My fan is running always on

General Discussion
1

Basic Information:

Printer Model: Self build Voron Trident 350mm
MCU / Printerboard: octopus v1.1
Host / SBC orangePi zero 3
klippy.log

klippy.log (24.7 KB)

Fill out above information and in all cases attach your klippy.log file (use zip to compress it, if too big). Pasting your printer.cfg is not needed
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Describe your issue:

…
After booting my MCU board. The hotend_Fan keep runing and the led on board show the FAN is working. But I set hotendFAN work when hit 50C°.
As far as I know, it should go off when recive klipper’s command from OrangePi boot up.
But for now, even my flippy say hotendFAN is off. That fan won’t be controled by any fan contronl.
I try to change that fan pin to another fan port. and change cfg to that pin, the cfg works well.
This also happening on my another MCU board Spider 3.0. With brand new flash.
I guess it’s a frimeware problem? or what did I somting wrong? make config? klipper cfg?

2

Unlikely, or this place would be full of such reports. Rather a local issue on your side, e.g.

  • Wrong fan port in relation to the config
  • Hardware defect, e.g. stuck MOSFET on a fan port
  • A heater_fan cannot be controlled manually
  • It is on as soon as the associated heater is active
  • The heater_temp directive tells Klipper BELOW which temperature the fan shall be turned OFF once it has been activated by the respective heater
3

The first possible came up to my mind is this, so I tried change to another fan port pin. The FAN off below 50C turns on above 50C. Seems work well.
Even I’m not config with this PIN port. The FAN also went on.

MOSFET is the thing I came up first. That’s why I try another board.
I will check that with my multimeter latter.

Thanks for the infomation. I also search a bit. Some disscuss saying that heater_fan port will go on as soon as MCU board power on. And goes down when Pi is up tell it to off when start.
It’s some kinda ‘insurance’ to keep mount of heater not melt. Is that correct?

4

I agree. Why don’t you post a schematics and your printer.cfg?

5

No, this is not correct.

[heater_fan hotend_fan]
pin = PE5
max_power = 1.0
kick_start_time = 0.5
heater = extruder
heater_temp = 50.0
  • The condition, on which the fan is turned on, is given by the heater directive. In this case: As soon as your extruder’s heater is active, the fan shall turn on
  • The heater_temp directly can be read as “turn off below”. In this case: Once the fan has become active due to extruder heater being active, the fan shall stay on, until the heater’s temperature dropped below 50°C → This temperature has to be chosen with this safety aspect in mind that neither the filament in the heat-sink / heat-break no the extruder’s mount shall be damaged.

What you need to be sure:

  • The extruder heater is indeed not active
  • You did not accidentally build your firmware with some pulled-high pins in GPIO pins to set at micro-controller startup
  • Validate your board’s firmware settings
  • Validate your electrical connections
6

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