After an anxious 48 hours things are finally clam and I have some time to report on the last couple of day’s developments.
Test loop, Idle
As you hopefully worked out from my previous - and uncharacteristically short - post, I began the initial water testing on Friday. (Sorry that one pic was all you got, suffice to say I was more than a little tired out by that point. You would not believe how many attempts it took just to type that one vaguely intelligible line)
. Though the process was not exactly plain sailing to begin with, I am delighted to say (at the risk of jinxing things)
that the test loop is now stable, the crosslinked pipework configuration works, and that the system has been filled and running completely leak free for a little under 36 hours so far. The Aquaero is hooked up to my test bench’s power supply (so the pumps are following my normal PC usage)
, going through several cycles of 4-6 hour continuous running, 1-2 hour breaks, and sitting idle overnight without any problems.
Test loop, Running
To take this back a bit, last week I was doing the air leak test of the individual components and subassemblies – which all went very well. Unfortunately when I tried to test the whole system, it was useless. I’d forgotten, because this little project has been going on a while now, that those reservoirs had been shortened (by about 15mm)
to fit the space more comfortably. Consequently the tubes lost their top screw thread and the caps have been reworked as push-fit. This doesn’t matter, because the water level doesn’t reach them, but it does mean that they are no longer air tight. Therefore, at that point, I just had to take the plunge and try it with water.
The vast majority of the loop was absolutely fine (thus far not one of those rotary fittings appears defective!)
, however those acrylic pipes at the bottom have been problematic. So I took them back out, checked and re-sealed the caps with even more flexible adhesive to be absolutely sure they were ok, and reinstalled them as carefully as I could. This appeared to work, and the system ran all afternoon and evening (continuously, from just after 5PM through to midnight)
without so much as a drop (whilst I paced around nervously, constantly checking, and taking some photos for you lot)
. Sadly, overnight, it leaked a distinctly unambiguous amount of water over a similar time period from several of the same places . However since late yesterday morning, after a lot of painstaking adjustments to the tightness of the compressions fittings, it has remained absolutely bone dry. Which is a massive relief.
I believe the reason why the leak showed up overnight is due to a small issue with backflow. From about nine tenths full, the reservoirs will drop down to half level as the pumps fire up and water starts to get circulated through the system (the return to the reservoirs is at the top and a lot of the CPU-side components are higher up in the case, so the loop will not fill completely under gravity alone)
. When the pumps turn off, the flow reverses under the head pressure, the water is forced back up through the bottom of the reservoirs, and they slowly rise to their previous level. This means that 1. The volume and weight of water in the reservoirs is a lot more when the system is idle - which I think is why the leaks in the lower acrylic pipes showed up during that time, rather than over an equivalent period when the system was running. 2. Every time the pumps turn off, air gets re-inducted into the top radiator - which more than a little unhelpful. 3. (and most importantly of all)
the reservoirs aren’t full to the top of the sleeve window during operation - and thus, as you can see from the pictures, only the bottom half looks the way it’s supposed to (utterly unacceptable!)
I really should have foreseen this one – but I didn’t. Fortunately it is a relatively simple fix, it just requires the addition of a check valve on the output from each reservoir to prevent any backflow of water.
Although I have (for the moment)
got those acrylic pipes sorted out, I must admit that I remain a little nervous about them. From what I can tell, the leak issue is to do with the seal at the O-ring rather than the seal between the tube and the cap. The rubber is quite thin and not that squishy, so it takes very little in the way of a misalignment for it not to compress evenly enough to seal properly. This may well just be down to shoddy preparation of the tubes on my part (more than likely, I am a total novice at this after all)
but it’s also not helped by the fact that three of those pipes are connected to an assembly of rotaries at both ends, so the whole thing is not particularly rigid. I’m a bit terrified about knocking one of the tubes, even slightly, during the hardware installation (probably whilst doing the awkward job of fitting the cables)
and then getting a nasty surprise when the loop is refilled. But then again some of that pipework does now have to be modified anyway (to fit the check valves mentioned above)
so perhaps I’ll simply make a better job of it 2nd time around.
Beyond this a few other little issues were identified during the test so far. Firstly the CPU-side flow sensor (the Bitspower one)
isn’t running. It may be that the jet pressure isn’t high enough and it needs the smaller reducer, but from the look of it I think it’s just stuck. Secondly the resistance of the GPU side isn’t nearly as high as I feared it might be, and as such the transfer tube isn’t fully able to compensate for the disparity when all three pumps are running at full speed. So No.1 and No.3 just need to be turned down a bit. Finally I discovered how very helpful it would have been if I’d actually remembered to label which set of cables goes to which pump.
All this notwithstanding - the concept works, the construction is holding, and - when full - the reservoir lighting effect looks the way I wanted it to. The water is currently going round and round on the inside of the tubes and not leaking all over the floor. So on balance, all things considered, I think we can chalk this one up as a success.
One more step forward.
Originally Posted by Kojaqe
Wonderfully , technically , creative build - subbed...
Thanks very much, its kind of you to say. I’m hoping it won’t be that much longer before you get to see the actual hardware fitted.