Dehumidifier displays P1 and stops dehumidifying; fan may continue to run.

Note: P1 on many Keystone dehumidifiers is not a fault but an indication that the unit is in defrost mode.

• Allow defrost cycle: Leave the unit plugged in and powered on. The compressor will stop while the fan runs to melt ice from the evaporator coil. P1 should clear automatically within 10–30 minutes.
• Check room temperature: If the room is below about 41–50°F (5–10°C), move the unit to a warmer area. Operating in very cold spaces will cause frequent defrost cycles.
• Clean filter and grilles: A dirty filter or blocked intake/exhaust reduces airflow and promotes icing. Remove and wash the filter; vacuum dust from the grilles.
• Persistent P1: If P1 never clears and the coil is heavily iced, unplug the unit and allow it to thaw completely. If icing recurs quickly in a warm room with clean filters, the evaporator temperature sensor or control board may be misreading and should be inspected.