How to power pump on and off.

[gulfcoastfella]

Hi,

My water cooling pump is powered directly through the power supply in my computer using a typical molex connector. How can I wire it so I don't have to turn off the power supply every time I shut down the computer?

 

[Cabbs]

So you want to keep the pump running by itself for testing purposes? Here's a simple trick:

-Unplug the PSU from everything except for the pump and anything else you may want running (like fans for whatever reason).

-Get a paper clip

-Connect paper clip to green wire and any black wire

This will start the power supply so you can run things like pumps, fans, lights, etc. without turning on your PC.

 

[setishock]

Only thing active after the system shuts down is the 3 and 5 volt standby. The green wire like Cabbs talks about is the start up command for the rest of the power supply. The gray wire tells the mother board the psu is up and running.
Now as I interpet your comment about not having to shut off the psu can be read in a couple of ways.
1 You want to leave the psu running to power some items even though the system is shut down. It's all or just the 3 and 5 volt standby. If the rest is on so is the computer.
2 Your pump connection is still live after system shut down. If that's the case then the HD's, and other 12 volt items will be powered up. I'd rma that sucker. It's a flake.
If you simply want to do testing on or leave items running like lights, a seperate psu would be the answer. You can find ones that fit in a 5 1/4 bay for very reasonable costs.

 

[Remeniz]

The only reason i'd want to keep the pump running after I shut down is to avoid any hotspots in the cooling loop. What would be ideal is a pump timer that keeps running for a set time after you shut down the computer.

One solution that came to mind is using two ATX PSU's, one for the computer and a low wattage ATX PSU for the pump. With a simple timer circuit, using the 555 timer IC, you can have the second PSU stay on for X seconds after the main ATX PSU shuts down. Or you can override the timer and have it running constantly, maybe for testing.

The only thing with this is you need a case that can accommodate two PSU's, a stripboard, the components and a little electrical knowledge.

This maybe way of the mark though as the OP's post is a bit vague.

 

[iPwn]

How can I wire it so I don't have to turn off the power supply every time I shut down the computer?

I could be wrong, but I believe the OP wants to have the Pump shut off when the computer is shut off instead of having to switch off the PSU...

 

[gulfcoastfella]

I could be wrong, but I believe the OP wants to have the Pump shut off when the computer is shut off instead of having to switch off the PSU...

Thank you InfectionZero. I don't know how components are switched on and off. I assumed that the power supply provides constant voltage on all rails regardless of the computers on/off status; thus, I was worried that the pump will continue to run when I turn the computer off, even though I want the pump to shut down with the computer. So does the motherboard control the power supply then?

 

[Remeniz]

... So does the motherboard control the power supply then?

Yea. When the computer shuts down the only live supplies from the PSU are the 3.3V and 5V rails.

 

[gulfcoastfella]

Thanks Remeniz. That's what I needed to know.

Thanks for humoring me, everyone. The pump starts and stops with the motherboard as I wanted.