My H2D top Vent won’t open fully.
The vent motor actuates, the vent closes fully, but on open it only goes partially open (no HMS error).
I can manually open it fully.
The printer will close the vent when it is opened partially or when I open it fully.
The Bambu Wiki photos leave a lot to be desired.
I have not taken the vent apart yet.
Has anyone had this exact top-vent behavior and figured out how to fix?
If yes, photos/video of the linkage points to check would be very helpful.
It has 2 positions that it can be in. Half or fully open, which depends on several conditions.
Please share photos with what distance it’s opening up to, add the type of material you are printing with when you measured the distance and a screenshot of the chamber temperature together with some information about room temperature would help a lot. At least I believe this would be sufficient to guesstimate the direction from there.
Here is mine: bamboozle lab PLA matte military war green, 21°C room temp, 26°C chamber, lower end of ventilation lid is pointing at 12mm here (this seems off, but is still ok-ish considering the room temp), I’ll open up a ticket for my case as I believe this has been different in the past (it was more than 12mm, could be: firmware, software, an issue, nothing)
First, are you saying that the vent is not always either fully closed or fully open, but sometimes partially open depending on the filament?
In the past, I have seen the vent fully open (that was in August, 2025 when I first got the printer.
More recently, it is never more than 50% open from it max. If it is open it is usually what you see in the attached photo.
The vent motor at the start of a print job will usually open the vent, I hear it close and then it opens again.
I’m currently printing Bambu Lab Matte.
The vent is barely open.
The room temp is 75 degrees F (24 degrees C)
The chamber temp is 35 degrees C.
I’m using standard Bambu profiles for my filament settings.
The current model is using all standard process settings in BS.
I did not know that.
Mine has not been fully open in several months (it is winter now, where I live).
It is usually barely open. There is a screenshot in a reply below.
The vent motor normally opens the vent a little, the vent closes and then it opens it again. Not every time, but most of the time.
That opening is way too small. This is not temp control and not a bug.
Since it still closes fully and the motor runs, the printer thinks it reached position. When it only opens a few mm it almost always means the top vent swing rod or linkage is bent or popped out. Usually happens if the lid got bumped.
See step 2 here, that shows the part:
Solution: I would open a Bambu support ticket with your photo or video. This is a mechanical issue and they normally send a replacement vent kit, I believe.
Bambu is sending me a replacement Vent kit.
Here is a picture of the connection to the vent/motor. The rod is always toward the bottom of the vent connection (that is the part on the far left of the photo). The pictures on the wiki are hard for me to compare. I’m hoping once the replacement part arrives and I take apart my vent, I’ll be able to see them better.
It definitely looks like the plastic around the shaft is split open.
Can you send a picture of what it should look like? I’ve looked at the wiki photos but don’t see it.
Its quite hard to make a proper picture of it.
I personally don’t like too much cooling, so this is fine in my opinion.
Yes, it is hard to make a picture of the vent connector.
From looking at yours, I can see where mine might be missing some plastic or maybe slipped on the shaft. I know better once I receive the replacement.
Thanks for sending that.
I received a replacement part from Bambu. Now I can tell that a plastic part on my printer has stripped so that the motor shaft freely spins instead of moving the vent. I decided to use an extended warranty from Microcenter to replace the H2D with an H2C. If I tried to fix the H2D and broke any of the plastic top front part, it would void the warranty.
Thanks for all of the replies. It did help me determine which plastic part was causing the problem. If Bambu would have had a picture of the “Air Intake Swing Rod” I could have seen that the hole was keyed (flat on one side).
