Voron Fan Replacement Guide — Complete Step-by-Step

Maintenance Beginner Electronics Cooling

Fans are the most frequently replaced components on any 3D printer — and Vorons are no different. Between enclosure heat, continuous operation, and ABS fumes, a Voron's fans typically last 6-18 months before bearing noise, reduced airflow, or complete failure. This guide covers every fan location on a Voron, specifications for replacement, step-by-step installation, wiring polarity, connector types, noise reduction, and cost-effective sourcing from China-direct suppliers. Last updated: May 2025.

Difficulty Level

Beginner to Intermediate. Fan replacement is the easiest maintenance task on a Voron. No calibration or tuning is needed — just unplug the old fan, install the new one, and secure the wiring. Most replacements take 10-20 minutes. The main pitfalls are getting the polarity wrong (easy to fix) or buying a fan with the wrong voltage or connector type.

Fan Locations and Functions

A typical Voron V2.4 or Trident has 4-6 fans, each with a specific role:

• Hotend fan (toolhead): Mounted on the Stealthburner or toolhead carriage. Cools the hotend heatsink to prevent heat creep. Must run at 100% whenever the hotend is above 50°C. Failure causes filament jams and heat creep. Standard: 4010 axial fan (40mm x 40mm x 10mm), 24V.
• Part cooling fan (toolhead): Mounted on the Stealthburner, ducted to direct airflow at the printed part. Critical for bridging, overhangs, and fine detail. Controlled by the slicer (typically 0-60% PWM). Standard: 5015 blower fan (50mm x 50mm x 15mm), 24V. Some builds use dual 5015 blowers for maximum cooling.
• Electronics bay fan (controller): Mounted in the electronics compartment, typically on the side panel or bottom. Exhausts hot air from the stepper drivers and controller board. Controlled by thermistor or always-on. Standard: 6025 axial fan (60mm x 60mm x 25mm), 24V. Some builds use 4010 or 4020 fans.
• Enclosure fan (Nevermore or exhaust): Optional but recommended for ABS printing. Mounted on the enclosure to circulate air through a carbon filter (Nevermore) or exhaust fumes outside. Standard: 6025 axial fan, 24V or 12V depending on the filter system.
• PSU fan (power supply): Internal to the power supply unit. Usually 6010 or 6025 fan. Replacement requires opening the PSU — not recommended unless you're experienced with electronics.
• Mainboard fan (optional): Some Voron builds add a small fan (3010 or 4010) directly on the mainboard's stepper driver heatsinks. Standard: 24V or 5V depending on the board.

Fan Specifications

Important: Always use 24V fans on Voron unless you have a 12V step-down converter. Connecting a 12V fan to a 24V supply will destroy the fan immediately (it may spin briefly at double speed, then burn out). Conversely, a 24V fan on 12V will barely spin and won't provide adequate cooling. Check your fan labels before installing.

Tools Needed

• Hex driver set: 1.5mm, 2mm for fan mounting screws.
• Small Phillips screwdriver: For removing printed fan shrouds and ducts.
• Wire strippers and crimpers: If you need to replace the connector or splice wires.
• JST connector kit: JST-XH 2-pin and PH 2-pin connectors + crimp pins.
• Multimeter: For testing fan voltage and polarity.
• Zip ties or spiral wrap: For cable management after installation.
• Safety glasses: If cutting zip ties near the fan blades.
• Isopropyl alcohol and lint-free wipe: For cleaning the fan mounting area and removing old dust.

Step-by-Step Fan Replacement

Step 1: Identify the Failed Fan

Before replacing, confirm which fan has failed. Common failure symptoms:

• No rotation: Fan doesn't spin when power is applied. Check voltage at the connector with a multimeter. If voltage is present (24V or PWM signal), the fan motor is dead.
• Grinding or rattling noise: Bearing failure. The fan will spin but makes noise. Replace immediately — a seized bearing can jam the fan, causing it to overheat and potentially melt the printed fan duct.
• Intermittent stopping: The fan starts, stops, or stutters. Usually a dry bearing or a loose internal connection. Replace.
• Reduced airflow: You can't feel air moving through the duct even though the fan is spinning. The blades may be clogged with dust, or the motor may have degraded and no longer spins at full RPM.
• Visible damage: Cracked housing, bent blades, broken mounting tabs.

For toolhead fans, you can test by setting the fan speed in Klipper: SET_FAN_SPEED FAN=heater_fan SPEED=1.0 or M106 S255 for the part cooling fan.

