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Water cooling problem

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Sharp

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Joined
Jun 9, 2001
I just built an evaporative cooler similar to the one in the nuclear cooling tower water cooling article but a little bit nicer [I plan on writing an article on it.] It keeps the [hot] water temp at 25ºC where ambient is 26ºC and humidity is 60%. My problem is this... MBM reports my temps as 36~40ºC [from sensor under proc, bent upward to make contact + a dab of thermal paste] which I feel is quite unacceptable especially for water cooling. As I said before the water temp after exiting the proc and north bridge blocks is 25ºC [1ºC below ambient.] I have a DangerDen Maze II block on the processor and I'm just wondering if the interface can really be so bad that there would be a 15ºC delta T. I took it off and re-applied the artic silver paste and that dropped the temps by about 7ºC [from 47 to 40.] The load is an Thunderbird 1460mhz 1.79V. I calculated the C/W somewhere between .17~.19, a good air cooler can do that! please somebody with watercooling experience help out here.

BTW can somebody post their hot water temps vs. MBM temps? specifically on an Abit kt7a/kt7a-raid
 
OP
Sharp

Sharp

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Jun 9, 2001
forgot to mention those temps are under full load, no load temps go down to about 2ºC over ambient [28ºC.] I have not measured the water temp at idle.
 

whiskeyinajar

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Jul 1, 2001
the mobo temp sensor has been known to be up to 10c off and what is your ambient temp that could be a reason for the bad temps
 
OP
Sharp

Sharp

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Jun 9, 2001
ambient is 26ºC, but the hot water return is 25ºC[actually below ambient due to it being an evaporative cooler.] I know the temps can be off by 10ºC but subtract 10 from 40ºC and you get 30, that's still 5ºC over water temp. I guess my main question is: is that normal?? How far over water temp is most people's processor
 

Robyn

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Jan 26, 2001
Well...if water temps are lower than cpu temps then it usual means the block is not flush with the cpu. Make sure the block is flat, I know I've heard many complaints particularly about the Maze2 not being flat.

What's your flowrate like? Not sure how evap cooling works, but you have to have a good flowrate in order to transfer heat.

But other than that, I cant think of any other reason why your cpu temps would be so high.
 

Flash

Member
Joined
May 21, 2001
Robyn (Jul 10, 2001 06:08 a.m.):
What's your flowrate like? Not sure how evap cooling works, but you have to have a good flowrate in order to transfer heat.

But other than that, I cant think of any other reason why your cpu temps would be so high.

Good point. What kind of pump are you using? You'll lose the benefit of the cool water if it's crawling through the water block.
 
OP
Sharp

Sharp

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Jun 9, 2001
I am using an Eheim 1250 pump. It's rated 317 GPH and is rated at 6'7" head. BTW I am using the motherboard temp sensor [the one under the socket] to measure temps. I am calibrating it now so I'll post in a little while the new [corrected] temps. If they still don't look so good I'll take the block off, clean it, and carefully redo everything :-( I think I might count the turns this time to make sure each side is equally tightened instead of using a ruler [couldn't hurt]
 

Ferg

Member
Joined
Dec 19, 2000
unless he has some ungodly lift then a 317 gph pump should be more than enough to cool the cpu. I think it is a bad temperature sensor. See what your temps are after it is calibrated. Anyway a C/W of .17 is pretty good. Only very few air cooled systems can do that and i bet that they are not as overclocked.
 
OP
Sharp

Sharp

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Jun 9, 2001
My temps are down to 36ºC today for stock speed [1333 Mhz.] Nothing has changed but that is 4ºC below the high temp before. I have it disasmbled right now and I'm scrubbing off all the arctic silver. I'm going to redo it all one last time. Currently the C/W calculated from room temp is 0.14~0.15 but room temp is 2º higher than water temp.

I have a Maze II block and a chipset cooler [in series.] The tower has a drop of about 2.5'. I plan to further cut back the drop size in the future [not sure how far.] I am also considering redesigning the whole thing to be about 14" high [6" for water reservoir, 8" for the drop.] I believe I could make a very high power cooler out of 3" tubing 6" or less high :) I'll work on those designs in the future...