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Read through the material below, then test your understanding.
Module Lessons
Electrical Principles & Diagnostics
Ohm's Law & Electrical Power
Protection Against Electric Shock
Electrical Statutory Regulations
BS 7671 & IET Guidance Documents
Reading Electrical Plans & Diagrams
Consumer Units & Protective Devices
Lighting & Power Circuits
Earthing, Bonding & ADS
Electrical Accessories
Current-Using Equipment & Specialist Controls
Effects of Electric Shock on the Body
Tool & Equipment Safety Classes
The Safe Isolation Procedure, Step-by-Step
Hand Tools for Electrical Work
Cable Types
BS 7671 Termination Requirements (Section 526)
Terminal & Connection Types
Cable Glands & Enclosure Entry
Terminating Flexes & Single-Core Cables
Terminating Flat Profile (Twin & Earth) Cable
Installing Main Protective Bonding
Fitting & Labelling BS 951 Bonding Clamps
Electrical Test Instruments
Central Heating Control Sequence of Operation
Diagnosing Boiler Thermostats & Fans
Diagnosing Air Pressure Switches
Diagnosing PCBs & Ignition Components
Diagnosing Thermocouples & Thermistors
Alternative & Emerging Heat Sources
Testing Immersion Heaters
Isolating & Correcting Appliance Faults
Lesson Overview
Master the electrical switching and operational sequences of domestic central heating controls, from room thermostat demands to motorised valve actuation, boiler ignition, and pump overrun.
Learning Objectives
Trace the electrical switching sequence through room thermostats, cylinder thermostats, and motorised valves.
Identify the core conductor colours and operational functions of standard two-port and three-port valves.
Describe the internal boiler start-up procedure from fan proving to flame rectification.
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