Step 2: Remove the Old Fan

Hotend fan (Stealthburner):

1. Power off the printer and disconnect the toolhead cable connector at the gantry cable chain.
2. Remove the Stealthburner front shroud. This is the printed part that covers the fans. It's typically held by 4x M3x8 screws on the front face of the Stealthburner.
3. Once the shroud is off, you'll see the hotend fan (4010 axial, located behind the hotend) and the part cooling fan (5015 blower, located on one or both sides).
4. Unplug the fan connector from the toolhead board (EBB36, SB2040, or breakout board). Note the connector type and wire colors for reference.
5. Remove the 2-4 small screws holding the fan to the printed mount. Be careful not to drop screws into the electronics compartment.
6. Gently pull the fan out. If it's stuck to the printed part with dust or adhesive residue, use a plastic spudger — don't pry with a screwdriver.

Electronics bay fan:

1. Power off and disconnect the printer power cable.
2. Remove the electronics bay side or door panel.
3. Locate the fan (usually mounted on the side panel or the bottom of the electronics compartment).
4. Unplug the connector from the mainboard or the dedicated fan header.
5. Remove the fan mounting screws. Some Voron builds use a printed fan mount that clips onto the extrusion — unclip it first.
6. Pull the fan out. If it's a panel-mount fan, note which direction the airflow arrow points (into the electronics bay or out).

Step 3: Prepare the New Fan

Before installing, verify the new fan specifications match the requirement:

• Check the voltage rating printed on the fan label. It must say 24V DC (or the appropriate voltage for your build).
• Check the air flow direction. Axial fans have arrows on the side showing rotation direction and airflow path. The airflow direction must match the original fan — usually blowing away from the hotend (for the hotend fan) or out of the electronics bay (for the electronics bay fan).
• Check the connector. If the new fan has a different connector than your board, you have three options: (1) cut the old connector and crimp it onto the new fan wires, (2) use a JST adapter cable, or (3) solder the new fan wires directly to the board (not recommended — it makes future replacements harder).
• If the new fan has bare wires, crimp a JST-XH or PH connector using your connector kit. The standard Voron wiring convention: Red = positive (+24V), Black = negative (GND). Connecting reverse polarity will not damage most fans — they simply won't spin. Just swap the wires.

Step 4: Install the New Fan

1. Position the fan in the mount with the correct airflow direction. For the hotend fan: air blows down through the heatsink. For the part cooling fan: air blows down through the duct toward the nozzle. For electronics fans: air blows out of the electronics bay (exhaust).
2. Secure the fan with the mounting screws. For 4010 fans: use M3x12 or M3x16 screws with nuts on the back side. For 5015 blowers: use M3x8 screws into the printed duct. Do not over-tighten — the fan housing is plastic and can crack. Snug is sufficient.
3. Plug the connector into the correct header on the toolhead board or mainboard. For toolhead fans: the hotend fan goes to the "FAN0" or "heater_fan" header, and the part cooling fan goes to the "FAN1" or "part_cooling_fan" header. Check your board pinout diagram.
4. Route the fan wires neatly and secure them with a zip tie or spiral wrap. Ensure wires don't block any cable chain movement or touch the hotend.
5. Reinstall the Stealthburner front shroud (for toolhead fans) or electronics bay panel (for electronics fans).

Step 5: Power On and Test

1. Reconnect power and turn on the printer.
2. Test the hotend fan: set the hotend to 60°C. The hotend fan should start spinning immediately (or within a few seconds if configured with a temperature hysteresis). If it doesn't spin, check the connector polarity and header assignment.
3. Test the part cooling fan: run M106 S255 in the Klipper console. The part cooling fan should spin at full speed. Run M106 S0 to turn it off.
4. Test the electronics bay fan: if it's configured as always-on, it should be running. If it's thermistor-controlled, heat the enclosure (or apply heat to the thermistor) to trigger it.
5. Listen for any unusual noise. A slight hum is normal; grinding, clicking, or scraping means the fan blade is hitting something or the bearing is defective. Stop the fan and check for obstructions or misalignment.

Step 6: Configure Fan Behavior (Klipper)

After installing a new hotend fan, verify your Klipper fan configuration. The hotend fan should run at 100% whenever the hotend is above 50°C. A common configuration:

[heater_fan hotend_fan]
pin: toolhead:PA0
max_power: 1.0
heater: extruder
heater_temp: 50.0

For the part cooling fan, slicer configuration overrides the Klipper defaults. Verify your slicer fan settings — Voron profiles typically set max fan speed to 60-80% for PLA and 0% for ABS (ABS does not require part cooling).

