# Part cooling fan speed not adjustable in mainsail

**URL:** <https://klipper.discourse.group/t/part-cooling-fan-speed-not-adjustable-in-mainsail/6553>\
**Category:** General Discussion\
**Created:** [February 10, 2023, 12:29pm UTC](https://klipper.discourse.group/t/part-cooling-fan-speed-not-adjustable-in-mainsail/6553 "2023-02-10T12:29:45Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Julio](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/julio/32/4001_2.png) [@Julio](https://klipper.discourse.group/u/Julio)\
**Post date:** [February 10, 2023, 12:29pm UTC](https://klipper.discourse.group/t/part-cooling-fan-speed-not-adjustable-in-mainsail/6553/1 "2023-02-10T12:29:45Z")

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### Basic Information:

Printer Model: V Core 3.1 500  
 MCU / Printerboard: btt Octopus Pro

So next in my klipper noob travels!

I can’t turn on or adjust the part cooling fan speed manually.  
M106 commands in console and the mainsail slider do nothing when no print is running.  
When printing, the fan starts up as expected but any manual adjustments just stops the fan, so on/off control only.

I have read through the thread on part cooling fan test (@mykepredko et al, dec 22) but i haven’t found any fan duplication, but as discussed there is a lot of included files in RatOS!!

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**Author:** ![LifeOfBrian](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/lifeofbrian/32/2380_2.png) [@LifeOfBrian](https://klipper.discourse.group/u/LifeOfBrian)\
**Post date:** [February 10, 2023, 12:48pm UTC](https://klipper.discourse.group/t/part-cooling-fan-speed-not-adjustable-in-mainsail/6553/2 "2023-02-10T12:48:43Z")

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Your klipper log should be needed here to check whether the fan declaration is correct.  
If the wrong cycle\_time (PWM rate) is set for the fan it might not react as intended.

Do you have a breakout board attached on the print head where the fan is connected to or directly connected to the board?  
Is the correct controllable fan connector used?

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**Author:** ![Julio](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/julio/32/4001_2.png) [@Julio](https://klipper.discourse.group/u/Julio)\
**Post date:** [February 12, 2023, 4:03pm UTC](https://klipper.discourse.group/t/part-cooling-fan-speed-not-adjustable-in-mainsail/6553/3 "2023-02-12T16:03:13Z")

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Nice and simple!

A 4 wire server fan isn’t variable speed if wired 2 wire (rad and black) it is just on off

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**Author:** ![LifeOfBrian](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/lifeofbrian/32/2380_2.png) [@LifeOfBrian](https://klipper.discourse.group/u/LifeOfBrian)\
**Post date:** [February 12, 2023, 4:26pm UTC](https://klipper.discourse.group/t/part-cooling-fan-speed-not-adjustable-in-mainsail/6553/4 "2023-02-12T16:26:08Z")

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Yes, if no PWM signal is detected its running at 100%.

But you can it wire with all 4 wires or at least with the PWM signal wire so you can control it.  
Having a 4 pin 4028 server fan working fine on my printer including RPM signal.

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**Author:** ![EddyMI3D](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/eddymi3d/32/1981_2.png) [@EddyMI3D](https://klipper.discourse.group/u/EddyMI3D)\
**Post date:** [June 18, 2024, 1:43pm UTC](https://klipper.discourse.group/t/part-cooling-fan-speed-not-adjustable-in-mainsail/6553/5 "2024-06-18T13:43:02Z")

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