TAZ5 Hexagon Hotend Fan

Just setup my Taz5 and plugged in the hotend, extruder and power cables for the two fans (one squirrel cage fan on the hotend fins, and the bigger fan for the Filament extrusion). Found that the two power cables for the fans can be swapped and at first I had them swapped (there was no mention in the manual about identifying what plug matches the other) and found the Larger fan would barely spin, switched the two cables and it now spins correctly and I can set it from the LCD and it will speed up as it should.

My question is the fan for the hexagon hotend fins still never spins up, is this automatic or is there some setting I’m missing to make it work?

I read elsewhere you don’t want to run it without the fan cooling it via the fins or it will burn out faster.

Also, I’m finding that mid prints the hotend clogs and chew the filament, could this be related to the hotend not cooling?

Thanks in advance.

The small blower fan should be on whenever the printer is on.


If it needs replacing, email support@lulzbot.com.



Well I’ve contacted support, we’ll see what they can suggest. Just to update though, I’ve tested the small hotend fan with a voltmeter, read a 4.95V on the meter, when the unit is up to temp. Found that at ambient temps I had no reading…so there must be some kind of temp sensor OR a bad power supply (more on that in a sec). I tested the fan by plugging into a 12v battery and it still will not power on, checked the shroud around it and it moves freely. I tried to remove the fan but found that the retaining screw wobbles like it’s bent and it will not unscrew…so that’s not an easy fix…if Lulzbot just sends me a fan. I did wire a temporary fan up to the hotend fins and finally completed my first print, I also loosened the Filament idler and that seems to have helped with the extrusion stopping mid print. But, that’s not my biggest problem now. After the second attempt on the octopus the unit shut off and restarted, I checked the power plug and it was secure, I cancelled the print and restarted and after the bed and hotend were up to temp I heard a popping / arcing sound coming from the power supply box…it then shut down again and restarted itself, after it reached operating temp again the popping and arcing buzzing from the power supply got worse…It’s now unplugged and making it’s way back into the box…sigh.

I had both problems exactly as you’ve explained. Here is what happened. The tiny fan that blows on the heat sink above the hot end is of UTMOST importance. Without that heatsink being cooled, the filament will melt above the hot end which is VERY bad (speaking from experience). It took me 4 days to unclog that heatsink. As for the power supply, my power supply died as well in the exact same way. do not get discouraged however, lulzbot’s support is extremely helpful and they will sort you out very quickly. Email support@lulzbot.com and let them know you need a new fan, power supply, and possibly a new hot end with heatsink if yours is clogged. I did not ask for a replacement hot end which I am regretting. I took mine apart and let the heatsink and nozzle sit in acetone for four days. It’s back together and working now but I get filament oozing out of the side of the nozzle and above the hot end. :frowning:

I had the same problem with my blower fan and was sent a new one. Pretty much couldn’t print anything without it blowing air on the heatsink. I used a battery powered fan to keep it cool enough to print a fan duct to reroute the nozzle fans air onto the heatsink but it didn’t work quite as well and I still had trouble with long prints.

I’ll chime in also. Have had the same Power supply issue and now my replacement is getting noisy. I also am having a lot of mid print issues with stripping the filament. Seems to be related to bad eSUN black HIPS partially clogging my nozzle whenever it is used. I get filament spiraling out then a hard clog that has to be torched out. PLA and ABS extrude fine once cleaned.


Email into Support@LulzBot.com with images of your leaking hot end and we’ll help.


Just set up my TAZ 5 today. Now I have a clogged nozzle and a burnt out squirrel cage fan. The two fans are different voltage though the connectors are the same. The box fan seems to be 12V and the squirrel fan is 5V. The instructions have no mention of this. Only after the clog, the smoke from the fan, and some investigation did I see the yellow paint marks on the underside of the one connector indicating which went with which.

I’ve emailed support and I’ll see what happens. I’m thinking a set of unique connectors will be coming along shortly. Replacing the fans of 50% of printers sold is gonna get expensive!

So after an entire wasted weekend of clearing clogs and trying to determine why I’m having problems with heat creep and that small fan I finally stumble across your post. A simple yellow dot on the bottom that the instructions (Taz 4 upgrade) fail to mention… Looking back, it actually does mention blue paint and I was confused at the time but I guess it all adds up now. Well, better late than never.

Just received my TAZ 5 just to end up like everyone else here. Didn’t see the yellow dot and had them cross now I have to wait till Monday just to put in an order for a squirrel cage fan. They should have at least swap the connectors from one another to unsure a simple mistake like this could be prevented.