Dehumidifier shows E4 and will not run the compressor

Safety: Unplug the unit. Beware of sharp metal edges around the coil.

Steps:

• Allow thawing: If the unit was operating in a very cold room, let it sit powered off for 1–2 hours to fully defrost. Restart and check if E4 clears.
• Locate defrost sensor: On many Meaco compressor dehumidifiers, the defrost NTC is clipped to the evaporator coil or suction line.
• Check attachment: Ensure the sensor is firmly clipped to the coil and has good thermal contact. Reattach if loose.
• Inspect wiring: Follow the sensor wires to the PCB. Look for chafing, cuts, or loose connectors. Reseat the connector.
• Test sensor: With power disconnected, measure resistance of the defrost NTC and compare to Meaco’s temperature‑resistance chart. Replace if open, shorted, or out of range.
• Replace parts: Install a new Meaco defrost NTC sensor if faulty. If the sensor is good but E4 persists, the main control PCB may require replacement.

Note: Operating the unit below the specified minimum room temperature can repeatedly trigger defrost errors. Check the user manual for the correct operating range.