Aprilaire dehumidifier display shows LO and unit does not dehumidify

Safety first: No internal work is required for basic checks; unplug before accessing sensors.

• Measure room temperature: Use a thermometer to confirm the space temperature. If below the unit’s minimum (often around 50°F/10°C), relocate the dehumidifier or warm the space.
• Check sensor location: Ensure the ambient/return temperature sensor is located where it senses actual room air, not against a cold exterior surface.
• Test sensor: With power off, measure resistance of the ambient sensor and compare to the thermistor chart. Replace the Aprilaire ambient temperature sensor if readings are incorrect.
• Restore power: After correcting temperature or replacing the sensor, restore power and verify LO clears.