Hot end failures are rare, but they do happen. Sometimes, over-loading or jamming filament can cause the hot end to leak excess or built-up filament. Other times, sharply tugging your filament from the filament feed port can strip your hot end of its internal Teflon. Or, your hot end’s safety fuse might switch off for your protection.
These are all issues that can be easily fixed with a hot end replacement. You can contact New Matter customer support should you need a hot end replacement. Follow these instructions, presented by Assistant Engineer Kendra, to replace your hot end.
1) Unload the filament and unplug your MOD-t
2) Check that your hot end has cooled down. You may need to wait for a few minutes. You can check the heat of the hot end by placing your hand near, but NOT ON, the hot end.)
3) Disconnect the wire contact from the base of the carriage.
4) Use the 10mm wrench (provided with new hot ends) to hold the nut at the top of the hot end in place and unscrew the hot end.
5) Grab your new hot end and line the screw up with the hole at the base of the carriage.
6) Screw the hot end into the carriage, using the wrench to hold the nut in place as you finish tightening the hot end. Make sure the hot end’s wires are facing the back of the carriage.
7) Re-connect the wire contact to the rear of the carriage’s base. Make sure the contact lines up properly.
8) Plug in your MOD-t, load filament, and get to printing!
TL;DR: You may need to change the hot end of your MOD-t at some point. You can get replacement hot ends from New Matter. Follow the instructions explained by Kendra in this video to successfully replace a hot end.