Mn Exam Prep Questions Flashcards
Which formula is used to determine the efficiency of the boiler based on heat absorption?
Output divided by the input
How many ways can heat be transferred?
3
How many types of heat are there?
3
How many different types of drafts are there ?
3
How many different types of boilers are there?
3
How many different types of low water fuel cut offs are in general use?
3
True or False?
A (RPZ) “reduced pressure zone” or back flow preventer prevents contaminated water from entering the domestic water supply.
True
Boiler and boiler fittings used in the state of Minnesota must be constructed to what code?
A.S.M.E.
What is the unit called that controls the starting and stopping of the burner by sensing the temperature of the water in a hot water boiler?
Aqua stat
Heat can be transferred in 3 ways and they are?
Conduction , Radiation , Convection
The first sequence in the series of automatic burner control is?
Purging
Air that mixed with the fuel at / or in the burner is called?
Primary air
Can a low water condition occur in a hot water heating type boiler?
Yes, for numerous reasons
Other than a safety relief valve… What other safety device should be installed on a hot water heating boiler ?
Low water fuel cutoff
What is the internal resistance to the flow of fuel oil?
Viscosity
Each boiler in a battery (piped together sharing the same common header)must have:
A main steam stop
What removes air from a hot water boiler system?
Air control
When a hydrostatic test of a boiler exceeds the maximum allowable working pressure, each safety valve ( if left attached to the boiler) should:
Have its valve disc held to its seat by means of testing clamp or “gag”
Why is a safety valve sealed?
To prevent tampering with pressure and capacity
Oxygen in a boilers water can cause?
Corrosion
In a steam boiler system the unit that turns the burner on and off based on steam pressure is the?
Pressure control
If water in the gauge glass is not visible because of failure of feed water supply, what should be done?
Shut off the fuel to the burner and secure the boiler.
What two scales does a pressure control have?
Cut in pressure and differential pressure.
What is the minimum size bottom blowdown line used on a miniature boiler?
1/2”
What is the minimum size drain required on a water column?
3/4”
What conditions are necessary to cause a furnace explosion?
Accumulation of unburned fuel,oxygen and an ignition source.
Low water cut out should be tested:
Daily
Can high pressure safety valve be used on the same boiler for low pressure?
Cannot be used
Gauge pressure + 14.7 psi is called what?
Absolute pressure
The unit that shuts off the burner in the event of low water is?
Low water fuel cut out
The evaporation of 34.5 pounds of water per hour from and at a temperature of 212*F is defined as:
One boiler horsepower
When a safety valve opens and closes rapidly it is referred to as:
Chattering
Furnace explosions are caused by a buildup of combustible gases/ vapors in the combustion chamber. What is the term used to remedy this condition?
Purging
In order for a fuel to burn it must be heated to:
It’s ignition temperature
Why is a pigtail or siphon required in steam pressure gauge lines?
To protect the gauge from a high temperature.
In a steam boiler system, what is the term used for replacing the water that has been lost by blowing down the boiler or through leaks in the system?
Make up water
Heating surface is defined as:
Water on one side / hot gas on the other side.
If a steam trap on a radiator (steam heating system)becomes water logged, what will happen?
The radiator will not heat the room properly.
What chemical is used as an oxygen scavenger?
Sodium sulfite
In a fire tube boiler, the water:
Surrounds the tubes.
When two bottom blowdown valves are used on a steam boiler, What valve is located closest to the boiler shell?
The quick opening valve.
Purpose of a safety valve on a steam boiler is to:
Prevent the pressure in a steam boiler from exceeding its maximum allowable working pressure.
The control designed as a safety backup (should the pressure control fail) is?
The high limit control.
The capacity of a safety valve used on a steam boiler is measured in:
Pounds of steam that can be discharged in 1 hour.
How does a pressure control attached to the steam space of a boiler control the burner operation?
Burner starts on pressure decreased stop on pressure increase.
When could stop valves be eliminated for a single hot water heating boiler?
When the boiler is located above the system.
In some heating systems the circulation pump is controlled by the?
Thermostat
What action should an operating engineer take if a defect is discovered in a boiler requiring repairs not of a routine nature?
Notify the boiler inspector.
Boilers are considered low pressure when:
Steam boilers are not over 15psi and liquid boilers are not over 160 psi and 250*F.
What boiler license is required to operate a boiler as a shift engineer in a plant having three boilers (each having 1660 sq ft of heating surface)?
Second class
A boiler weighs 1000lbs. empty. Filling the boiler with water to its normal operating level requires 500 gal. What is the total weight of the boiler and water?
5165lbs.
8.34lbs. * boiler operating gal. + weight of boiler = total weight
What type of valve is permitted to shut off a steam gauge?
