WAEC syllabus 83/WAEC-Refrigeration-and-Air-Conditoner-Engineering-Syllabus
WAEC Refrigeration and Air Conditoner Engineering Syllabus

SCHEME OF EXAMINATION

The examinations shall consist of three papers, all of which must be taken. Papers 1 and 2 shall be composite and will be taken at one sitting.

Paper 1: This will consist of forty compulsory multiple choice questions. Candidates will be allowed 1 hour for the paper. It will carry 40 marks.

Paper 2: There shall be five essay questions out of which candidates will be expected to answer any four in 1 hour 30 minutes for 60 marks.

Paper 3: There shall be two practical questions for candidate to answer one of them within 2 hours for 100 marks.

A list of materials (cutting list) shall be made available to the schools not less than two weeks before the paper is taken for their procurement and preparation for the examination. Candidate shall carry out the task in the presence of an examiner.

Alternatively, the Council may consider using the alternative to practical work testing method in the event of constraints on requisite facilities. In this case, two compulsory questions shall be made available for candidates to answer within 2 hours for 100 marks. The paper shall test candidates’ real life experience in the workshop, abilities to identify and use requisite tools, use of measuring instruments and trouble shooting, etc. Free hand sketches of hand tools, circuits and wiring diagrams of refrigeration and air-conditioning systems may also be required.

DETAILED SYLLABUS

S/NO.

TOPIC

 

CONTENT

 

PRACTICAL

1

Safety and first aid in the

1.1.

Workshop rules and regulations

 

 

 

workshop.

1.2.

Safety devices/equipment – helmet,

1.2.1

Identification and

 

 

 

goggles, safety boots, hand gloves,

 

operation of various types

 

 

 

overall, apron sand bag, fire

 

of fire extinguishers

 

 

 

extinguishers, etc.

 

 

 

 

1.3.

Accident: causes and prevention

 

 

 

 

 

techniques.

 

 

 

 

1.4.

First Aid – materials for First Aid,

 

 

 

 

 

charts, posters and first aid box, etc.

 

 

 

 

1.5.

Application of first aid materials.

 

 

2

Energy, matter and power.

2.1.

Definition of energy

 

 

(a)  Energy

2.2.

The process of energy

2.2.1. Demonstration of

 

 

 

conversion electrical to

conversion of

 

 

 

mechanical, gas to vapour,

mechanical to heat

 

 

 

mechanical to heat.

energy e.g. rubbing of

 

 

2.3.

Meaning of internal energy.

palms.

 

 

2.4.

Enthalpy of a fluid substance,

 

 

 

its pressure, volume and

temperature

 

 

 

of internal energy.

 

 

(b)

Nature of matter.

2.5.

The ph diagram of refrigerant.

 

 

 

2.6.

State of matter – solid, liquid,

2.6.1.  Demonstrate the

 

 

 

gas or vapour.

 

conversion of ice

 

 

 

 

 

block to water.

 

 

2.7.

Change of state of matter.

 

(c)

power.

2.8.

The meaning of power.

 

 

 

 

2.9.

Calculation of power used by a

 

 

 

 

compressor.

 

 

 

 

2.10.

Unit of power: watts and

 

 

 

 

kilowatts unit of heat: joules

 

 

 

and kilojoules.

 

 

3                        Temperature and pressure.

(a)   Temperature and

its measurement

3.1.

Concept of temperature.

 

3.2.

Different types of thermometer

 

 

e.g. gas, resistance, liquid and

 

 

thermocouple.

 

3.3.

Temperature scale conversion

 

 

 

-

centigrade to Fahrenheit

 

 

 

-

Celsius to Kelvin

 

 

 

-

Fahrenheit to rankine

 

 

3.4.

International practical

 

 

 

temperature

 

 

 

-  The boiling point of oxygen

 

 

 

 

182.97ºC

 

 

 

 

-  The triple point of water

 

 

 

 

0.01 ºC

 

 

 

 

-  The boiling point of water

 

(b) Pressure and its

 

 

100 ºC

 

 

measurement

3.5.

Concept of pressure

 

 

3.6.

Different types of pressure

3.6.1. Demonstration of the

 

 

measuring devices e.g.

use of a barometer.

 

 

barometer, manometer,

 

 

 

bourdon tube gauge.

 

 

3.7.

Pressure measurement

 

 

3.8.

Uses of suction and high

3.8.1.  Demonstrate how

 

 

pressure gauges.

suction and high

 

 

 

 

 

 

pressure gauges are

 

3.9.

Effects of temperature, pressure

used to determine the

 

 

and volume in refrigeration and

performance of a

 

 

air conditioning systems.

refrigerant.

 

3.10.  Gas law, Boyles law, Charles

 

 

 

law and Dalton’s law.

 

 

3.11.

Calculations involving general

 

 

 

gas law. Formulae:-

 

 

 

- P1 V1 = P2V2

 

 

 

- P1 =

P2

 

 

 

 

 

T1

T2

 

 

 

 

- V1 = V2

 

 

 

 

- T1

T2

 

 

 

 

- P1 V1 = P2V2

 

 

 

 

 

T1

T2

 

3.12 Plotting various temperature scales

4 Refrigeration and air conditioning systems.

(a)

Introduction to

4.1.

Refrigeration cycle – Evaporation,

 

 

refrigeration.

 

compression, condensation and

 

 

 

 

expansion.

 

 

 

4.2.

Layout diagram of refrigeration

 

 

 

 

systems.

 

 

 

4.3.

Types and applications of the

 

 

 

 

various forms of refrigeration.

 

 

 

4.4.

Principles of operation of forms

 

 

 

 

of refrigeration system.

