AC & Fridge Repair Course
COURSE SYLLABUS
PART ONE (THEORY CLASS CONTENT)
AC Systems, Refrigeration & PCB Diagnostics
1. Introduction to Voltage, Current, Power, Resistance & Frequency
- Types: AC voltage, DC voltage
- Definition and SI unit (Watts)
- Real power, reactive power, apparent power
- Relationship: P = V × I 1.4 Voltage–Current–Power Relationship
- Ohm’s Law: V = I × R
- Practical examples 1.5 Resistance & Inductance Characteristics
- Frequency and motor RPM relationship
2. Measuring Instruments ( Multimeter & Clamp Meter)
- Working principle
- Measurement of AC/DC voltage and current
- Working principle (Hall effect)
- Non-contact current measurement
- Safety precautions 2.4 Real-Life Applications
- Field use of measuring instruments
3. Conductors, Semiconductors & Insulators
- Conducting characteristics
- Applications in AC wiring 3.2 Semiconductors
- Role in electronics and PCBs
- Basics of diodes and transistors 3.3 Insulators
- Definition and examples (PVC, rubber)
4. Circuits & Their Types
- Normal operating circuit
- Current flow path
- Causes and hazards
- Protection devices (fuse, MCB)
- Definition and causes
- Overload vs. short circuit
- Protection using OLP / breakers
5. Electrical Connections
- Current behaviour in series
- Parallel Connection
- Current division rule
- Application SCR Connection
- Motor connection via SCR
- Capacitor connection in SCR circuits
- Start and run capacitor wiring
6. Switches & Control Devices
- One-way and two-way switch operation
- Semi-Automatic Switch, Relay switch principle
- Thermostat and pressure switches
- Role in AC automation
7. Introduction to Air Conditioning — Types & Classification
- Definition and unit of refrigeration (TR/BTU)
- Working principle overview
- Vapour compression cycle of AC
- Split AC — wall-mounted indoor/outdoor unit
- Cassette AC — ceiling-mounted, 360° airflow
- Window AC — single-unit installation
- VRF (Variable Refrigerant Flow) — multi-zone system
- Chiller AC — water-cooled large-scale cooling
- Portable AC — freestanding, no permanent installation 7.3 Capacity Calculation
- BTU/TR calculation formula
- Sizing AC based on room dimensions & affecting load calculation
- 4 Indoor vs. Outdoor Unit Classification
- Types of refrigerants (R-22, R-410A, R-32)
- Compression → Condensation → Expansion → Evaporation
8. Indoor Unit — Components & Functions
- Installation bracket types & Material and assembly
- Heat absorption process
- Coil design and fin arrangement
- Frosting and defrost cycle 8.4 Drainage System
- Condensate collection tray
- Drain pipe routing and blockage
- Condensate pump (if applicable) ,Blower Motor / Indoor Fan
- Speed control via PCB
- Motor testing and replacement,Swing / Stepper Motor
- Thermistor (room & coil temp)
- Hall sensor IR receiver (remote signal)
- Step-down from 220 V to low voltage
- PCB replacement procedure & Wire & Pipe Connectors
- Wiring harness connections
- Flare and compression pipe fittings
- Leak prevention best practices
9. Outdoor Unit — Components & Functions
- Reciprocating, rotary, scroll types
- Accumulator role in liquid protection
- Compressor testing (OLP, winding resistance)
- Axial fan blade design & Fan motor winding check
- Capacitance testing (μF), Start and run capacitor roles
- Heating and cooling mode switching
10. Pressure — Types & Measurement
- Standing pressure (static)
- Running pressure (dynamic)
- Discharge pressure (high side)
- Low-pressure / vacuum gauge meter
- High-pressure gauge meter
- Compound gauge meter
- Vacuum & Vacuum Process
PART TWO (PRACTICAL CLASS CONTENT)
1.Multimeter Practice
- Measuring AC DC voltage (mains supply)
- Clamp meter vs. inline method & NCV Test
- Non-contact voltage test usage
- Live wire detection procedure
- Testing wire continuity
- Motor winding continuity check
- Switch and fuse testing
2. Circuit Design & Testing
- Design open circuit layout
- Cold test and Hot test (unpowered continuity check)
- Controlled short circuit design
3. Connection Layout & Testing
- Design source and load in parallel
- SCR wiring for motor
- SCR wiring for compressor
- Functional test and verification
4. Switch Connection & Testing
- Wiring layout test procedure
- Wiring layout for two-location switching
- Testing both switching positions
- Staircase wiring application & Relay Switch
- Coil and contact terminal identification
- Control circuit and load circuit wiring
- Relay actuation test using supply voltage
5. AC Component (Compressor) Individual Testing
- Terminal identification (C, S, R)
- Winding resistance check
- Running test with capacitor P5.2 Fan Motor
- Winding resistance test
- Capacitor connection and test
- Speed verification & Four-Way Valve
- Energising coil and verifying valve shift
- Mode-switching confirmation & Blower Motor
- PCB-controlled operation test & Swing / Stepper Motor
- Connection to PCB signal output
6. Thermal Sensor Connection & Testing
- NTC thermistor resistance vs. temperature
- Connection to PCB sensor input
- Fault simulation and response & Hall / Blower Sensor
- Hall-effect speed sensor wiring
- Signal output verification
- PCB feedback testing & IR Receiver
- IR signal pin identification
7. Full System PCB Connection Wiring & Integration
- Connect all indoor components to PCB
- Signal mapping: sensors, motor, valve, display
- Power-on test and fault-code check & Indoor–Outdoor Wire Connection
- Identify communication and power terminals
- Interconnection cable wiring
- Signal continuity verification & Complete AC System Wiring
8. Power Supply PCB Board — Advanced Level
- AC-line to DC-line tracing
- Filter circuit identification & PFC circuit tracing
- SMPS and buck-boost conversion & Power Factor Correction
- Voltage regulator track identification
- MCU/processor pinout mapping
- Input and output line tracing & Driver & Load Tracing
- Relay driver circuit
- Transistor, thyristor ,Zener . TVS diode identification testing
- SCR and other driver components, Safety & Voltage Regulation Components
9. Refrigeration Practical Skills (Pressure Checking)
- Vacuum gauge, pressure gauge, compound gauge Reading standing and running pressures
- Pipe cutter selection and technique
- Burr removal procedure, correct pipe sizing and Brazing
- Torch and brazing rod selection
- Nitrogen purging during brazing
- Joint quality inspection & Swaging & Flaring
- Swaging , Flaring tool and correct flare angle
- Fitting ,leak prevention and Leakage Test
- Acceptable pressure hold criteria & Vacuum Procedure
- Connecting vacuum pump to system
- Micron gauge verification and hold test & Gas Filling (Charging)
- Refrigerant type and cylinder identification
- Charging by weight / pressure / sight glass
10 .Fault Diagnosis & Error Code Analysis
- Reading error codes from display/PCB
- Tracing electrical fault from code
- Repair and verification & Mechanical Fault Diagnosis
- Interpreting refrigerant-related error codes
- Pressure and temperature cross-check
- Scenario-based fault diagnosis exercises
- Course Duration: 60-75 Days
- Training Time: 1.5 Hours Per day
- Course Contain: Theory 20% + Practical 80%
- Language of instruction:Nepali/Hindi /English
- Eligibility Criteria: 8 to 10th Class(At Least Completed Grade 8)
- Group structure: 6 Participants per group
- New classes starts on: 1st,10th and 20th(Every Month)
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