# Only prints 3 colors 4th printhead not used **URL:** \ **Category:** U1 Toolchanger\ **Created:** [March 7, 2026, 12:35am UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393 "2026-03-07T00:35:52Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![cdemaris](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/cdemaris/32/16589_2.png) [@cdemaris](https://forum.snapmaker.com/u/cdemaris)\ **Post date:** [March 7, 2026, 12:35am UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/1 "2026-03-07T00:35:52Z")
Only prints 3 colors 4th printhead not used defaults to the 1st printhead. Not getting any error messages just doesn’t print with the 4th head. Any ideas? ---
**Author:** ![Fishstyx](https://avatars.discourse-cdn.com/v4/letter/f/d78d45/32.png) [@Fishstyx](https://forum.snapmaker.com/u/Fishstyx)\ **Post date:** [March 7, 2026, 12:50am UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/2 "2026-03-07T00:50:55Z")
I just received my U1 and had exactly the same issue with one of the printheads. The issue was a piece of melted filament obstructing the filament path in the very top section of the hot end. The simple fix was to remove the hotend and do a cold pull procedure. In my case it was just a small piece of filament obstructing the path so simply heating up a small allen wrench to melt into and stick to the obstruction so I could pull it out and whala, all fixed. The filament obstruction must have been left over from QC testing at the factory because this was my first attempt at printing the dragon benchy included in the unit. ---
**Author:** ![Fishstyx](https://avatars.discourse-cdn.com/v4/letter/f/d78d45/32.png) [@Fishstyx](https://forum.snapmaker.com/u/Fishstyx)\ **Post date:** [March 7, 2026, 12:57am UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/3 "2026-03-07T00:57:05Z")
I just reread your post and it seems the unit isn’t even pickup up the 4th prinhead. Sounds like an electrical connection issue. Do you see all printheads present in the control menu? Does the calibration pickup that printhead during the leveling process? ---
**Author:** ![cdemaris](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/cdemaris/32/16589_2.png) [@cdemaris](https://forum.snapmaker.com/u/cdemaris)\ **Post date:** [March 7, 2026, 1:46am UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/4 "2026-03-07T01:46:56Z")
Well I have been trouble shooting it the filament loader doesn’t push the filament all the way to the printhead. It has about 3 more inches to go in the tube. I have to manually push the filament into the printhead during loading. So it seems my 4th printhead autoloader doesn’t have enough power to get the filament all the way to the printhead. Yes I did cut the filament at a 45 degree angle, actually did several cuts. ---
**Author:** ![Fishstyx](https://avatars.discourse-cdn.com/v4/letter/f/d78d45/32.png) [@Fishstyx](https://forum.snapmaker.com/u/Fishstyx)\ **Post date:** [March 7, 2026, 2:17am UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/5 "2026-03-07T02:17:32Z")
The filament pre-load will push the filament intentionally to about 3” before the toolhead. This is normal if this happened when you inserted the filament into the loader. It only pushes the filament the rest of the way during the filament loading process which you must initiate from the panel. The filament should be cut square at the end, no angle. Have you run the flow calibration? That will push filament to each head. This is where I discovered my blockage because after the calibration there was no yellow filament in the poop tray. Does your fourth printhead get picked up during calibration or does it behave as if the 4th printhead doesn’t exist? You said in the original post that 4th print isn’t used and that it uses the 1st printhead instead. This indicates the printer doesn’t ‘see’ the fourth printhead which sounds like an electrical connection problem with that printhead. Maybe an issue with the USB C connection. ---
**Author:** ![cdemaris](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/cdemaris/32/16589_2.png) [@cdemaris](https://forum.snapmaker.com/u/cdemaris)\ **Post date:** [March 7, 2026, 2:43am UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/6 "2026-03-07T02:43:51Z")
The fourth printhead participates in calibration. I have to manually load the filament and have got it to extrude. When I go to a print job it doesn’t use the 4th printhead. I am going to rearrange the printheads tomorrow to see if it is that particular printhead. ---
