Heater Block Assembly Replacement

The heater block assembly, comprised of the heater block, heater cartridge, heat break, nozzle, and temperature sensor, is considered to be a single replaceable component.

Heater block assembly

Required Tools & Equipment

  • Heater Block Assembly with desired nozzle size
  • Small pair of vise-grips
  • Wire cutters (optional)

Use the wire cutters to snip the filament just above the extruder. Open the extruder to allow the filament to move inside. Alternatively, you can remove the filament by heating up the hot end to the appropriate extrusion temperature for the material, opening the extruder, and pulling out the filament. Allow the hot end to fully cool.

Extruder tabs in “open” position

Unplug the two connectors for the heater and temperature sensor.

Unplug heater cartridge connector Unplug temperature sensor connector

There is a small piece of PTFE tubing running from the bottom of the extruder through the heat sink into the top of the heat break. This is a crucial piece of the filament feed path. It may stick in the heat break and come out when you remove the heater block assembly. Be careful not to lose it, and make sure to replace it when you install the new assembly.

Use the vise-grips to clamp the heater block as shown below and carefully twist clockwise to unscrew the entire assembly from the water cooled heat sink.

Be careful not to bend the heat break while removing the assembly Applying force as shown with the arrows in the figure below should ensure you do not damage the heat break as you unscrew the assembly.

Remove the heater block assembly as shown

Screw in the new heater block assembly, being careful not to bend the heat break. You should be able to do this by hand. Hand-tighten.

Plug in the wiring for the heater and temperature sensor using the heat shrink labels on the wiring harness as guidance. Make sure the wiring is not obstructing movement in the X-axis or blocking the end stop switches from triggering. Check that the areas circled in the figure below are clear.

Area to avoid placing wires

Last modified: August 3, 2020