3 pin pump to 4 pin header

[Presian]

Hello ,

I will be buying Cooler Master Seidon 120v , the fan needs 4pin headers and the pump needs 3 pin headers but i dont have 3 pins on my motherboard i have second 4 pin header if i connect the pump in the 4 pin header will there be any problems ?

 

[raisonjohn]

You can plug 3-pin connectors on a 4-pin header like this:

Note that your 4-pin fan is a PWM fan that requires a 4-pin PWM header for it to function as intended. The 4th pin provides the PWM signal to your fan which allows it to change speed while using full +12V provided by the PWM header.

On the other hand, your 3-pin pump (as well as 3-pin fans) functions as a DC pump/fan. Plugging this on a 3-pin DC header will allow such pump/fan to change speed by variable voltage supplied by the DC header.

If you plug a 3-pin pump/fan on a 4-pin PWM header, such pump/fan will run in full speed 24/7 due to the constant +12V the PWM header provides.

Some motherboards have 4-pin headers that are not true-PWM headers (the 4th pin is physically there, but has no electrical connection). You need to consult your motherboard's manual if such 4-pin header that you'll plug your 4-pin fan and your 3-pin pump/fan into is a PWM or a DC header.

Note that some motherboards have special features in the BIOS for you to select how such 4-pin headers function. You can choose the fan header to work either in PWM-mode (constant +12V with PWM signal) or in DC-mode (variable voltage with no 4th pin connection).

More often than not, it is recommended that AIO pumps should be run in constant speed to maintain constant liquid flow and to prevent the pump motor to experience more wear-and-tear if speed varies all the time.