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Stationary Engineer Exam 268 Questions
with correct Answers 2025
To prevent cavitations most pump are stamped with a? - ✅Net Positive Suction Head What two types are of condense return systems. - ✅Mechanical return systems - use traps and pumps to aid in condensate return; Gravity return systems - use gravity to bring condensate back To prevent super heater from overheating on start up what should you do? - ✅Either flood the tubes with Water or the super heater should be vented to the atmosphere by a free blow valve until the boiler goes online. This device acts as a check valve in both directions and keeps the pump primed? - ✅Foot valves are used for pumps under suction pressure to prevent back flow on the suction line. How does steam flow through pipes? - ✅Larger diameter slower the flow; smaller diameter higher velocity; Pressure difference draws flow This pump has a water piston directly connected to a steam driven piston via rod. - ✅Reciprocating A boiler system has a single boiler supplying 160 psi steam; what valves are necessary? - ✅an OS&Y shutoff valves are required on both supply and return. On a piston type trap what would cause it to open? - ✅Cold Condensate (Answers on test was steam psi drop and temp drop) If you open or close a steam stop valve to quick it will cause what? -
✅Water Hammer When testing a low water fuel cutoff using an evaporation test you need to secure all the; what going to the boiler? - ✅Feed water When 2 boilers are on the same common steam main there must be 2 OS&Y valves - ✅The 1st valve being an Automatic Non-return valve and an ample free blowing drain between them An Automatic Nonreturn valve prevents backflow if one boiler goes down and is found on. - ✅The main steam line between the boiler and the steam stop valve What is put on a boiler after repairs? - ✅R Stamp What is the first thing you do when shutting down a boiler? - ✅Turn off the fire or Extinguish fire. How much clearance from the top of the boiler is needed for a HP boiler that produces 70000 lbs of steam? - ✅7 feet On a gas fired boiler what is the proper gas to air mixture - ✅30%-70% and in special arrangements it can be as high as 100%. ANSWER CHAPTER 11 remember % What is the total hardness in a system that was found to have calcium hardness of 60ppm and magnesium hardness of 18ppm and carbon hardness of 12 ppm? - ✅TH=(Ca x 2.5) + (Mg x 4.1)\nTH=(60 x 2.5) + (18 x 4.1)\nTH= 150+73.8 =( 223.8 PPM) How often should a complete external inspection of the boiler be done? - ✅Once a Shift
✅Black Liquor is the by product of wood pulp processing in the paper making industry. What does Black liquor boiler known for? - ✅Steam generation and recovery of soda ash Maximum line voltage for control on a boiler? - ✅150 volts Under what code are boilers designed and constructed? - ✅ASME- CSD 1 How many low water cut offs are needed per code for a hot water system when a boiler has inputs greater than 400,000 btu per hr - ✅1 LWCO is needed. What is the minimum and maximum size for a safety valve per code for boilers? - ✅Minimum 3/4" and Maximum 4 1/2" What stamp is put on a boiler after repairs? - ✅"R" What is the equalizing system used for? - ✅The equalizing system is for warming up the steam lead. A blowdown valve is located at the lowest water space of a boiler for three purposes - ✅1. to remove precipitated sludge or loose scale \n2. To permit rapid lowering of the boiler water if it has become too high accidentally \n3. As a means of removing water from the boiler so that fresh water may be added to keep the concentration of solids below the point where difficulties may be experienced. In the old power boiler which type of feed-water regulators were not used? - ✅Electronic
After opening a boiler for repairs how much oxygen is needed? - ✅19% What is the first thing you do when shutting down a boiler? - ✅Turn off (extinguish fire) What is the legal limit of acceptable asbestos particles? - ✅0.1 fibers per cubic centimeter What is CREEP? - ✅Creep is defined as the slow deformation of material with time; with the deformation taking place at elevated temperatures with no increase in stress. What is the BTU content of Anthracite coal? - ✅14000 btu/lb What substance transfers electrical current in a photocell? - ✅Electricity will flow when the CADMIUM is exposed to sufficient light. What device acts as a check valve in both directions and keeps pumps primed? - ✅FOOT VALVES are used for pumps under suction pressure to prevent backflow primed? on the suction line. What protects boilers from explosion in the furnace? - ✅A flame guard system is an arrangement of flame detection system; interlocks; and relays which will sense the presence of a proper flame in a furnace and cause fuel to be shut off to the furnace if a hazardous condition develops (improper flame or combustion). What size pipe is used as a header in a boiler operating at 100psi? - ✅6 inches
