HVAC Procedure and Performance Guide

Test hermetic compressor

Training for this procedure can be found in these courses:

                         131 – Oil Heat l  and  161 – Boilers l


Hermetic compressor must be tested according to manufacturer’s specifications.  Condition of electrical system must be determined and compressor operating current must be measured.  Applicable safety procedures must be followed.


  1. Review job order and manufacturer’s specifications.
  2. Determine compressor operating criteria.
  3. Voltage requirements.
  4. Resistance of motor windings.
  5. Rating of capacitors.
  6. Full load current rating.
  7. Normal standard operating pressure for refrigerant used.
  8. Collect tools, equipment and materials.
  9. Put on safety and protective equipment and apparel.
  10. Disconnect electrical power to equipment.
  11. Remove access cover(s) and wiring box cover(s).
  12. Discharge and disconnect capacitors.
  13. Test capacitors using a capacitor analyzer according to manufacturer’s instructions.
  14. Check for shorts.
  15. Determine if rating meets specifications.
  16. Check bleeder resistor if present.
  17. Inspect capacitor for signs of overheating.
  18. Disconnect compressor windings.
  19. Test compressor windings for grounds, open windings and shorts according to manufacturer’s instructions.
  20. Reconnect compressor windings and capacitors and connect ammeter in motor circuit.
  21. Connect refrigeration manifold gage set to system.
  22. Reconnect equipment power, start system and adjust temperature controls to bring system to full-load operating condition.
  23. Check motor current and compare to specifications.
  24. Allow system to stabilize and check compressor suction and discharge pressures.  Compare to specifications.