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Discussion Starter · #1 ·
Hey folks. So I'm about a month into my first open loop, temps and performance have been fine, but I'm noticing a peculiar issue: my little flow meter (Bykski Inline Flow Meter and Thermometer Safety Module w/ OLED Display ) has been steadily reporting lower and lower flow rates over time. I had it set at about 3.8 L/min @ 75% pump speed (2x D5 pumps, tested independently to confirm working). I noticed it slowly falling over time so I would bump the pump speed up to compensate. At this point I'm at about 95% pump speed (reported speeds in the bios have not fallen) but the flow meter is reporting just 2.9 L/min at the day and time of this post which is almost a full L/min lower than when I started, and at a higher pump speed.

A visual inspection of the CPU and GPU block (as best I can without draining; liquid is semi-transparent) shows nothing unusual. The spinning flow indicator on the distro plate does not appear to be turning any slower than it ever did. And again, the pump speeds shown in the bios have not fallen. Is there something I'm missing here that could be causing this? Should I be concerned that something I don't see is going on in the loop or is this just a "cheap flow meter" accuracy drift issue? At what point should I take action, if any? I'm a bit hesitant to drain the loop right now because I don't have any of this particular fluid handy to replace it with after a flush, but I do have an alternate clear fluid I can drop in if that is the recommendation here.

Thanks as always.
 

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Have you noticed if the water is not jumping around in the reservoir as much? Some things that have hurt flow in my limited experience:

1) Clear buildup on CPU block fins that I couldn’t see through acrylic top.

2)Soft tubing collapse caused by the vacuum pressure from 2 pumps. This happens on the tubing run that goes into the first pump.
 

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Discussion Starter · #3 · (Edited)
Thanks for the response.

Water seems to be jumping the same as always coming back into the reservoir. Tubing is acrylic so pinches would not be a culprit here (unless something went terribly wrong lol). On the subject, both pumps are the same (different locations in the loop), running off a PWM splitter to ensure the same RPM.

edit: just checked each pump separately. they are working as expected. Each gets about 1.8 L/min separately on the meter. Currently 2.8 L/min combined on the flow meter. Definitely showed a much higher reading a month ago. Nothing has changed with the setup.
 

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i havent had this issue per se but I have the same flow meter and it's not great. my flow rate stays constant but after about a day of uptime the total flow in liters turns into a garbled mess of symbols, and in the past day my flow rate now reads zero. if I restart the computer all the bugs go away but they slowly come back. I think its just these particular flow meters


edit: nevermind mine is a barrowch
 

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I would get it nice and heat soaked under full load and record all the relevant temps. If the flow keeps dropping, keep testing until you see it affecting your temps. That's when I would drain the loop to investigate.
 

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Robotic Chemist
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Sounds like a clogging block to me. :(
 

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I have the same flow meter/thermometer, but unlike you, my flow rate hasn't changed. The cable on this flow meter is so flimsy I broke mine. I had to buy a JST cable from China and I was fortunate to have rightly guessed the size (two-pin micro JST GH 1.25). About the pins, it's just positive and ground so there's no data signal. That means you can't upgrade any firmware.
 

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Discussion Starter · #9 ·
Sounds like a clogging block to me. :(
is that possible in a rigorously cleaned, new system only a month in?

I would get it nice and heat soaked under full load and record all the relevant temps. If the flow keeps dropping, keep testing until you see it affecting your temps. That's when I would drain the loop to investigate.
I'll do that. Run some games and record the max temps from hwinfo. But just eyeballing HWinfo, temps seem about the same as always. I know the GPU hasn't change temps because I keep watch that like a hawk. CPU might be a different story.

Thanks for the suggestions, everyone.
 

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I think it's probably the fault of a crappy flow meter than any blockage issues if you vigorously cleaned the system prior to use. What did you clean it with, a Blitz kit?

Sent from my SM-G965U using Tapatalk
 
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