Circulating Bubbles. Help?

[UnusualSuspect]

Hey,

I've got my watercooling setup all ready to go, but I've run into one problem with it. The pump seems to be circulating small air bubbles. If I do the switch on/switch off thing then the bubbles slowly dissipate, but as soon as I leave it running for about 30 seconds or so, the bubbles start to reappear. The reservoir makes weird gurgling sounds and the bubbles start travelling up the first tube again.

For a pump I'm using the Laing DDC with Alphacool top and res bay, which I figure is the problem. As the water churns about from having it thrown at speed into the bay, the pump is sucking down the occasional bits of air and blowing them back into the tubes.

Is there any way of stopping this? I figure if I can't sort this out then I'll put in a T bend, strip out the res and use the Laing purely as a pump. It just seems a bit weird that this wouldn't have been designed out of the whole setup. Maybe the water is just travelling too fast? Is there a way to slow it down?

Any help would be appreciated, I'm at my wits end here. On a side note, however, I put the loop into the computer for a test run, only plugged in the necessary stuff - motherboard, graphics card - and in the BIOS I was getting a rather satisfying 28-32c temperature reading. This frankly amazes me, as previously on air it was sitting a good 10-15c higher. Awesome.

For reference: Res/Pump -> GPU -> CPU -> Rad -> Res/Pump

I get a lot of bubbles coming out of the GPU - EK8800 - they appear like a small stream travelling down the centre line of the tube and into the CPU block.

 

[UnusualSuspect]

Bubbles will disappear and be purged from the system given time. I disturbed mine two weeks ago and still occasionally here the odd bubble get nudge out of one of the radiators.

One thing I would say is your loop doesn’t seem to be right. I would say it needs to go res/pump > Rad > CPU > GPU > Res/pump.

How long roughly? I mean, I have a ton of tiny bubbles taking up residence here.

And I read that the design of the loop doesn't really matter, because the temperature is going to stay the same regardless of which goes where. However, if you think it will make a difference, I can just reverse the tubing in/out of the pump. Read my loop backwards.

 

[UnusualSuspect]

Is it possible you have a tiny leak? Somewhere air is just making its way in to the system?? Don't want to scare you but it might be worth getting some loo roll and wiping around all the joins to see if you pick up any moisture.

Bingo! That part I mentioned, where theres a spiral of air bubbles coming out of the graphics card. I found a tiny spot of water there. Probably the barb needs tightening slightly. Will try that next.

 

[UnusualSuspect]

So, I changed the loop so its Res/Pump -> Rad -> CPU -> GPU -> Res/Pump.

Still getting the same problem. The amount of air bubbles is insane, especially coming out of the GPU block. No idea why this is happening, I'm thinking of just completely removing the GPU from the loop and sticking the Chipset block in instead. I kept it out originally because I only have a 1 fan radiator and figured the temperatures wouldn't be worth it.

I'm going to try two things. 1) Remove the GPU block and insert the Chipset block in its place. If I still get bubbles coming from the pump then I'm going to do 2) Remove the res from the pump and put in a T section. And if that still doesn't work, I give up.

With the GPU and CPU in at the moment, I'm getting temperatures of 46c GPU and 37c CPU, which isn't too bad. 10c off what I used to have. The noise from the pump is just too much though, with the air being channeled through it.

Just as a side question. The 3 pin on the pump. Is that meant to be plugged in to anything, or is it an optional source of power? Not sure what to do with that.

 

[UnusualSuspect]

I've seen 6 or 7 systems now where the DDC 18W is just too much for a short, low restriction loop. With an EK reservoir, a massive cyclone effect is seen and air is injected into the loop, with the Alphacool reservoir top, the same thing happens except that it's more of a foamy thing. Try running it at 5V and see it improves - it generally does.

Thats exactly whats happening, its like a cyclone of air bubbles coming from the EK block, and I get a foamy thing happening in the alphacool res. How do I turn it down to 5v? Will have to try that.

 

[UnusualSuspect]

I've seen 6 or 7 systems now where the DDC 18W is just too much for a short, low restriction loop. With an EK reservoir, a massive cyclone effect is seen and air is injected into the loop, with the Alphacool reservoir top, the same thing happens except that it's more of a foamy thing. Try running it at 5V and see it improves - it generally does.

I found out about the 4-pin connectors online and switched it around, and you're right. No more bubbles, not even the spiralling ones coming from the GPU block. Theres a few small ones that seem to be stuck, but I imagine they'll slowly work their way out.

The water is moving very slowly though. Does that make a difference? I don't know if its me being paranoid or what, but the temperatures seem a centigrade or two higher since switching.

 

[UnusualSuspect]

Then try 7V for a nice compromise?

How do you get 7v?

What I read is basically on a four pin you have: 5v - 5v Earth - 12v Earth - 12v.

How do you get 7v out of that? 12v with a 5v earth is the only thing that combines to the right amount, but wouldn't that leave those 7 volts unearthed and thus dangerous to the circuit?