PC won't boot with WC pump connected

MarnickV

Commendable
Jan 14, 2017
2
0
1,510
After adding a GPU block to the watercooling loop, the PC now won't turn on with the pump connected. We're using an Aquastream 12V model. Disconnecting the pump (molex) will make the computer boot just fine. Here's where the fun starts. If the pump is connected AFTER the PC has already booted it will run and work just fine. It will also work fine if it's connected to any external PSU using the green and black wire trick. Just not with the PSU that's currently in use. A Corsair CX650M. Does anybody here have any ideas?
 

MarnickV

Commendable
Jan 14, 2017
2
0
1,510
Not quite sure why but it turns out the PSU required atleast one HDD to be connected in order not to freak out. Maybe because the 5V pin on the Aquastream isn't actually connected the PSU detects this as a short? No idea, but hooking up all the other devices and simply finish building the system fixed the issue. The computer now instantly boots as it should.

//Edit: It turns out the unconnected 5V pin triggers the PSU into short circuit prevention mode. Make sure you have at least another 5V/12V peripheral connected, i.e. HDD or SDD. And you won't encounter any more issues.