What exactly is happening here (water trying to flow up unused inlet tube and out top of res)?

lopoetve

Fully [H]
Joined
Oct 11, 2001
Messages
30,100
IMG_9365.jpg


Was playing some hardcore doom eternal. The like to the left is the actual inlet from the radiator below, the line in the middle bottom is the drain line (loops around back). Up top is the fill and an optional inlet (with straw that goes down into the res) - and water has started to fill that. At one point, it filled enough to actually push out around the plug and leaked into the top hat of the res (Corsair XD7). Do I have the wrong kind of plug up there? Too little water letting that air expand and push it up the tube? Tried opening the fill (as you can see) and that didn't change it. Letting the system cool a bit before I touch it.
 

Nobu

Supreme [H]ardness
Joined
Jun 7, 2007
Messages
4,721
Pressure from expansion due to heat is compressing the air in that tube as the water expands into the space.
 

lopoetve

Fully [H]
Joined
Oct 11, 2001
Messages
30,100
Pressure from expansion due to heat is compressing the air in that tube as the water expands into the space.

Ok, so I need more liquid (as liquid doesn't expand, just air) in the res? I did check for bubbles in the system (4 times now - didn't get any on the last test, but did get a few on the first three).
 

Nobu

Supreme [H]ardness
Joined
Jun 7, 2007
Messages
4,721
Ok, so I need more liquid (as liquid doesn't expand, just air) in the res? I did check for bubbles in the system (4 times now - didn't get any on the last test, but did get a few on the first three).
Liquid does expand, just not nearly as much. Could also be the air outside the tube in the res pushing it up though, I guess.
 

lopoetve

Fully [H]
Joined
Oct 11, 2001
Messages
30,100
Liquid does expand, just not nearly as much. Could also be the air outside the tube in the res pushing it up though, I guess.

That's what I thought at first, but opening that plug didn't seem to change anything. This also only seems to happen ~sometimes~ - other times I'll play for an hour or two (or run prime/3dmark stress tests), and it won't go up the tube even an inch.

Guess I'll get a new stopper for that one and add more coolant - was saving the spare bottle for once 3090 came out to add it to the loop.
 

Nobu

Supreme [H]ardness
Joined
Jun 7, 2007
Messages
4,721
That's what I thought at first, but opening that plug didn't seem to change anything. This also only seems to happen ~sometimes~ - other times I'll play for an hour or two (or run prime/3dmark stress tests), and it won't go up the tube even an inch.

Guess I'll get a new stopper for that one and add more coolant - was saving the spare bottle for once 3090 came out to add it to the loop.
Did you add coolant and then close the loop while it was warm/hot? That might explain the descrepency. I kinda doubt it's leaking, but I guess you can't rule out the possibility.
 

lopoetve

Fully [H]
Joined
Oct 11, 2001
Messages
30,100
Did you add coolant and then close the loop while it was warm/hot? That might explain the descrepency. I kinda doubt it's leaking, but I guess you can't rule out the possibility.

Once it settles, it always settles at exactly the same point, so unless it makes it to the top (which has happened once), I'm not losing coolant anywhere I can see.

Thinking about the last time I filled it - it might have been running for a little bit, but that was weeks ago. It's been 100% level, then I'll game, and sometimes the straw will start to fill.
 

lopoetve

Fully [H]
Joined
Oct 11, 2001
Messages
30,100
have you tilted it around to make sure you dont have an air pocket.

Yep. Four times. First three I got a couple of tiny bubbles out, last time didn't get anything out - and I tilted it pretty far over every time (imagining what a bubble would do to try and force it out). Shaking it too. Short of actually putting hte case on a rotisserie to spin it, that is - and making sure I didn't dry-run the pump.
 
