I have been printing for ~2 months now on my P1S. Every time I start a print or change the filament in multi-color prints, the chamber fan goes to 100% which is super loud. I can’t find any setting to edit this Bambu Studio, I just have to be around to set the chamber fan manually back down it 70%. There was a post about this 7 months ago but it didn’t help me with my problem.
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Set it in the slicer under the filament cooling section:
Auxiliary Fan speed: X%
Exhaust Fan Speed: Y% - usually 70% does the job
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That worked, Thank You!
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Nevermind, the chamber can went right back to 100% after a filament change. I cannot find the exhaust fan setting for any of my PLAs, is there any other way to fix this?
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I guess one would have to find out why this happens by piecing together the Gcode templates of the printer + filament and also analyzing the generated gcode after slicing.
M106 controls the fans during the whole procedure, with M106 P3 directly addressing the chamber fan, and no index addressing all installed fans (for example M106 S255 will set all fans to 100%).
The fans spin up at multiple points during the printer initialization/start, but whilst printing, the filament settings for the chamber fan should be honored.
Can you provide a simple .gcode example that showcases the behaviour?
The only thing that I can imagine is that some command sets a fan speed for some reason (either directly or for all fans), but further code fails to reset the chamber fan speed.
Does the chamber fan speed stay at 100% after a filament change for the rest of the print? Or is this just temporary?
I did not notice any of the mentioned behaviour on filament changes with multi color prints on my P1S when printing or slicing with the latest version of Bambu Studio. Do you use Orca by any chance?
EDIT: I’ve noticed that Bambu Studio does not have the Exhaust Fan Setting under the (Advanced) Filament options.
@crazyOC8 , did you try out using Orca Slicer and adjusting these settings?
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They were added to Bambu Studio in the last firmware update, and now i have all my filaments set to 70%. Problem has been fixed, thanks you two. Before, the exhaust/chamber fan was set too off but it still went on. I will provide a sample benchy once I slice it. I have a backup of my old settings
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Interesting, because I don’t see the exhaust fan option in any of the filament presets with Bambu Studio 1.8.4.51 with my P1S at 01.05.02.00. I only see those options in Orca Slicer.
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I updated 20 mins before posting that last message, so it is a very new feature.
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OKAY. I just noticed that I’m having the same issue with a certain print.
The chamber fan just goes brrr. To 100%, although it has been set to run at 70%.
Aaaand there’s a simple explanation. At least in my case.
If you take a look at the filament start G-Code …
For Bambu PLA Basic it is around 78.5% (200) chamber fan for heatbed temps >55°C, around 60% (150) for heatbed temps > 50°C, and around 20% (50) for beds > 45°C.
For my other Filament (Polymaker Polyterra PLA) it’s 100% (255) for any bed temp above 45°C and 70ish% (180) for bed temps > 35°C.
This explains why my chamber fan goes up to 100% … it’s in the filament start code for Polyterra PLA.
It’s just super strange that exhaust fan setting in Orca does not affect the speed at all. For Bambu I need to manipulate the filament start code - but in Orca … I need to check “Activate Air Filtration” for the values below to honored. Then the last section of the filament gcode will be evaluated (because “air filatration” is ON), setting the chamber fan speed to the value set in the Cooling tab.
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in my case, I set the filament to PLA silk when it was a Matte PLA. Idk why setting it back to matte turned off the chamber fan because my other silk PLAs do not do this.
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I have the same problem on my P1S since upgrading Bambu Studio today to 1.91.66.
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Same… after the upgrade the stupid fan goes to 100 % all the time. Running several printers at the same time is a noise party…
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Just had the same thing here, did an update fired it up and good god it was loud! I hope a fix will be incoming soon.
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Try using orca slicer until it is fixed.
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It’s definitely an issue with the software because I didn’t upgrade and my chamber fan is normal.
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for the first time I’ve experienced this yesterday. Printer wasn’t software upgraded recently, neither was the slicer (but that’s irrelevant). I printed a presliced multicolor file from BBL handy and chamber fan went up to 100% even during auto leveling. It is most probably a software issue as the handy app showed “slicing” before downloading the presliced file (haven’t seen that before), which could have effected the cooling settings.
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@crazyOC8 @GhostSeven @Warmup @Carlos_Ayala @user_1902567722
So for all of you, its NOT a bug its actually a FIX. Its HIGHLY DOUBTFUL going to be fixed as it IS a fix.
What I hear you cry? yes, its a fix. yes, its legit. The Machine start code, prior to ACTUALLY PRITING was incorrectly set to 70%, what your “used” to hearing. Its been now set to 100% PRIOR to printing to resolve some PLA jamming issues reported by numerous time to Bambu. I am not afflicated with Bambu (wish i was) however its in various placecs, code changes, machine code changes etc if your willing to search, including a mucch bigger thread on this forum and Github where the bug (original 70% fan code) was reported and fixed).
GitHub Link - Chamber fan goes to 100% when warming bed at begining of print job · Issue #4054 · bambulab/BambuStudio · GitHub
Post by Bambu Rep
And the bug it fixed with the incorrect machine code.
However, I just got a CONFIG update - that I guess with all the reports, has lowered it back to 45?
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On my x1c when the material colour changed the chamber fun went down to 0% during the first change and then it went to 10% after the second colour change.
Can anyone explain that? Is this normal?
Thank you
Fulv 
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could be there to keep chamber temps under a certain value, on the first color change your printer was probably cooler inside and didn’t need to push some hot air out