Water temperature probe placement

[Genesius]

Hi all!

I have bought a water temp sensor for my crazy cooling rig, but where should I place it?

I can put it just before the cpu
just after the cpu

which do you think matters more? the temp going in or out? or does it simply not matter

 

[CDNMeatShield]

what unit are you using to read the temp data?
Ive got the TMS 205 with expansion board.
with that I have 10 points I can monitor for heat and 2 flow rate meters as well.
I HIGHLY recommend getting it.
withthat said if you don't I'd put the temp sensor after your CPU as you want to keep track of what its doing and not b4. the CPU may have a temp sensor that can be read via CPUZ or ... the temp MAY be in the range of +10 above the water temps.

hope this helps.
CS

 

[Genesius]

Thanks or that.

I have an Aquaero 5LT. I just purchased a second probe and decided not to be such a tight-arse, so now I will be able to take temperature readings of the water before and after the cpu and set alarms and fan profiles according to the water temp and not the cpu temp.

I can add a flow meter to the Aquaero but its not really worth it IMO, the water is either flowing or its not.

 

[SuB]

Doesn't matter where you put it. Water temp throughout the loop won't change by more than 1 degree.

Edit: Also, I'm not sure I'd gear the fans to the temp over core-temp.... core temp can go up much faster than that of the fluid that's cooling it (always the way with water).

I guess if you want a more gradual, average increase.. but it you want to react to load, I'd keep it tied to the core temps.

 

[Genesius]

Doesn't matter where you put it. Water temp throughout the loop won't change by more than 1 degree.

Edit: Also, I'm not sure I'd gear the fans to the temp over core-temp.... core temp can go up much faster than that of the fluid that's cooling it (always the way with water).

I guess if you want a more gradual, average increase.. but it you want to react to load, I'd keep it tied to the core temps.

EXAMPLE
Core temp fluctuates a lot more than the water temp in the loop. Increasing the fan speed on the radiator will cool the water in the rad not the cpu directly. if the cpu goes from 25C to 70C the water in the loop might go up by 5C. so the fans only have to control that 5C temperature difference in the loop as that's the ONLY thing the rad fans can control.

I have decided to put a probe either side of the cpu so I can watch the temperature change and this will give me a better understanding of how well my cpu block is doing.

 

[CDNMeatShield]

flow rate does mater
I have D5 Vario. At setting of 3 of 5. pushing water through 10 feet of 1/2" hose 2 gpu 1 CPU 1 Northbridge triple 120 rad...**see my build** I'm getting 0.8 -0.9 GMP.
At room temp of 21C i'm idling at 23C. Load of 12 hrs of BF3 will not get this past 49C. slowing or speeding up of the water WILL make a difference to your set up and everyone is different.
EG I'm going to add a second D5 to go from my res to the Rad *a 10C drop in temp* then to a second pump through my manifold.

I have to also say that if your core temp is OVER 10C difference to your water you have put too much thermal past on. My CPU water temp and core temp are 8-10C off ALWAYS. Same with GPU.

If you have a look at my picture you can see that my GPU temp on precision X reads 34C. GPU-Z reads 35C, my water temp reads 27C and these are both on the same line of water. My CPU is the same 28C

 

[SuB]

I have decided to put a probe either side of the cpu so I can watch the temperature change and this will give me a better understanding of how well my cpu block is doing.

They will both read almost exactly the same or MIGHT vary by 0.1c

Personally I'd put it hidden as far out of sight as I can so it's neat.

honestly it doesn't go in one side warm, and come out the other warmer.. it's moving WAY too fast

 

[CDNMeatShield]

I have no idea how you can say that...
your telling me that my temp reading 23C into my CPU and 28C out is NOT heating up my water that fast?? AT 3 LITERS a MIN....
Please sir explain that to me

 

[Genesius]

flow rate does mater
I have D5 Vario. At setting of 3 of 5. pushing water through 10 feet of 1/2" hose 2 gpu 1 CPU 1 Northbridge triple 120 rad...**see my build** I'm getting 0.8 -0.9 GMP.
At room temp of 21C i'm idling at 23C. Load of 12 hrs of BF3 will not get this past 49C. slowing or speeding up of the water WILL make a difference to your set up and everyone is different.
EG I'm going to add a second D5 to go from my res to the Rad *a 10C drop in temp* then to a second pump through my manifold.

