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Water Temp impacting Flow Rate?

clshades

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One side note the reason i chose series was for redundancy since check valves are not common place in computer liquid cooling. In parallel if 1 pump fails and there is no check valves the least restrictive path will be backwards through the other pump. I think your diagram actually covers that (that is a check valve after the pump isn't it?) just not everyone has played with dual pumps to even encounter that information.

In series if one pump dies it isn't much worse than having an extra 90' elbow in the loop depending on the pump model.

*I had the dual pumps when the mayhem pastel separated on me
Yes that's a typical reason for series. when you don't need head pressure. You would need a swing checks or spring checks to counter short circuiting. I prefer swing checks, less flow restriction. It would be nice to see some new options come up for the larger water cooling builds. It is possible to put a check on the pump itself.
 
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bjcsoln

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I just added the RPM rate to my AIDA panel (in addition to the flow rate) so that might be the next test I do after I confirm about the EK Fog / viscosity impacting the flow rate. I really should be gaming, but then I get side tracked on stuff like this..
 

bjcsoln

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Okay, so some updates on this - nothing has changed in my loop except for the draining of the mystic fog to be replaced with mayhem's clear killer. And I am still getting dramatic swings in flow rate with only a few degrees in temp change.

And again, noting that
a) these temps are still well within acceptable limits
b) the flow rate reported amount is not accurate as the barrow sensor is calibrated for a 10m tube and I am using 16m, but using the variance in % flow rate is practical.
c) DDC 3.4 PWM pump is set to max
d) 1 GPU, CPU, 240 rad and 360 rad

When the coolant temp is below 35c, flow rate is ~7.5L/Min. When the coolant hits 40c this rate will drop to ~1-2 L/Min.

This just doesn't sound right - I don't think it should be impacted that much (or maybe I am wrong). Is the heated fluid increasing the pressure on the loop (due to expansion) which impacts the flow rate? Is it the mayhem additive? Should I even be worried about this (god damn AIDA panel and all this data!!)?

While I am probably over panicing about this, it just doesn't feel like the flow rate should be impacted this much with just a small change in coolant temp.

Any thoughts here?
 

Sagath

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Is the system pressure locked? I'd be interested to see if you opened the fill cap up if this problem went away.
 

clshades

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I put a pressure relief vent on my system in the fill port of my dual bay reservoir. You will see pressure changes as the temps fluxuate. Similar to this, I don't see the one I used, it had a small plastic tube you could put on it which wasn't needed in my setup. It will let the air out if it pressures up from heat.

 

JD

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Sounds like it could just be the sensor too that "fails" when it heats up? The Barrow one I have, it makes a whining noise at certain temperatures so I'm not sure how much I would trust it...
 

bjcsoln

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Sounds like it could just be the sensor too that "fails" when it heats up? The Barrow one I have, it makes a whining noise at certain temperatures so I'm not sure how much I would trust it...
JD, in this case I get the same consistent results over and over again so I don't think it is the meter. When the temps go up to the 38-40c, the flow drops dramatically.

And I did pull out a cap in the loop to release any pressure - that did not make a difference so I think it is something else.
 

clshades

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JD, in this case I get the same consistent results over and over again so I don't think it is the meter. When the temps go up to the 38-40c, the flow drops dramatically.

And I did pull out a cap in the loop to release any pressure - that did not make a difference so I think it is something else.
That shouldn't happen. Is the flow meter impellor based?
 

JD

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When the temps go up to the 38-40c, the flow drops dramatically.
Do you actually observe this outside of what the flow meter tells you? A drop of 5L/min should be noticeable in your reservoir or a block if you look carefully with a flashlight.
 

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