fluid that pushes fluid away from the outlet so it pulls in air every 10-15 seconds.

The other issue is that Alphacool didn't supply the vendors with the required O rings that line the pump as well as the flanges. This was one of the major sources of noise issues for a lot of people. They were sent to me by Performance PC's right away after I contacted them, but it still didn't fix the issue above.

Some QC issues with mine
1) The threads on the acrylic gave out (and I never overtighten) after remounting the pumps only a few times.
2) The faceplate was on upside down. When i unscrewed it to switch it around, the black coloring is an adhesive between the two pieces of acrylic, and it came off in spots.
3) The brass logo sticker was totally skewed and on crooked.

I recognize that these can be one off problems, so I wouldn't use it to say 'this res is bad', but the fact that it got through QC in this state makes me a bit unhappy.
 
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Just been doing some more tinkering and through the fortune/misfortune of having a pair of pumps I've noticed a distinct difference between the 2 which I can only think comes down to manufacturing.
One of the pumps emits a high frequency whine which isn't particularly loud or intrusive but the other produces a more low frequency vibration like the impeller hasn't been balanced properly.
I initially wondered if it was the pump housing in the res causing the issue, so I ran them both briefly dry and the results confirmed my findings one produces more noise at a more audiable/annoying frequency than the other. Considering these things are mass produced I would have expected some minor manufacturing tolerances, but the pumps sound like 2 entirely different units.
 
Not Impressed at all.

I would advise anyone against buying these pumps, they are incredibly noisy and incredibly variable.
I've got one that emits a hum, I guess it's not really that bad but I can hear it above the anything else in the house including the 7 fans all at 12 volts in my HAF X. The other one sounds like a coffee grinder and you can hear that from upstairs.
I don't know if you can consider these to be faulty units, as they do pump (not that impressively as it turns out) but by christ they are noisy.

They will stay in my rig for as long as it takes to get a DDC/D5 replacement.

I dunno if i've broken rules by doing this, but I took a video. The system is bled, on switch on both pumps are running then 2/3rds of the way through I cut power to the noisy one.

http://youtu.be/iGoMvQs-7eE

AVOID!!!
 
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Wasn't so bothered about the image quality, it was more the audio I was after. Youtube wouldn't let me attach audio from my IPhone. It's an Olympus SP-500UZ stills camera it did what I needed it too. ;)
 
You've mounted the pumps wrong...

I had the same kind of problem, you need to loosen the screws, make sure both screws are secured by the same amount.

It's not the pump making the noise, it's catching on the acrylic
 
Ha, was it always like that? Or did you never test it outside the loop?

Basically, I dont think they give you the right screws. They're a massive pain to mount, but make sure you dont over tighten things as they catch on the inner side of the res. I'd RMA the noisy pump, and run the res with the cap on until you get the new one.

I dont think they pumps are that bad, just the mounting sucks, and the screws they give you are very short, making you inclined to overtightening
 
It's always been noisy. Wasn't until it went in the rig and then started vibrating the hell out of the chassis that it became a headache.
I've got a replacement coming but when it gets fitted i'm going to take my dremel to res I think to see if I can smooth the flow path out........never thought I would be "porting" a reservoir!!!!

They are ok pumps, they aren't spectacular though but at £13 they aren't going to be, not entirely sure I trust them but a single is holding up on it's own at the minute.
 
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