**Author:** ![cdemaris](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/cdemaris/32/16589_2.png) [@cdemaris](https://forum.snapmaker.com/u/cdemaris)\ **Post date:** [March 7, 2026, 8:35am UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/7 "2026-03-07T08:35:37Z")
Well I swapped the printhead in the 4th position with the one in the 3rd position. Redid all the calibration with no errors. When I print it defaults to the 1st printhead again. My number 4 spot isn’t working when it comes time to print. ---
**Author:** ![Wyphorn](https://avatars.discourse-cdn.com/v4/letter/w/ebca7d/32.png) [@Wyphorn](https://forum.snapmaker.com/u/Wyphorn)\ **Post date:** [March 7, 2026, 9:31am UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/8 "2026-03-07T09:31:57Z")
But did you load the 4th extruder? Mine will throw an error when the filament is just in the tube and not in the print head. There is a runout sensor for this. ---
**Author:** ![cdemaris](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/cdemaris/32/16589_2.png) [@cdemaris](https://forum.snapmaker.com/u/cdemaris)\ **Post date:** [March 7, 2026, 2:41pm UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/9 "2026-03-07T14:41:15Z")
Yes, I swapped the print heads and this time the auto loading process worked without an error. First time issues were me fumbling it the first time. I also ran some nozzle cleaning filament I have through the print head. So Load, Calibration, Leveling out worked without error. All four print heads show on the sctreen with the correct colors. If I print a small calibration print with all four colors. Number 4 print head is not used. If I print with only #4 it defaults to number 1. ---
**Author:** ![fatboy1271](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/fatboy1271/32/31087_2.png) [@fatboy1271](https://forum.snapmaker.com/u/fatboy1271)\ **Post date:** [March 7, 2026, 3:35pm UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/10 "2026-03-07T15:35:46Z")
Did you put in a Support ticket? Make sure to do that, as well as posting here. ---
**Author:** ![cdemaris](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/cdemaris/32/16589_2.png) [@cdemaris](https://forum.snapmaker.com/u/cdemaris)\ **Post date:** [March 7, 2026, 3:50pm UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/11 "2026-03-07T15:50:31Z")
I contacted support. I also looked for trouble shooting guides and videos. Didn’t find anything with my specific problem. This is not unusual as I seem to be able to have technology problems nobody else in the world has. Other than the 4th print head I am pretty impressed with the printer. ---
**Author:** ![Fishstyx](https://avatars.discourse-cdn.com/v4/letter/f/d78d45/32.png) [@Fishstyx](https://forum.snapmaker.com/u/Fishstyx)\ **Post date:** [March 7, 2026, 4:35pm UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/12 "2026-03-07T16:35:05Z")
It sounds like you have a tricky situation. I can’t think of a reason why it the fourth toolhead would work for calibration (leveling and extrusion) but then switch to #1 during a print. What do you see on the device monitor page in Snorca when you try to print the 4 color dragon benchy? Specifically, do you see the data for all four toolheads? You should see temps for all of them and have the option to pickup Tool4 manually. ---
**Author:** ![TiBr](https://avatars.discourse-cdn.com/v4/letter/t/dbc845/32.png) [@TiBr](https://forum.snapmaker.com/u/TiBr)\ **Post date:** [March 7, 2026, 5:08pm UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/13 "2026-03-07T17:08:02Z")
But you have already set different materials/colors on the U1 for 1 and 4, right? If not, the lowest spool will be used automatically until it is empty, and then it will switch. ---
