Docsity
Docsity

Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity


Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan


Guidelines and tips
Guidelines and tips

up Stationary Grade 3 Engineering License Exam Questions and Answers, Exams of Engineering

up Stationary Grade 3 Engineering License Exam Questions and Answers

Typology: Exams

2024/2025

Available from 01/21/2025

examguide
examguide 🇺🇸

4.7

(23)

8.6K documents

Partial preview of the text

Download up Stationary Grade 3 Engineering License Exam Questions and Answers and more Exams Engineering in PDF only on Docsity!

up Stationary Grade 3 Engineering

License Exam

how can you loose your license? - Answer- 1) drinking on the job

  1. sleeping on the job
  2. negligence
  3. unsafe work
  4. signing a falsified license application for someone
  5. failing to renew your license annually what must you do if you change jobs? - Answer- notify city hall if you change jobs, address or retire why should you do rounds? - Answer- Find and correct problems to prevent breakdowns. keeping permanent records will make it easy to forecast most breakdowns because you will get to know equipment what is a steam boiler? - Answer- closed vessel, PARTIALLY FILLED WITH WATER, under pressure that transforms water to steam with the application of heat. what are the requirements of a good boiler? - Answer- 1) simple
  6. designed to accommodate expansion and contraction
  7. adequate steam and water space
  8. efficient
  9. responsive to demands
  10. accessible for cleaning and repairs
  11. safe Name and describe 3 types of heat transfer used in boiler operation - Answer- 1) RADIANT HEAT - transmitted from hot body to a cold body by means of direct radiation (heat from sun reaches us by radiation)
  12. CONDUCTION - physical contact (coffee cup is heated by conduction when hot coffee touches the cup)
  13. CONVECTION - carried along by a moving part such as air or water (your living room is heated by warm air from your furnace in another location what is a combustion chamber? - Answer- the area of the boiler where COMPLETE burning of the fuel occurs what is an internally fired boiler?

name 4 types - Answer- those in which the grate and combustion chamber are enclosed within the boiler shell.


  1. Scotch marine
  2. Vertical firetube
  3. Locomotive
  4. Cast iron package boiler what is an externally fired boiler

name 4 types - Answer- the setting, including the furnace and grates is separate and distinct from the boiler shell.


  1. horizontal return tubular (HRT) set in brick
  2. some watertube
  3. cast iron set in brick
  4. Stirling boiler
  5. Heine boiler what is a crown sheet and its purpose?

what is a tube sheet and its purpose? - Answer- in a vertical firetube boiler holds the tubes and is thicker because it is exposed to the fire.


holds the tubes and does not see the fire what is a waterleg on a boiler? - Answer- space between the outer shell and the furnace containing boiler water. it absorbs heat that would be wasted and increases the capacity of the boiler. the surfaces are flat and must be stayed. is an HRT Boiler set level or inclined and why?


are HRT Boiler tubes set level or inclined and why? - Answer- INCLINED 1-3" front to rear to permit drainage and removal of water impurities


INCLINED with the boiler Name 2 way to support and take care of expansion of an HRT Boiler


Which way is best? - Answer- 1) Suspended from hangars and supported by overhead beams

  1. Set on saddles equipped with rollers to permit movement of the boiler as it expands and contracts

Suspended from hangars and supported by overhead beams is best because it works no hardship on the furnace walls

what is a longitudinal joint?

what is a circumferential joint? - Answer- LONGITUDINAL JOINT = seam running the length of the shell and is butt strap construction or fusion welded. it is above the fireline to avoid overheating.


CIRCUMFERENTIAL JOINT = lap joint running the circumference of the drum what is the difference between a flue and a tube? - Answer- 1) Flue - 4" or more in diameter measured internally

  1. Tube - 4" or less in diameter measured externally what is a drypipe and where is it located? - Answer- a steam separator located within the boiler shell and connected to the steam outlet. its upper surface is perforated. steam enters the perforations rapidly changing its direction of flow causing droplets and impurities to separate from the steam before entering the steam outlet. describe a Scotch Marine Boiler?

how it is fired - Answer- it is an internally fired self contained horizontal return firetube boiler.


it is a cylindrical shell containing the combustion chamber and tubes that are surrounded by water. how is a Stirling Boiler suspended? - Answer- lugs on the ends of the upper drums rest on the beams of its structure. the lower (MUD) drum is suspended from the tubes and is free to move by expansion. describe the circulation of water within the Stirling Boiler - Answer- feed water enters the top rear drum, passes down the rear tubes to the mud drum. steam and boiler water go up the front and center tubes to the front and center drums. CIRCULATING TUBES allow boiler water to pass between the drums. what does not go out as steam, goes back down the rear tubes. what provisions are made for tube removal on water boilers? - Answer- 1) some tubes are left out

