Keystone Coil Icing / Frost Buildup

Dehumidifier freezes up; evaporator coil becomes a solid block of ice.

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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

Low ambient temperature, restricted airflow due to dirty filter or coil, low refrigerant charge, faulty evaporator temperature sensor not initiating defrost, fan running too slowly

How to Fix / Troubleshooting

Safety: Unplug the unit before defrosting. Do not chip ice with sharp tools.

Steps:

  • Thaw the unit: Turn off and unplug the dehumidifier. Allow all ice to melt naturally; place towels to catch water.
  • Clean airflow path: Wash the filter and vacuum dust from the evaporator and condenser coils.
  • Check room temperature: Move the unit to a warmer room if ambient temperature is below about 60°F (16°C).
  • Verify fan speed: Ensure the fan runs strongly; replace the fan motor if weak.
  • Sensor check: Inspect the evaporator temperature sensor for proper placement and connection. Replace if faulty.
  • Persistent icing: If icing continues despite proper airflow and temperature, a refrigerant or compressor issue is likely and requires professional service.
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Repair Difficulty

Hard 4/5

Required Part

Evaporator Temperature Sensor (Coil Thermistor)
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