Modular Cooling Fan Mount for FYSETC Catalyst‑K

This is a modular cooling system designed specifically for the FYSETC Catalyst‑K motherboard. The mount consists of two parts:

• Main Fan Mount Body

• Interchangeable Blower Ducts

  • 3‑Driver Duct — cools Motor E1, Motor E0, and Motor X

  • 5‑Driver Duct — cools all five drivers on the Catalyst‑K

Features

• Modular duct system (swap between 3‑driver and 5‑driver versions)

• Dedicated blower cooling for stepper drivers

• 4010 fan cooling for the MCU and board surface

• Clean cable routing with underside hooks and zip tie positions

• Uses Catalyst‑K’s FAN1 and COOL‑FAN headers

Fan Header Information (Important)

FAN1 (J25) — Blower Fan

• Connector: JST‑XH 2‑pin (2.54 mm)

• Voltage: Selectable via jumper (5 V / 12 V / 24 V)

COOL‑FAN (J29) — Motherboard Cooling Fan

• Connector: JST‑PH 2‑pin (2.0 mm)

• Voltage: Selectable via jumper (5 V / 12 V / 24 V)

Make sure to set the voltage selection jumpers on the Catalyst‑K board to match the fans you are using.

Klipper Configuration (NOTE: I have yet to test this. Verify everything first with the Catalyst Wiki)

Blower Fan on FAN1 (J25)

Add this to your printer.cfg:

ini

[fan_generic driver_fan]
pin: PA3
max_power: 1.0
shutdown_speed: 0
kick_start_time: 0.5
cycle_time: 0.010

This will show up in Mainsail or Fluidd as Driver Fan.

When Using the 3‑Driver Duct (E1, E0, X Only)

If you are not cooling all five drivers, you will want to remap your stepper assignments depending on your setup.

For the 3-driver duct I am using:

• X → X‑MOT

• Y → E0‑MOT

• Z → E1‑MOT

Then ensure your printer.cfg uses the correct pins for each axis. (Example mapping shown below — adjust to your machine as needed.)

Keep the [stepper_x] as is.

[stepper_y]
step_pin: PD5
dir_pin: PD6
enable_pin: !PD4
[tmc2209 stepper_y]
uart_pin: PD7

[stepper_z]
step_pin: PE6
dir_pin: PC13
enable_pin: !PE5

[tmc2209 stepper_z]
uart_pin: PC14

If you are using the 5‑driver duct, no changes are needed. Just uncomment the other driver blocks.

Bill of Materials (BOM)

• 1× 3‑pin 4010 fan (for board cooling)

• 1× 2‑pin 4010 blower fan (for driver cooling)

• 4× M3×18 mm screws (for 4010 fan)

• 4× M3 nuts

• 4× M2.5×10 mm screws (for blower + duct)

• 4× M2.5 nuts

• 3× M2.5×24 mm screws (mounting the assembly to the printer)

• 2× zip ties (cable routing)

Print Settings

• Walls: 3

• Infill: 15%

• Material: PLA or similar

• Optional: TPU for vibration/noise reduction pads

No supports required.

Assembly Instructions

1. Install the 4010 Fan

• Place the 4010 fan into the main body.

• Secure using 4× M3×18 mm screws and M3 nuts.

*Note: Due to space constraints, it is not recommended to install anything larger than a 4010 (i.e. 4015, 4020) unless you remove the bottom printer cover and have taller feet.

2. Install the Blower Fan

• Position the blower fan on the mount.

• Install the first M2.5×10 mm screw on the side farthest from the drivers.

3. Attach the Duct

• Place the 3‑driver or 5‑driver duct onto the blower.

• Install 2× M2.5×10 mm screws to secure the duct to the blower.

• Install the final screw on the far side of the duct.

4. Cable Routing

• Route both fan cables along the underside.

• Use the built‑in hooks and zip ties to secure the wiring.

5. Mount to the Printer

• Use 3× M2.5×24 mm screws to mount the fan assembly and motherboard together onto the printer frame.

*Note: I highly recommend sticking heatsinks on the larger chips on the board. The usb chip in particular likes to get hot, which can lead to disconnects. 

6. Connect the Fans

• Plug the blower fan into FAN1 (J25) — JST‑XH 2‑pin.

• Plug the 4010 fan into COOL‑FAN (J29) — JST‑PH 3‑pin.

Double‑check your voltage jumper settings before powering on.