--- title: How to check the operation of the cooler fan (BCN3D Sigma) description:   The cooler fan it's an essential component on your BCN3D Sigma, since it prevents the hotend from overheating, which would cause underextrusion issues, and eventually clog your hotend. Depending on --- [Skip to content](https://support.bcn3d.com/knowledge/check-operation-cooler-fan-bcn3d-sigma#main-content) English Show submenu for translations [Contact support](https://support.bcn3d.com/knowledge/kb-tickets/new?hsLang=en) [Customer portal](https://support.bcn3d.com/repair-service?hsLang=en) ![knowledge-base-header-bcn3d-logo.png\]](https://support.bcn3d.com/hs-fs/hubfs/Knowledge%20base/Header/knowledge-base-header-bcn3d-logo.png?height=40&name=knowledge-base-header-bcn3d-logo.png) - [Default HubSpot Blog](https://blog.bcn3d.com/) Open main navigation Close main navigation - [Default HubSpot Blog](https://blog.bcn3d.com/) - English Show submenu for translations - [Contact support](https://support.bcn3d.com/knowledge/kb-tickets/new) - [Customer portal](https://support.bcn3d.com/repair-service) - [BCN3D forum](https://www.bcn3d.com/community/) [BCN3D forum](https://www.bcn3d.com/community/) Hello. How can we help you? - There are no suggestions because the search field is empty. 1. [Knowledge base - BCN3D](https://support.bcn3d.com/knowledge?hsLang=en) 2. [Sigma + Sigmax](https://support.bcn3d.com/knowledge/sigma-sigmax?hsLang=en) 3. [Troubleshooting](https://support.bcn3d.com/knowledge/sigma-sigmax?hsLang=en#troubleshooting) # How to check the operation of the cooler fan (BCN3D Sigma)   The cooler fan it's an essential component on your BCN3D Sigma, since it prevents the hotend from overheating, which would cause underextrusion issues, and eventually clog your hotend. ![cooler-fan-close-up](https://support.bcn3d.com/hs-fs/hubfs/Knowledge%20base/Sigma-Sigmax%20R19/how%20to%20check%20the%20operation%20of%20the%20cooler%20fan/cooler-fan-close-up.png?width=336&name=cooler-fan-close-up.png) Depending on your Sigma model, the cooler fan will operate differently, so check the last 4 numbers on your printer serial number to know what cooler fan version you are using. You can check your printer's serial number on the info screen on the LCD or on a sticker underneath the printer.  | **Serial Number** | **Cooler fan model** | **Operation** | | --- | --- | --- | | 0000 to 1146 | Regular fan | Should turn on automatically when printer is turned on | | 1147 or higher  | Smart fan  | Should turn on automatically when hotend temperature is over 90º. |   The Smart fan is available as an upgrade for Sigma, so even if your printer's serial number is lower than 1146 it could have the smart fan installed. If you are not sure, check your extruder board model: ![extruder-board-check](https://support.bcn3d.com/hs-fs/hubfs/Knowledge%20base/Sigma-Sigmax%20R19/how%20to%20check%20the%20operation%20of%20the%20cooler%20fan/extruder-board-check.png?width=600&name=extruder-board-check.png) ![extruder-board-models-smart](https://support.bcn3d.com/hs-fs/hubfs/Knowledge%20base/Sigma-Sigmax%20R19/how%20to%20check%20the%20operation%20of%20the%20cooler%20fan/extruder-board-models-smart.png?width=600&name=extruder-board-models-smart.png) In case the cooler fan doesn’t work, turn off and disconnect the printer, and then check that the flat cable is well connected to the extruder board. ![turn-off-printer](https://support.bcn3d.com/hs-fs/hubfs/Knowledge%20base/Sigma-Sigmax%20R19/how%20to%20check%20the%20operation%20of%20the%20cooler%20fan/turn-off-printer.png?width=600&name=turn-off-printer.png) ![check-hotend-FFC-connection](https://support.bcn3d.com/hs-fs/hubfs/Knowledge%20base/Sigma-Sigmax%20R19/how%20to%20check%20the%20operation%20of%20the%20cooler%20fan/check-hotend-FFC-connection.png?width=600&name=check-hotend-FFC-connection.png) If the fan still doesn’t work, the problem could be on the fan or the extruder board. If you have an external power supply you can try to power the fan with it to see if it turns on. - Regular fan works at 24V DC - Smart fan works at 12V DC In case you can’t power it externally, install the extruder board of the head that works to the problematic one following these steps: 4.1. Turn off and disconnect the printer. 4.2. Loosen the two screws to remove the Connection cover. 