30550/30551 V1 Transition Trainees Assessment - PDF

PGD Core 30550v1 and 30551v1 ed1.0 30550 | Version 1 | Level 4 | Credits 10 30551 | Version 1 | Level 4 | Credits 7 Name (First/Last): Company/Employer: National Student Number (NSN):...

PGD Core 30550v1 and 30551v1 ed1.0 30550 | Version 1 | Level 4 | Credits 10 30551 | Version 1 | Level 4 | Credits 7 Name (First/Last): Company/Employer: National Student Number (NSN): Te Pūkenga Number: (if known) Phone Number: Email: Introduction In this assessment This is a transition assessment based on your previous work. To complete this assessment, you must have completed: 30551: Position, install, commission, and maintain low pressure hot water supply systems. For this assessment, you be required to answer questions relating to hot water systems. You should be able to complete the assessment without assistance. A copy of the unit standard can be found on the NZQA website http://nzqa.govt.nz/. Health and Safety All practical activities are to be carried out in a way that avoids harm to people and damage to property, environment, existing installed services, materials, tools, and equipment. Requirements You must hold a current limited certificate or exemption under supervision as issued under the Plumbers, Gasfitters, and Drainlayers Act 2006. You may refer to current legislation and Standards during the assessment. All activities and evidence presented must comply with legislation, policies and procedures, ethical codes, Standards, site/industry practice, and any manufacturer’s instructions, specification and data sheets. Credit for this unit standard does not entitle the candidate to legally perform certain electrical aspects of this work unless registered or supervised by a registered person under the provisions of the Electricity Act 1992. No electrical work is required for this assessment. Declaration I am confident that I can operate all equipment and complete the tasks in a safe and responsible manner without causing a hazard or harm to myself or to other people. Apprentice name: Signature: Date: 30550v1 and 30551v1 ed1.0 Page 2 of 7 Questions 1. Match the following terms to their definitions: Conduction, convection, corrosion, friction, radiation, thermosiphon The movement of water (or other fluid) heating. As it heats, it becomes less dense and will rise, and cooler water will fall to take its place. The thermal energy given off by a material e.g. the heat from a fire Heat transfer through direct physical contact e.g. water in direct contact with an immersion element. Damage and breakdown of metal over time. The difference in densities of the water at different temperatures drag and push the water. For example, wetback systems use this process to circulate water between the cylinder and the fire to continuously heat the water. The resistance to motion of one object moving relative to another. This is often seen on long pipe lengths or sharp bends in the system. 2. Explain hydraulic gradient, and how it applies when installing a low pressure hot water system. 30550v1 and 30551v1 ed1.0 Page 3 of 7  3. You need to replace an outlet tap in a boiling water unit as it no longer closes properly. Your boss mentions that it is probably due to the hard water in the area. What is hard water, and how would this impact the outlet tap of the boiling water unit? 4. A customer originally chooses a 135 litre capacity hot water cylinder for their 4 bedroom home. You suggest a larger capacity cylinder. What are three reasons that the customer should go from a smaller to larger capacity cylinder? 5. Fill in the blanks below, describing where you would position seismic restraints on a hot water cylinder. G12/AS1 gives acceptable solutions of structural support. The restraints must be _______ max from the top and bottom of the cylinder. An extra centre strap is needed if the water heater is over ___________. 6. A sacrificial anode must be screwed to the threaded connection point, as per the manufacturer’s instructions. Explain how a sacrificial anode protects the hot water cylinder. 30550v1 and 30551v1 ed1.0 Page 4 of 7  7. Describe the difference between direct and indirect heating of a hot water supply system. 8. When commissioning the system, why is it important to check the temperature being supplied to the outlets? Reference any relevant legislation/codes/standards in your answer. 9. Draw an example diagram of a mains pressure valve vented storage water heater system. 30550v1 and 30551v1 ed1.0 Page 5 of 7  10. When upgrading from a low pressure to a mains pressure hot water system, what are three things that you need to consider? 11. What are two differences between positioning a low pressure open vented system and a mains pressure valve vented system? 12. What special feature does a mains pressure system have if it is an indirect system? 13. In a mains pressure system, why are both a cold water expansion valve and a temperature pressure relief valve installed? 30550v1 and 30551v1 ed1.0 Page 6 of 7  14. Is an electric continuous flow water heating system a controlled or uncontrolled heat source? Explain your answer, including the difference between uncontrolled and controlled heat sources. 15. You have been called to check an older mains pressure valve vented (MPVV) system. Recently the owners have found that they have poor hot water flow from all their outlets. Give two potential causes of poor hot water flow from all outlets, and how you would fix these issues. Cause 1: Fix: Cause 2: Fix: 16. The pressure relief valve on a mains pressure system is continually discharging water. What should you do to fix the fault? 30550v1 and 30551v1 ed1.0 Page 7 of 7 Sign off Name: NZQA Number: Address: Phone: Job Date NYC/C Tutor Install a low pressure open vented hot water 1 system Install a low pressure valve vented hot 2 water system 3 Install a push through hot water system 4 Install a wetback system Candidate verification I confirm that the answers I provided with this assessment are all my own work. Apprentice name: Signature: Date: Assessor verification I confirm that all the conditions of this assessment have been met. Trainee has achieved: 30550 Demonstrate knowledge of the installation, commissioning, and maintenance of hot water supply systems (version 1, level 4, credits 10) Assessor name: Signature: Date: 30550v1 and 30551v1 ed1.0 Page 8 of 7