Joined
Apr 5, 2016
Messages
2,195
If you're not using that inlet on the top of your res, you should take it apart and remove the downpipe. It serves no purpose and creates the potential for issues like this. If the water was creeping up it, then the plug on that port was not sealing properly, either.
 

lopoetve

Fully [H]
Joined
Oct 11, 2001
Messages
30,100
If you're not using that inlet on the top of your res, you should take it apart and remove the downpipe. It serves no purpose and creates the potential for issues like this. If the water was creeping up it, then the plug on that port was not sealing properly, either.

Can you remove the downpipe? I'll google, but I hadn't seen a way.
 

jmilcher

Supreme [H]ardness
Joined
Feb 3, 2008
Messages
4,671
If you're not using that inlet on the top of your res, you should take it apart and remove the downpipe. It serves no purpose and creates the potential for issues like this. If the water was creeping up it, then the plug on that port was not sealing properly, either.
I was thinking the same thing. It could only creep up if the seal on the stop is leaking air out.
 
Joined
Apr 5, 2016
Messages
2,195
As others have said, if the liquid is being pressed up though that tube, the culprit is expansion somewhere in your loop. It's not outrageous to believe that even a tiny pocket of air in a rad could expand enough to do this. It would only take a couple in/h2o pressure difference - which is a tiny fraction of a PSI - to raise the fluid through that tiny column.

If it's possible for you to do so, I'd highly advise that you replumb the return to the res to utilize that downpipe as your return line. In my experience, bottom-return reservoirs take ages to bleed the loop, because any air returning to the res from the loop has a really high chance of being sucked right back through the pump. The purpose of the downpipe when used that way is to place the return under your water line so you're not aerating your loop with a "waterfall" back into the res.
 

lopoetve

Fully [H]
Joined
Oct 11, 2001
Messages
30,100
So I bought new plugs (wanted to replace the plastic ones with better ones anyway) - pulled off the one on the straw and immediately, bubbles as air flooded in. Sealed it up with the new plug, fired the system up - no water in the tube (100% air) after several hours of doom ultimate. Huh.

VanGoghComplex - thought about replumbing - that would go from the bottom rad up and around back into the top, which is ... doable, but would be more complex than the little loop now. I may redo it once I get a 3080 under water, as I have to drain/tweak at that point anyway. Wouldn't be hard to make an additional line, block that inlet, and re-route. But for the moment, it seems to be fine.
 
Joined
Apr 5, 2016
Messages
2,195
So I bought new plugs (wanted to replace the plastic ones with better ones anyway) - pulled off the one on the straw and immediately, bubbles as air flooded in. Sealed it up with the new plug, fired the system up - no water in the tube (100% air) after several hours of doom ultimate. Huh.

VanGoghComplex - thought about replumbing - that would go from the bottom rad up and around back into the top, which is ... doable, but would be more complex than the little loop now. I may redo it once I get a 3080 under water, as I have to drain/tweak at that point anyway. Wouldn't be hard to make an additional line, block that inlet, and re-route. But for the moment, it seems to be fine.
Wait, you were using the plastic dust plug as a cap? That explains everything - that thing wasn't a watertight piece, it was just there for shipping. I thought it looked funny in your pictures!
 

Nobu

Supreme [H]ardness
Joined
Jun 7, 2007
Messages
4,721
Wait, you were using the plastic dust plug as a cap? That explains everything - that thing wasn't a watertight piece, it was just there for shipping. I thought it looked funny in your pictures!
Wait...

View attachment 276288

Was playing some hardcore doom eternal. The like to the left is the actual inlet from the radiator below, the line in the middle bottom is the drain line (loops around back). Up top is the fill and an optional inlet (with straw that goes down into the res) - and water has started to fill that. At one point, it filled enough to actually push out around the plug and leaked into the top hat of the res (Corsair XD7). Do I have the wrong kind of plug up there? Too little water letting that air expand and push it up the tube? Tried opening the fill (as you can see) and that didn't change it. Letting the system cool a bit before I touch it.
Huh...

Yeah, they might work, but I wouldn't trust 'em. Should be good now that you swapped them out.
 
Top