Boiler Operator Exam Questions With Answers Latest Updated 2023/2024 100% Verified

Boiler Operator Exam Questions With Answers Latest Updated 2023/2024 100% Verified. What is the most important valve on a boiler? - Answer safety valve How often should a steam boiler have a bottom blow down? - Answer whenever tests of the boiler water indicate high chemical con- centration or high total dissolved solids How is a flame scanner tested? - Answer One method is to remove the scanner from its sighting tube and cover it with your hand, which should shut off the burner. The second method is to secure the fuel going to the burner to simulate a fuel failure, which should cause the scanner to shut the burner off on safety lockout. What methods can be used to determine the water level in a boiler? - Answer blow down the gauge glass and watch the action of the water leaving and returning to the glass. The second method is to use the three try cocks and observe what comes out of the top try cock, middle try cock, and bottom try cock when they are opened. With an NOWL, the top try cock should discharge steam, the middle try cock should discharge a mixture of water and steam, and the bottom try cock should discharge water. What is the main cause of smoke? - Answer smoke could be caused by cold fuel oil, poor atomization, insufficient primary and secondary air, a dirty burner, or fuel oil impinging on the brickwork. .What are the different types of draft used in boilers? - Answer natural draft and mechanical draft. Mechanical draft can be further clas- sified as forced draft, induced draft, or combination forced and induced draft. What is the function of a check valve on a feedwater line? - Answer prevents water from leaving the boiler when the vacuum pump or boiler feedwater pump stops. What is the function of a stop valve on a feedwater line? - Answer The stop valve is required in the event the check valve malfunctions (sticks open or closed). The stop valve could then be secured (closed) and the check What actions would be required if a safety valve was popping and the steam pressure indicated 30 psi on the boiler? - Answer (1) Secure the burner. (2) Allow steam pressure to drop to approximately 15 psi. (3) Use the safety valve test lever to test the safety valve(s) by hand. (4) If the safety valve(s) pop open and reset at the proper blow- back, raise the steam pressure to see if the safety valve(s) popped by pressure. (5) If the safety valve(s) popped by pres- sure, determine why the pressure control did not function properly. Note: The boiler in question should not be left unattended. A new boiler should be warmed up and cut in on the line if there is one available. If this is the only boiler in the plant, it must be attended 24 hours a day until it can be taken off-line and given a complete safety check. What are perfect, complete, and incomplete combustion? - Answer Perfect combustion is the burning of all the fuel using the theoretical amount of air. minimum amount of excess air. Incomplete combustion is when all the fuel is not burned, resulting in soot and smoke. Perfect combustion can only be achieved in a laboratory setting. Complete combustion is the burning of all the fuel using the What could cause a furnace explosion? - Answer caused by a buildup of highly combustible gases or fumes that ignite when exposed to a spark, pilot flame, or radiant brickwork. .What are the steps necessary in preparing for a boiler inspection? - Answer ? Once a boiler is off-line, the following safety checks must be made: (1) The main steam stop valve(s) (some boilers have two) must be closed, locked out, and tagged out. To tag out a valve means to mark it so it will not be opened by mistake. Some plants attach a sign to the valve wheel that reads "Danger! Personnel in boiler-do not open." (2) The boiler vent or top try cock should be checked to see that it is open. This ensures there is no vacuum inside. (3) The feedwater line to the boiler must be closed, locked out, and tagged out. If there is an automatic city water makeup valve, it must be secured also. How often should a gauge glass be blown down? - Answer should be blown down once a shift or whenever the operator questions the level of water boil What is the difference between a forced-circulation hot water heating system and a natural-circulation hot water heating system? - Answer In a forced-circulation system, the system is closed to the atmosphere and water is forced (circulated) through the heating system using circulating pumps. In a natural-circulation system, the system is open to the atmosphere. What procedure is followed when performing a hydrostatic test on a boiler? - Answer the boiler must be completely filled with water. To perform a hydrostatic test, the following operations must be carried out: (1) If the water column has a whistle valve, it must be removed and plugged. (2) The main steam stop valve must be closed. (3) The safety valve(s) must be removed and blank flanges installed, or the safety valves must be gagged. (A gag is a clamp that prevents the valve from popping open without damaging the valve.) (4) The boiler vent must remain open until water comes out and then is closed. (5) Pressure on the boiler is brought up to 11⁄2 times the MAWP. (The pressure must be under control so that it does not exceed this pressure by more than 10 pounds.) What does the acronym NOWL stand for? - Answer Normal operating water level What does the acronym MAWP stand for? - Answer Maximum allowable working pressure What is the cause of carryover? - Answer (1) carrying too high a water level, (2) high boiler wa- ter surface tension, and (3) opening the boiler main steam stop valve too quickly What is the difference between natural and mechanical draft? - Answer Natural draft is created by the height of the stack and the difference in temperature of the gases of combustion in the stack and the air outside the stack. Mechanical draft is caused by a fan. What causes a feedwater pump to become steambound? - Answer when the temperature of the water in the open feedwater heater gets too hot and water in the suction line going to the feedwater pump flashes into steam. What is the difference between a fast gauge and a slow gauge? - Answer A fast gauge is a pressure gauge that reads more steam pressure than is actually pres- ent in the boiler. A slow gauge is a pressure gauge that reads less steam pressure than is actually present in the boiler. What is the cause of foaming in a boiler? - Answer caused by impurities in the boiler water. A surface blowdown is used to remove impurities in the boiler water that cause foaming. What is the difference between a gate valve and a globe valve? . - Answer An open gate valve offers no restriction to the flow of the material passing through it. A gate valve must always be fully open or fully closed. A globe valve has mate- rial flowing under a valve seat and has some resistance to flow. A globe valve is used for throttling (varying the rate of flow) service by partly opening or closing What is the difference between a watertube boiler and a firetube boiler? - Answer In a watertube boiler, water passes through tubes that are surrounded by gases of combustion. In a firetube boiler, gases of combustion pass through tubes that are surrounded by water