Class: Senior Secondary School 1 (SS1 / SSS 1)
Term: 3rd Term
Week: 12
Age: 15 years
Duration: 45 minutes
Subject: Refrigeration And Air Conditioning
Curriculum Theme: Trade
Previous Lesson: Basic Tools Used In Refrigeration And Air Conditioning: Identification and Uses.
Topic: Servicing an Air conditioner Tools and procedures for servicing a window unit air condition
Subject Matter: Servicing tools, servicing procedures, safety precautions

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:

Identify and list common tools used for servicing a window unit air conditioner.
Outline the basic procedures for servicing a window unit air conditioner.
State important safety precautions to observe during air conditioner servicing.

Affective Domain:

Appreciate the importance of regular maintenance for air conditioners.
Pay close attention to safety guidelines during practical demonstrations.
Show willingness to follow proper servicing procedures.

Psychomotor Domain:

Correctly identify actual servicing tools when presented.
Demonstrate simple steps like cleaning an air filter or using a cleaning brush.
Practice wearing appropriate personal protective equipment (PPE) during simulated servicing.

Participate actively in class discussions about air conditioner maintenance.
Collaborate with peers to discuss different servicing challenges.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Basic Technology (JSS 1-3) / Senior Secondary Education Curriculum for Technical Vocational Education (SSS 1-3)
State Unified Scheme of Work for Refrigeration and Air Conditioning SSS 1
Adeola, J. A. (2015). Refrigeration and Air Conditioning Technology for Senior Secondary Schools. Ibadan: Spectrum Books.

Instructional Materials

The teacher will teach this lesson with the aid of:

Service gauge
Vacuum pump
Spanner set
Cleaning brush
Screwdriver set
Multimeter
Safety gloves and goggles
A sample window unit air conditioner (if available) or diagrams/charts of one
Whiteboard and markers

Rationale for the Lesson

This lesson helps pupils understand how to maintain air conditioning units, which is important for their efficiency and longevity. Knowing the correct tools and procedures also prepares pupils for potential careers in appliance repair and maintenance.

Prerequisite/Previous Knowledge

Pupils should have basic knowledge of electrical safety and the general components of an air conditioner.

Lesson Content/Board Summary

Servicing a Window Unit Air Conditioner

Servicing Tools for Window Unit Air Conditioners

Various tools are used for the effective servicing and maintenance of window unit air conditioners.

The following are common tools:

Screwdriver Set: Used for removing and fastening screws of various sizes.
Spanner Set: Used for loosening and tightening nuts and bolts.
Pliers: Used for gripping, bending, and cutting wires.
Service Gauge: Used to measure refrigerant pressure in the system.
Vacuum Pump: Used to evacuate air and moisture from the refrigeration system.
Cleaning Brush: Used for cleaning dust and debris from coils and filters.
Multimeter: Used to check electrical continuity, voltage, and resistance.
Safety Gloves and Goggles: Essential for personal protection against cuts, chemicals, and debris.
Fin Comb: Used to straighten bent fins on evaporator and condenser coils.

Procedures for Servicing a Window Unit Air Conditioner

Regular servicing ensures the air conditioner operates efficiently and lasts longer. The procedures generally involve:

The following are typical steps in servicing a window unit air conditioner:

Disconnect Power: Always switch off and unplug the unit from the power source before starting any work.
Remove Outer Casing: Carefully remove the front grille and outer casing to access internal components.
Clean Air Filter: Remove the air filter and wash it with soap and water, then allow it to dry completely.
Clean Evaporator Coils: Use a soft brush or a specialized coil cleaner to remove dust and dirt from the indoor (evaporator) coils.
Clean Condenser Coils: Clean the outdoor (condenser) coils with a brush or high-pressure water spray to remove accumulated dirt, leaves, and debris.
Check Fan Blades: Inspect and clean the blower fan blades and the condenser fan blades for dirt buildup.
Inspect Drain Pan and Line: Clean the drain pan to prevent algae growth and ensure the drain line is clear of blockages.
Check Electrical Connections: Inspect all wiring and connections for any signs of wear, corrosion, or looseness. Tighten if necessary.
Check Refrigerant Levels (if applicable): A qualified technician may check refrigerant pressure using a service gauge and recharge if necessary (this requires specialized training and equipment).
Reassemble and Test: Once all components are clean and checked, reassemble the unit, plug it in, and test its operation.

Safety Precautions During Air Conditioner Servicing

Observing safety precautions is important to prevent accidents and injuries during servicing.

