CERTIFICATE IN FRIDGE REPAIRING ( S-002 )

Refrigerator Repair and Maintenance Syllabus

This syllabus outlines a comprehensive training program for individuals seeking to acquire skills in the repair and maintenance of domestic and commercial refrigerators. The program covers theoretical knowledge, practical skills, and safety procedures essential for a successful career in appliance repair.

Module 1: Introduction to Refrigeration Principles (8 Hours)

• 1.1 Basics of Heat Transfer:

  • Conduction, Convection, Radiation

  • Insulation principles in refrigerators

• 1.2 States of Matter and Phase Changes:

  • Evaporation, Condensation, Melting, Freezing

  • Latent heat and sensible heat

• 1.3 Principles of Refrigeration Cycle:

  • Compressor, Condenser, Evaporator, Expansion Device

  • Pressure-Temperature relationships

  • Refrigerants: types, properties, environmental impact (CFCs, HCFCs, HFCs, Natural Refrigerants)

• 1.4 Types of Refrigerators:

  • Single-door, Double-door, Side-by-side, French-door

  • Direct cool vs. Frost-free systems

  • Commercial refrigerators (reach-ins, walk-ins, display cases)

Module 2: Refrigerator Components and Their Functions (12 Hours)

• 2.1 Mechanical Components:

  • Compressor: Types (reciprocating, rotary, inverter), operation, troubleshooting

  • Condenser: Air-cooled, water-cooled, forced draft, natural convection

  • Evaporator: Fin and tube, bare tube, plate type

  • Expansion Devices: Capillary tube, thermostatic expansion valve (TXV)

  • Accumulator and Filter Drier: Purpose and function

• 2.2 Electrical Components:

  • Thermostat: Types (mechanical, electronic), function, calibration

  • Relays: Start relay (PTC, current, potential), overload protector (OLP)

  • Capacitors: Start capacitor, run capacitor

  • Fans: Condenser fan, evaporator fan, defrost fan

  • Heaters: Defrost heater (resistance, bimetal)

  • Sensors: Temperature sensors (thermistor), door switches

  • Control Boards: Electronic control units (ECUs), display panels

  • Lighting: Interior lights, LED lighting

• 2.3 Other Components:

  • Door gaskets and hinges

  • Drain pan and drain tube

  • Ice makers and water dispensers (components, operation, troubleshooting)

  • Evaporator drain heater

Module 3: Tools and Equipment (8 Hours)

• 3.1 Basic Hand Tools: Screwdrivers, pliers, wrenches, wire strippers, multimeter

• 3.2 Refrigeration Specific Tools:

  • Manifold gauge set (R134a, R600a, R290 compatibility)

  • Vacuum pump and vacuum gauge (micron gauge)

  • Tube cutter, flaring tool, swaging tool

  • Brazing/soldering torch and consumables

  • Leak detectors (electronic, soap bubble)

  • Refrigerant recovery unit

  • Charging scale

• 3.3 Safety Equipment:

  • Safety glasses, gloves, protective clothing

  • Fire extinguisher

  • First aid kit

Module 4: Troubleshooting and Diagnostics (16 Hours)

• 4.1 General Troubleshooting Principles:

  • Systematic approach to problem-solving

  • Listening to customer complaints

  • Visual inspection

• 4.2 Common Refrigerator Problems and Solutions:

  • No Cooling/Insufficient Cooling:

    • Compressor not running (electrical, mechanical)

    • Refrigerant leaks (diagnosis, repair)

    • Blocked capillary tube/filter drier

    • Fan motor issues (condenser, evaporator)

    • Thermostat/sensor malfunction

    • Defrost system failure (heater, bimetal, timer)

  • Excessive Freezing/Frost Buildup:

    • Defrost system issues

    • Door gasket leaks

    • High humidity

  • Refrigerator Not Starting:

    • Power supply issues (outlet, cord, fuse, breaker)

    • Thermostat failure

    • Relay/OLP malfunction

    • Compressor short/open circuit

  • Noisy Operation:

    • Fan motor issues (bearings, obstructions)

    • Compressor vibrations

    • Loose components

  • Water Leakage:

    • Clogged defrost drain line

    • Cracked drain pan

    • Water dispenser leaks

  • Bad Odors:

    • Clogged drain pan

    • Food spoilage

• 4.3 Electrical Diagnostics:

  • Using a multimeter for voltage, current, resistance, and continuity checks

  • Reading wiring diagrams and schematics

  • Testing individual electrical components

• 4.4 Refrigeration System Diagnostics:

  • Reading manifold gauges to diagnose system pressure issues

  • Understanding superheat and subcooling (basic concepts)

  • Leak detection techniques

Module 5: Repair Procedures (20 Hours)

• 5.1 Safety Procedures:

  • Electrical safety (lockout/tagout)

  • Refrigerant handling safety

  • Personal protective equipment (PPE)

• 5.2 Component Replacement:

  • Compressor replacement (evacuation, charging)

  • Condenser/Evaporator replacement

  • Thermostat/Sensor replacement

  • Fan motor replacement

  • Defrost heater/bimetal/timer replacement

  • Relay/OLP/Capacitor replacement

  • Door gasket replacement

  • Ice maker and water dispenser repair

• 5.3 Refrigerant System Service:

  • Refrigerant recovery procedures (EPA guidelines, if applicable)

  • System evacuation using vacuum pump

  • Refrigerant charging (weighing method, superheat/subcooling method)

  • Brazing and soldering techniques (leak-free connections)

  • Filter drier replacement

  • Flushing a contaminated system (brief overview)

• 5.4 Wiring and Control Board Repair:

  • Repairing damaged wiring

  • Replacing control boards (troubleshooting, programming if applicable)

Module 6: Preventive Maintenance and Customer Service (4 Hours)

• 6.1 Importance of Preventive Maintenance:

  • Extending appliance lifespan

  • Improving efficiency

  • Preventing costly breakdowns

• 6.2 Maintenance Tasks:

  • Cleaning condenser coils

  • Checking door gaskets

  • Cleaning drain pan and drain line

  • Checking fan operation

  • Inspecting electrical connections

• 6.3 Customer Service Skills:

  • Effective communication

  • Professionalism and ethics

  • Explaining repairs clearly

  • Handling difficult customers

Module 7: Advanced Topics and Emerging Technologies (4 Hours)

• 7.1 Inverter Refrigerators:

  • Inverter compressor technology

  • Variable speed drives (VSDs)

  • Troubleshooting inverter systems

• 7.2 Smart Refrigerators:

  • Connectivity and smart features

  • Basic diagnostics via smart apps

• 7.3 Natural Refrigerants:

  • Hydrocarbons (R290, R600a) safety and handling

  • CO2 (R744) systems (brief overview)

• 7.4 Energy Efficiency:

  • Understanding energy ratings

  • Tips for improving refrigerator efficiency

Assessment:

• Written Examinations (Multiple Choice, Short Answer)

• Practical Examinations (Troubleshooting and Repair Simulations)

• Case Studies and Problem-Solving Exercises

Recommended Resources:

• Refrigerator service manuals (manufacturer-specific)

• HVAC/R textbooks and reference guides

• Online technical forums and repair communities

• Safety data sheets (SDS) for refrigerants