Water cooling loop flow issue

[mikeschroder87]

Hey all,

I'm having an issue with my hardline cooling loop. I am unable to get any water flow beyond the cpu block. This video may be able to explain it better:

https://youtu.be/NHdNbfgqeOM

TLDW: My configuration is pump/res to gpu block (2) to Rad, then cpu block, then back to res. Coolant was pushed all the way through the loop, but trickled past the cpu block, then no flow into the block was observed. I've tried tilting the case in every direction, and adjusting the pump speed but nothing seems to help the coolant flow into the cpu block.

This configuration has worked for me previously in the past, I'm just trying to determine which part(s) of my loop may be causing the issue. I've recently drained the loop and rebent one of the tubes as part of my yearly maintenance.

 

[RememberThe5th]

Hello,
The possible thing might be that somehow the water is hold by vaacum in there. as the water didn't continue into reservoar the bulb is stuck there soo the water, did you actually open the cap of reservoar to let air out?

Did you check that fittings are all okay and not leaking? (just for my information)

 

[mikeschroder87]

Hello,
The possible thing might be that somehow the water is hold by vaacum in there. as the water didn't continue into reservoar the bulb is stuck there soo the water, did you actually open the cap of reservoar to let air out?

Did you check that fittings are all okay and not leaking? (just for my information)

Hey Robert,

I did indeed remove the cap from the res, and rotated the case with the cap off. I even spilled some coolant from the top by accident.

I removed every piece of tubing and seated them again to ensure that each connection is still water tight.

Any other suggestions?

 

[rubix_1011]

Looks like a combination of restriction and airlock.

Where your coolant returns to the reservoir, is this port blocked somehow? Is there a way to fill your reservoir more, also?

Your radiator is likely full of air, as is the tubing just exiting your CPU block which tells me your pump cannot push coolant through the air pocket. Air is compressible which is why it maintains, liquid is not. You need some form of way to essentially allow the gas bubble to get displaced by coolant and one way is to run your pump with the reservoir top vented.

 

[n0ns3ns3]

Are you planing to cool SLI + CPU with a single radiator ?
what can actually help the liquid to be pushed through the loop is switching the ports on the radiator - i mean when the case is on the side, inlet is lower than outlet. it would also help if you connected the GPUs in parallel

 

[mikeschroder87]

Looks like a combination of restriction and airlock.

Where your coolant returns to the reservoir, is this port blocked somehow? Is there a way to fill your reservoir more, also?

Your radiator is likely full of air, as is the tubing just exiting your CPU block which tells me your pump cannot push coolant through the air pocket. Air is compressible which is why it maintains, liquid is not. You need some form of way to essentially allow the gas bubble to get displaced by coolant and one way is to run your pump with the reservoir top vented.

Hi Rubix.

I'm attempting to run the pump with the reservoir open at the top, but its been running for hours now and it doesn't seem to be making any progress.

I think you're dead on with the air pocket theory however. I want to try draining the loop sometime tomorrow and removing the 90 degree fitting near the end of the loop as I suspect that is causing some restriction of flow.

 

[mikeschroder87]

Are you planing to cool SLI + CPU with a single radiator ?
what can actually help the liquid to be pushed through the loop is switching the ports on the radiator - i mean when the case is on the side, inlet is lower than outlet. it would also help if you connected the GPUs in parallel

Thanks for the tips, I will use this the next time I do a build like this. While these issues are valid, I don't feel like they are causing the problem outright.

Edit: Yes, I have been cooling all three blocks with one radiator, but to be fair it is a huge one.

 

[n0ns3ns3]

reconnecting tubes is not much of an effort to reduce the flow restriction (parallel GPU).

As for the rad, huge would mean it is at least 480mm long and over 40mm thick with fans in push pull.

 

[rubix_1011]

When you power the pump on, do you leave the cap vented? You will want to do this when you're filling the loop so that air can be displaced by coolant. Otherwise, it has nowhere to go and will attempt to compress, meaning your coolant will halt.

Agree on making the GPU flow parallel rather than serial, but you should still see movement.

