TL;DR
Hopper level sensor faults interrupt material flow to the processing machine. Inspect the sensor lens for resin coating and verify cable integrity before replacing the sensor.
What you might see
- level sensor alarm on the dryer controller
- material loading stops or fails to trigger
- dryer reports hopper empty when material is present
- continuous loading cycle running without filling the hopper
Likely causes
Optical or capacitive sensor lens coated with resin dust or material buildup
Sensor cable damaged or connector loose from material hopper vibration
Sensor mounting bracket shifted from hopper vibration changing detection angle
Sensor failed from long-term heat exposure inside the hopper
Required tools
- Dry cloth or compressed air
- Multimeter
- Replacement level sensor (matching type)
- LOTO kit
Safety first
- Lock out the dryer before reaching into or near the hopper opening.
- Dryer hoppers retain heat after shutdown. Allow cooling or use heat-resistant gloves.
Procedure
- 1
Stop material loading and lock out the dryer before accessing the hopper sensor.
- 2
Open the hopper access port and locate the level sensor on the hopper wall.
- 3
Clean the sensor face with a dry cloth or compressed air. Remove any resin dust or material buildup from the lens or face.[1]
- 4
Inspect the sensor cable and connector for damage or looseness. Re-seat any loose connector.
- 5
Check the sensor mounting bracket for rotation or shifting. Re-align the sensor to point toward the center of the hopper at the correct fill height.[1]
- 6
Restore power and test the sensor by manually placing material in the hopper and confirming the sensor state changes on the controller.
- 7
If the sensor does not respond after cleaning and re-alignment, measure the output signal with a multimeter. Replace the sensor if it fails to switch at the correct material level.
Sources
Conair Conair Carousel Plus Material Dryer / Drying System general technical documentation, Conair
Conair Carousel Plus dryer operator manual, hopper sensor maintenance and troubleshooting (general)
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Stop fixing the same fault twice.
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