Question about fan control

  • Hello so a little background. I have an ender 3 that I have install a duet 2 wifi in. I believe I am almost done. I just got done making sure all thermistors and heaters works properly. Homing works. Bltouch is setup and is working properly I believe.

    I still have a few small things to do. I cannot for the life of me figure out how to get the print cooling fan to turn on. I have it hooked up to an always on slot on the board and set it up the same as the hot end fan.

    So the hotend fan comes on works no problem but the print cooling one will not come on. They are both two wire fans.

    Any idea what I am doing wrong here?

  • The part cooling fan shouldn't be connected to an always on fan connector if you wish the fan to be controlled via Gcode or thermostatically.

    If you made a mistake and mean you have it plugged into one of the Fan 0, Fan 1, or Fan 2 connectors, and have it setup the same way as the thermostatically controlled hotend fan, but it's not working it could be several things. Can you post your config.g file?

    I suspect you have not enabled thermostatic control of the fan port, whereas Fan 1 is thermostatically enabled by default. This is the H parameter I believe.

  • Moderator

  • @bot

    lol I saw at bot and actually had to look again. Thanks for the not actually a bot.

    So I initially had it hooked up to an always on port to make sure it would spin. It didnt so I though well maybe it has to be on the other connector so I hooked it upto Fan0. I got it set to come on when the hotend gets to 80°c. But that doesnt function either.


  • @phaedrux
    Yes I have. I even read through it again just now. I am new to 3d printing. This install was a pain. I've spent 17 hours so far over the course of 3 days trying to get the wiring done. Installed and firmware configured. Im on the last part of it. Few small things to get going..

    Im also having an issue with extrusion. But I will make a new post about that.

  • Moderator

    Does the fan work anywhere? Do any of the fans work? It's possible you've blown the fan fuse.

    You've only got 1 fan defined in your config. and It's setting the Fan0 port as if it were the hotend fan.

    It's recommended you connect the part cooling fan to Fan0, Hotend to Fan1, and maybe a case fan to Fan2.

    Here's my config as an example.

    M106 P0 S0 H-1 C"Part Cooling"      ; Set fan 0 (Part cooling blower) G-code controlled. Thermostatic control is turned off
    M106 P1 F30000 S1 H1 T45 C"Hotend Fan"   ; Set fan 1 (Hotend fan) Thermostatic control. Turns on when hotend reaches 45c
    M106 P2 F30000 L0.0 X0.05 B0.5 T45:70 H100:101:102 C"Duet Fans" ; monitors MCU temp and driver flags

  • @phaedrux

    Ok Yes I figured I would just let the hotend fan run whenever the power was on so i connected to always on. It spins just fine. Just cant get the part cooling fan to work

  • @phaedrux

    Ok so for the hell of it I hooked both the hotend and part cooling fan0 and fan1. Both dont work

    I've checked all three fuses and they are ok

  • Moderator

    Try again, but this time change your fan commands in config.g to look like this

    M106 P0 S0.5 H-1
    M106 P1 S0.5 H-1
    M106 P2 S0.5 H-1

    That should turn all 3 fan ports on at 50% for testing.

  • That worked

  • @jtroutt19 OK they are working with temp now. Not sure what I was doing wrong. I need to take a break seems like

  • Moderator

    Ok, so if you plug the fans into the recommended ports and follow the fan config example I posted above you should be good to go.

    Part cooling on Fan0, Hotend on Fan1
    M106 P0 S0 H-1 C"Part Cooling"
    M106 P1 S1 H1 T45 C"Hotend Fan"

  • @phaedrux

    Yip So the firmware config tool sets them up like this

    M106 P1 S1 I0 F500 H1 T45

    So exactly like you showed. I removed the "I" and the "F" and they started working like they should.

    Thank you very much for you help.

  • @phaedrux
    One more thing right quick the Part cooling fan is not shutting off when temp drops below 45°c. Hotend fan does

  • Moderator

    That's because the part cooling fan isn't thermostatically controlled. It's controlled by the slicer in the gcode, or manually with the slider in DWC.

  • @Phaedrux

    Ok I see it now. Right on thanks again

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