The handling of damp magnesium oxide insulation depends on the degree of moisture. The key is to immediately disconnect the power and test the insulation resistance. If the resistance is <10 MΩ, the heating element must be replaced; if it is between 10–100 MΩ, drying or partial repair can be attempted as an emergency measure.
1. Immediate Power Disconnection and Safety Isolation
If the equipment reports leakage protection, grounding fault, or abnormal heating, immediately disconnect the power supply; remove the heater only after it has completely cooled down to avoid short circuits or electric shock risks from live operation.
2. Quick Insulation Test
Use a 2500V megohmmeter to measure the insulation resistance between the heating element and the casing:
<10 MΩ: Severely damp; do not continue use;
10–100 MΩ: Remedial measures can be attempted; proceed to the next step.
3. Emergency Recovery for Slight to Moderate Moisture Infestation
Low-Temperature Baking + Self-Heating Dehumidification (On-Site Feasibility)
Place the heating element in an oven and pre-bake at 80℃ for 2 hours;
Increase the temperature to 120℃ and maintain for 4 hours;
After removal, apply 50% of the rated voltage for 30 minutes to further dehumidify using self-heating;
After cooling, retest the insulation resistance; ≥100 MΩ indicates success.
Do not directly bake at high temperatures to prevent water vapor pressure from causing the tube shell to bulge.
Partial Cutting and Reconnection (Only for Moistened Terminals)
Cut at least 50mm inward from the moisture point;
Re-crimp the leads, ensuring contact resistance ≤ 0.03Ω;
Multi-layer sealing: Wrap with waterproof tape → Apply heat shrink tubing and heat to shrink → Optional silicone coating for enhanced protection;
The treated tube must pass a 2500V insulation test.
This is a temporary solution; it is recommended to replace the entire tube for long-term stability.
4. Emergency Response to Severe Moisture Infestation
The product is irreparable if any of the following conditions occur:
Insulation resistance < 10 MΩ;
Bulging, cracking, or presence of white crystals (Mg(OH)₂) on the casing;
Carbonization due to high-temperature aging.
In this case, you should:
Immediately replace the heating element;
Or send it back to the factory for professional refilling and sintering.