A tee or lever handle valve.
What is a draft gauge?
Manometer.
When adding water to a hot water heating system, if the pointer on the pressure gauge rises quickly it is an indication of:
A water logged expansion tank.
The maximum temperature to be carried on a low pressure hot water boiler is:
Less than 250*F.
The popping pressure of a safety relief valve on a low pressure hot water heating boiler cannot exceed:
160 psi
The bottom blowdown line on a steam boiler system is located at the:
Lowest point of the waterside on a steam boiler.
How can you tell the maximum allowable working on any boiler?
Look at the settings of the safety valve or safety relief valve.
For the purpose of rating boiler horsepower (for engineer license classification only) how many sq. Ft of heating surface shall be considered equivalent to one boiler horsepower for conventional boilers?
10 sq. Ft
In a hot water boiler system, what valve is installed to reduce incoming city water pressure to the hot water boiler operating pressure?
Pressure reducing valve.
What device could be found in a hot water boiler heating system?
Safety relief valve, temperature pressure gauge, Aqua stat, expansion/compression tank.
If you fail a state of Minnesota boiler operators license exam… How long must you wait before you can retake the exam?
30 days.
What is a boiler called that furnishes hot to be used externally to itself?
A hot water supply boiler
What is the maximum size safety valve that may be installed on a low pressure boiler?
4 1/2 “
What does a flue gas analyzer measure?
The percentages of carbon monoxide, carbon dioxide, and oxygen.
What is recommended for boilers that will be out of service for a long time and have the possibility of freezing?
A dry lay up.
In a hot water heating system, what would prevent the hot water from circulating through a room heating unit?
Trapped air.
True or False
Draft is the difference in pressure between two points that cause air.
True.
What is used to ensure that all of the fuel is properly burned (to attain a better efficiency in heat release)?
Excess air.
If a deposit of carbon appears on the rear wall of the combustion chamber (of the mechanical pressure type oil burner) a good procedure is to:
Try a wider angle nozzle.
The rapid burning of fuel and oxygen that results in the release of heat is called:
Combustion.
A slow opening valve used as a bottom blowdown valve requires how many complete 360 degree turns to open?
5 turns
In a steam boiler system, a possible water hammer is caused by:
Carryover.
When applying a hydrostatic test on a boiler, the water temperature should be:
70*F
The valve that is installed when it is desirable to control the rate at which water flows is called a:
Globe valve.
If a condensate pump becomes steam bound and stops delivering water what could be done?
Increase head pressure.
On a steam boiler, what is the unit called that is used to reduce the amount of movement of water, so the boiler operator can get an accurate reading of the water level in the gauge glass?
Water column.
After repair work is done on the boiler, a test is used to check for leaks:
Hydrostatic test.
The dial on the pressure gauge used on a low pressure boiler should be graduated:
One and one half to two times the maximum allowable working pressure
The three basic types of low pressure boilers are:
Fire tube, water tube, and cast iron sectional.
If idle boilers are left filled with water, what precautions should be taken to prevent corrosion and oxygen pitting?
Keep the boiler water properly treated (chemically)
The term used for the evaporative capacity output of a steam boiler is expressed in:
Pounds per hour.
The term used when small particles of water are carried over into the steam lines is called:
Priming.
What boilers license is required to be in charge of a boiler plant having two boilers (each having 2500 sq. ft. of heating surface)?
1st Class
For each eng. lic. Fill in the blanks, indicating how large of a boiler they can be in charge of: Special eng. 1st class 2nd class Chief engineer
Special engineer 50 horsepower, 2nd class 100 horsepower, 1st class 500 horsepower, Chief engineer unlimited horsepower.
When testing the low water fuel cutoff, why should the burner be firing?
To see if the burner shuts off.
How often should safety valves be tested on a low pressure boiler?
Monthly.
What is the term used when a safety valve pops open, when the pressure exceeds the maximum allowable working pressure, stays open until a sufficient amount of steam is released, and when there is a definite drop in pressure inside the boiler?
Blowdown blowback.
What is the minimum size pipe that is used to connect the water column to the boiler?
1”
The most important safety devices on a steam or liquid boiler is what?
The safety or safety relief valve.
Where is the breaching located at for a steam or hot water boiler?
Between the boiler and the chimney.
What boiler license is required for operating boilers as a shift engineer in a plant having three boilers with heating surfaces of 1500 sq ft, 1500 sq ft, 2000 sq ft?
2nd Class
What three things are required to support combustion?
Fuel, heat, and oxygen.
What can result if condensate is picked up with the steam as it travels through the main stream branch lines?
Water hammer.
What are used to direct the flow of gases through out the boiler?
Baffles.
