Dear Neen,
Have a nice day! What's your pump?
For example, you can connect the BPTA-PSC-SOC to your power and turn on the pump without powering on the MB/CPU. You can check it here in 1:04 of the youtube video. Any questions, feel free to contact us.
https://shop.bitspower.com/index.php?route=product/product&product_id=7951&search=SOC
https://www.youtube.com/watch?v=f53IFvIKL2w&t=21s