Compressors, Condensers and Evaporators
How the major components of refrigeration and air conditioning systems work, fail and are replaced, followed through a second-year apprentice at an HVAC-R contractor in Louisville: compressor types, ratings and compression ratio; reciprocating, scroll, rotary, screw and centrifugal compressors and their capacity control, including inverter drives; oils, oil return, refrigerant migration and compressor failure modes; air-cooled condensers and head pressure control; water-cooled and evaporative condensers, cooling towers and Legionella control; evaporators, frost and defrost; driers, receivers, accumulators and other accessories; diagnosing component problems; compressor and coil replacement with burnout cleanup; and brazing and nitrogen pressure testing under ASHRAE 15 and the mechanical code.
RAC-210 12 lessons · 4 h 7 min ▶ Video lessons coming soon
Offered by HSM University · HVAC-R
This is the American version of this course. See the Canadian version.
What you'll learn
- Explain the role of the compressor in the refrigeration cycle, distinguish compressor types and constructions, read compressor nameplates and calculate compression ratio from absolute pressures
- Describe how reciprocating compressors work, calculate displacement and clearance volumetric efficiency, and explain capacity control and the main reciprocating failure modes
- Explain how scroll compressors compress and comply, apply the precautions for phase rotation and vacuum, and compare staged, modulated, tandem and inverter-driven capacity control
- Describe rolling piston, rotary vane, screw and centrifugal compressors, their capacity control and service needs, and evaluate part-load chiller performance with IPLV
- Select oils compatible with refrigerants, explain oil return and refrigerant migration, and identify compressor failure modes from the evidence they leave, including acid testing
- Explain the zones of an air-cooled condenser, use condenser split and heat rejection to assess performance, maintain condensers and explain cold-weather head pressure control
- Describe water-cooled and evaporative condensers and cooling towers, use approach, range, evaporation and blowdown, and apply water management practices that control Legionella
- Compare DX and flooded evaporators, relate evaporator TD to humidity and capacity, and explain the defrost methods, controls and faults of coolers and freezers
- Explain the purpose, placement and failure of filter-driers, sight glasses, receivers, accumulators, oil separators, solenoid and check valves and other accessories
- Apply a systematic method to diagnose compressor, condenser, evaporator and refrigerant circuit faults from pressures, temperatures, superheat, subcooling and current
- Replace compressors and coils correctly, judge burnout severity and carry out cleanup and follow-up that protect the replacement
- Braze refrigeration joints with a nitrogen purge under safe hot work practices, pressure-test with dry nitrogen and interpret standing tests with temperature correction
Course content
12 lessons · 4 h 7 min total · final exam
- 1 Compressors: what they do and how they are built 23 min · quiz
- 2 Reciprocating compressors 20 min · quiz
- 3 Scroll compressors and capacity control 21 min · quiz
- 4 Rotary, screw and centrifugal compressors 18 min · quiz
- 5 Compressor lubrication, oil return and failure modes 22 min · quiz
- 6 Air-cooled condensers and head pressure control 20 min · quiz
- 7 Water-cooled and evaporative condensers and cooling towers 20 min · quiz
- 8 Evaporators, frost and defrost 21 min · quiz
- 9 System accessories: driers, receivers, accumulators and separators 19 min · quiz
- 10 Diagnosing compressor, condenser and evaporator problems 22 min · quiz
- 11 Replacing compressors and coils, and burnout cleanup 18 min · quiz
- 12 Brazing, pressure testing and the capstone repair 23 min · quiz
- E Final exam 20 questions
Requirements
Recommended background. You can start any course at any time.
Description
How the major components of refrigeration and air conditioning systems work, fail and are replaced, followed through a second-year apprentice at an HVAC-R contractor in Louisville: compressor types, ratings and compression ratio; reciprocating, scroll, rotary, screw and centrifugal compressors and their capacity control, including inverter drives; oils, oil return, refrigerant migration and compressor failure modes; air-cooled condensers and head pressure control; water-cooled and evaporative condensers, cooling towers and Legionella control; evaporators, frost and defrost; driers, receivers, accumulators and other accessories; diagnosing component problems; compressor and coil replacement with burnout cleanup; and brazing and nitrogen pressure testing under ASHRAE 15 and the mechanical code.