How to Replace MoSi2 Heating Elements in a Nabertherm LHT 01/17 D: A Professional Lab Guide
Introduction
In the world of high-end dental aesthetics, the performance of your sintering furnace is only as good as its heating elements. For users of the Nabertherm LHT 01/17 D, maintaining the 4-element molybdenum disilicide (MoSi2) system is critical for achieving consistent Vita shade-perfect results.
In this guide, we break down the professional replacement process using WallaBC WL 1800 elements, ensuring your furnace operates with a safety margin of up to 1800°C and a temperature uniformity of <±5°C.
1. Pre-Installation: Safety & Fragility Warnings
Before touching the equipment, remember that MoSi2 is extremely brittle at room temperature.
-
Power Down: Disconnect the mains power connector entirely.
-
Cooling: Wait until the furnace and all connected parts have cooled to room temperature.
-
Handling: Never apply a bending or twisting force to the elements. We highly recommend two people perform the replacement to ensure vertical stability.
2. Dismantling the Old Elements
-
Remove the Exhaust Tube: Use an Allen key to remove the exhaust air tube from the furnace top.
-
Access the Elements: Remove the furnace hood to expose the ceramic element holders and wiring.
-
Take Photos: (Expert Tip) Take photos of the cable routing before disconnecting. This simplifies the wiring of your new WallaBC elements.
-
Disconnect: Loosen the aluminum braids from the contact clips.
-
Extraction: Carefully loosen the ceramic holders and lift the old elements straight up and out of the furnace chamber.
3. Precision Installation of WL 1800 Elements
When installing your new WallaBC WL 1800 elements, precision is the difference between a 100-cycle and a 1,000-cycle lifespan.
A. The Vertical Alignment
Ensure the elements are suspended vertically. They must never touch the insulation walls or the bottom of the furnace chamber. Contact during heating will cause immediate failure due to thermal expansion stress.
B. Defined Torque Settings (Critical Step)
According to the Nabertherm 01/17 D technical specifications, you must use a torque wrench to avoid crushing the elements:
-
Ceramic Element Holders: Tighten to exactly 1 Nm.
-
Aluminum Braids to Cable Lugs: Tighten to 6 Nm.
Pro Tip: Ensure the aluminum braids have a visible "loop" or slack. MoSi2 elements grow approximately 4% in length during heating; without this slack, the mechanical tension will snap the element.
4. The Commissioning Process: Creating the "Hermetic Seal"
New WL 1800 elements require a Pre-Set Program to create a protective oxide coating.
Why is this necessary? At operating temperatures, a high-purity SiO₂ (silicon dioxide) glaze forms on the element. This glaze creates a hermetic seal that prevents metallic contamination. Without this step, your zirconia may experience shading issues (ΔE > 0.5). Run the furnace empty through its pre-set oxidation cycle before your first production batch.
5. Troubleshooting Common Installation Issues
| Symptom | Root Cause | Solution |
| Element snaps during heat-up | Zero slack in the aluminum braids. | Re-install with a stress-relief loop. |
| Connection area overheating | Torque on contact clips is < 6 Nm. | Re-tighten connections to specification. |
| Uneven shading in Zirconia | Elements not vertically aligned. | Ensure all 4 elements are at the same height. |
Conclusion
By following these steps and using WallaBC WL 1800 Molybdenum Disilicide Heating Elements, you ensure your Nabertherm furnace remains the gold standard for dental zirconia sintering.
Looking for the highest purity replacements? View the WL 1800 Series in our 2026 Catalog or contact our technical team for compatibility confirmation for your specific Nabertherm model.
