A cautionary tale about AquaComputer's Cuplex Kryos PRO CPU block

[Colonel_Panic]

I wanted to share with the board something that just happened with my watercooling system.

Two weeks ago my "big rig" POSTed and life was good. I scored a 7.3 on the WEI and core temps on my i7 950 were about 38 C at idle, and maxed at about 60 C under extreme load. This was possible because flow was approximately 55 L/hour based on my Aqua Aquaero meter.

Then last week, the flow suddenly dropped to zero, and I shut the system down before any damage could occur (water temperature went up about 15 C). I started a little mechanical engineering troubleshooting to try to narrow down the problem, and after removing a few things from the loop, I ruled out the filter, flow meter and visually checked the mosfet/NBSB blocks. That left the CPU and VGA blocks, which I tackled today. The graphics card cover was fine, so I sealed that up, but the CPU block produced the problem (shown in the first photo).

http://www.wesg.ca/jE8

It appeared that the sediment/gunk built up from the previous owner's choice of coolant had plugged the cooling fins drawing heat from the chip. This was completely choking the flow.

http://www.wesg.ca/s89

This photo shows the block's design and the reason the gunk had stopped the flow. The oval mark on the left block is the O ring that seals out the inner area, leaving the only escape through the fins. While great for cooling, it is prone to blockages. I tried alcohol towels and running water, and eventually got it fairly clean thanks to some compressed air.

http://www.wesg.ca/gzD

I had hoped the filter I installed would catch most of the debris in the line, but apparently not. Thanks to this design, I can likely expect another occurrence in the future. What does everyone else do to avoid gunk buildup? I guess I just have to flush the lines more often, but what's a good "flushing agent"? Aqua used to sell another CPU block that was not only more efficient at cooling, but also less prone to this sort of problem. For some reason they don't sell this any longer, and the only choice is the Kryos series.

 

[AdvanSuper]

Did you flush the rad prior to installing?

 

[Tsumi]

Flush the radiator.

Use only distilled water. I have not noticed anything at all in my reservoir in the 6 months that I have used it. The only things you should be adding to your water is either PT Nuke or a silver killcoil, or both.

 

[Colonel_Panic]

I scrubbed the Reserators as best as I could before I added the coolant, but I'm guessing there was a lot of stuff in there. I suppose the best thing to do to prevent this is to flush the radiators now... that'll be tonight's job.

 

[theseeker]

I noticed you stated the previous owner. It has been well documented that you should always dssassemble Aqua blocks when new as they sometimes ship with gunk. I have had this happen to me in the past and I always check new blocks when I get them. It doesnt happen often, but it does happen.
It would be interesting to know what the previous owner used in his loop. A number of todays additives cause problems. Feser 1 caused me major nightmares and now I only use demin or distilled H20 with a few silver fittings.