HVAC 210W - Commercial Air ConditioningCredits: 3
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. Credit may be earned in either HVAC 210W or RHA 210W but not in both.
Prerequisite(s): MATH LEVEL 4 and HVAC 146
Corequisite(s): None
Lecture Hours: 35 Lab Hours: 10
Meets MTA Requirement: None
Pass/NoCredit: Yes
Outcomes and Objectives 1. Demonstrate knowledge of electrical motors and compressors used in single- and three-phase equipment.
A. Identify electrical characteristics of single-phase motors and compressors.
B. Identify electrical characteristics of single-phase Permanent Split Capacitor motors (PSC motors).
C. Explain how a current relay works on single-phase split-phase motors and compressors.
D. Explain how a voltage relay works on single-phase split-phase motors and compressors.
E. Identify how a three-phase motor works.
F. Define the term poly-phase in relation to three-phase motors and compressors.
G. Identify overload requirements of a single-phase motor.
H. Identify overload requirements of a three-phase motor.
I. Identify and trace how a single-phase multi-speed motor is wire wound.
J. Identify and trace how a three-phase multi-speed motor is wire wound.
K. Identify and trace how a single-phase motor can be made reversible.
L. Explain and trace how a three-phase motor can be made reversible.
M. Explain Delta wound motors.
N. Explain Wye wound motors.
2. Demonstrate knowledge of electric controls and control circuits.
A. Trace low voltage circuits on a wire diagram.
B. Trace three-phase line duty circuits on a wire diagram.
C. Identify low voltage controls.
D. Identify line duty voltage controls.
E. Identify low voltage safety circuits.
F. Identify three-phase compressor safety circuits.
3. Demonstrate knowledge of airflow designs.
A. Identify how air shutters work
B. Identify how damper controls work.
C. Identify temperature designs for medium and high temperature air conditioning systems.
D. Explain the Psychometrics of air conditioning.
E. Use wet bulb temperature and dry bulb temperature on a Psychometric chart to find:
1. Dew point
2. Total heat content of 1 lb. of air
3. Moisture content of the air
4. Relative humidity
5. Specific volume of air
F. Perform an air balance.
G. Identify duct system pressures.
1. Static pressures
2. Velocity
3. True velocity pressure
4. Total air pressure
5. Pitot tube pressures
H. Identify design conditions for high-efficiency equipment.
I. Identify design conditions for standard efficiency units.
J. Find equipment efficiency ratings. (EER-SEER)
4. Demonstrate knowledge of pressure and flow controls.
A. Identify how head pressure control works.
B. Identify how heat exchangers work.
C. Explain how heat reclaim works.
D. Define and measure superheat.
E. Explain sub cooling.
F. Explain condenser flooding.
G. Explain floating head pressures.
H. Identify these types of compressors and their operation:
1. Reciprocating
2. Screw
3. Rotary
4. Scroll
5. Centrifugal
I. Calculate compression ratio.
J. Calculate absolute pressures.
K. Identify expansion valve types.
L. Explain how an expansion valve works.
M. Identify the four basic components of the compression refrigeration cycle.
1. Compressor
2. Condenser
3. Expansion devise
4. Evaporator
N. Define how an Evaporator Pressure Regulator works (EPR valve).
O. Explain the operation of a direct-acting evaporator pressure EPR valve.
P. Explain how multiple evaporators work.
Q. Explain how a crankcase pressure regulator works.
R. Explain how a relief valve works.
S. Explain the four methods of heat control.
1. Fan cycling using a pressure control
2. Fan speed control
3. Air volume control using shutters and fan cycling.
4. Condenser flooding devices.
T. Explain low ambient head pressure controls.
U. Explain how liquid line solenoids work.
V. Explain how pressure switches work.
1. Low-pressure switch-closes on a rise in pressure
2. High-pressure switch-opens on a rise in pressure.
3. Low ambient control-closes on a rise in pressure
4. Oil safety switch (has time delay)-opens on a rise in pressure
W. Explain how refrigerant check valves work.
X. Explain how a site glass works.
Y. Explain how a multi-circuit distributor works.
Z. Explain how drier filters work.
1. Liquid line drier
2. Suction line drier
AA. Explain how an accumulator works.
BB. Explain how refrigerant hand valves work.
1. Discharge service valves
2. Refrigeration line service valves
3. Diaphragm valves
4. Ball valves
CC. Explain how oil separators work.
DD. Explain how vibration eliminators work.
EE. Explain the values of crankcase heat.
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