✅Slag inclusion forming a lamination at the time the plate was rolled at the steel mill. A blister is a separation of the metal from the shell plate caused by impurities rolled into the shell plate when formed. With normal oxygen and low alkalinity. what is added to the boiler water? - ✅Neutralizing Amines Which chemical is used to combat scale? - ✅Combined phosphate treatment- sodium phosphate Other than sulfite what chemical is used to combat corrosion in boilers? - ✅Hydrazine What will neutralize acid? - ✅Alkali and Lime Soda What mechanical device is used to remove scale from firetubes? - ✅A tube rattler or vibrator What percentage of the pressure should a boiler have before you test the lever of a safety valve? - ✅75% Where is internal corrosion most likely to occur on a vertical tube boiler? - ✅Water leg-Mud leg What are the minimum and maximum sizes permitted for blow down valves or connections? - ✅3/4"minimum 2 ½ " maximum A boiler operating at a pressure of 65lbs. What is the smallest size feed and blow off connections if the safety valve is set at 90 psi? - ✅½ " feed ¾ " blow off
How often should water columns and water glass levels be checked on a high pressure boiler? - ✅(Once A Shift)\nAt the beginning of each shift - beginning of the work effort What takes no actual action chemical part in combustion? - ✅Nitrogen How many ppm of EDTA are needed to tie up 1ppm of hardness? - ✅EDTA requires 10ppm of EDTA and 5 NTA to tie up each 1ppm hardness. On a package boiler; how many ways could cause fire puffs when it is started up? - ✅6 ways 1-poor starting draft 2-incorrect firebox 3-wrong burner nozzle 4-lean fire 5- insufficient gas pilot or excessive gas pilot 6-water in the oil What is the grade of light domestic fuel oil? - ✅Grade 1 ( Number 1 ) How often should you test the operating control? - ✅Annually How often should the testing and inspecting of the burner component? - ✅Annually A lead sulfite photocell is what type of flame sensor? - ✅Infrared light sensing What is the least amount of oxygen needed when a nitrogen blanket is used? - ✅19% How should a boiler be prepared for inspection? -
✅Disodium phosphate and trisodium phosphate What chemical compounds in water cause permanent hardness? - ✅Calcium sulfate and magnesium sulfate What factors must be taken into consideration when choosing a control for a boiler? - ✅6 factors 1. Steam pressure 2. Furnace pressure and draft 3. air pressure and flow 4. feed water pressure and flow 5. Flue gas flow & composition 6. proper ignition & burner - flame control How many safety controls shut down a boiler when an unsafe condition occurs? - ✅7 controls 1. Pressure limit or temperature 2. Low water fuel cutoffs 3. Flame failure safeguard systems 4. Automatic ignition controls 5. oil and gas fuel shutoffs/valve controls 6. air and fuel pressure interlock controls 7. feed water regulating controls In a steam generating system what is blamed on chemical treatment but is in fact part of a boiler design? - ✅Poor circulation Class A Fires??? - ✅Wood - sawdust - paper - rags Class B Fires?? - ✅Flammable liquids - oils - tars and gasses Class C Fires?? - ✅Electrical equipment What is the minimum clearance required when a boilers capacity is 5 000btus hr over 1000sq ft heating surface or an imput over 5 000 000 btus hr? - ✅7 feet Under what code are oil fired boilers and their control systems covered? -
✅O.F.B 726
A data plate has what information?? - ✅manufacturer - model serial number - stamp of approval When working in a boiler work permits should be aquired when? - ✅For Each Shift ASME code requires that a LWCO control be tested by evaporation how often?? - ✅Monthly ASME CSD1 requires the main gas burner to have what? - ✅2 manual shutoff valves. pg 81 1004.1 code book A HYDROSTATIC test is done at what pressure? - ✅1.5 times the MAWP or 50% over MAWP How many low water cutoff are needed per code on a hot water system? - ✅One LWCO is needed when the boiler input is greater than 400 000 btus What gages are on a steam boiler? - ✅pressure gage - water gage glass What gages are on a HW boiler? - ✅pressure - Temp Name three types of low water cutoffs. - ✅1. float magnetic (rod to magnet to mercury switch) 2. Float linkage- link to mercury switch 3. Submerged electrode- water
✅FOOT VALVES ARE USED ON PUMPS UNDER SUCTION PRESSURE AND PREVENT FLOW ON SUCTION
LINE
WHAT PUMP HAS A WATER PISTON DIRECTLY CONNECTED TO A STEAM DRIVEN PISTON VIA A ROD?
