HVAC 233W - Commercial Refrigeration III

1. Demonstrate knowledge of multiplex commercial refrigeration systems.
   1. Define different types of multiplex systems.
   2. Explain the applications for multiplex systems.
   3. Describe how compressors are connected on a rack system.
   4. Describe physical construction of a rack and associated piping.
   5. Explain the advantages of a multiplex system.
   6. Identify an even or uneven parallel compressor rack.
   7. Define a cascade and centrifugal system.
2. Demonstrate knowledge of commercial refrigeration/multiplex controls.
   1. Explain and set oil controls on rack systems.
   2. Explain and adjust oil controls on a multiplex compressor system.
   3. Explain and adjust valves in the piping on a multiplex system.
   4. Explain and adjust compressor cycling controls.
   5. Explain and adjust condenser controls.
3. Identify defrost types and their operations.
   1. Explain hot gas defrost cycle.
   2. Explain cycle off defrost cycle.
   3. Explain electric defrost cycle.
   4. Setup and troubleshoot defrost systems.
4. Identify multiplex evaporator systems.
   1. Explain and setup evaporators on multi-coil cases.
   2. Set super heat adjustments on multi-coil cases.
   3. Explain and adjust EPR valves for multi-case system.
   4. Explain and adjust temperatures on multi-case systems.
5. Diagnose and repair multiplex systems.
   1. Diagnose high side and low side problems on a multiplex system.
   2. Diagnose temperature problems on evaporators and condensers.
   3. Diagnose evaporator problems and defrost cycle problems.
   4. Diagnose mechanical problems with the compressor systems.
   5. Diagnose electrical controls and three-phase power problems.