Dehumidifier displays P1 and stops dehumidifying; fan may run briefly then stop.

Note: On many Tosot dehumidifiers, P1 is not a fault but an indication that the unit is in automatic defrost mode.

User actions:

• Allow defrost: Leave the unit plugged in and powered on. The compressor will stop while the fan may run to melt ice from the coil. Normal operation should resume automatically after several minutes.
• Check room temperature: If the room is below about 41–50°F (5–10°C), move the dehumidifier to a warmer area. These units are designed for moderate temperatures.
• Clean filter and grilles: Remove and wash the air filter. Vacuum dust from intake and exhaust grilles to improve airflow.
• Inspect for icing: With power off, remove the front cover and look at the evaporator coil. If heavily iced, let it fully thaw, then restart.

If P1 never clears:

• The defrost/evaporator sensor may be reading incorrectly. Follow the E2/E4 sensor checks and replace the sensor if out of spec.