-SQA- SCOTTISH QUALIFICATIONS AUTHORITY Hanover House 24 Douglas Street GLASGOW G2 7NQ NATIONAL CERTIFICATE MODULE DESCRIPTOR -Module Number- 4280130 -Session-1990-91 -Superclass- XJ -Title- GAS SERVICES: ELECTRICAL WORK ON DOMESTIC GAS APPLNCES (X 1 1 / 2 ) -DESCRIPTION- Purpose This module is designed to further the knowledge and skills required to carry out electrical work on domestic gas appliances. It is aimed at those following a career in the service sector of the gas industry and receiving complementary industrial experience. Preferred 4280080 Gas Services: Free Standing Domestic Gas Entry Level Cookers (x 2) 4280050 Gas Services: An Introduction to Electrical Work Outcomes The student should: 1. convert electrical circuit diagrams to functional flow format; 2. wire mains voltage electrical components found on a domestic gas appliance; 3. rectify an electrical fault on a domestic gas cooker. Assessment Procedures Acceptable performance in the module will be satisfactory achievement of all the Performance Criteria specified for each Outcome. The following abbreviations are used below: PC Performance Criteria Instrument of Assessment
Note: The Outcomes and PCs are mandatory and cannot be altered. The may be altered by arrangement with SQA. (Where a range of performance is indicated, this should be regarded as an extension of the PCs and is therefore mandatory.) LO1 CONVERT ELECTRICAL CIRCUIT DGRAMS TO FUNCTIONAL FLOW FORMAT PC (a) The identification of circuits and components is correct and in accordance with manufacturer's instructions. (b) The functional flow diagram is correct in terms of: flow of electrical energy; position of main live conductor; control sequence; earth provision; neutral termination; (vi) terminal identification and colour code; (vii) crossing of wires; (viii) component identification. (c) The completed diagram is technically correct and comparable in quality to the manufacturer's own circuit. Assignment The student will be set an assignment to test comprehension of converting electrical circuit diagrams to functional flow format. The student should be provided with a manufacturer's wiring diagram (schematic or illustrated) of a domestic gas cooker with mains voltage electrical components. The circuit should include the following components: auto oven timer oven solenoid spark ignition unit for all burners oven light all associated switches 2
The student will be required to convert the diagram to functional flow. To complete the exercise the following equipment should be made available: A4 plain paper coloured pencils ruler compass suitable reference material The student will be required to undertake the given task in accordance with the Performance Criteria above. Satisfactory achievement of the Outcome will be based on all Performance Criteria being met. OUTCOME 2 WIRE ELECTRICAL COMPONENTS FOUND ON DOMESTIC GAS APPLNCES PCs (a) The cables, components and connectors are suitable in terms of type, size and quantity. (b) The wiring of the circuit is correct in terms of manufacturer's instructions or supplied diagram. (c) The routing and connecting of cable to components is completed neatly and safely. (d) The commissioning of the circuit is correct in terms of: (e) (f) checking operation of test meter; identification and isolation of electrical source; sizing of electrical fuse; preliminary electrical system checks; checking operation of circuits and controls. Working practices followed are safe. Tools used are appropriate to the task. Practical Exercise The student will be set a practical exercise to test the application of knowledge and skills required to wire mains voltage electrical components found on domestic gas appliances. 3
The student will be required to wire the circuit on a test board. The completed exercise will include the wiring of: auto oven timer oven solenoid spark ignition unit oven light all associated switches To complete the exercise the following equipment should be made available: single core cable (various colours) all necessary tools test board with relevant components and test lead with 13 amp plug manufacturer's instructions and other suitable reference material work bench with 13 amp electrical socket The student will be required to undertake the given task in accordance with the Performance Criteria above. Satisfactory achievement of the Outcome will be based on all Performance Criteria being met. OUTCOME 3 RECTIFY AN ELECTRICAL FAULT ON A DOMESTIC GAS COOKER PCs (a) The preliminary testing of the circuits is in accordance with gas industry requirements. (b) The testing of components and circuits is correct in terms of gas industry requirements and manufacturer's instructions. (c) The location and repair of the fault is correct in terms of: logical method; appropriate diagnosis; isolation; subsequent testing. (d) (e) (f) The checking of the appliance is correct in terms of operation and setting of controls. Working practices followed are safe. Tools used are appropriate to the task. 4