The following are important safety measures:

Always Disconnect Power: Ensure the unit is unplugged from the electrical outlet before touching any internal parts.
Wear Personal Protective Equipment (PPE): Use safety gloves, goggles, and appropriate footwear.
Work in a Ventilated Area: Ensure good airflow, especially when using cleaning chemicals.
Handle Refrigerants Carefully: Refrigerants can cause frostbite and are harmful if inhaled. Only trained personnel should handle refrigerants.
Beware of Sharp Edges: Many parts of an AC unit can have sharp edges; handle them with care.
Avoid Water on Electrical Parts: Be careful not to spray water directly onto electrical components during cleaning.
Use Correct Tools: Use the right tool for each task to avoid damage to the unit or injury to yourself.

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils and asks them what they know about air conditioners and why they are serviced. The teacher then introduces the topic: “Servicing an Air conditioner: Tools and procedures for servicing a window unit air condition.”
Pupils’ Activity: Pupils respond to the teacher’s questions and listen attentively to the introduction of the topic.
Learning Point: Pupils are engaged and the lesson topic is introduced.

Step 2: Presentation of Servicing Tools

Time: 10 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher presents various servicing tools (actual tools or diagrams) and explains their uses, relating them to the servicing of a window unit air conditioner. The teacher writes key tools on the board.
Pupils’ Activity: Pupils observe the tools, listen to explanations, ask questions, and take notes.
Learning Point: Pupils identify and understand the function of different tools used in AC servicing.

Step 3: Presentation of Servicing Procedures (Part 1)

Time: 10 minutes
Teaching Skill: Elucidation/Explanation
Teacher’s Activity: The teacher explains the initial steps of servicing a window unit air conditioner, starting from disconnecting power to cleaning air filters and coils. The teacher emphasizes the sequence of steps.
Pupils’ Activity: Pupils listen, take notes on the procedures, and ask clarifying questions.
Learning Point: Pupils learn the initial practical steps involved in AC servicing.

Step 4: Presentation of Servicing Procedures (Part 2)

Time: 5 minutes
Teaching Skill: Explanation
Teacher’s Activity: The teacher continues with the remaining servicing procedures, including checking fan blades, inspecting drain pan, checking electrical connections, and reassembly. The teacher highlights the importance of thoroughness.
Pupils’ Activity: Pupils continue to listen, understand the complete sequence, and take notes.
Learning Point: Pupils complete their understanding of the full servicing process.

Step 5: Discussion on Safety Precautions

Time: 5 minutes
Teaching Skill: Discussion/Emphasis
Teacher’s Activity: The teacher leads a discussion on critical safety precautions that must be observed during air conditioner servicing, emphasizing the dangers of electricity and refrigerants. The teacher writes these on the board.
Pupils’ Activity: Pupils contribute to the discussion, share their ideas on safety, and note down the precautions.
Learning Point: Pupils understand and appreciate the importance of safety during AC servicing.

Step 6: Practical Demonstration/Observation

Time: 5 minutes
Teaching Skill: Demonstration
Teacher’s Activity: If possible, the teacher briefly demonstrates or shows images/videos of simple servicing steps like removing an air filter, cleaning it, or wearing PPE. The teacher encourages pupils to observe closely.
Pupils’ Activity: Pupils observe the demonstration or visual aids and relate them to the procedures discussed.
Learning Point: Pupils get a visual understanding of the practical aspects of AC servicing.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

Mention three tools used for servicing a window unit air conditioner.
State any two steps involved in servicing a window unit air conditioner.
Why is it important to disconnect power before servicing an AC unit?
List two safety precautions to observe when servicing an air conditioner.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 0 minutes
Teaching Skill: Summarization/Assignment
Teacher’s Activity: The teacher briefly summarizes the main points of the lesson and gives pupils an assignment to draw and label five tools used for AC servicing.
Pupils’ Activity: Pupils listen to the summary and copy the assignment.
Learning Point: The lesson is concluded, and pupils have a follow-up task.

Lesson Keywords

Servicing – The act of maintaining or repairing a machine or system.
Air Conditioner – An appliance that cools and dehumidifies the air in an enclosed space.
Window Unit – A self-contained air conditioning unit designed to fit into a window opening.
Refrigerant – A substance used in a refrigeration cycle to absorb and release heat.
Evaporator Coils – The indoor coils of an AC unit where refrigerant absorbs heat from the room air.
Condenser Coils – The outdoor coils of an AC unit where refrigerant releases heat to the outside air.
PPE – Personal Protective Equipment, such as gloves and goggles.

Differentiation

The teacher will provide additional visual aids and simplified explanations for pupils who may struggle with understanding technical terms. Advanced learners will be encouraged to research different types of air conditioners and their specific servicing requirements, and to assist slower learners during practical observation sessions.

Note for teachers using this lesson plan

Teachers should ensure they have the necessary tools or clear diagrams to effectively demonstrate the lesson content. Emphasize safety precautions strongly and ensure pupils understand their importance before attempting any practical activities. Encourage questions and foster a hands-on learning environment where possible.