Why Is My Refrigerator Not Cooling?

The Short Answer

When a high-end refrigerator stops holding temperature, the cold is usually still being made but not moving. A frosted-over evaporator, a stalled evaporator fan, or a defrost system that quit will all leave the cabinet warm while the compressor runs. Dirty condenser coils and a low refrigerant charge are the next most common causes. The display rarely tells you which, so the diagnosis is done with a thermometer and a meter, not the front panel.

Most Common Causes

• Frosted evaporator. A dead defrost heater or terminator lets ice choke airflow across the coil.
• Failed evaporator fan. Cold air is made but never pushed into the cabinet.
• Dirty condenser coils. Common near Boulder's open space and in homes with pets; the compressor overheats and loses efficiency.
• Drifting thermistor. The board thinks the box is cold enough and never runs a full cycle.
• Sealed-system leak. A slow refrigerant loss shows as gradual warming on one or both compartments.

Notes by Brand

The failure is similar across brands, but where you look differs. On Sub-Zero built-ins, a dual sealed system means one compartment can warm while the other holds, so we test both circuits. On Liebherr and Thermador, a numbered fault code often points straight at a sensor or fan. On Viking and True Residential, we work symptom to cause because those units report through behavior rather than a coded display. On Miele and Monogram refrigeration, an F-code or a service reading narrows the search to the defrost or fan circuit quickly.

Symptom Reference

FAQ

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