Dehumidifier displays P1 and does not start dehumidifying.

Safety first: Unplug the unit before inspecting internal components.

Steps:

• 1. Check room temperature: If the space is below approximately 41–50°F (5–10°C), many Carrier dehumidifiers will enter P1 defrost or low-temperature protection. Move the unit to a warmer area if possible.
• 2. Inspect for frost: Remove the front cover and look at the evaporator coil. If it is heavily iced, allow the unit to sit unplugged until all ice melts. Place towels to catch water.
• 3. Clean filter and coil: A dirty filter or coil can cause low coil temperature and icing. Clean both thoroughly.
• 4. Verify fan operation: Ensure the fan runs when the unit is on. Poor airflow can cause the coil to freeze and trigger P1.
• 5. Check defrost sensor: If P1 appears even in warm conditions and no ice is present, the defrost/coil sensor may be misreading. Test and replace the sensor as needed (see E3/E4 procedures).

Note: P1 is often a normal mode indicating the unit is defrosting. If it cycles in and out of P1 but still removes moisture, no repair may be needed.