Noise Reduction Tips

Voron fans can be noisy, especially the 5015 blowers for part cooling. If noise is a concern:

• Upgrade to quality fans: Sunon, Delta, NMB, and Orion fans are significantly quieter than generic Chinese fans. A Sunon 4010 (MF40101VX-1000U-A99) runs at 24 dBA vs 35 dBA for a generic fan. Cost: $8-15 vs $2-4 on China-direct.
• Reduce PWM frequency: Klipper defaults to 25 Hz PWM frequency for fans, which can cause audible whine. Change to 20-25 kHz (ultra-quiet PWM) in your printer.cfg: pwm_freq: 25000. Note: not all fan controllers support high-frequency PWM — test before adopting.
• Use a fan silencer / resistor: Adding a 100-ohm resistor in series with the fan reduces voltage by 1-2V and drops noise significantly. Do not use this for the hotend fan — reduced speed causes heat creep.
• Software fan curve: Configure the part cooling fan to start at 20% speed and only increase as needed. Most PLA prints look identical at 40% fan vs 100% fan, but the noise difference is substantial.
• Sound dampening mount: Use printed fan mounts with rubber vibration dampers. Several Voron user mods include fan mounts with rubber grommets. Search for "Voron fan dampener" in the user mods repository.
• Enclosure acoustics: Add acoustic foam panels to the inside of your Voron enclosure (on the non-ventilated panels). This absorbs fan noise without affecting airflow.

Cost Breakdown (China-Direct Pricing)

China-Direct Sourcing Tips

• Sunon and Delta fans are worth the premium: Generic $2 fans typically last 3-6 months. Sunon or Delta fans ($6-10) last 1-3 years. For the hotend fan, where failure means a ruined print or a fire risk, the premium is justified.
• Check the connector before buying: Many AliExpress fan listings come with bare wires or Dupont connectors, not JST. Read the description carefully or ask the seller. If the fan doesn't come with the right connector, budget $5 for a JST connector kit and 15 minutes for crimping.
• Buy a pack of 2-3 fans: Fan costs are low enough that buying spares is cheap insurance. A $6 Sunon 4010 fan costs the same whether you buy one or three — shipping is often the same regardless.
• Look for "sleeve bearing" vs "ball bearing": Ball bearing fans last 3-5x longer than sleeve bearing fans in hot enclosures (enclosure temperatures above 50°C). Ball bearing fans cost $1-2 more but are worth it. The specifications usually say "ball bearing" or "dual ball bearing" in the listing.
• Winsinn and GDSTime: These are two reliable mid-range fan brands on AliExpress. They're better than no-name generic fans but not as good as Sunon/Delta. Good budget option if Sunon is sold out.

Troubleshooting

Fan Doesn't Spin

Check voltage at the connector with a multimeter (expect 24V when the fan should be running). If voltage is present, the fan is defective or the polarity is wrong. Try swapping the two wires. If the fan still doesn't spin, return it — you may have received a 12V fan or a DOA unit. If voltage is not present, check the board header, the pin configuration in Klipper, and the fuse (if applicable).

Fan Makes Grinding Noise

This is usually a bearing defect or the fan blade hitting the housing. Stop the fan immediately — a fan with seized bearings can draw excessive current and damage the fan header on your board. Replace the fan. For the hotend fan, do not attempt to lubricate the bearing — the fix is temporary and the fan will fail again within days.

Fan Spins Backwards (Blows Air in the Wrong Direction)

Most 24V DC fans are polarized — swapping the positive and negative wires reverses the motor direction on some models. On others, the fan simply doesn't spin. If your fan blows in the wrong direction, physically flip the fan around in the mount. This is much easier than rewiring. Check the airflow arrows on the fan label to confirm the intended direction.

Hotend Fan Not Spinning at Temperature

Check your Klipper configuration for [heater_fan hotend_fan]. The heater_temp setting is the trigger temperature — if it's set to 60°C and your hotend is at 55°C, the fan won't spin. Lower the trigger temperature to 50°C. Also check that the fan is assigned to the correct pin.

Part Cooling Fan Stuttering at Low Speeds

Some fans do not start spinning at PWM values below 10-15%. This is normal for many Chinese blower fans. Set your slicer minimum fan speed to 15% or higher. If the stuttering is audible at low speeds, increase the PWM frequency to 25000 Hz in Klipper.

Part Numbers and Specifications

• Hotend fan (V2.4/Trident): 4010 axial, 24V, 0.08-0.12A, JST-XH 2-pin. Sunon MF40101VX-1000U-A99 or equivalent.
• Part cooling fan (V2.4/Trident): 5015 blower, 24V, 0.15-0.25A, JST-XH 2-pin. Sunon PF50151BX-000U-S99 or equivalent.
• Electronics bay fan (V2.4): 6025 axial, 24V, 0.10-0.20A, bare wire or JST-XH 2-pin. GDSTime GD6025 or similar.
• Hotend fan (V0.2): 3010 axial, 24V, 0.05-0.08A, JST-PH 2-pin. Smaller due to V0.2's compact toolhead.
• Part cooling fan (V0.2): 3010 or 4010 blower, 24V, 0.10-0.15A, JST-PH 2-pin. Some V0.2 builds use a 4010 axial for part cooling.

Need replacement fans for your Voron? We stock factory-direct 24V fans in all standard sizes — 4010 axial, 5015 blower, 6025 axial — from Sunon, Delta, and reliable generic brands. All fans come with pre-crimped JST connectors for drop-in replacement. No wiring, no crimping, just plug and print.