See the attached document for a presentation on Copeland. Scroll compressor failures and how to prevent them. Here is an overview. 

Overview:

This training document is a curriculum guide focused on understanding, diagnosing, and preventing compressor failures—specifically with Copeland™ scroll compressors. It is designed for HVACR technicians and includes both theoretical and practical teaching points.

Key Topics Covered:

1. Scroll Compressor Basics:

   • Explains scroll operation—suction, compression, discharge.

   • Highlights importance of operating within manufacturer-specified conditions.

2. Operating Conditions & Envelopes:

   • Compressors must operate within specific temperature/pressure envelopes.

   • Repeated operation outside these conditions leads to premature failure.

3. General Operation Guidelines:

   • Discharge line temperature < 225°F (6” from compressor).

   • Maintain proper superheat and voltage within 10%.

   • Use correct oil type/amount, especially when retrofitting.

4. Common Causes of Failure:

   • Mechanical: Oil dilution, flood back, flooded starts, overheating, mis assembly.

   • Electrical: Miswiring, faulty start components, voltage issues, contactor problems.

5. Failure Mechanisms Explained:

   • Oil Dilution/Lack of Lubrication: Leads to bearing wear and scroll galling.

   • Overheating: Caused by high compression ratios, high superheat, poor charge.

   • Slugging: Caused by refrigerant migration and flooded starts.

   • Non-Condensables: Improper vacuum procedures lead to copper plating and oxidation.

   • Debris in System: Result of poor installation practices, can cause internal damage.

6. Electrical Failures:

   • Often stem from mechanical issues.

   • Types of burns indicate failure source: spot burn (voltage spike), start winding burn (bad start cap/relay), general burn (voltage/cooling).

7. Proper Replacement Practices:

   • Follow correct evacuation, pressure testing, drier replacement.

   • Clean systems thoroughly and eliminate root causes to prevent repeat failure.

8. Root Cause Diagnosis:

   • Emphasizes importance of diagnosing underlying issues, not just replacing failed parts.

   • Encourages clear communication with customers (e.g., explaining "topping off" myths).

9. Best Troubleshooting Methods:

   • Use of forms, flowcharts, and a repeatable methodical process.

   • Advocates carrying troubleshooting aids to develop consistent diagnosis habits.

Punch List of Checks for Compressor Operation and Service:

• Confirm operation within temperature/pressure envelope.

• Check discharge line temperature (< 225°F, 6” from compressor).

• Verify proper superheat per OEM specs.

• Ensure voltage within ±10% of rating.

• Confirm system has proper oil type and level (especially with retrofits).

• Avoid running in vacuum—prevents arcing and terminal damage.

• Prevent refrigerant flood back and flooded starts.

• Maintain proper compression ratio for application (High/Med/Low Temp).

• Verify shell temperature (< 200°F at bottom).

• Pull vacuum to 500 microns or below.

• Replace both suction and liquid line driers after failure.

• Avoid non-condensables (e.g., air, nitrogen)—ensure proper vacuuming.

• Eliminate foreign debris—use nitrogen during brazing, avoid hacksaws.

• Use forms or flowcharts to document diagnostics and aid in root cause analysis.

• Always identify and correct the root cause before replacing the compressor.

• Always verify proper rotation on 3-phase compressors.