  1. the tubes are staggered
  2. sometimes, every other row is omitted What is a water tube boiler?

list 5 advantages

list 5 disadvantages

name 4 types - Answer- in a water tube boiler, products of combustion pass around tubes containing boiler water


ADVANTAGES:

  1. rapid steamers
  2. use less water
  3. less chance of explosion
  4. no flat surfaces
  5. smaller tube sizes

DISADVANTAGES:

  1. elaborate settings
  2. field assembled
  3. initial cost per pound of steam is higher
  4. greater number of openings thus more air infiltration
  5. require more floor space

TYPES:

  1. B.&W.
  2. Stirling
  3. Heine
  4. "D" type what is a fire tube boiler?

list 5 advantages

list 5 disadvantages

name 4 types - Answer- in a fire tube boiler, products of combustion pass through tubes or flues surrounded by water.


ADVANTAGES:

  1. very little setting required
  2. factory assembled for fast installation
  3. low initial cost
  4. can be made portable
  5. compact

DISADVANTAGES:

  1. slow steamers
  2. limited in pressure and capacity
  3. liable to disastrous explosions because drums and joints are set over the fire
  4. inefficient
  5. inaccessible for inspection

TYPES:

1) H.R.T.

  1. locomotive
  2. Scotch Marine
  3. Vertical fire tube What type stays are used in wet back (Scotch Marine) type boilers? - Answer- stay bolts and through stays. these sometimes will have a telltale drilled in them describe a sectional boiler - Answer- the sectional headers are built up of vertical sections or units. a sufficient number of sections are clamped together to form the desired boiler size. these boilers can be erected in an existing building by carrying them in piece by piece what is a superheater?

what are the advantages of a superheater? - Answer- a super heater is a device used to raise the temperature of steam without raising its pressure.


  1. increases efficiency of the boiler
  2. delivers dryer steam
  3. dryer steam can be transmitted long distances with minimal heat loss
  4. dryer steam reduces condensation and erosion what is a radiant type superheater?

what is a convection type superheater?

what is the third type of superheater? - Answer- A radiant superheater is set over the fire to absorb radiant heat from the furnace by direct radiation


a convection superheater is placed in the gas passage of the furnace, usually between the first and second pass. little to no radiation will reach this type


the third type is a combination of radiant and convection what is an economizer?


what is a air pre-heater? - Answer- an economizer is a heat exchanger designed to recover waste heat from the products of combustion by pre-heating the feedwater. It's located in the breaching between the boiler and stack. NOTE: there is great economy in heating feedwater.


the air pre-heater consists of a series of tubes or plates that have hot gasses on one side and incoming air on the other. heat in the hot gasses leaving the boiler is recovering by the incoming air.


(both reduce stack temperatures and increase boiler efficiency) what is a water wall? - Answer- a set of tubes containing boiler water set in the refractory. they absorb heat that would otherwise be lost to the refractory and they increase the capacity of the boiler what is A.S.M.E. and its purpose?


what code of information is stamped on the boiler?

what is an A.S.M.E. symbol stamp?

where are the code markings found on a boiler? - Answer- American Society of Mechanical Engineers has written a set of minimum standards for the safe construction of pressure vessels.


stamped on the boiler shell or a plate attached to the shell will be:

  1. model and serial numbers
  2. safe working pressure
  3. date of manufacture
  4. horsepower rating
  5. square feet of heating surface
  6. steam generation in pounds per hour
  7. fuel designed for
  8. ASME stamp

the ASME symbol stamp will identify the boiler or accessory type.

fire tube boiler - it may be located by the water column near the front right side water tube boiler - it will be located next to the manhole on the steam drum what is the cross section of a 1" bolt? - Answer- DxDx.7854(1/4pi) 1x1x.7854=.7854 sq.in. show your work and label everything! what is an alloy?


name 5 - Answer- a mixture of two or more metals.