4.3. Remove the two pieces of PLA to release the aluminum part from the head. ![turn-off-printer](https://support.bcn3d.com/hs-fs/hubfs/Knowledge%20base/Sigma-Sigmax%20R19/how%20to%20check%20the%20operation%20of%20the%20cooler%20fan/turn-off-printer.png?width=600&name=turn-off-printer.png) ![remove-extruder-board](https://support.bcn3d.com/hs-fs/hubfs/Knowledge%20base/Sigma-Sigmax%20R19/how%20to%20check%20the%20operation%20of%20the%20cooler%20fan/remove-extruder-board.png?width=600&name=remove-extruder-board.png) 4.4. Disconnect all the cables from the extruder board. 4.5. In the problematic head, remove the two pieces of PLA and disconnect the flat cable, the hotend and the cooler fan from the extruder board. 4.6. Connect the flat cable, the hotend and the cooler fan of the problematic head to the extruder board of the head that works. Make sure all the cables are properly connected. ![remove-extruder-board2](https://support.bcn3d.com/hs-fs/hubfs/Knowledge%20base/Sigma-Sigmax%20R19/how%20to%20check%20the%20operation%20of%20the%20cooler%20fan/remove-extruder-board2.png?width=600&name=remove-extruder-board2.png) 4.7. Turn on the printer. 4.8. In the Temperature menu, heat the hotend of the problematic head and check if the cooler fan works when it reaches the 90⁰C. ![preheat hotend](https://support.bcn3d.com/hs-fs/hubfs/Knowledge%20base/Sigma-Sigmax%20R19/how%20to%20check%20the%20operation%20of%20the%20cooler%20fan/preheat%20hotend.png?width=577&name=preheat%20hotend.png) If the cooler fan works, the extruder board is probably damaged, so it will have to be replaced. You can purchase a new extruder board contacting your direct seller or our sales department at sales@bcn3d.com. - **Reference name:** Extruder board - **SKU:** 10910 Notice the original extruder board for the regular fan is discontinued, so If you have to update your extruder board make sure to get the corresponding cooler fan as well: - **Reference name:** Cooler fan 3010 12V  - **SKU:** 11034 If the cooler fan still doesn’t work, turn off and disconnect the printer. Connect the flat cable of the head that works properly to the problematic head (as explained in point 4.6 of the previous procedure). - If the cooler fan works, the problem can be the flat cable. Check the flat cable is well connected to the mainboard and that it does not have any damaged pins. - If the cooler fan still doesn’t work, it must be replaced. - **Reference name:** Cooler fan 3010 12V  - **SKU:** 11034   #### **[Forum community](https://support.bcn3d.com/knowledge/bcn3d-forum-community?hsLang=en) **   Repair didn’t go as planned? Check out our **[forum community](https://support.bcn3d.com/knowledge/bcn3d-forum-community?hsLang=en) **for troubleshooting help.   It's important to keep your printer in good shape to make the most out of it. In this chart, you can find a list of the extruder maintenance procedures and how frequently these should be done. [Maintenance Plan](https://support.bcn3d.com/knowledge/maintenance-plan-bcn3d-sigma?hsLang=en)   ![bcn3d-recycle](https://support.bcn3d.com/hs-fs/hubfs/Knowledge%20base/Tools/bcn3d-recycle.png?width=27&name=bcn3d-recycle.png)  Take your e-waste to a certified recycler. [Check how we do it in BCN3D.](https://support.bcn3d.com/knowledge/environment-bcn3d?hsLang=en)   | --- #### RELATED ARTICLES | | --- | | [![check flat cable eng](https://support.bcn3d.com/hs-fs/hubfs/Knowledge%20base/Related%20Articles%20English/check%20flat%20cable%20eng.png?width=600&name=check%20flat%20cable%20eng.png)](https://support.bcn3d.com/knowledge/check-flat-cable-connections-bcn3d-sigma?hsLang=en)   | [![manually unload filament eng](https://support.bcn3d.com/hs-fs/hubfs/Knowledge%20base/Related%20Articles%20English/manually%20unload%20filament%20eng.png?width=600&name=manually%20unload%20filament%20eng.png)](https://support.bcn3d.com/knowledge/unload-filament-bcn3d-sigma?hsLang=en)   | | --- | --- | | **You can help improve the BCN3D Knowledge Base.