For Hard Faults, Replace Directly Replace without repair right away if any of the following situations arise:
Full Open Circuit: The internal wire core is totally destroyed; resistance measured with a multimeter yields infinite values; and the temperature controller immediately gives fault codes like OPEN and Err.
Severe Leakage/Short Circuit: Measurement findings are significantly distorted because either the wire core insulation is destroyed or the PT100 resistance is far below 100Ω at room temperature.
Physical harm: The measurement is totally disabled by water or oil intrusion; the wire is clearly damaged or peeling; and the probe protective tube is fractured.
Surpassing Ageing Lifespan: The inaccuracy keeps rising after several calibrations and adjustments following regular use for more than three years, suggesting that the natural lifespan has passed.
Replace Following Performance Deterioration Troubleshooting If the following circumstances continue, rule out environmental intervention first; if nothing changes, replace:
Extreme Temperature Drift: Temperature fluctuations and abnormally slow temperature rise; even after changing the PID, the inaccuracy is still greater than ±5°C, well outside the instrument's stated accuracy.
Temperature measurement response is significantly delayed: Although the hot runner's real temperature has increased, the sensor reading lags behind by several degrees for a considerable amount of time. Sensitivity is not increased by cleaning or modifications.
Thermoelectric potential deviation exceeds limits: The output thermoelectric potential deviation regularly above the permitted range when compared to the standard calibration table and cannot be adjusted through calibration.
30-Second On-Site Fast Diagnosis Without Tools: These two techniques can be applied for fast diagnosis in the absence of a multimeter:
Comparison Method: Measure the same spot in the hot runner at the same time using a qualified and calibrated thermocouple. Replace the thermocouple immediately if several measurements reveal a consistent discrepancy greater than ±3°C to 5°C.
Operating Condition Verification Method: Replace the thermocouple directly if, even after ruling out loose wiring, the temperature display constantly and erratically varies when the hot runner is running at a steady temperature.
This set of requirements reduces the possibility of hot runner temperature control failure due to malfunctioning operation and prevents premature replacement and needless cost waste.
