MCCCD Official Course Competencies:

HVA112  2004 Fall – 2011 Fall

Heating and Air Conditioning

1.

Describe the history of heating and air conditioning. (I)

2.

Explain the refrigeration cycle including basic components and their functions. (II)

3.

Explain factors that lead to human comfort including rate of body heat production, body temperature, temperature-humidity relationships and clothing. (III)

4.

Define specific terms used in psychometrics and coordinate points on the psychometric chart related to conditions of a specific environment. (IV)

5.

Identify specific types and styles of cooling equipment. (V)

6.

Explain purposes of forced-air systems including individual components. (VI)

7.

Explain the operation of operating and safety controls including thermostats, relays, contactors, high and low pressure controls, thermocouples, stack switches, overloads, time delay relays, defrost timers and defrost termination thermostat. (VII, XIX)

8.

Explain the operation of the compressor starting component for permanent split capacitor (PSC) motors. (VIII)

9.

Compare and contrast operating conditions above and below design conditions. (IX)

10.

Explain how a heat pump differs from an air conditioner. (X)

11.

Explain heat source and heat rejection medium for differing types of heat pumps. (XI)

12.

Define terms associated with heat pumps including coefficient of performance, balance point, auxiliary heat and ambient temperature. (XII)

13.

Use troubleshooting and repair skills to maintain heat pump and air conditioning units while following safety protocols and refrigerant recovery and handling techniques. (XIII)

14.

Compare the characteristics of combustion gases. (XIV, XV)

15.

Adjust energy input for gas-fired furnaces while adhering to safety protocols. (XVI)

16.

Describe safe venting techniques and equipment for gas furnaces. (XVII)

17.

Maintain gas-fired and electric heating devices while adhering safety protocols. (XV, XVIII, XIX)

MCCCD Official Course Outline:

HVA112  2004 Fall – 2011 Fall

Heating and Air Conditioning

I. History of Heating and Air Conditioning

A. Heating

1. Wood

2. Coal

3. Electric

4. Gas

5. Hydronic

6. Other (geothermal, solar, infrared)

B. Air Conditioning

1. Ventilation

2. Direct expansion

3. Hydronic

II. Basic Refrigeration Cycle

A. Components/functions

1. Compressor

2. Condenser

3. Metering device

4. Evaporator

B. Functions

1. Compressor

2. Condenser

3. Metering device

4. Evaporator

III. Comfort

A. Factors

1. Temperature

2. Humidity

3. Air movement

4. Air cleanliness

B. Food energy to body energy

1. Metabolism

2. Men

3. Women

4. Elderly

C. Body temperature

1. Conduction

2. Convection

3. Evaporation

4. Radiation

D. Comfort chart

1. Temperature-humidity relationship

2. Type of clothing

IV. Psychometric Charts Terms/Points/Applications and Conditions for Standard Air

A. Terms

1. Dry bulb (DB)

2. Wet bulb (WB)

3. Dew point (DP)

4. Relative humidity (RH)

5. Humidity ratio (W) (grains of water per lb. of dry air)

6. Enthalpy (h) (BTU per lb. of dry air)

7. Sensible heat ratio (SHR)

8. Specific volume (V) (cubic feet per lb. of dry air)

B. Points

1. Dry bulb line(s)

2. Wet bulb line (s)

3. Dew point line(s)

4. Relative humidity lines

5. Humidity ratio scale

6. Enthalpy scale

7. Cooling coil performance lines

C. Application

1. Room conditions

2. Sensible heat ratio line (SHRL)

3. Leaving conditions

4. Apparatus dew point

5. Sensible heat process

6. Minimum ventilation

7. Humidifying

8. Cooling and dehumidifying

9. Heating and humidifying

10. Cooling and humidifying

11. Chemical dehumidifying

D. Conditions for standard air

1. 14.7 psi

2. 69º F

3. 13.34 ft3/lb

4. .075 lb/ft3

5. .24 BTU/lb

V. Types/Styles of Cooling Equipment

A. Evaporative coolers

B. Packaged equipment

C. Split systems

D. Hydronic systems

E. Variable Air Volume Systems

VI. Forced-Air Systems

A. Purposes

B. Components

1. Blower (fan)

2. Air supply system (supply duct)

3. Return air system (return duct)

4. Grill

5. Registers

VII. Safety and Operating Controls

A. Thermostat

1. Low voltage

2. Line voltage

B. Relays

1. Coil voltage (s)

2. Voltage contact (s) switch

3. Current rating

C. Contactors

1. Coil voltage (s)

2. Current rating

D. Pressure switches

1. High pressure

2. Low pressure

E. Overloads

1. Heat active

2. Current active

3. Heat and/or current active

4. Two wire

5. 3 wire

6. Internal

7. External

F. Time delay relay (short cycle relay)

G. Other

VIII. Starting Components (PSC motors)

A. Running capacitor

B. Hard start kit

1. Starting capacitor

2. Potential relay

IX. Operating Conditions Versus Design Conditions

A. Load added by humidity

B. Outside ambient below design conditions

C. Outside ambient above design conditions

D. High efficiency - all conditions

E. Manufacturer's charts

1. Superheat

2. Charging

F. Voltage at unit to unit rated voltage

X. Heat Pump Operation Versus Air Conditioner

A. 4-way valve

B. Accumulator

C. Check valves

D. Indoor coil

E. Outdoor coil

F. Defrost cycle

G. Refrigerant flow for heating and cooling

H. Comparison - air conditioner

XI. Heat Pumps

A. Types

1. Air to air

2. Water to air

3. Ground to air

4. Air to water

5. Water to water

B. First term - heat source

C. Second term - heat rejection medium

XII. Terms and Performance Relationship

A. Coefficient of performance (COP)

B. Balance point

1. System capacity

2. Building heating load

C. Auxiliary heat

1. Defrost

2. Compensate for equipment deficiency

D. Ambient temperature to heat capacity

XIII. Heat Pump Controls

A. Low voltage thermostats

1. Single stage

2. Multi-stage

B. Relays

1. Change over

2. Defrost

3. Fan

4. Compressor

C. Heating controls

1. Outdoor thermostat

2. Thermostatic overloads

D. Defrost timers

E. Defrost termination thermostats

F. Other

XIV. Heat Sources and Combustion Gases

A. Heat sources

B. Combustion

XV. Gas-Fired Heaters

A. Gas orifices, burners, and flames

1. Orifices

2. Main gas burners

3. Forced draft burners

4. Pilot burners

5. Electric ignition

6. Flame types

B. Heat exchangers

1. Primary heat exchangers

2. Secondary heat exchangers

C. Troubleshooting and repair

D. Safety

XVI. BTU Adjustments

A. Meter timing

B. Regulator adjustment

C. Gas piping

D. Orifice size

E. Safety

XVII. Venting

A. Venting (general)

B. Draft diverter

C. Vent piping

D. Vent design

E. Power venting

F. Automatic flue damper

G. Safety

XVIII. Electric Heaters

A. Types of equipment

B. Air flow

C. Types of installations

D. Troubleshooting and repair

E. Safety

XIX. Basic Heating Controls/Characteristics/Functions

A. Thermostats

B. Power sources

C. Fan controls

D. Limit controls

E. Main gas valves

F. Pilot safety devices

G. Mill volt devices

H. Automatic ignition device

I. Furnace wiring

J. Electric furnace controls