What Is a Compressor?

The compressor is the pump at the heart of the sealed system — it pressurizes refrigerant gas so it can release heat outside the unit, then draws it back in to absorb heat from inside. It's the single most expensive component in most refrigerators and wine coolers, and the one every other sealed-system part depends on.

Signs of failure: a compressor that runs constantly without ever cycling off, a loud buzzing or clicking every few minutes with no cooling, or a compressor housing that's hot to the touch. Total silence after a power cycle can also mean the compressor itself has died.

Frequently Asked Questions

Is it normal for a refrigerator compressor to feel hot?

Yes — a warm compressor is normal while it runs, since compressing refrigerant generates heat as part of the cycle. The concern is a compressor that is very hot and paired with poor cooling, which is when a diagnostic is worth booking.

Can a refrigerator compressor be repaired instead of replaced?

The compressor itself is a sealed unit that gets replaced, not repaired — but not every "bad compressor" symptom is actually the compressor. A failed start relay or overload protector can make it seem like the compressor won't start, and those are inexpensive parts by comparison, which is exactly what a diagnostic rules out first.

Why is my refrigerator not cooling, but the freezer still works (or vice versa)?

Some premium built-in refrigerators — Sub-Zero's Dual Refrigeration is the best-known example — use separate compressors and sealed systems for the refrigerator and freezer sections. If only one side has lost cooling, the fault is almost always isolated to that side's compressor, evaporator, or fan, not the whole unit.