E4
Challenge Refrigeration System Protection / High or Low Temperature Fault

Dehumidifier stops mid-cycle and displays E4; unit may beep repeatedly.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Overheated compressor due to blocked airflow, low refrigerant charge causing coil freeze, faulty overload protector on compressor, defective high-temperature sensor on discharge line

How to Fix / Troubleshooting

Safety: Unplug the unit. Do not attempt to open the sealed refrigeration system yourself; refrigerant work must be done by a certified technician.

Steps:

  • Check airflow: Remove and clean the air filter. Inspect the front and rear grilles for dust or obstructions. Ensure at least 20–30 cm clearance around the unit.
  • Inspect for icing: Remove the bucket and look at the evaporator coil. If it is heavily iced, allow the unit to defrost completely (leave unplugged for several hours) and then restart in a warmer room.
  • Check ambient conditions: Challenge dehumidifiers typically require room temperatures above ~5–10°C. Operating below this can trigger protection errors.
  • Inspect compressor area: With the rear cover removed (unit unplugged), visually check the compressor and its overload protector/relay for signs of overheating (discoloration, burnt smell).
  • Reset thermal protection: After cooling for at least 30 minutes, plug the unit back in and try again. If E4 returns quickly, there may be a deeper refrigeration or sensor issue.

Important: If you suspect low refrigerant (hissing, oily residue on joints, poor water extraction) or a faulty compressor, contact a professional. Do not attempt to cut or open refrigerant lines.

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Repair Difficulty

Professional Required 5/5
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