Check loose air holes for rust or moisture
If you find rust or moisture near a hot runner vent, it means internal condensation or a possible water pipe rupture. Moisture can cause a fatal short circuit to the heater. If the machine is shut down at night or on weekends instead of running all year round, the chance of such condensation on an injection mold increases.
You should have measured the resistance of the heater when you first started using it, […]