I have to also say that if your core temp is OVER 10C difference to your water you have put too much thermal past on. My CPU water temp and core temp are 8-10C off ALWAYS. Same with GPU.

If you have a look at my picture you can see that my GPU temp on precision X reads 34C. GPU-Z reads 35C, my water temp reads 27C and these are both on the same line of water. My CPU is the same 28C

Flow rate does matter but as my system only has one speed, it doesn't matter to me. Also my system has 6.5-7 litres of water in it so my fans very very rarely kick in. The 10C thing was just an example.

They will both read almost exactly the same or MIGHT vary by 0.1c

Personally I'd put it hidden as far out of sight as I can so it's neat.

honestly it doesn't go in one side warm, and come out the other warmer.. it's moving WAY too fast

I will try and hide them. But I have to disagree, water does go in one side at room temp and out hotter and depending on how fast the flow rate is depends on how hot, also how well your CPU block transfers the heat from it to the water running through it. If your water goes in and out of the blocks at the same temp, why have a rad? Where does that heat energy go?

I have no idea how you can say that...
your telling me that my temp reading 23C into my CPU and 28C out is NOT heating up my water that fast?? AT 3 LITERS a MIN....
Please sir explain that to me

 

[CDNMeatShield]

Yes I also have a 3 liter res and the total volume is about 5 in the system.
beauty of 1/2" lines

 

[Genesius]

Wow what res do you have? That's a fair bit of water, I know mine is a lot but I thought 1-1.5 litres was about standard

 

[CDNMeatShield]

see my build here

 

[alpenwasser]

I'm getting 0.8 -0.9 GMP.

I've looked at your setup (sweet btw, as mentioned in your intro thread ), and from what I can tell you have one flow meter before the first manifold and one after the second one (if that's incorrect, feel free to clarify)? In that case you are not getting 0.9 GPM ond the CPU loop part itself I'd reckon.

I have to also say that if your core temp is OVER 10C difference to your water you have put too much thermal past on.

Not necessarily. If you start upping core voltage this is easily possible (expected, even), even in a perfectly tuned setup.

I have no idea how you can say that...
your telling me that my temp reading 23C into my CPU and 28C out is NOT heating up my water that fast?? AT 3 LITERS a MIN....
Please sir explain that to me

Question: This is 23C into the CPU block, 28C out of the CPU block, not 23C around first manifold, 28C around second manifold (just to be sure )?
Again, flow rate in the CPU part is not actually 3 lpm if I have understood your flow meter setup correctly. I would be very interested to get the actual flow rate in the CPU part of your parallel loop.
BUT: This is extremely unusual. For most people temp differences between different parts of the loop are indeed lower than that. I'm not saying your readings are wrong, but in 10 years of water cooling myself and perusing forums I have never once encountered anyone with similarly extreme data.

But I have to disagree, water does go in one side at room temp and out hotter and depending on how fast the flow rate is depends on how hot, also how well your CPU block transfers the heat from it to the water running through it. If your water goes in and out of the blocks at the same temp, why have a rad? Where does that heat energy go?

It indeed never goes in and comes out at the exact same temp. But if you have high enough flow rates (most w/c setups) it will only have an extremely small temperature difference. Of course the temperature needs to change at least a little, otherwise no heat could be transferred from block to water .

As an example, have a look at some of the radiator reviews (yeah, I know, we're talking about blocks here, but the principle stays absolutely the same. A radiator is just a block "in reverse" from the point of view of the water. What heat comes into the water in the blocks must go out in the rads, after all) from martinsliquidlab.

For example, this one.

Temps into the radiator for the three different fan speeds are: 36.79, 36.01, 36.29 deg C.
Temps out of the rad are: 36.56, 35.54, 35.55 deg C, respectively.
So temp differences are 0.23C, 0.47C, 0.74C, if I have done my math correctly.