  1. brass
  2. bronze
  3. steel
  1. stainless steel
  2. cast iron at what pressure is the use of cast iron fittings permitted? - Answer- 15 psi. or 250*F. Not to exceed either one what is meant by "Factor of Safety"? - Answer- the bursting pressure divided by the working pressure or the comparison of the tensile strength to the actual working stress what is the Factor of Safety for Boilers, Flywheels and Pipe? - Answer- New boilers is 4 Pre-owned boilers constructed to ASME code is 5 Flywheels is 4 Pipe is 8 what is a lap joint?

what is a butt joint?

what is a butt-strap joint? - Answer- LAP JOINT = when one plate overlaps the other and is joined


BUTT JOINT = when two ends of the plate meet end to end and are joined

BUTT-STRAP JOINT = when two ends of the plate meet end to end and are joined by a plate. (one plate is a single butt strap joint / two plates are a double butt strap joint) is the longitudinal joint the strongest part of the boiler - Answer- NO! it is the strongest type joint, but any joint is the weakest part of a boiler two boilers are make of the same grade of steel, same thickness of plate and same type of joints. one is 30" in diameter the other is 60" diameter. which will withstand the greatest pressure and demonstrate your answer - Answer- the 30" boiler-it has less total pressure on the shell. DxDx.7854(1/4pi)xpsi 30x30x.7854x120 psi = 84,823 lbs. total pressure 60x60x.7854x120 psi = 339,292 lbs. total pressure show your work on everything! what are tube ligaments? - Answer- the area between the tube holes on the tube sheet what type stays are used in the heads of water tube boilers?


why? - Answer- there are no stays

the head of the boiler drum is shaped with a die, which dishes and forms them in to the shape they would take as a result of the pressure to which they will be subjected why is a row of tubes sometimes left out of an HRT boiler? - Answer- to improve circulation reducing carryover in a firetube boiler how are the tubes secured in a tube sheet and why?


in a watertube boiler how are the tubes secured in a tube sheet and why?

in a water tube boiler why are only some of the tube ends beaded? - Answer- fire tube boiler - they are rolled then beaded to keep them from pulling out and to prevent heat damage


water tube boiler - they are rolled then flared to keep them from pulling out

for drainage of the top drums and to prevent air pockets in the lower drums. is it necessary to brace or stay a flat surface?


name 3 types of stays - Answer- YES, to overcome the force on heads and flat surfaces. Where there are no tubes, braces and stays must be provided to prevent bulging of the boilerplate.


  1. through bolt
  2. stay bolt
  3. diagonal stay
  4. gusset stay describe a through stay

why are hollow through bolts used on water legs? - Answer- a through stay is a rod threaded on both ends, held in place with nuts on the inside tightened against nuts on the outside of the plates. it runs from one tube sheet or flat surface to the other.


a small hole is drilled into the stay bolt so if it failed a leak will develop and be detected at once describe a diagonal stay


describe a gusset stay

where would each be used? - Answer- DIAGONAL STAY = made of flat materials similar to the boiler shell and is attached directly to the boiler shell and head or tube sheet


GUSSET STAY = made of boilerplate riveted to the shell and head or tube sheet by means of angle iron. MORE RIGID


both are used to brace right angle surfaces why are hand-holes and man-holes made oval instead of round?


what are the minimum sizes for man-hole and hand-hole openings? - Answer- so they can be inserted into and removed from their respective openings in the boiler


man-hole = 10x16 or 11x hand-hole = 2-3/4 x 3-1/ what is thermal efficiency?


what is considered a good percentage? - Answer- the ratio of heat absorbed by the water (TO) the heat provided by the fuel


a good percentage is 85%, some boilers made today can reach 95% how do you determine boiler capacity?


what is boiler heating surface? - Answer- BOILER CAPACITY = total heating surface

BOILER HEATING SURFACE = any area that has hot gases on one side - boiler water on the other. MEASURED FROM THE FIRE SIDE. what is furnace volume?


is furnace volume measured in square feet or cubic feet? - Answer- FURNACE VOLUME = the space available for complete combustion of the fuel before the products of combustion enter the heat absorbing sections of the boiler. varies with the type of fuel used


cubic feet what is superheated steam?


does its temperature rise? - Answer- SUPERHEATED STEAM = steam that has been heated to a higher temperature, but its pressure remains the same


YES define flash point


define ignition point

define pour point - Answer- FLASH POINT = the lowest temperature at which vapors of a substance will make a flash of flame but not continue to burn when exposed to open flame


IGNITION POINT = the lowest temperature at which vapors of a substance will ignite and burn continuously when exposed to open flame


POUR POINT = the lowest temperature at which liquid will flow define combustion - Answer- a CHEMICAL REACTION between oxygen and combustibles. it is the process of rapid OXIDATION by which the heat stored in fuel is released what is rate of combustion?


