Need help understanding the function of the heat sink fan
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Need help understanding the function of the heat sink fan  

New Member
Need help understanding the function of the heat sink fan

NEED HELP, or in the very least some recommendations. I recently built the Prusa i3 MK3S+, and I am having a big problem getting filament (Prusament ) through the printer. In the first startup, I ran the Wizard, and was pleased to see that everything was perfect. Then I proceeded to run the XYZ calibration and was rewarded with the congratulations message that all was well. Next , this is where the issue , or problem came up. The next thing I did, or should I say tried to do was the first layer calibration. I started by feeding the filament manually through the extruder, and it worked without any issue as long as I kept pushing it through. The minute I reset the feeder , and then tried to print, all I got for my trouble was a blockage of the extruded. This forced me to disassemble the extruded in order to clear out the blockage. This operation has happened no less then four times in the past week. There is no way I can get filament though the nozzle during an attempted print. I have had to replace on multiple occasions not only the nozzle, but also the heat brake, and even the PTFE tube in the heat sink itself, to try and get it back up and running. My question is this, should the heat sink fan be running whenever I try to print, the first layer. I noticed that even though the Wizard is indicating that both fans are " OK " I can't understand why the heat sink fan does not come on when I try to print the first layer. I might be mistaken, but my guess is that with the absence of the fan actually working, the minute I insert any filament into the extruder, it blocks up before having time to exit the nozzle. I am it's wit's end with this printer, not being able to get it up and running correctly. I also have to two Ender 3 Pro's, and they have been in operation for more then three months now, and I have yet to get any problems with blockage. Do I need to tell you that I will really appreciate the time anyone you will take to address my concerns.

Posted : 23/09/2021 8:09 pm
Illustrious Member
Definitely confirm that you don't have the 2 fans swapped and/or reversed

The heatsink cooling fan should come on whenever the nozzle is heated up and stay on. Its job is to keep airflow moving over the heatsink fins. The part cooling fan is often off on layer one and turned on and off throughout the print based on slicer settings. I'd start with:

  • Double-check that your fan cabling is correct.
  • Fan facing is correct. Air should be pulled from the outside and blown across the heatsink fins.

If you're at all uncertain of any of this, take advantage of the support you paid for. Log in to the online store and contact support via chat. They are very good and will work through the problems with you.

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 23/09/2021 8:27 pm
New Member
Topic starter answered:
Quick turn around

Thank you for your prompt response, I will take a closer look as soon as I can.

Posted : 24/09/2021 2:00 am