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Unresolved Heat break fan getting hot

Discussion in 'Troubleshooting' started by steveiforgot, Aug 12, 2021.

  1. steveiforgot

    steveiforgot New Member

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    So I just had to replace my board for my ender 5 pro with a skr 2 board. I’ve finally got the homing issues fixed, and I noticed something….

    Once the heat block fan starts up, it begins to heat up at the center of the fan, to the point it quickly becomes hot to the touch. So I’m unsure if the fan itself has become faulty, or is there a voltage setting on the skr 2 I need to change? Or something in the marlin firmware? I know the 3 fans are supposed to be controllable, I just can’t find info on the how
    I believe they are plugged into pb5, and pb6 if that helps at all?
     
    #1 steveiforgot, Aug 12, 2021
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    The fan on the hotend is a 12v fan so as long as it is getting 12v (and not, say, 24v) it should be fine.
    It could be the bearings in it are wearing..

    On the RAMPS only the parts fan is controllable, not the hotend fan nor the fan under the printer that cools the electronics.
     
    #2 mark tomlinson, Aug 13, 2021
  3. steveiforgot

    steveiforgot New Member

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    They were both recently replaced, so I’m not sure how they’d be worn out already. I have replacements being sent just in case as I have no backups, was going to just plug them in and test for heating when they arrive, not sure what else to do
     
    #3 steveiforgot, Aug 13, 2021
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Getting new, bad parts is not unheard of and is more frequent from the discount sellers. Just has to be mentioned because it will cause the symptoms you have.

    Just be sure you haven't altered the power to the components (everything still running on the Robo 12v, 300w power supply). You can also make sure that when on the hotend you can (with no power on) easily spin the hotend fan by hand (finger). The hotend fan DOES NOT go to the control board, it goes directly back to the 12v power supply and should always run if the printer is on. The RAMPS had it tapping off just after the power supply connection on the R1+ (but it was still directly tied to the power supply) and the older models (like the beta) had it tied directly to the power supply.
     
    #4 mark tomlinson, Aug 14, 2021
  5. steveiforgot

    steveiforgot New Member

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    Ok, I ordered a set of 24v fans just to test.
    But far as wiring, currently, they are on pn5, and pb6 on the skr 2 board (I’m not sure if or how to tell if it set to 12v or 24. it should be fine connected to the board though, it does always run (the fan that blows onto the top part of the hotend area, it will turn on as soon as the hotend makes any movement commands to it.
    I haven’t fully tested that the blower fan will turn on when the print runs since I haven’t stRted trying to print anything as of yet (avoiding a short/fire is top priority and all)
     
    #5 steveiforgot, Aug 14, 2021
  6. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    The only fan that needs to be controlled is the parts fan. The one that cools the electronics (on the bottom of the printer) should always be on too.
    That is all three of the stock fans -- parts cooling fan, hotend fan and electronics fan on bottom.
     
    #6 mark tomlinson, Aug 14, 2021
  7. steveiforgot

    steveiforgot New Member

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    I have the fans for the case (modifies case, 3 40mm fans, powered directly, and always on when the machine powers up
     
    #7 steveiforgot, Aug 14, 2021
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  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Good idea. I added a rather large one that sits adjacent the RAMPS/MEGA and it exhausts air from the printer pulling it across the electronics.
     
    #8 mark tomlinson, Aug 14, 2021

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