Dual Pump Loop - Leaking

[StarTrek133]

Hi Everyone .. 

 

So I have been working on this build for 2 years now and now that I have everything needed I have ran into a few issues and need help .. 

 

So I figured out why I was leaking from the bottom of Res A .. It was because having two pumps running full speed I was getting back pressure and causing it to leak from the bottom .. By slowing the pumps down to 20% (1500 rpm) that fixed the issue ..

 

But now I have another issue .. what is slowly happening over time is Res B is draining into Res A and causing the fluid to raise to the top and leak out the top ..

 

I have tried turning Res A pump up to move the fluid out faster , but didn't solve the issue ..

 

Any thoughts / advice .. Really dont want to do dual loops as I am not sure how I would run the lines .. but might have too I dont know .. 

 

Thanks .. 

[MageTank]

17 minutes ago, StarTrek133 said:

Hi Everyone .. 

 

So I have been working on this build for 2 years now and now that I have everything needed I have ran into a few issues and need help .. 

 

So I figured out why I was leaking from the bottom of Res A .. It was because having two pumps running full speed I was getting back pressure and causing it to leak from the bottom .. By slowing the pumps down to 20% (1500 rpm) that fixed the issue ..

 

But now I have another issue .. what is slowly happening over time is Res B is draining into Res A and causing the fluid to raise to the top and leak out the top ..

 

I have tried turning Res A pump up to move the fluid out faster , but didn't solve the issue ..

 

Any thoughts / advice .. Really dont want to do dual loops as I am not sure how I would run the lines .. but might have too I dont know .. 

 

Thanks .. 

Start with isolation. Drain the loop (I know it sucks), plug a leak tester into Res B and confirm the res/pump are all solid. After that, cap off the end of each run leading out from Res B and confirm they are air tight. Continue adding more pieces of the loop back into the order until you encounter the first leak. It's a slow process, but its also one that is guaranteed to work.

 

Trust me, I know how annoying it can be to find leaks:

 

I have two radiators on the sides and 2 more in the back. One of my radiator POM tops had damaged threads and was leaking there. I had to plump this one piece at a time to eventually find the damaged threads because the leak was so small the old soapy water method simply didn't work.

 

Also, I like your chassis, mind telling me what it is?

[BiotechBen]

If you were able to get tops for the res that also had fittings, you could have an overflow equalizer at the top to mitigate the draining into one over the other problem.

[MageTank]

Just now, MageTank said:

Start with isolation. Drain the loop (I know it sucks), plug a leak tester into Res B and confirm the res/pump are all solid. After that, cap off the end of each run leading out from Res B and confirm they are air tight. Continue adding more pieces of the loop back into the order until you encounter the first leak. It's a slow process, but its also one that is guaranteed to work.

 

Trust me, I know how annoying it can be to find leaks:

 

 

I have two radiators on the sides and 2 more in the back. One of my radiator POM tops had damaged threads and was leaking there. I had to plump this one piece at a time to eventually find the damaged threads because the leak was so small the old soapy water method simply didn't work.

 

Also, I like your chassis, mind telling me what it is?

I just realized I didn't even read the core problem. Forgive my dumbness, it leaks out sometimes. 

 

23 minutes ago, StarTrek133 said:

But now I have another issue .. what is slowly happening over time is Res B is draining into Res A and causing the fluid to raise to the top and leak out the top ..

You shouldn't be seeing this at all, assuming both pumps are set to run at the same static speeds (no variable speeds tied to sensors) and both are flowing in the same direction. Right now, it sounds like pump B is pushing fluid faster than pump A is "pulling" fluid through it. Assuming both reservoirs were full with no air in them (and no cavitation in the pump, no excessive turbulence), you shouldn't be seeing this at all. 

 

Certainly a tricky one.

[manikyath]

two pumps with their own res in one loop sounds like problematic at best. presuming they are currently series, hooking them up in parallel may help with the balancing, although i'm not sure why you would have two pumps to begin with.

 

past that..

54 minutes ago, StarTrek133 said:

So I figured out why I was leaking from the bottom of Res A .. It was because having two pumps running full speed I was getting back pressure and causing it to leak from the bottom .. By slowing the pumps down to 20% (1500 rpm) that fixed the issue ..

NO, very bad.

it's still very much a potential leak, you just dont have enough water pressure to visibly push past the seal. the seal is faulty, fix it or replace it.

[LIGISTX]

11 minutes ago, manikyath said:

wo pumps with their own res in one loop sounds like problematic at best. presuming they are currently series, hooking them up in parallel may help with the balancing, although i'm not sure why you would have two pumps to begin with.

I agree. The only reason to run two pumps is if you have independent loops for CPU and GPU. There is not much reason to do this beyond just "cuz its cool looking", but putting them in series is just a waste and can cause issues.

 

I understand you already have it all plumbed up and holes drilled for this, but if it were me, I would take out one of the D5 pump internal's and just let it free flow, and only use a single pump. The actual "pump" part of the D5 you can just pull out once you take it apart.

[Ralphred]

5 minutes ago, manikyath said:

two pumps with their own res in one loop sounds like problematic at best

Indeed, from a fluid dynamics point of view you need to split the loop before the pumps, put some kind of backcheck valve on the outputs, then join them again. But even then this allows "pump A" to pressurise the "pump B" reservoir through the rest of the loop without some kind of "ballcock" system in place to check against this (which could be simply down regulating the opposing pumps output when a reservoir is above a certain level) but you are into custom pump control circuity then, and who know what the pumps are designed to run at/be driven by.

[StarTrek133]

Hey Everyone .. thanks for the help so far .. .I have already replaced all the o-rings in bottom Res .. I have also used the EK-Leak Tester as well on the loop .. The loop itself is fine but for some strange reason the Pump/Res both have a slow leak .. what is also strange is that there is pressure because when trying to take the tops off there normally stuck down from the pressure or running the system ..

 

I wanted to the dual pumps for redundancy as well .. I also wanted one loop with the double Rad for max cooling ..

 

Also for those who wanted to know its a Corsair 900D Super Tower Case ..