Flow rate was ~1.5 GPM.

If you really wanted to get into the science behind this, you'd have to model the system and do some steady-state calculations on it with basic thermodynamics. We actually did this in a lecture once for a plate heat exchanger to find out if it's more efficient to have the liquids flowing in opposite or the same direction for better heat exchange (it's opposite, by the way ).

 

[Genesius]

Very detailed as usual alpenwasser! I do enjoy reading longer posts. Yeah CDN your setup is sick!, why do you go from a thin hose at the rad to a thicker hose in the rest of the rig? Is it because it splits off 2 ways or is it just that Zalman made the res that way? I like the copper as well.

As it is this thread has gone a bit off track, so I'll add this for,any future reader.

I found out that it doesn't really matter where you put the temp probe if you have only 1, as long as your system is set up with a good flow rate.

However if you have 2 probes like I now do, it would be good to place one on the input side of the hot area (GPU,CPU,ram cooling) and one on the output after the hot area. Then you can see how much the water is heated by that area and adjust the flow rate accordingly. I'm still not convinced that a flow meter is necessary. I will be setting my fans up using the average between the input and output temp.

 

[CDNMeatShield]

Genesius: as Zalman comes from the factory with 1/4" out and I did a step to 1/2". That will be replaced in the next week when I do a swap to 1/2" QDC then a 1/2" re run in and out.
Ill put together a show vid of my "loop" today some time and post it. I'll point out my temp marks.

A Flow meter is not necessary but why not, the more info about my sys the better.
My flow video

 

[Genesius]

yeah if a flow meter was included for the Aquaero I would but aquacomputer try and squeeze every penny out of you buy not including anything with the controller.

I suppose they cant include too much because the system can be used for so many things, but they don't even include mounting ears to mount the thing!

A flow meter for the aquaero 5 is £35 so not worth the added expense when flow rate is something I cant control, if I had a D5 I probably would.

 

[alpenwasser]

Very detailed as usual alpenwasser! I do enjoy reading longer posts.

Yeah I have a tendency to spontaneously produce massive walls of text if given the right topic. Glad they are appreciated by at least someone :lol:

Ill put together a show vid of my "loop" today some time and post it. I'll point out my temp marks.

Very much looking forward to that.

EDIT, because simultaneous post

yeah if a flow meter was included for the Aquaero I would but aquacomputer try and squeeze every penny out of you buy not including anything with the controller.

I suppose they cant include too much because the system can be used for so many things, but they don't even include mounting ears to mount the thing!

A flow meter for the aquaero 5 is £35 so not worth the added expense when flow rate is something I cant control, if I had a D5 I probably would.

I think quite a few people aren't really interested in flow rates but wish to use the Aquaero more as a fancy fan controller. So they would be paying quite a bit extra for something they don't need (this is based on extensive market research done by my imagination ).

I've been using Aquacomputer stuff for about 10 years now, and while build quality and performance has always been very good to phenomenal in my personal experience, they have never reallly been very generous with accessories.

And in the end, what matters are the actual temps of your hardware. What flow rate or water temps you have isn't really all that important (not that I'm not curious myself, very much so, but necessities these things are not imho).

/EDIT

 

[Genesius]

I understand what your saying and this is my first Aquacomputer product, and I'm impressed with it, but it should have included mounting ears. How do they expect it to be installed? So it was £80 for the Aquaero 5 LT plus £9 for the ears, but then if you run 4 fans at low speed the unit starts to over heat so you need to buy the heatsink which I think should have also been included. As it comes you get a great fan controller that you can't mount and can't control fans with because the unit overheats trying to dissipate the energy when the fans slow. These 2 items aren't optional n my opinion, they should be there.

Flow meters and water temp sensors should remain optional extras because as you say there are people who don't use this for water cooling at all.

 

[CDNMeatShield]

Please have a look at Koolance TMS 205

 

[Genesius]

Looks good but I've already got the aquaero and I'm happy with it