Heater Cartridge Replacement

This modification applies to V1 of the Duplicator i3. Performing this mod may void your warranty.  Proceed at your own risk.


This is not a required modification but there is some discussion on the size of the heater cartridge and the size of the hole in the heater block not matching up. The oem heater core is 6mm in diameter. The heater block hole for the heater is sized at 1/4″ and the heater cartridge does not always make contact on all sides. This can cause heating inefficiency or the ability to heat to higher temperatures. This mod uses a heater cartridge with a diameter of 6.35 and fits the hole perfectly. The heater is also short and fits completely inside the block without excess sticking out (important when using certain cooling shrouds). The wires are also nice and are not nichrome so there is no extra heat generated by the wires like the oem version. This is important because there have been cases of the heater wires getting hot enough to melt some of the other wires in the cable chain. Most of the heater cartridges you find on eBay and Amazon are the 6mm size. The correct size for the Duplicator I3 block is hard to find.

Removing the Heater Cartridge
Installing the new Heater Cartridge
Reconnecting the Wires



Removing the Heater Cartridge
  • Move the Z up until it is about half way up. This allows you to gain access to the heater set screw.
  • Power off the unit
  • Looses the set screw on the bottom of the heater block. It may be covered by the insulation but is located centered on the nozzle about 1/4″ away (it will be located on the center line of the heater cartridge hole).
    Heater Cartridge Set Screw
  • Remove the heater cartridge from the hole.
Installing the new Heater Cartridge

There are a couple of ways to connect the new heater cartridge wires. I opted to use a two pin terminal block so it would be easier to remove my heater assembly later if I needed to work on it. The other way would be to use a couple of wire crimps or buttsplices to connect the wires to the old wires just like the way the original cartridge was connected.

  • Remove the old heater cartridge by prying the old crimps open or if there is enough wire pulled out of the cable chain (this should be done already. (See info about the Recall notice) cut the wires off just above the crimps.
  • Solder a two pin terminal to the wires coming from the controller (don’t forget to use heatshrink on the wires)
    or use crimps / buttsplice connectors to connect the wires from the new heater cartridge after the next few steps.
  • Carefully bend the wires coming out of the new heater cartridge over so they are at a 90° angle.
    New Heater Cartridge Installed
  • Slide the new Heater Cartridge into the heater block with the wires pointed towards the temperature sensor location (towards the X carriage).
  • Tighten the setscrew on the bottom of the heater block.
Reconnecting the Wires
  • Route the heater cartridge wires behind the extruder assembly between the bracket and the stepper motor.
  • Determine where the new wires need to be cut at (leave enough to screw into the terminal block or crimp onto the original wire harness).
  • Cut the new wires to length then strip the end of the wires long enough to either screw into the terminal block or crimp onto the existing heater wire harness.
    Heater Cartridge Wires
  • Screw the wires into the terminal block or Crimp the wires to the original harness and cover with heat shrink.
    Heater Cartridge Wires in Terminal Block

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