does air and fuel have any relationship in figuring the rate of combustion? - Answer- the rate at which the heat stored in fuel is released


YES, when oxygen and combustibles are mixed in definite proportion at an elevated temperature, given proper time, will combine completely define primary air


define secondary air

define excess air

is secondary air necessary in a boiler and why? - Answer- PRIMARY AIR = enters the furnace with the fuel and determines the rate of combustion


SECONDARY AIR = creates turbulence around the fuel to complete the burning process


EXCESS AIR = is more than what is theoretically needed for complete combustion

YES, secondary air is introduced above the fuel bed to burn combustible gasses what are the three "T's" of combustion? - Answer- 1) time

  1. temperature
  2. turbulence define PSI

define PSIG

define PSIA - Answer- POUNDS PER SQUARE INCH = pressure exerted on a surface

POUNDS PER SQUARE INCH GAUGE = pressure that is read on a gauge

POUNDS PER SQUARE INCH ABSOLUTE = gauge readings plus atmospheric pressure could too much secondary air have a bad effect on the efficiency of a boiler? - Answer- YES, excess secondary air will not enter into the reaction and will pass through the furnace wasting heat out the stack what percent of air is oxygen by volume?


what percent of air is oxygen by weight? - Answer- % of oxygen in air by volume is 21%

% of oxygen in air by weight is 23% define perfect combustion


define complete combustion

define incomplete combustion - Answer- PERFECT COMBUSTION - burning all the fuel using only the theoretical amount of air


COMPLETE COMBUSTION - burning all the fuel using more than the theoretical amount of air


INCOMPLETE COMBUSTION - when a portion of the fuel remains unburned because of insufficient amounts of air in a flue gas analysis, what do you consider a good percent of CO2? - Answer- good = 12% to 15% ideal = 20% (mostly unattainable) how is density of smoke measured?


how do you use a Ringlemann Chart? - Answer- With an opacimeter or Ringlemann chart.


  1. hold at arms length looking through the hole in the chart
  2. observers line of sight should be a right angle to the direction of smoke travel
  3. observer should be no less than 100ft or no more than 1/4 mile from the stack
  4. observer should not look toward bright sunlight
  5. the background immediately behind the top of the stack should be free of buildings or other dark objects
  1. compare the shade or density of the smoke seen through the hole to the corresponding shade on the chart what grades of smoke are allowed in the City of Omaha boiler operation? - Answer- no darker than grade 1 for more than 5 minutes/hour and no more than 3 times in a 24 hour period what are seven heat losses in a boiler? - Answer- 1) moisture in the air
  2. moisture in the fuel
  3. moisture formed in the burning of hydrogen
  4. incomplete combustion
  5. unburned carbon in the ash
  6. heat carried away in dry flue gasses
  7. radiation
  8. blowdowns what is the heat content of one pound of a good coal and of one pound of carbon? - Answer- Coal = 13,000-14,000 BTUs Carbon = 14,540 BTUs what is an Orsat Apparatus?

where is it used?

why is it used? - Answer- a flue gas analyzer detecting amounts of CO, CO2 and O2 in flue gasses


combustion gasses are sampled from the last pass or the breeching

to determine combustion efficiency and excess air what is a Fyrite analyzer?


where is it used?

why is it used? - Answer- a flue gas analyzer to determine the amounts of CO2 and O in flue gasses


combustion gasses are sampled from the last pass or the breeching

to determine combustion efficiency what is a pyrometer?


where would it be located on a boiler? - Answer- thermometer for measuring temperatures above the range of mercury

in the hot gas passages and in the refractory what are tuyeres (tweyars)? - Answer- air-admitting grates on stokers what is a waterback? - Answer- a water wall that is behind the grate on a stoker and its purpose is to cool the wall to prevent clinkers from sticking to the back wall define purging


name two types - Answer- purging = the forced removal of combustibles from the firebox.