**Author:** ![CCBox1411](https://avatars.discourse-cdn.com/v4/letter/c/4491bb/32.png) [@CCBox1411](https://forum.snapmaker.com/u/CCBox1411)\ **Post date:** [March 7, 2026, 5:44pm UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/14 "2026-03-07T17:44:57Z")
As already said… Make sure your filament is set and loaded on the actual U1 touch pad. Make sure Orca sees all 4 heads and filaments. I had issues before, especially after a power down, where it would pick up a head but not put it fully into ‘parking place’ which led to an error that it had not connected said head. It was completely random and varied between heads. The latest FW and physically swapping the USB head leads around appears to have cured it (fingers crossed), but I still occasionally get a filament error which I solve by just cancelling the warning and hitting resume on the print. I think Snapmaker may have set some of the head location, and filament tension tolerances a bit too tight, but who knows, I’m just a Muppet who enjoys printing trinkets lol. ---
**Author:** ![cdemaris](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/cdemaris/32/16589_2.png) [@cdemaris](https://forum.snapmaker.com/u/cdemaris)\ **Post date:** [March 7, 2026, 11:00pm UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/15 "2026-03-07T23:00:25Z")
I resolved all my filament issues. Now I am suspecting an Orca G-code problem. If I print the little dragon preloaded in the machine print head 4 works. If I import into Orca and color the item myself and generate G-code it doesn’t work. The picture shows the dragon and a little game token I printed separately. The white area on the game token was colored yellow #4 printhead as a test. ---
**Author:** ![cdemaris](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/cdemaris/32/16589_2.png) [@cdemaris](https://forum.snapmaker.com/u/cdemaris)\ **Post date:** [March 7, 2026, 11:00pm UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/16 "2026-03-07T23:00:48Z")
![image000000](https://us1.discourse-cdn.com/flex022/uploads/snapmaker/original/3X/9/d/9da1009a05ad10b9435f60bf2a608d50e9a78758.jpeg) ---
**Author:** ![xchrisd](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/xchrisd/32/1503_2.png) [@xchrisd](https://forum.snapmaker.com/u/xchrisd)\ **Post date:** [March 8, 2026, 8:18pm UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/17 "2026-03-08T20:18:38Z")
Did you check your gcode for T4 (or T0 - T3) commands? Open a topic and share your 3mf and gcodes with support, please: [https://snapmaker.formcrafts.com/u1-troubleshooting-request](https://snapmaker.formcrafts.com/u1-troubleshooting-request) ---
**Author:** ![cdemaris](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/cdemaris/32/16589_2.png) [@cdemaris](https://forum.snapmaker.com/u/cdemaris)\ **Post date:** [March 9, 2026, 12:31am UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/18 "2026-03-09T00:31:12Z")
I didn’t check the G-Code commands. I did download the current Orca version from Orca. OrcaSlicer\_Linux\_AppImage\_Ubuntu2404\_V2.3.1 Used it to run a print and print tool number 4 worked. Went back to Snapmaker Orca Snapmaker\_Orca\_Linux\_AppImage\_Ubuntu2404\_V2.2.4\_Beta Same print Tool head #4 was not used and it defaulted to #1. ---
**Author:** ![Burgerboy](https://avatars.discourse-cdn.com/v4/letter/b/0ea827/32.png) [@Burgerboy](https://forum.snapmaker.com/u/Burgerboy)\ **Post date:** [March 13, 2026, 1:07pm UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/19 "2026-03-13T13:07:19Z")
Did you raise a ticket on this? I seem to be having the same problem with Toolhead3 on a model I’ve painted in Snorca & tried again in Orca. Bizzarely I did get it to work the first time I did it in Orca then regen’ed it because my support settings weren’t quite right and then it ignore Toolhead3 during the print. Checking the Gcode didn’t highlight anything as it correctly changes to T2 at the correct layer ---
**Author:** ![cdemaris](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/cdemaris/32/16589_2.png) [@cdemaris](https://forum.snapmaker.com/u/cdemaris)\ **Post date:** [March 13, 2026, 2:38pm UTC](https://forum.snapmaker.com/t/only-prints-3-colors-4th-printhead-not-used/41393/20 "2026-03-13T14:38:31Z")
The only solution so far is in Orca under Process switch from Global to Objects. Change the default color on your model or models to the color of your Tool Head #3. Then it should print correctly. This is not a satisfactory solution but it does work, at least for me.