Question Psu fan not spinning

[The invincible]

Hi, recently I bought corsair vengeance 750m PSU and I marked when I switch on my system the fan spins and after that it stops.The vendor said its depends on system heat. I ran multiple softwares even including renders on it but that doesn't effect the spins. So like to know does the system needs more heat to spins the fan or its automated.Anyone please suggest.

My configs are:-
Intelcore i7 8700 3.2ghz
Asus rog sprix z390f motherboard
Corsair vengeance lpx 32gb 3200mhz ram
Zotac rtx 2070 amp 8gb gpu.

 

[Dark Lord of Tech]

It needs to have a decent load on it to spin. Takes quite a bit to make it have to turn on.

 

[Dark Lord of Tech]

It's a very good PSU.

 

[The invincible]

Okay. So at what temperature the fan will spin any idea.

 

[Dark Lord of Tech]

I have a Corsair RM1000i , RMx850 and SF600 and because of the ZERO RPM mode , they rarely come on.