EN
  • Čeština
  • Español
  • Italiano
  • Deutsch
  • Polski
  • Français
  • 日本語
Login

How to replace a hotend heater (MK4/MK3.9)

How to replace a hotend heater (MK4/MK3.9)

How to replace a hotend heater (MK4/MK3.9)
Relevant for:
Last updated 2 months ago
How to replace a hotend heater (MK4/MK3.9)
 Difficulty
Moderate
 Steps
18
 Available languages
CSPLDEESITFRJA

Step 1 Introduction

Introduction
Introduction
This guide will take you through the replacement of the hotend heater on the Original Prusa MK4 and MK3.9.
All necessary parts are available in our eshop prusa3d.com.
Note that you have to be logged in to have access to the spare parts section.

Step 2 Tools necessary for this chapter

Tools necessary for this chapter
Tools necessary for this chapter
Tools necessary for this chapter
For this chapter, please prepare:
T6 Torx key
Cloth or piece of fabric 15x15 cm to protect the heatbed
Small brass brush for cleaning the hotend

Step 3 Preparing the printer

Preparing the printer
Preparing the printer
Unload the filament from the printer.
It's recommended to take off the spool holder from the printer.
Move the Z-axis to the center position to easily access the extruder from the top and bottom.

Step 4 Cleaning the hotend

Cleaning the hotend
Cleaning the hotend
Cleaning the hotend
Cleaning the hotend
WARNING: The hotend and heatbed are very HOT. Do not touch these parts!!!
For the following steps, it is necessary to have the heaterblock and the hotend clean from the remains of the filament.
If you have a Prusa hotend sock on the hotend, remove it.
On the printer screen, go to Control -> Temperature -> Nozzle Temperature and using the knob set 250°C.
Wait at least 5 minutes. The remains of the filament must be warmed up slightly so that they can be removed more easily.
Using the brass brush, carefully clean the heaterblock and the hotend from the filament residue. Avoid contact of the brush with the hotend cables, as this could cause a short circuit.
When the heaterblock and the hotend are perfectly clean, cool down the printer. On the screen, navigate to Preheat -> Cooldown.
Wait until the hot parts are cooled down to ambient temperature. It takes approximately 10 minutes.

Step 5 Protecting the heatbed

Protecting the heatbed
Protecting the heatbed
Turn the printer OFF and unplug the power cable from the PSU (Power Supply Unit).
Make sure the printer parts - print head and heatbed are cooled down at room temperature.
Turn the printer off and unplug it from the socket!
Before proceeding any further, it is recommended to protect the heatbed first!
Take off the flexible steel sheet.
Use any cloth or piece of fabric, which is thick enough and cover the heatbed. This will ensure you won't damage (scratch) the surface during the disassembly.

Step 6 Accessing the hotend cables

Accessing the hotend cables
Accessing the hotend cables
Accessing the hotend cables
Slide the Loveboard-cover up and remove it from the extruder. There are two cutouts on the back of the part, which you can grab for easier removal.
Open the fan-door widely.

Step 7 Disconnecting the hotend cables

Disconnecting the hotend cables
Disconnecting the hotend cables
Disconnecting the hotend cables
Disconnecting the hotend cables
Each connector has a safety latch. It is necessary to press the latch before disconnecting. Otherwise, the connector may get damaged.
Disconnect the hotend heater cable.
Disconnect the hotend thermistor cable.
Remove the heatsink fan cable, hotend thermistor, and hotend heater cables from the cable channel and leave them free for now.
If necessary, remove the other cables that overlap them.

Step 8 Removing the hotend

Removing the hotend
Removing the hotend
Removing the hotend
Grasp the hotend with your hand.
Use your other hand to loosen the two thumb screws. There is no need to remove them completely, a few turns are enough.
Slide out the hotend assembly from the heatsink.
At the same time push the hotend cables behind the heatsink out of the extruder.

Step 9 Removing the heater

Removing the heater
Removing the heater
Removing the heater
Removing the heater
Using the T6 Torx key loose the screws.
Remove the heater from the heaterblock.

Step 11 Installing the hotend heater

Installing the hotend heater
Installing the hotend heater
Installing the hotend heater
Insert new grub screws and screw them using a TX 6 key. A few turns are enough for now.
Insert the new heater all the way into the heaterblock.
Align the bottom surface of the heater with the bottom surface of the heaterblock.
Make sure your heater is aligned with the bottom side of the heaterblock.
Using a longer side of a TX 6 Torx key, gently tighten two grub screws while keeping the heater in position. Do not overtighten.

Step 12 Inserting the hotend

Inserting the hotend
Inserting the hotend
Inserting the hotend
Locate the hole in the heatsink from the bottom of the extruder and insert the hotend into the heatsink.
At the same time, push the hotend cable behind the heatsink fan up to the electronics.
Push the hotend assembly all the way into the heatsink. There should be approximately a 2 mm gap between the heatsink and the brass part of the nozzle.
Orient the hotend assembly so that the HOT symbol on the heaterblock faces forward.
While pushing the hotend assembly in, firmly tighten the lower thumb screw and the upper thumb screw. Avoid pinching any cable between the screws and the heatsink!

Step 13 Connecting the hotend

Connecting the hotend
Connecting the hotend
Connecting the hotend
Connect the hotend thermistor to the top left slot on the LoveBoard.
If you have the hotend thermistor with a long cable, make a loop near the connector. Do not twist the cable too much.
Connect the hotend heater to the black slot on the upper part of the LoveBoard.

Step 14 Guiding the hotend cables

Guiding the hotend cables
Guiding the hotend cables
Guiding the hotend cables
Locate the cable channel behind the thumb screws. Guide the hotend thermistor cable through the channel first. Then insert the hotend heater cable.
Guide the heatsink fan cable as you can see. Push it in the cable channel.
If you have removed other cables, return them to the channel.

Step 15 Arranging the cables

Arranging the cables
Arranging the cables
Arranging the cables
Arranging the cables
Close the fan-door.
Arrange all the cables according to the picture. All cables must be squeezed as close to the extruder body as possible so as not to interfere with the cover in the next step.

Step 16 Covering the LoveBoard

Covering the LoveBoard
Covering the LoveBoard
Covering the LoveBoard
Slide the Loveboard-cover on the extruder. And push it down.
Be careful not to pinch any cables!
When the cover is properly and completely inserted, you will feel a slight "click" of the rear latch.

Step 17 Final check

Final check
Final check
Final check
To check if everything is connected correctly go to Control -> Temperature -> Nozzle Temperature and set any temperature at least above 200°C.
Go back to the main screen and watch on the bottom bar to see if the temperature rises.

Step 18 That's it!

That's it!
That's it!
Great job! You just successfully replaced the hotend heater on your Original Prusa MK4/MK3.9.
Was this guide helpful?

Comments

Still have questions?

Still have questions?

If you have a question about something that isn't covered here, check out our additional resources.
And if that doesn't do the trick, you can send an inquiry to [email protected] or through the button below.

Contact us