Practical Exercise The student will be set a practical exercise to test the application of knowledge and skills required to rectify an electrical fault on a domestic gas cooker. The student will be required to repair the appliance and its associated controls in a provided work area. The area should contain the following: (vi) an existing gas installation terminated with bayonet connection for cooker a gas cooker with mains voltage controls including auto oven feature a pre-programmed electrical fault on the cooker an approved test meter complete with operating instructions an adjacent 13 amp electrical socket a set of manufacturer's instructions and other suitable reference material The student will be required to undertake the given exercise in accordance with the Performance Criteria above. Satisfactory achievement of the Outcome will be based on all Performance Criteria being met. 5
The following sections of the descriptor are offered as guidance. They are not mandatory. CONTENT/CONTEXT Safety regulations and safe working practices and procedures should be adhered to at all times. Corresponding to Outcomes 1-3: 1. Wiring diagrams used on gas appliances: circuit, illustrated, schematic and functional flow. Advantages and limitations of each type of diagram. Basic principles of functional flow wiring diagrams. An introduction to the wiring diagrams found on domestic gas appliances. The operation of electric controls found on gas appliances. Sequence of operation of electric components on cookers and wall heaters. Method of converting circuit, illustrated and schematic diagrams to functional flow format. Converting manufacturer's diagrams for cookers and wall heaters to functional flow. 2. Identifying electrical components found on gas appliances. Cables and method of jointing when wiring circuits on gas appliances. Wiring cooker circuits on test boards with the aid of appropriate circuit diagrams. Wiring a wall heater circuit on a test board with the aid of a circuit diagram. Connecting cable to 3 pin plug. Selecting and fitting the correct fuse. Carrying out preliminary electrical system checks on circuits using a test meter which is proved to be working correctly. Checking operation of circuits and setting automatic oven timers. Demonstration of operation of controls and setting of automatic timers. The importance of all work complying with current IEE Wiring Regulations. 3. Common faults and fault finding procedures. The use of fault finding aids from various sources such as manufacturers' instructions. The adoption of a systematic approach to the diagnosis and rectification of all types of mains voltage electrical faults on domestic gas appliances. Tracing circuit and checking components on appliances using an approved test meter which is operating correctly. Applying safe working practices ie isolating appliance and components prior to working on circuitry. Carrying out preliminary electrical system checks. Diagnosing and rectifying electrical faults on a selection of domestic gas cookers. Ordering and replacing spare parts. The importance of all work complying with current IEE Wiring Regulations. 6
SUGGESTED LEARNING AND TEACHING APPROACHES This module should integrate technology with laboratory and workshop exercises. Laboratory and workshop activities should be centred on practical assignments based on well designed task sheets. Each procedure should be explained, demonstrated and followed by supervised student participation. The student should work alone to complete the given practical exercises. A selection of schematic, illustrated and functional flow diagrams depicting the wiring of various domestic appliances should be made available. Laboratory exercises involving the wiring, fault finding and testing of appliance circuits should be used to assist the student in the understanding of the topic. A variety of typical electrical connectors as found on gas appliances should be used in all wiring exercises. Where possible, correct wiring colour code should be used. The student should progress to the workshop where he/she can repair and rewire gas appliances incorporating mains voltage controls. At all times during the module the student should be actively encouraged to make use of reference material such as gas industry publications, manufacturer's instructions, course handouts and electrical test meter instruction booklet. The relevant safety precautions when working with electricity should be stressed to student. Copyright SQA 1990 7