  1. pre-purge = before the pilot is lit
  2. post-purge = after the combustion cycle what precautions are needed before a gas, oil or pulverized coal fire is lit? - Answer- purge all the combustibles before you light the pilot. (pilot must be on before the fuel starts) what are pulsations?

how would you correct this condition? - Answer- pulsations = when the flame leaves the burner tip and then returns. this may become so severe that the combustion consists of a series of small explosions.


how to correct: pulverized coal or oil furnace = the proper air-fuel mixture. gas furnace = increase the draft how do you pipe an oil supply line from the tank to the burner? - Answer- 1) oil flows from the storage tank through the suction strainer

  1. steam or electric driven pump
  2. relief valve
  3. steam or electric heater
  4. discharge strainer
  5. low oil pressure switch
  6. firing rate control valve
  7. low oil temperature switch
  8. safety shut off valve
  9. high oil pressure switch
  10. on to the burner or tank return (manual isolation valves and bypasses must be installed for all devices so the boiler stays on line during repair)

what are some of the difficulties you may encounter when operating an oil fired plant?

if you are firing #4 oil and lose oil pressure, what are the first two things you would look for?


when would you change a strainer? - Answer- difficulties may include:

  1. pump failure
  2. plugged strainer
  3. sludge
  4. low oil pressure
  5. low oil temperature
  6. oil too heavy to flow
  7. vapor in the pump
  8. air in the suction line
  9. improper venting of the tanks
  10. faulty atomization
  11. worn burner tip
  12. carbon formation on the burner tip

1st two things to look for:

  1. pump failure
  2. plugged strainers

you would valve over to a clean strainer if the delta-P was excessive name three types of nozzles used in oil burners.


explain where secondary air is admitted. - Answer- nozzles:

  1. rotary atomizing
  2. steam atomizing
  3. air atomizing
  4. pressure atomizing

secondary air is admitted around the tip. under what conditions must fuel oil be heated?


how is it heated?

how hot is it heated? - Answer- #4/5/6 oils need to be heated

steam and electricity can be used to heat oil

oil should not be heated to more than 10F below its flash point. (rule of thumb is) #4 - 135F #5 - 185*F

#6 - 220*F

what is a gun type burner?

name its parts - Answer- gun type burner = an assembly found on package boilers

parts:

  1. blower
  2. igniter
  3. transformer
  4. nozzles
  5. dampers
  6. PRV
  7. oil pump
  8. metering valve
  9. oil or gas solenoid
  10. fire eye you are operating on gas and the gas company calls and tells you to go to oil right away. your oil type is #6 and it's ice cold. what will you do and how will you heat the oil to operating temperature so you can fire the boiler? - Answer- 1) call your gas company and plead for more time
  11. call your boss to get help
  12. try to heat the lines with steam hoses or any way you can conceive
  13. maybe call your oil company to bring in a tanker with heated oil, etc...
  14. use your imagination (think outside the box)
  15. DON'T GET CAUGHT IN THIS SITUATION! draw a picture of low pressure gas piping to a burner - Answer- must include:
  16. main gas shut off
  17. valve
  18. a tee to the pilot w/shut-off valve and pilot solenoid
  19. manual reset valve
  20. gas pressure switch
  21. PRV with vent
  22. main gas solenoid
  23. mixing chamber
  24. blower pushing through the venturi
  25. into the burner the gas meter for your boiler malfunctions and you have to shut off all gas. how can you keep your boiler on line? - Answer- if you have an alternate fuel, hook up a propane bottle with a regulator to the pilot name 5 electrical devices used on a boiler - Answer- 1) oil pumps
  26. flame controls
  1. flow switch
  2. damper motor
  3. CCTV cameras what is natural draft?

what causes natural draft? - Answer- when the weight of the warm air in the stack is less than the cool air around the stack which causes an upward flow pulling air through the furnace


the heavier, cool air outside the stack gives a push to the warm lighter air in the stack causing air to flow through the furnace how is the flow of natural draft controlled? - Answer- by automatic electric or pneumatic controlled dampers that are mounted in the breeching and/or the burner does the diameter or height of a stack have an effect on the draft? - Answer- yes diameter = determines the volume height = determines the velocity how is draft measured?


what is a draft gauge used for?

how is it installed? - Answer- in inches of water with a manometer or "U" gauge

a draft gauge is used to measure the pressure difference of the boiler room and inside the setting or firebox


one tube end is connected into the breeching and the other end is open to the boiler room (or atmosphere). Pressure moves the liquid in the tube. the difference is read in tenths of an inch. when would you employ forced draft? - Answer- when you fail to have sufficient natural draft through the boiler what is mechanical draft?


name and describe 3 types - Answer- the adding of fans to make up for insufficient natural draft


