fill with water before powering up the system;
- fill the reservoir
- hotwire the psu, with the hard drive and pump attached, so the pump starts to fill the tubes
- keep adding water to the loop until the system has the right amount of water.
- leave it turned on for a few hours, to check for leaks.
- turn of your system.
- connect everything
- close everything
Okay you don't need the pc running at this point. You can cause damage when you run the pc without the cpu water block fully working. There's an easy way.
You can turn on the power supply by itself. You can hot wire the PSU by connecting the green and any of the black on the mother power connector. Then plug just the pump and then plug and power up the PSU and it should be running. Fill it up and bleed the air out. Let it run for several hours to make sure there's no leakage on the loop.
When everything is good to go then hook up everything and run some test.
some PSU require to have something connected when they are turned on or they could get damaged; that's why i recommend hard drive; and the pump.
in case the pump doesn't start immediatly, the PSU isn't damaged because the HD is still on it.
To turn on an ATX power supply that isn't connected to a motherboard use a wire or paper clip to short the green wire (PS_ON) to any one of the black wires.
Always test the water stuff before hooking it all up. I believe the instructions say this. What I usually and others do is get everything close to being ready execpt water and then take all the stuff out and fill it up near the sink..
I have used a 12 volt dc power pack to start them up, I used a 3 pin wire connecter from and old fan to hook up the power pack to the pumb.