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Grade 4 Stationary Engineer License Practice Exam Questions and Answers, Exams of Engineering

Grade 4 Stationary Engineer License Practice Exam Questions and Answers

Typology: Exams

2023/2024

Available from 01/21/2025

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Grade 4 Stationary Engineer License

Practice Exam

what is a boiler - Answer- a closed metal container (pressure vessel) which water is heated to produce steam or heated water what is steam - Answer- the vapor that forms when water is heated to its boiling point when did the greatest impact of the use of steam power occur - Answer- during the industrial revolution 18th and early 19th century who invented the steam engine and when - Answer- James Watt of Scotland in 1736 How is steam produced - Answer- water is heated to 212 degrees at atmospheric pressure state the first law of thermodynamics - Answer- energy cannot be created or destroyed but may be changed from one form to another state the second law of thermodynamics - Answer- heat always flows from a material at a high temperature to a material at a low temperature what is sensible heat - Answer- heat that causes a temperature change that can be measured with a thermometer or sensed by a person what is latent heat - Answer- head identified by a change of state and no temperature change what is a BTU - Answer- the amount of energy required to raise the temperature of 1 lb of water 1 degree fahrenheit name 3 ways heat is transferred - Answer- conduction, convection, and radiation How is heat generated in a boiler - Answer- by the combustion of a fuel name the 3 conditions of combustion - Answer- perfect, complete. or incomplete name the 3 classifications of combustion air - Answer- primary air, secondary air, and excess air

describe the 4 systems all steam boilers operate using - Answer- feedwater system, fuel system, draft system, and steam system what does the feedwater system do? - Answer- supplies the proper amount of water to the boiler what does the draft system regulate? - Answer- the flow of air to and from the boiler what does the fuel system do - Answer- provides fuel for combustion to generate the necessary heat in the boiler what does the steam system do? - Answer- collects, controls, and distributes the steam produced an the boiler what are symbols used for - Answer- to represent lines, boiler fittings, and accessories on drawings what is MAWP - Answer- Maximum Allowable Working Pressure. The recommended maximum pressure at which a boiler can be safely operated what is the MAWP of a low pressure boiler - Answer- not more than 15 psi what is the MAWP of a high pressure boiler - Answer- more than 15 psi what is a firetube boiler - Answer- a boiler in which heat and gases of combustion pass through tubes surrounded by water what is a watertube boiler - Answer- a boiler in which water passes through tubes surrounded by gases of combustion what is a cast iron boiler - Answer- a boiler that has gases of combustion flowing around cast iron sections that contain water what is an electric boiler - Answer- a boiler that generates heat by electrical resistance or an electric are what is a condensing boiler - Answer- a boiler designed to recover some of the heat normally discharged to the atmosphere in the gases of combustion what does a safety valve do - Answer- prevents the boiler from exceeding its MAWP and is the most important valve on a boiler what is the safety valve capacity - Answer- the amount of steam in pounds per hour that the safety valve is capable of venting at its rated pressure

how often should a try lever test be performed - Answer- every 30 days the boiler is in operation at what pressure should the try lever test be performed - Answer- a minimum of 5 psi who should make adjustments or repairs to a safety valve - Answer- the manufacturer or an authorized representative of the manufacturer what is a pop test - Answer- test performed to determine if a safety valve opens at the proper pressure within allowable tolerances what does a steam pressure gauge do - Answer- displays the amount of pressure in the boiler what is hydrostatic pressure - Answer- the weight of water (0.433 psi per vertical foot) what is a siphon - Answer- provides a water seal to prevent contact with live steam what is a vacuum gauge - Answer- indicates the amount of vacuum (pressure below atmospheric pressure) present in the boiler who should make repairs to a pressure gauge - Answer- manufacturer or authorized representative of the manufacturer why should you never add water to a boiler if there is no water in a gauge glass - Answer- adding water to a boiler with a low water condition could cause a boiler explosion what is the purpose of a water column - Answer- a water column reduces the turbulence of boiler water to provide an accurate water level in the gauge glass what does a gauge glass indicate - Answer- water level in the boiler what are try cocks used for - Answer- to determine the boiler water level if the gauge glass is not functiona how is sludge and sediment removed from the gauge glass and water column - Answer- blowdown what are bottom blowdown valves used for - Answer- to release water from the bottom of the boiler describe the bottom blowdown valve order - Answer- the valve closest to the boiler is always opened first and closed last

what is the purpose of the bottom blowdown - Answer- water level control, sludge and sediment removal, and dumping the boiler name 3 components that prevent damage to the sewer system - Answer- a blowdown tank, blowdown separator, and heat exchanger when should a boiler never be dumped - Answer- when hot what is a fusible plug - Answer- a warning device used to indicate extreme overheating of the boiler from a low water condition where is the fusible plug usually located on a Scotch Marine Boiler - Answer- in the top of the combustion chamber or in the rear tube sheet above the highest row of tubes how often should fusible plugs be replaced - Answer- annually during boiler inspection what size is the boiler vent line - Answer- half inch or three quarter inch piping where should the boiler vent line connect - Answer- to the highest part of the steam side of the boiler what should a safety valve never be used for - Answer- venting a boiler when is it safe to open the steam side of the boiler - Answer- when there is no steam pressure on the boiler, the boiler is cool enough to dump, and no vacuum is present in the boiler when should the boiler vent be open - Answer- when filling the boiler with water and when filling up the boiler before cutting the boiler in on-line state 3 things that a pressure control does - Answer- a pressure control is a switch that starts the burner, controls the firing rate, or shuts down the burner based on steam pressure what does the operating control do - Answer- initiates the burner start up sequence and burner shutdown sequence as required what is the purpose of the high limit control - Answer- senses steam pressure and automatically shuts down the burner if the operating limit control fails what does the modulating control do - Answer- controls the firing rate of the burner in what state should the burner be started and shut down - Answer- low fire what is a heat exchanger - Answer- an auxiliary device commonly used with boilers to transfer heat from a hotter fluid to a cooler fluid

name two types of heat exchanger protection from overpressure - Answer- thermal expansion safety relief valve or rupture disc