  1. INDUCED DRAFT = a fan in the breeching between the boiler and the stack pulling air through the furnace. the boiler operates below atmospheric pressure
  2. FORCED DRAFT = a fan at the point of air entry pushing air through the furnace. the boiler operates above atmospheric pressure.
  1. BALANCED DRAFT = the addition of both forced and induced fans, and the boiler operates slightly below atmospheric pressure, about .05 to .10 inches water column. what is a pressurized furnace?

why is it not desirable on large boilers? - Answer- PRESSURIZED FURNACE = has a fan placed at the point of air entry to maintain the furnace above atmospheric pressure pushing the products of combustion through the furnace and out the stack.


flue gasses can leak into the operating areas and become a health hazard how do you control the dampers on a large fan from a remote location? - Answer- the control panel sends a signal to electric or pneumatic actuators that move the damper linkages if maintenance was done on your boiler, put back in operation, and the stack temperature was higher than normal, what would you look for as the cause? - Answer- water tube boiler = most likely defective or missing baffles fire tube boiler = could be missing turbulators or blocked tubes where are turbulators used and what is their purpose? - Answer- used in the tubes of a fire tube boiler to increase heat transfer to the tubes how often should you test the low water cutoffs and fully describe 3 ways of safely doing this. - Answer- 1) at least once a shift furiously blow down the water column and insure that the water returns rapidly and smoothly into the glass

  1. EVAPORATION METHOD = once a month done by securing the feed pump and allowing the water to evaporate from the boiler on low fire only. DO THIS WITH SUPERVISION AND REMAIN ALERT DURING THE TEST.
  2. SLOW DRAIN METHOD = once a month done by securing the feed pump and slowly blow down the boiler on low fire only. DO THIS WITH SUPERVISION AND REMAIN ALERT DURING THE TEST. how often should you blow down your sight glass?

what would you do if the glass broke while the boiler was operating? - Answer- the start of each shift


  1. put on safety equipment
  2. operate gauge glass shut-off valves
  3. use tri-cocks to check water level during the repair
  4. open blow-down for the gauge glass
  1. remove all the broken glass
  2. install the new glass with new washers
  3. very slowly, open the top shut-off to warm the glass
  4. close the blow-down
  5. slowly open the bottom shut-off what would cause a false level in the sight glass? - Answer- 1) sight glass closed
  6. sediment accumulation
  7. tilted boiler
  8. foaming because of over firing or high TDS
  9. improperly installed water column
  10. leaking top sight-glass washer if it were -35*F and you had no water showing in the boiler sight glass, your supervisor told you to keep firing, what would you do? - Answer- TURN IT OFF !!! under no circumstances can you fire an unsafe boiler! what is the smallest pipe allowed for a water column?

what style fittings are used to pipe a water column and why? - Answer- 1" made of brass, extra heavy iron or steel


crosses and tees for cleaning and inspection describe how to pipe a water column on an H.R.T. boiler - Answer- 1) the top of the column is connected to the top of the steam shell

  1. the bottom is connected to a point 6" below the center of the drum
  2. the bottom of the sight glass is 3" above the top row of tubes and at least 2" above the fusible plug
  3. the gauge glass must be 1/2" in diameter
  4. blow off not less than 3/4"
  5. crosses and tees are used instead of elbows for cleaning and inspection draw a safety water column complete with all devices - Answer- pic what appliances can be connected to a water column? - Answer- any device that does not consume steam
  6. alarms
  7. steam gauge
  8. pressure controls
  9. damper regulators
  10. feedwater regulator

How can you determine if a water gauge glass is properly set on a fire tube boiler? - Answer- by filling the boiler with water to normal operating level and measuring the depth of the water to the top row of tubes how high above the top row of tubes in an HRT boiler must the lower gauge cock be set to have a safe amount of water at this point? - Answer- at least 3" above the top row of tubes name 3 appliances that can warn you of low water - Answer- 1) water sight glass

  1. low water alarm
  2. fusible plug if your boiler has only one low water cutoff, what is the ASME code requirement? - Answer- it must be a manual reset. Side note: the City of Omaha requires one to be a manual reset even if you have 2 cutoffs. if there is repair work done on the boiler there must be a manual reset added. what is the purpose of a high fire limit control on a boiler?

what is a modulating control? - Answer- it proves that the forced fan damper has fully opened prior to starting the pre-purge period to insure adequate purge air flow.


it adjusts the firing rate of the burner to maintain the boiler steam pressure is an automatic shutoff allowed between the boiler and the water column? - Answer- NO, only between the water column and gauge glass what type valves are allowed between the boiler and the water column? - Answer- only O.S. and Y valves or stopcocks which are locked or sealed open. (outside screw & yolk) name 2 types of fusible plugs - Answer- 1) fire side

