Hi everyone,
I need your help…again. I have a Wanhao Duplicator 4s and I want to install cooling fan… I have no idea how to do it 
…my power supply runs at 24V …here are some pictures…Where should I connect my new fan( which I haven’t bought yet)?..It seems there is an extra FET, should I use that one? Thanks in advance
I don’t know much about the Wanhao but normally the fan has to be connected to the controller board and not the the power supply. You have to know what voltage is used for the fan on your controller board - most PC style fans will work with 12V but there are also 5V, 18V a.s.o style fans out there in the wild.
To get it right you have to:
- check the controller boards documentation for the place and specs for the fan.
If your Wanhao is controlled by a MightyBoard the connection diagram shows where to connect the fan http://cdn.shopify.com/s/files/1/0299/7809/files/Mighty_Board_Rev._A.pdf?1337
If you don’t have or find any electrical specs you should measure the voltage on the fan connector but be patient as the signal might be PW-modulated so a multimeter will not do.
As far as i understand http://wanhaousa.com/collections/electronics/products/cooling-fan-kit - it looks to me as if you have to solder a FET (thats the component that can drive the fans desired output voltage) onto the wanhao controller before using any cooling fan.
This has been great thank you so much.
Yes , I have a Mightyboard. I’ve just checked and the an should be 12V…The FET is already there( as shown in the picture) does is mean that it has been soldered already?..Many thanks
@Nayda_Florez if the fan FET is already on your controller boar it is already soldered to it otherwise the component would fall of the board 
Yeah! I don’t have to solder then…One last question… My fans are 40mm do I have to buy the exact same size ?
I think it’s better to stick with the default size at the beginning. If you don’t use the same size as wanhao has designed it for, you will have to create your own fan bracket. If the original bracket design is flawed or the overall cooling system has some disadvantages you can start to tweak it by your own.
Carsten you are my saver! Thank you SO MUCH!
buy a 24V fan
What’s the fan for @Nayda_Florez ???
It’s for fan layer??? Or you wanna always on fan??? If you wanna a always on fan, you should have to conect no your power supply (a 24V fan as @marc_kerger says) or look for a 12V pin in your controller board, ramps 1,4 have one, i’m shure your board too
Hi MakerGal, its for fan layer, I want to get better prints! I’ve already bought the 12v fan and I’m gonna control it from the motherboard…