How to Quickly Troubleshoot Hot Runner Thermocouple Problems?

Efficient troubleshooting of thermocouple faults is critical to minimizing production downtime in injection molding. Common faults include open circuit, short circuit, reversed polarity, unstable temperature, slow response, and abnormal reading. Technicians can use a multimeter to check resistance and continuity for quick diagnosis. An open circuit shows infinite resistance, usually caused by broken wires or loose connectors. A short circuit shows zero resistance, often due to damaged insulation or melt penetration. Reversed polarity results in incorrect or fixed temperature readings. Unstable readings may come from electromagnetic interference, poor contact, or calibration drift. Slow response indicates improper probe placement or sensor aging. After identifying the cause, solutions include rewiring, replacing the sensor, correcting polarity, tightening terminals, or recalibrating the controller. Protective measures such as cable sleeves and proper routing can prevent repeated failures. This article provides a step‑by‑step troubleshooting process, common error codes, quick inspection methods, and on‑site repair skills, helping maintenance teams solve problems efficiently and maintain continuous production stability.