Help needed on a first loop


New member

I have ordered alphacool parts for a workstation, for my company.
The build is done, but I'm not able to make the water loop work: The pump does nothing, the cooling liquid does not move.

My setup is (see attached picture):
Eisbaer extreme 280 core -> Eisblock Aurora XPX Pro -> Nexxxos XT45 3x120

The reservoir on the eisbaer is full, I moved the PC so that the liquid fill the loop, and the loop is now 90% full. But I guess that I need the pump to work, to push water from the reservoir to the loop, so that I can fill the reservoir again.
But, when I turn on the computer (a few seconds only), I dont hear the pump, the water does nothing...
I double checked that everything is connected correctly: fans on the eisbaer are working, the pump is connected to a PWM port on the motherboard, and the pump is connected to the power supply.

This is not my first build, but this is my first build with watercooling. I must have missed something, any advice is welcome!




Active member
Staff member
Hi @gside
From time to time it can happen that when the molex plugs are connected, a pin comes loose. And then no electricity can flow. Check whether the pins on the plug from the power supply to the pump are all properly inserted. I've already had the case with my pc myself. My English is not the best, I do my best to write correctly. I hope I can help


New member
Thanks Luckystricker, yes any help is welcome!

I have checked the molex plug, and changed from molex and power splly connector, I think everything is fine on this side.
Now that I have moved my PC again, there is no air left, at least visible, in the tubes, only some air inside the CPU waterblock.
And it seems that now, I can hear the pump, with water noise, and irregular frequency, but I have no clue, once I have removed the air on the loop, how to make that pump.... pump.
I even tried with the top filling cap opened, to run the system, but no coolant is pushed through the loop.


New member
Hi everyone,
Finally, the watercooling loop works.
I have to put the PC flat, to remove the air contained into the waterblock, and turn on the PC in that position. So, this was the air contained in the waterblock that blocked the flow.