  1. water side refers to the side where they are installed what is a bourdon tube? - Answer- a curved tube with an oval cross-section. one end is attached to the frame and pressure connection. the other end is attached to a pointer by linkage and gears. an increase in pressure tends to straighten the tube; its motion is transmitted to the pointer. what is a siphon tube and what is it used for? - Answer- a siphon tube or pigtail loop protects the mechanism of a gauge from live steam. what pressure range should the steam gauge be when used on a boiler? - Answer- it should be a compound gauge at least 1 1/2 times the maximum allowable working pressure

where is the steam gauge connected to the boiler?

how do you properly mount a steam gauge to a boiler? - Answer- mounted on top of the water column or the the top of the steam drum.


gauge is mounted with:

  1. a siphon tube
  2. a isolation valve
  3. a test connection name 3 types of feedwater regulator systems - Answer- 1) On-off = float or probe
  4. Modulating = thermodynamic or thermohydrolic
  5. Metering = 2 or 3 element why is a boiler feed pump used on some boilers and not others? - Answer- you will not need a pump if the operating pressure of the boiler is below city water pressure what is the most important valve on a boiler? - Answer- SAFETY VALVE! what is a safety valve?

how does it operate? - Answer- a device to EXPEL ALL EXCESS steam pressure from a boiler


the huddling chamber causes the valve to open fully and quickly causing a definite drop in pressure before closing a safety valve is limited to how many square feet of heating surface? - Answer- any boiler with more than 500 square feet of heating surface must have 2 or more safety valves if a safety valve lifts at 100 psi, what pressure should it close?


what are the requirements governing safety valve blow down? - Answer- 96 to 98 psi

safety valves shall operate without chattering with a blow down of not more than 4% of the set pressure and in no case less than 2 lbs. (100x4%=4 so 100-4=96) how do you determine if a boiler has sufficient safety valve capacity? - Answer- accumulation test = determines if the valves will discharge all the steam generated by the boiler without allowing the pressure to rise more than 6% above where the valve is set and in no case by more than 6% above the maximum allowable working pressure of the boiler

how must a safety valve be connected to the boiler? (pic thumb and fingers) - Answer-

  1. independent of any other steam connection
  2. close as possible without any unnecessary piping
  3. screwed into the boiler shell or fastened to a flange welded to the shell
  4. connected to stand upright
  5. vents must be fastened to the building and not connected to the valve!!! at what temperature does a safety valve on a superheater have to be protected with heat resisting materials? - Answer- 450*F how do you regulate the blow down of a safety valve? - Answer- the blow down is adjusted by adjusting the blowback ring, the spring or both (about 10%). ONLY TRAINED AND LICENSED PERSONNEL SHOULD ADJUST SAFETY VALVES! how often is it recommended to test your safety valves manually and how often under pressure? - Answer- manually = every 30 days under pressure = annually how is a super heater protected? - Answer- each superheater must have one or more safety valves near their outlet with the pressure set below those on the boiler insuring a constant flow of steam through the superheater a boiler designed to operate at 125 psi is now operating at 15 psi, what changes will be made to the safety valve? - Answer- if change is permanent, install a safety valve with:
  6. a larger disk
  7. lower pressure rating on an Ashton type safety valve, a screw adjustment is labeled O and S. what do these letters stand for?

what adjustments can you make? - Answer- Open & Shut

I'm not certified to make adjustments what is a surface blow-off?


where is it employed?

why is it used? - Answer- removal of oil and contaminants from the surface of boiler water


the take-off is located in the top 3-4" of boiler water.

It controls the total dissolved solids (TDS) what is a continuous blow down system?

where is it installed? - Answer- based on water analysis the surface blow down is metered for a continuous flow.


the take-off is located just below the normal operating water level (NOWL) in the steam and water drum how should a continuous blow-down be piped as it leaves the boiler and why? - Answer- piped through:

  1. a heat exchanger or flash tank
  2. to the blow-down tank

to recover heat when is the best time to blow down a boiler?


how long do you bottom blow the boiler?

what important safety procedure is observed when using a bottom blow down? - Answer- during light loads because more of the sludge has settled to the bottom.


about 10 seconds, depending on boiler type and size.

do not take your hand off valve once opened until you have closed it! where is the bottom blow down pipe connected to an HRT boiler?


what type valves are used on the bottom blow down?

what order are they placed and how should you blow down a boiler using those valves?

what size piping is used in the blow down line? - Answer- rear of the boiler drum, on underside of the shell.


