Maricopa Community Colleges  ABC269   19962-20032 
Official Course Description: MCCCD Approval: 11/28/95
ABC269 19962-20032 LEC 1 Credit(s) 1 Period(s)
HVAC Controls and Heat Tracing
Heating, ventilation and air conditioning (HVAC) control systems including temperature sensing devices, control components, National Electrical Code (NEC) requirements, solid state controls, packaged HVAC units, programmable controllers and installation procedures. Heat tracing and freeze protection including explanation of use, types of systems, installation procedures, inspection and maintenance and NEC requirements. Prerequisites: (Indentured status with the Arizona Builders Alliance)or permission of the apprenticeship coordinator.
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MCCCD Official Course Competencies:
 
ABC269   19962-20032 HVAC Controls and Heat Tracing
1. List and define trade terms associated with HVAC systems. (I)
2. Identify and describe HVAC controls and their operating principles. (II)
3. Select proper control transformers for specific HVAC control systems. (III)
4. Describe the operating principles of starting relays, variable speed motor controls, defrost timers, pressure switches, flow switches, solenoid valves, short-cycle timers and overcurrent protection devices. (IV)
5. Describe the installation of controls for gas burner systems, commercial systems, and industrial HVAC systems. (V)
6. Explain the operating principles of solid-state programmable controllers. (VI)
7. List and define trade terms associated with heat tracing and freeze protection and describe the uses of these systems. (VII)
8. Describe specific types of heat tracing systems used in embedded and exposed installations. (VIII)
9. Describe the control of heat-tracing systems. (IX)
10. Explain the installation and insulation of embedded and exposed heat tracing systems. (X, XI)
11. Describe the use and control of heat cable for freeze protection. (XII)
12. Identify specific NEC requirements for heating systems. (XIII)
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MCCCD Official Course Outline:
 
ABC269   19962-20032 HVAC Controls and Heat Tracing
    I. Trade Terms
        A. Amplification
        B. Bimetal strip
        C. coaxial cable
        D. Cathode-ray tube
        E. Control
        F. Diode
        G. Fiber optics
        H. Gate
        I. Integrated circuit
        J. SCR silicon-controlled rectifier
      II. HVAC controls
          A. Temperature sensing devices
            1. Expansion of metal
            2. Thermocouples
            3. Resistance temperature detectors
            4. Thermistors
            5. The PN junction (diodes)
            6. Expansion due to pressure
          B. Other ABC269Effective Term:
        III. HVAC control components
            A. Basic controls
              1. Thermostat
              2. Control transformers
              3. Fan controls
              4. Limit controls
              5. Thermocouple
              6. Firestat
            B. Motor starters
              1. Protector relay (lockout) control circuit
              2. Time-delay relay
              3. Disconnect switch and NEC requirements
              4. Solenoid valve
            C. Control wiring for furnaces
            D. Trouble shooting conventional HVAC controls
          IV. Solid-state HVAC controls
              A. Solid-state components - semiconductors
              B. Silicon controlled rectifiers
              C. Solid-state motor controls
                1. Timers
                2. Anti-short cycling devices
                3. Starting relays
                4. Defrost control module
                5. Motor protection
            V. Packaged HVAC units
                A. Cooling cycle
                B. Heating cycle
              VI. Programmable controllers
                  A. Components
                    1. Power supply
                    2. Central processing unit (CPU)
                    3. Program loader or terminal
                    4. I/O track
                  B. Input modules
                  C. Output modules
                  D. Programming a programmable controller
                  E. Developing a program
                  F. Installation hints
                VII. Heat tracing and freeze protection
                    A. Terms and definitions
                      1. Dead leg
                      2. Dielectric heating
                      3. Heat sink
                      4. Hysteresis
                      5. Induction heating
                      6. Impedance heating ABC269Effective Term:
                      7. Resistance heating element
                      8. Skin effect heating system
                      9. Other
                    B. Reasons for heat tracing
                      1. Freeze protection
                      2. Dew point
                      3. Viscosity control
                  VIII. Types of heat tracing systems (embedded and exposed)
                      A. Steam heat tracing
                      B. Hot liquid tracers
                      C. Electric resistance heat tracing
                      D. Induction heat tracing
                      E. Zone heaters
                    IX. Control of heat tracing systems
                        A. No control or self regulating
                        B. Ambient-sensing
                        C. Line sensing
                        D. Dead leg
                      X. Installation of heat tracing systems
                          A. Pre-installation checks
                          B. Installation
                        XI. Insulation of heat tracing systems
                            A. Post installation inspection
                            B. Operation
                          XII. Heat cable for freeze protection
                              A. Pipes
                              B. Roofs and gutters
                              C. Snow melting
                              D. Control of heating cable
                            XIII. NEC requirements for de-icing and snow melting equipment
                                A. Article 426
                                B. Embedded systems
                                C. Exposed systems
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