Thermocouple replacement

The thermocouple is the part tightened in the bandheater. The thermocouple ensures that the temperature of the bandheaters is measured. It may happen that one of the thermocouples fails. The faulty thermocouple can be replaced with a new thermocouple.

This guide describes step by step how the old thermocouple must be removed from the bandheater and how the new thermocouple can be installed.

Before you start

Collect the following items:

  • Soft cloth or towel
  • Hex key 2.5 mm for M4 bolts
  • Tie wrap
  • Rubber gloves
  • Wrench 10
  • Piece of foam or wood or something similar to bring the machine up to height
  • Service package: New thermocouple, metal tie wrap

Remove top hood

Step 1: Follow the instructions to remove the top hood first and after finishing continue to step 2.

Raise the machine

Step 2: The machine must be brought up to height to remove the winder cover. Use a piece of foam or a piece of wood or something similar to bring the machine to the right height.

Remove winder plate

Step 3: Remove the winder side plate. First unscrew the adjusting knob by hand.

Step 4: Now unscrew the 6 bolts with the Allen key. First unscrew 5, shown with the red arrows. Loosen the bolt with the blue arrow indicated last. Beware! The winder plate can now fall off the machine. If the winder plate is loose, carefully place it somewhere where it can not be damaged.

Wear rubber gloves

Step 5: Wear rubber gloves to protect your skin against irritation caused by the isolation wool

Remove isolation wool

Step 6: Depending which thermocouple must be replaced, cut and remove the first, second, third or the fourth tie-wrap. Thermocouple number 1 is located at the front of the machine at the nozzle. Thermocouple number 4 is located at the end of the barrel, closest to the hopper.

Step 7: Open up isolation wool and spread to such an extent until the failed thermocouple is exposed.

Unscrew the thermocouple

Step 8: Carefully unscrew the thermocouple with a spanner from the heater, but make sure to do it gently.

Step 9: Cut with a cutter the ty-raps which belong to the faulty thermocouple.

Step 10: Unplug the faulty thermocouple free from the Devoboard, which is placed on the side of the machine. The first left plug is for thermocouple 1, next to it is the plug for thermocouple 2, 3 and 4.

Place the new thermocouple

Step 11: Take the new thermocouple out of the packaging and place it back in the bandheater.

Step 12: Tighten the thermocouples hand tight and then another eighth turn (1/8) to a quarter turn (1/4) carefully with a spanner. Note, the thermocouples do not have to be turned very tight, otherwise they will be damaged in the heater.

Cable management

Step 13: Lay the cable of the new thermocouple again gently through the frame and connect it with a ty-rap.

Step 14: Plug the cable into the Devoboard.

Restore isolation wool

Step 15: Fold isolation wool back around the extruder and use new tie wraps to hold the isolation wool on its place.

Mount upper plate

Follow these steps in reversed order to mount the upper plate back on the machine.