 

[mikeschroder87]

Thanks to everyone who has looked at this or is currently. Update for you guys:

I removed the 90 degree fitting at the intake close to my reservior, to see if that fitting was responsible for the reduced flow. Sadly the flow did not change with a single piece of pipe.

I'm certain that the problem is either in the radiator or the cpu block, but I'm leaning toward the radiator. Does anyone have any ideas on how I can remove the air pressure from the radiator?

 

[rubix_1011]

When you are running the pump, is the reservoir cap open or otherwise vented?

 

[mikeschroder87]

When you are running the pump, is the reservoir cap open or otherwise vented?

Yes, it is. I ran the pump overnight with the cap off.

 

[rubix_1011]

Oooooh....I wouldn't step away from that pump running until you are certain it's actually moving coolant. If the pump manages to get an air pocket, you'll permanently damage the bearings. Those pumps are designed to always have coolant pumping through them.

Let me take another look at your video and try to see if there's anything that stands out. Can you post photos here? Like from IMGUR, Flickr or something similar?

 

[mikeschroder87]

Oooooh....I wouldn't step away from that pump running until you are certain it's actually moving coolant. If the pump manages to get an air pocket, you'll permanently damage the bearings. Those pumps are designed to always have coolant pumping through them.

Let me take another look at your video and try to see if there's anything that stands out. Can you post photos here? Like from IMGUR, Flickr or something similar?

I can post pictures, but I won't be home for another 5 hours or so. Bummer about the pump, is there a chance that it is damaged? I can order another.

 

[rubix_1011]

It's hard to say whether it is damaged or not. Next time you switch it on, note whether the fluid level moves or attempts to flow when the pump spins up. If it acts like it is at rest when power is off and then turns on and suddenly attempts to 'work' normally, it is likely OK. I am trying to determine if there is anything obstructing the rest of your loop from the CPU block back to your reservoir. Coolant makes it to the CPU block inlet (did it get there quickly, or simply trickle in?) but seems to struggle beyond it.

 

[n0ns3ns3]

Fill the res to the top, lay the case on the side, turn the pump on.
And do the observation rubix was talking about.
If the liquid moves on pump start, probably the pump is OK.
It looks like you are using some sort of D5 pump. Is it PMW or has the manual control ?
Some older PWM D5 variants din't go to full speed without PWM signal.

 

[animosityy]

Have you taken your CPU block apart recently? Even with the pump running near its minimum speed it should be making it though the loop. It looks to me like the jet plate or some other internal portion of your CPU is blocking flow. I would suggest taking the CPU block of and opening it up, cleaning it, and making sure it is assembled properly.

 

[animosityy]

Have you taken apart your CPU block recently? The pump should be plenty powerful enough even at the lowest speed to push fluid through your loop. I would suggest taking the CPU block apart, making sure the jet plate is still positioned correctly, and then giving it a good cleaning. You have have a clog from previous coolants or somehow jarred the block, moving the jet plate and blocking flow.

EDIT: Sorry for the double post. The website froze and made me thing I had to retype it! Oops!

 

[mikeschroder87]

Have you taken apart your CPU block recently? The pump should be plenty powerful enough even at the lowest speed to push fluid through your loop. I would suggest taking the CPU block apart, making sure the jet plate is still positioned correctly, and then giving it a good cleaning. You have have a clog from previous coolants or somehow jarred the block, moving the jet plate and blocking flow.

EDIT: Sorry for the double post. The website froze and made me thing I had to retype it! Oops!

Hi. I have not checked the CPU block. This sounds like a good idea. I want to try this next. I should be able to take a look at it tonight.

 

[mikeschroder87]

Hey guys, I solved the problem. Here is what I did:

Drained and disassembled the loop, flushed the CPU block, flushed the radiator, and toggled the pump speed down and up again. The loop filled up instantly.

Thanks to everyone who helped me resolve this.

 

[rubix_1011]

Interesting. Wonder what it was.

Anyway, very good news and glad to hear that you're up and running. Keep us updated with anything new.