Compressor seizure refers to a phenomenon where relative moving components become locked and unable to operate during compressor operation, typically caused by poor lubrication or contamination. This condition indicates compressor damage and most commonly occurs at friction surfaces including sliding bearings/crankshaft interfaces, cylinder/lower bearing contacts, and piston/cylinder rolling friction surfaces.

Common Causes of Compressor Seizure:

1. Insufficient or Poor-Quality Lubricant

Lubricating oil forms protective films between moving components to reduce friction. Insufficient lubrication leads to direct metal contact between pistons, crankshafts and other parts, accelerating wear. Poor-quality oil may fail to provide adequate lubrication and can decompose at high temperatures, generating harmful deposits that worsen operating conditions, ultimately causing seizure.

2. Foreign Object Ingestion

Microscopic particles in the operating environment can enter through refrigerant circuits or failed air filters. Any foreign material contacting pistons can obstruct movement, with severe cases causing seizure. Metal fragments or other debris circulating in the system may also enter cylinders, causing damage.

3. Overload Operation

Operating beyond design parameters (excessive load or unstable voltage) creates additional stress, raising internal temperatures and degrading lubrication. This accelerates wear and may lead to seizure.

4. Improper Refrigerant Charge

Both overcharging and undercharging cause problems. Overcharging can introduce liquid refrigerant into the compressor ("liquid slugging"), diluting oil and mechanically impacting components. Undercharging reduces efficiency, forcing extended operation that increases wear risk.

5. Manufacturing Defects or Assembly Errors

Material selection flaws, machining inaccuracies, or improper component installation (incorrect positioning or insufficient fastening) can all lead to operational abnormalities that may result in seizure.

6. System Blockages

Flow restrictions create uneven pressure distribution, significantly increasing discharge pressure. This overloads the compressor, raising motor temperatures. High temperatures degrade lubricant performance (thinning or evaporation), potentially leading to seizure.