How to Repair a Leaking Hot Runner Heater

I. Minor Leakage (Insulation Resistance 0.5MΩ~5MΩ, Insulation Deterioration Warning) Drying and Dehumidification: Remove the leaking heater from the hot runner and place it in a 150℃ constant temperature oven for 4-6 hours to completely remove moisture adsorbed inside the magnesium oxide insulation layer. Retesting and Verification: After drying and cooling to room temperature, retest the insulation resistance with a 500V megohmmeter. Once the value is confirmed to have recovered to ≥5MΩ, it can be reinstalled and used. Applicable Scenarios: Minor insulation dampness caused by a humid environment or long-term shutdown, without heating wire touching the shell or insulation layer damage. II. Moderate Leakage (Local Insulation Layer Damage, No Heating Wire Melting) Locating the Damage Point: Disassemble the heater casing, accurately locate the localized damage to the magnesium oxide insulation layer and the slight contact of the heating wire with the shell, and cut off the damaged section of the heating wire. Refilling with Magnesium Oxide Powder: Insulate both ends of the cut heating wire, refill with high-purity, high-temperature magnesium oxide powder, and compact to restore insulation performance. Insulation Reinforcement Treatment: Wrap the repaired heater with a high-temperature resistant PTFE insulating film and install an alumina insulating bushing to prevent recurrence of short-circuit leakage. Post-Repair Testing: After installation, perform a high-temperature insulation retest at room temperature + 320℃ to confirm that the insulation resistance meets standards, there is no dynamic leakage voltage, and the sensor shows no crosstalk fluctuations. III. Severe Leakage (Heating Wire Melted, Large-Area Insulation Burned, Casing Breakdown) Direct Replacement with a Brand New Heater: Remove the damaged, leaking heater and select an original high-temperature resistant heating coil with matching heat flow channel power and size to avoid using incompatible, low-priced parts. Synchronous Replacement: Simultaneously replace aging heating cables and oxidized aviation connectors to prevent insulation defects in old parts from causing further leakage. Post-installation full verification: The second full-process testing was completed, confirming that the high-temperature pressure holding was qualified, thermal shock stability met standards, and temperature data remained stable without fluctuations after 4 hours of continuous operation. IV. Leakage Root Cause Prevention and Optimization All heater circuits are equipped with leakage protection circuit breakers with an operating current set to 30mA. Leakage automatically cuts off high-voltage power upon initial leakage, preventing prolonged crosstalk to the sensors. A full-system insulation test is conducted every 3 months, simultaneously with the calibration of the Husky K-type coupler probe, to provide early warning of potential insulation degradation.