** If you feel there are guides that we are missing or you found any error, please use this form to report it. **[Report form](https://share.hsforms.com/1F7t1sBuOQyWlAeRwwFSjgQ3fec5)** :) | | --- | - [Omega](https://support.bcn3d.com/knowledge/omega?hsLang=en#main-content) - [Manuals & Downloads](https://support.bcn3d.com/knowledge/omega?hsLang=en#manuals-downloads) - [First steps](https://support.bcn3d.com/knowledge/omega?hsLang=en#first-steps) - [Maintenance](https://support.bcn3d.com/knowledge/omega?hsLang=en#maintenance) - [Tips](https://support.bcn3d.com/knowledge/omega?hsLang=en#tips) - [Troubleshooting](https://support.bcn3d.com/knowledge/omega?hsLang=en#troubleshooting) - [Epsilon Series](https://support.bcn3d.com/knowledge/epsilon-series?hsLang=en#main-content) - [Manuals & Downloads](https://support.bcn3d.com/knowledge/epsilon-series?hsLang=en#manuals-downloads) - [First steps](https://support.bcn3d.com/knowledge/epsilon-series?hsLang=en#first-steps) - [Maintenance](https://support.bcn3d.com/knowledge/epsilon-series?hsLang=en#maintenance) - [Tips](https://support.bcn3d.com/knowledge/epsilon-series?hsLang=en#tips) - [Troubleshooting](https://support.bcn3d.com/knowledge/epsilon-series?hsLang=en#troubleshooting) - [Sigma Series](https://support.bcn3d.com/knowledge/sigma-series?hsLang=en#main-content) - [Manuals & downloads](https://support.bcn3d.com/knowledge/sigma-series?hsLang=en#manuals-downloads) - [First steps](https://support.bcn3d.com/knowledge/sigma-series?hsLang=en#first-steps) - [Maintenance](https://support.bcn3d.com/knowledge/sigma-series?hsLang=en#maintenance) - [Tips](https://support.bcn3d.com/knowledge/sigma-series?hsLang=en#tips) - [Troubleshooting](https://support.bcn3d.com/knowledge/sigma-series?hsLang=en#troubleshooting) - [Smart Cabinet](https://support.bcn3d.com/knowledge/smart-cabinet?hsLang=en#main-content) - [Manuals & Downloads](https://support.bcn3d.com/knowledge/smart-cabinet?hsLang=en#manuals-downloads) - [First steps](https://support.bcn3d.com/knowledge/smart-cabinet?hsLang=en#first-steps) - [Maintenance](https://support.bcn3d.com/knowledge/smart-cabinet?hsLang=en#maintenance) - [Troubleshooting](https://support.bcn3d.com/knowledge/smart-cabinet?hsLang=en#troubleshooting) - [Filaments](https://support.bcn3d.com/knowledge/filaments?hsLang=en#main-content) - [Tips](https://support.bcn3d.com/knowledge/filaments?hsLang=en#tips) - [PLA](https://support.bcn3d.com/knowledge/filaments?hsLang=en#pla) - [Tough PLA](https://support.bcn3d.com/knowledge/filaments?hsLang=en#tough-pla) - [TPU](https://support.bcn3d.com/knowledge/filaments?hsLang=en#tpu) - [PET-G](https://support.bcn3d.com/knowledge/filaments?hsLang=en#pet-g) - [BVOH](https://support.bcn3d.com/knowledge/filaments?hsLang=en#bvoh) - [PVA](https://support.bcn3d.com/knowledge/filaments?hsLang=en#pva) - [ABS](https://support.bcn3d.com/knowledge/filaments?hsLang=en#abs) - [PP](https://support.bcn3d.com/knowledge/filaments?hsLang=en#pp) - [PA](https://support.bcn3d.com/knowledge/filaments?hsLang=en#pa) - [PAHT CF15](https://support.bcn3d.com/knowledge/filaments?hsLang=en#paht-cf15) - [PP GF30](https://support.bcn3d.com/knowledge/filaments?hsLang=en#pp-gf30) - [PET CF15](https://support.bcn3d.com/knowledge/filaments?hsLang=en#pet-cf15) - [Metal Pack](https://support.bcn3d.com/knowledge/filaments?hsLang=en#metal-pack) - [BCN3D Stratos](https://support.bcn3d.com/knowledge/bcn3d-stratos?hsLang=en) - [BCN3D Cloud](https://support.bcn3d.com/knowledge/bcn3d-cloud?hsLang=en#main-content) - [BCN3D Cloud Teams](https://support.bcn3d.com/knowledge/bcn3d-cloud?hsLang=en#bcn3d-cloud-teams) - [Sigma + Sigmax](https://support.bcn3d.com/knowledge/sigma-sigmax?hsLang=en#main-content) - [Manuals & Downloads](https://support.bcn3d.com/knowledge/sigma-sigmax?hsLang=en#manuals-downloads) - [First steps](https://support.bcn3d.com/knowledge/sigma-sigmax?hsLang=en#first-steps) - [Maintenance](https://support.bcn3d.com/knowledge/sigma-sigmax?hsLang=en#maintenance) - [Tips](https://support.bcn3d.com/knowledge/sigma-sigmax?hsLang=en#tips) - [Troubleshooting](https://support.bcn3d.com/knowledge/sigma-sigmax?hsLang=en#troubleshooting) - [Tips](https://support.bcn3d.com/knowledge/tips?hsLang=en#main-content) - [Design 3D](https://support.bcn3d.com/knowledge/tips?hsLang=en#design-3d) - [3D printer](https://support.bcn3d.com/knowledge/tips?hsLang=en#3d-printer) - [Previous models](https://support.bcn3d.com/knowledge/previous-models?hsLang=en#main-content) - [Manuals & downloads](https://support.bcn3d.com/knowledge/previous-models?hsLang=en#manuals-downloads) - [Maintenance](https://support.bcn3d.com/knowledge/previous-models?hsLang=en#maintenance) - [Default HubSpot Blog](https://blog.bcn3d.com/) [![Chill listening crop-3](https://support.bcn3d.com/hs-fs/hubfs/Logo_200px_horizontal_negro.png?width=100&height=40&name=Logo_200px_horizontal_negro.png "Chill listening crop-3")](https://support.bcn3d.com/knowledge?hsLang=en) Knowledge base Copyright © 2026, BCN3D Headquarters