2 slow opening or 1 quick & 1 slow opening valves

the quick opening valve is installed next to the boiler and opened first/closed last.

the piping must be at least 1" and not greater than 2 1/2" in diameter. 3/4" is allowed on boilers of less than 100 sq ft heating surface what is a slow opening valve? - Answer- a screw type valve that requires at least 5 full turns from closed to open position what is a plug valve?


why is it used on blow down lines? - Answer- a circular, tapered plug ground down to fit into the valve body. when open - a hole through the plug aligns with the hole in the valve body. when closed - the holes are out of line.


its shearing action cuts through scale and it will not fail open how is a blow down tank piped?


how does it work?

why isn't any blow down connected directly to the sewer? - Answer- 1) blow down enters the tank above the water line and maintained in the tank against a splash guard.

  1. vent in the top of the tank to prevent back pressure
  2. vent in tank discharge line to prevent siphoning
  3. drain valve and manhole in tank for cleaning

the discharge line is opposite the inlet, resulting in the cooler water being discharged first.


flash steam and hot water directly into the sewer:

  1. might injure someone
  2. will damage the sewer what is a non-return valve?

where is it located?

why does it have a drain? - Answer- automatic stop check valve to prevent a back-flow of steam when the boiler pressure falls below that of the header


as close to the boiler as possible and between the boiler and the header valve.

to remove condensate make a drawing of 3 boilers in battery showing the steam header, valves and piping - Answer- (pic) 3 boilers 3 non-return valves w/condensate drain valves 3 header valves w/condensate drain valves steam header isolation valve/strainer/isolation valve what is a soot blower?


how does it work?

name 2 types - Answer- a device using jets of steam, compressed air or both to remove the ash and slag from the fire side of the tubes.


a revolving blow-arm equipped with properly spaced nozzles that is operated by a chain and wheel while the boiler is in service.


  1. manual
  2. automatic how do you operate a manual soot-blower?

what happens if the condensate isn't drained from the soot-blower steam supply prior to using the soot-blower? - Answer- 1) always with the boiler on high fire.

  1. slowly open the main steam supply until the piping is hot.
  2. close drains and start a slow rotation of the hand-wheel, which opens the steam to the soot-blower.
  3. rotate the element 360* without stopping and make sure the steam to the soot-blower stops.
  4. close the steam supply and open the drain valve.

  1. condensate in the steam supply will warp and break the elements
  2. when discharged into fire box, it will form sulfuric acid
  3. it will pack soot onto the tubes
  4. it will cut into the tubes. how can you tell if the soot blowing had any effect on the boiler? - Answer- decrease in stack draft & temperature describe a glove valve and where is it used most often?

how do you pipe a globe valve?

name 6 places for a bypass - Answer- it consists of a plug or disk that is forced into a tapered hole called a seat. it can be plugged or damaged easily and has more resistance to flow, therefore it is not used as a steam stop valve.


it is used most for throttling such as in a bypass, so the supply comes in under the disk

common around:

  1. strainers
  2. pumps
  3. PRV's
  4. traps
  5. header valves
  6. check valves
  7. control valves

describe a gate valve

where it is used most often? - Answer- a valve with a wedge shaped gate which is raised or lowered into a passageway. the wedge-shape tightens against the sides of the slot when closed. it offers little resistance to flow when fully open and should not be used to throttle.


for isolating devices for repair or to shut off the flow to the boiler what are rising stem valves?


what are non-rising stem valves? - Answer- rising = has a stem that rises as the valve opens


non-rising = has a stem that stays stationary explain the letters SWP and WOG found on the side of a valve? - Answer- SWP = maximum Steam Working Pressure rating WOG = maximum Water, Oil or Gas pressure the valve may be used for (ie. 140 SWP & 40 WOG) describe a balanced (double seated) feed water valve?


why is it used? - Answer- a valve with two disks and two seats. one disk opens with the pressure and one against


with forces balanced, it opens easily what is a pressure-reducing valve (PRV)?


where is it used? - Answer- PRV automatically reduces high pressure and maintains a lower delivery pressure


used for:

  1. heating systems
  2. cookers
  3. city water makeup
  4. control air, gas or oil to a boiler what is a check valve? - Answer- valve that allows flow in only one direction name the valves found on a boiler - Answer- 1) safety valve
  5. water level control valve
  6. drain valve