Commercial Refrigeration IIIHVAC 233W
Prerequisite: RHA 122 and RHA 225. Examines and identify refrigeration units associated with supermarket applications and the food industry. Diagnoses multiplex systems and self-contained equipment for medium/low temperature applications such as piping and trouble shooting mechanical and electrical components. (45-30)
Outcomes and Objectives
Demonstrate knowledge of multiplex commercial refrigeration systems.
- Define different types of multiplex systems.
- Explain the applications for multiplex systems.
- Describe how compressors are connected on a rack system.
- Describe physical construction of a rack and associated piping.
- Explain the advantages of a multiplex system.
- Identify an even or uneven parallel compressor rack.
- Define a cascade and centrifugal system.
Demonstrate knowledge of commercial refrigeration/multiplex controls.
- Explain and set oil controls on rack systems.
- Explain and adjust oil controls on a multiplex compressor system.
- Explain and adjust valves in the piping on a multiplex system.
- Explain and adjust compressor cycling controls.
- Explain and adjust condenser controls.
Identify defrost types and their operations.
- Explain hot gas defrost cycle.
- Explain cycle off defrost cycle.
- Explain electric defrost cycle.
- Setup and troubleshoot defrost systems.
Identify multiplex evaporator systems.
- Explain and setup evaporators on multi-coil cases.
- Set super heat adjustments on multi-coil cases.
- Explain and adjust EPR valves for multi-case system.
- Explain and adjust temperatures on multi-case systems.
Diagnose and repair multiplex systems.
- Diagnose high side and low side problems on a multiplex system.
- Diagnose temperature problems on evaporators and condensers.
- Diagnose evaporator problems and defrost cycle problems.
- Diagnose mechanical problems with the compressor systems.
- Diagnose electrical controls and three-phase power problems.