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Commercial Air Conditioning

HVAC 210W

Commercial Air Conditioning

HVAC 210W

Course Description

Prerequisite: MATH LEVEL 4 and HVAC 146 (or RHA 146). Develops an understanding of AC electrical fundamentals concerning the operation, installation, and analysis of HVACR components and control circuits used in commercial air conditioning systems. Examines single- and poly-phase transformers and motors, heating and air conditioning controls, commercial timers, motor starters, contactors, relays, and other control devices. Focuses on rooftop units, split system air-conditioning units, and self-contained air-conditioning units. Includes hands-on training on wiring diagrams, wiring projects, and sealed systems. Credits may be earned in either HVAC 210W or RHA 210W but not in both. (35-10)

Outcomes and Objectives

Demonstrate knowledge of electrical motors and compressors used in single- and three-phase equipment.

Objectives:

  • Identify electrical characteristics of single-phase motors and compressors.
  • Identify electrical characteristics of single-phase Permanent Split Capacitor motors (PSC motors).
  • Explain how a current relay works on single-phase split-phase motors and compressors.
  • Explain how a voltage relay works on single-phase split-phase motors and compressors.
  • Identify how a three-phase motor works.
  • Define the term poly-phase in relation to three-phase motors and compressors.
  • Identify overload requirements of a single-phase motor.
  • Identify overload requirements of a three-phase motor.
  • Identify and trace how a single-phase multi-speed motor is wire wound.
  • Identify and trace how a three-phase multi-speed motor is wire wound.
  • Identify and trace how a single-phase motor can be made reversible.
  • Explain and trace how a three-phase motor can be made reversible.
  • Explain Delta wound motors.
  • Explain Wye wound motors.

Demonstrate knowledge of electric controls and control circuits.

Objectives:

  • Trace low voltage circuits on a wire diagram.
  • Trace three-phase line duty circuits on a wire diagram.
  • Identify low voltage controls.
  • Identify line duty voltage controls.
  • Identify low voltage safety circuits.
  • Identify three-phase compressor safety circuits.

Demonstrate knowledge of airflow designs.

Objectives:

  • Identify how air shutters work
  • Identify how damper controls work.
  • Identify temperature designs for medium and high temperature air conditioning systems.
  • Explain the Psychometrics of air conditioning.
  • Use wet bulb temperature and dry bulb temperature on a Psychometric chart to find:
  • Perform an air balance.
  • Identify duct system pressures.
  • Identify design conditions for high-efficiency equipment.
  • Identify design conditions for standard efficiency units.
  • Find equipment efficiency ratings. (EER-SEER)

Demonstrate knowledge of pressure and flow controls.

Objectives:

  • Identify how head pressure control works.
  • Explain how an accumulator works.
  • Identify how heat exchangers work.
  • Explain how refrigerant hand valves work.
  • Explain how heat reclaim works.
  • Explain how oil separators work.
  • Define and measure superheat.
  • Explain how vibration eliminators work.
  • Explain sub cooling.
  • Explain the values of crankcase heat.
  • Explain condenser flooding.
  • Explain floating head pressures.
  • Identify these types of compressors and their operation:
  • Calculate compression ratio.
  • Calculate absolute pressures.
  • Identify expansion valve types.
  • Explain how an expansion valve works.
  • Identify the four basic components of the compression refrigeration cycle.
  • Define how an Evaporator Pressure Regulator works (EPR valve).
  • Explain the operation of a direct-acting evaporator pressure EPR valve.
  • Explain how multiple evaporators work.
  • Explain how a crankcase pressure regulator works.
  • Explain how a relief valve works.
  • Explain the four methods of heat control.
  • Explain low ambient head pressure controls.
  • Explain how liquid line solenoids work.
  • Explain how pressure switches work.
  • Explain how refrigerant check valves work.
  • Explain how a site glass works.
  • Explain how a multi-circuit distributor works.
  • Explain how drier filters work.