 

 

 

4.5.

Functions of the component and

 

 

 

 

accessories e.g. relay, solenoid

 

 

 

 

valves, capacitors and

 

 

 

 

thermostat.

 

(b)

Refrigerants

4.6.

Definition and types of

4.6.1. Identification of

 

 

 

refrigerants

refrigerant by cylinder

 

 

 

 

colours.

 

 

4.7.

Chemical names and formulae.

 

 

 

4.8.

Properties and uses of

 

 

 

 

refrigerants.

 

 

 

4.9.   Refrigerants flow controls e.g.

 

 

 

 

TEV, AEV, capillary tube.

 

 

 

4.10.

Operations of refrigerant flow

 

 

 

 

controls.

 

(c)

Air-Conditioning

 

 

4.11.1. Demonstration of air

 

processes

4.11.

Psychometric properties of air.

conditioning principle

 

 

 

 

by sling

 

 

 

 

psychometer.

 

 

4.12.  The processes of air

 

 

 

 

conditioning: heating and

 

 

 

 

cooling.

 

 

 

4.13.

Latent and sensible heat,

4.13.1   Demonstration of the

 

 

 

saturated and super-saturated

difference between

 

 

 

vapour.

latent and sensible

 

 

 

 

heat by use of

 

 

 

 

methylated spirit on

 

 

 

 

human skin.

  1. Compressors, Condenses and Evaporators

(1)    Compressors

5.1. Types of compressors

 

 

 

5.2

Construction of compressors.

 

 

 

 

 

 

5.3.

Working principles of

 

 

 

 

(b)

Condensers.

 

compressors.

 

 

 

 

 

 

5.4.

Construction of condensers.

 

5.4.1.

Demonstrate how to

 

 

 

 

 

 

 

service a

 

 

 

5.5.

Calculation of heat load on

 

 

condenser.

 

 

 

 

condensers.

 

 

 

 

 

 

5.6.  Types and functions of liquid

 

 

 

 

 

 

 

receiver and service valves.

 

 

 

 

 

 

5.7.  Principle of operation of liquid

 

 

 

 

 

 

 

receiver and service valves.

 

 

 

 

 

 

5.8.

Types of evaporators.

 

 

 

 

 

 

5.9.  Construction and services of

 

 

 

 

 

 

 

evaporators.

 

5.9.1.

Demonstrate how to

 

 

 

5.10. Working principles of

 

 

service evaporators

 

 

 

 

evaporators.

 

 

 

 

 

 

5.11.  Heat load estimates on

 

 

 

 

 

 

 

evaporators.

 

 

 

6.

Workshop practices.

 

 

 

 

 

 

(a)  Basic tools used in

6.1.

Basic tools – hacksaw, coil

 

 

 

 

 

refrigeration and

 

spring benders, reamers, tube

 

 

 

 

 

air-conditioning

 

cutters, etc.

 

 

 

 

 

workshops

6.2.

Tools and procedures for

 

6.2.1. Servicing of a window

 

 

 

 

servicing window unit air-

 

 

air-conditioner.

 

 

 

 

conditioner.

 

 

 

 

(b)

Fault diagnosis and

6.3.

Different methods of diagnosing

 

 

 

 

 

trouble shooting.

 

faults systematic and

 

 

 

 

 

 

 

observation.

 

 

 

 

 

 

6.4.

Common faults in refrigeration

 

 

 

 

 

 

 

systems and their symptoms –

 

 

 

 

 

 

 

leakage, faulty units, faulty

 

 

 

 

 

 

 

compressor, poor cooling

and

 

 

 

 

 

current leakage.

 

 

 

 

 

 

 

 

 

 

 

 

 

6.5.   Techniques of effective repairs

 

 

 

 

 

 

in refrigeration and air-

 

 

 

 

 

 

 

conditioning systems.

 

 

 

 

 

 

6.6.

Techniques of trouble shooting

 

 

 

 

 

 

 

in a given system.

 

 

 

 

(c)

Maintenance and

6.7.

Testing for leakages, polarity,

 

6.7.1. Demonstrate how to

 

 

Testing

 

insulation continuity, pressure

 

 

test for leakages,

 

 

 

 

and efficiency.

 

polarity continuity and

 

 

 

 

 

 

efficiency.

 

 

 

6.8.

Maintenance of compressors,

 

6.8.1.

Demonstrate how to

 

 

 

 

evaporators, motors,

 

 

repair faults in

 

 

condensers, valves,

compressors,

 

 

 

accumulators and contactors.

evaporators, motor

 

 

 

 

and condensers.

7

Installation processes

 

 

 

 

(a)  Piping, Ducting and

7.1.

Concept of piping, ducting and

 

 

Trunking

 

trunking.

 

 

 

7.2.

Piping a condenser and an

 

 

 

 

evaporator.

 

 

 

7.3.   Ducting, trunking and installation

7.3.1.  Installation of a

 

 

 

of air-conditioners.

split air-conditioner.

7.4.   Piping, ducting and trunking tools

         – mallet hammer, flaring tools,

 

 

silver tape, dot-punch, bending

 

spring,

 

 

amaflex, hacksaw, PVC

pipes.

 

 

7.5.   Types, functions, operations and

(b)

Motors and

 

application of motors and

 

 

generators

 

generators.

 

 

 

 

7.6.

Installation procedures for

 

 

 

 

motors and generators.

 

 

 

7.7.

Maintenance of motors and

7.7.1  Servicing of motors

 

 

 

generators in a refrigeration

and generators.

 

 

 

system.

 

 

 

 

7.8.

Working principles of cold room.

(c)

Cold room

7.9.

Cold room installation

 

 

 

 

 

 

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