✅RECIPRICATING
What causes a piston type trap to open? - ✅cold condensate (on test the steam psi drop and temp drop was used) Quickly opening a steam valve will cause _______ ________. - ✅water hammer What mechanical device removes scale from a watertube boiler? - ✅a tube turbine What causes blistering? - ✅A slag inclusion forming a lamination at the time the plate was rolled in the steel mill and it's actually a seperation of metal from the shell plate caused by impurities rolled into the shellplate when it was formed. To internally remove oxygen from the boiler use______ ________. - ✅Sodium Sulfite A positioning control system is used on a ______ ________ - ✅a process boiler A saybolt universal is a - ✅measurement of viscosity Creep gets worse with _______________ __________ - ✅elevated temps
What type of valve WOULD NOT be a good choice if sediment were present - ✅GLOBE How many btus does it take to take 10 lbs of steam from 40 to 41 degrees - ✅10 btus 1btu=1lb What is it called when you let a peice of equipment fail before you repair/replace it? - ✅Breakdown maintenance What percent of blistering or buldging is ok? - ✅2% What kind of boiler are staybolts found on? - ✅Fire tube boilers A 8 foot length of tube or shell can take up to ___% sag or bend and still be used without replacing? - ✅2% What does a low water cutoff do in a low water condition? - ✅Shuts off fuel supply What is the first indication of a low water condition - ✅A red hot crown sheet If a boiler exceeds 100psi it must have how many blowdowns? - ✅ 2 What is the appropriate test for checking porosity of the metal? - ✅PULSE ECHO ( A TYPE OF ULTRASONIC)
What is the purpose of a condensor in a refrigerant system? - ✅to bring refrigerant to a liquid state Why is oil in a refrigerating system? - ✅lubricates and cools compressor How is moisture removed from a refrigerant system? - ✅filter dryer What type of gas DONT you use to leak test an AC system? - ✅OXYGEN What is the maximum voltage on a boiler control circuit? - ✅150 VOLTS A fuel oil that has an API of 32 has how many btus per lb of heating? - ✅ 19490 Which fuel oils need heating? - ✅#4;#5;# What size pipe is used as a header in a boiler operating at 100 psi? - ✅6 inches What function can an operator contribute towards boiler function? - ✅saftey - efficiency - log plant readings How is heat transferred in a boiler? - ✅CONVECTION - CONDUCTION - RADIATION
What is not an organic sludge conditioner? - ✅Amines Which by-product has the largest heating value? - ✅Butane An increase in 10-20 degrees can reduce creep life by how manuy years - ✅10- which coal burns with a yellow flame? - ✅Bituminous What nondestructive testing is best for testing thickness of plates and tubes? - ✅Ultrasound On a 2"valve auxillary staem what valves are needed? - ✅Single supply OS&Y What are the min and max size of a safely valve per code for boilers? - ✅Min 3/4 and max 4 1/ What stamp is put on a safety valve after its been repairs? - ✅VR stamp How often do you test your float controls on a hot water boiler? - ✅Weekly How often do you test a safety valve with pressure? - ✅Annually
What is the minimum clearance of boilers without manhole covers on top? - ✅2 ft Under what code are oil fired boilers & their control systems covered? - ✅Listed & labeled in accordance with UL 726.NFPA 8501 How high is a pull station mounted on a wall? - ✅48 inches When working in a boiler; work permits should be acquired? - ✅For the work shift. To inspect a boiler they must be what? - ✅Be employed either by the state or by an insurance company licensed to write boiler and pressure vessel insurance in that jurisdiction ASME CSD 1 requires the main gas burners train to have what? - ✅2 manual safety shutoff valves Welds must be approved and witnessed who? - ✅Authorized inspector. Hydrostatic test is done at what pressure? - ✅1.5 times the MAWP or 50% over MAWP During a hydro test if the boiler leaks who do you notify? - ✅Authorized boiler inspector and they will advise you what to do. How many low water cut offs are needed per code for hot water boiler systems? - ✅When the boiler has an input greater than 400 000 BTU's per hr 1 L.W. cutout is needed
What are the minimum and maximum sizes permitted for blowdown valves or connection? - ✅1 min & 2-1/2 max If a boiler has 1" blow down pipe; what diameter should the boiler blow down tank air vent should be? - ✅2.5" What are 3 low water cutouts? - ✅(Float magnet type - it has a plunger on a float rod an a permanent magnet with a mercury switch) (Float-linkage type- a linkage connected to a mercury switch) (Submerged-electrode type- uses an electrode make the complete burner circuit) What does a low water cut out do in a low water condition? - ✅Shuts off the fuel supply when it drops below the visible level Boiler that exceeds 100 psi must have how many blow downs - ✅TWO How many times the safety valve setting should the pressure gauge be? - ✅1-1/2 to 2 times When blowing down the water column you notice the gauge glass slowly returns to the normal level; this could be indication of what? - ✅The bottom of the gauge glass is clogged and giving a false reading How many inches should the lowest visible level in the gauge glass be in a boiler? - ✅TWO inches What are the minimum gauge glass connection and drain? - ✅1/2 connection and 1/4 drain
