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106 Cards in this Set
- Front
- Back
primary air |
control of combustion rate which determines the amount of fuel burned |
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scale is formed on heating services at approximately what temperature
|
150 degrees |
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blow downs should be done for how long
|
5 to 10 seconds. |
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a continuous blowdown is what? |
discharges water at a controlled rate to insure proper chemical concentration in the boiler water |
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pop test |
determines if the safety valve opens at the proper pressure |
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blow back |
a drop in pressure after the safety valve has been released |
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M.A.T.T |
m-mixture of air and fuel a- atomization of fuel t-temperature t- time to complete combustion |
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siphon |
a bent tube between the boiler and boiler fitting to prevent contact with steam |
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boiler horsepower |
evaporation into steam at 34.5 lbs with a water temp at 212 degrees F |
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one boiler horsepower is equivalent to what |
33,472 btu/hr |
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where must the water column be located |
lowest visible part of the gauge glass 2-3 inches above the highest heating surface located at the NOWL |
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safety valve should be trylever tested how often |
every 30 days |
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perfect combustion |
fuel is burned using only the theoretical amount of air |
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secondary air |
controls combustion efficiency and how completely fuel is burned |
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hydrostatic air |
weight of water per vertical foot |
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what is purging |
the process of using air to discharge residual fuel oil in the boiler nozzle |
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atmospheric pressure |
14.7 PSI |
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total force |
the total amount of force acting against the safety valve disc |
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low pressure boiler limist |
steam boilers not to exceed 15psi and hot water boilers not to exceed 160psi and 250 degrees near the boiler outlet |
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safety valve capacity |
the amount of steam per hour that the safety valve is capable of venting |
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latent heat |
identified by a change in state but no change in temperature |
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the area on a safety valve that increases surface area and total force applied |
huddling chamber |
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bottom blowdown line is what |
piping located at the lowest point of the water side of a boiler |
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bottom blowdown valve is located where |
on the blowdown line |
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compression tank |
absorbs water pressure in the hot water boiler system |
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firebox boiler |
firetube boiler that has a roundtop and flat sides |
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first law of thermodynamics |
energy cannot be created or destroyed but can be changed from one form to another |
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second law of thermodynamics |
heat always flows from a material with a high temperature to a material with a low temperature |
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float thermostatic steam trap is what |
it has a ball float that opens and closes a discharge valve depending on amount of condensate in the chamber |
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forced draft |
mechanical draft from air PUSHED through the boiler with fans located in the front of the furnace |
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high limit control |
a pressure control that senses steam pressure and automatically shuts down the burner if the operating limit control fails |
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induced draft |
a mechanical draft from air PULLED through the boiler furnace with fans located in the breeching |
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outside stem and yoke valve (OS and Y valve) |
a gate valve that indicates if its open depending on the position of the stem |
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pressure control |
a switch that starts the burner, controls the firing rate or shuts down the burner based on steam pressure |
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priming |
large slugs of water are carried into the steam line |
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radiation |
heat transfer that occurs as radiant energy with out a material carrier |
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return steam trap |
removes condensate from steam lines and heating units and discharges it directly into the boiler |
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surface blowdown valve is what/where |
on the surface blowdown line and is used to release water and surface impurities from the boiler |
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thermodynamic steam trap is what |
a single movable disc that raises to allow the discharge of air and cool condensate |
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try cocks |
is a valve located on the water column used to determine the boiler water if the gauge glass is broken |
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all steam boilers operate using what systems |
feed water, fuel, draft, and steam system |
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a vacuum gauge is what
|
indicates the amount of vacuum (pressure below atmospheric pressure) in the boiler
|
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quick opening valve |
is a lever-operated valve that functions as a sealing valve and is always opened first and closed last |
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a slow-opening valve |
is used as the blowing valve and takes all the wear during blowdowns |
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can a safety valve be used to vent a boiler? |
NEVER |
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how often should a fusible plug be replaced? |
annually |
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the ASME code only requires fusible plugs on what kind of boiler? |
coal burning boilers. But they can still be used on gas/oil boilers |
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what is a fusible plug? |
a warning devise used to indicate extreme over heating. |
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what is an operating control? |
It initiates the burner start up sequence and shut down sequence. |
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what is a high limit control? |
it senses steam pressure and automatically shuts down the burner if the operating limit control fails. |
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what is the function on a modulating control? |
Controls the firing rate of the burner. |
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check valve |
allows water to flow in one direction. |
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what is the function of a condensate return tank? |
it is a boiler accessory that collects condensate returned from the boiler. |
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how often should a automatic makeup water feeder be blown down? |
at least once a week |
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what is a strainer? |
it protects the automatic makeup water feeder from scale or lime deposits from city water |
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how many low water fuel cutoffs must there be? |
at least one |
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a thermostatic steam trap is what?
|
a steam trap that has a bellows filled with fluid that boils at steam temperature
|
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float thermostatic steam trap
|
a ball float that opens and closes a discharge valve depending on the amount of condensate in the chamber.
|
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inverted bucket steam trap |
steam enters the bottom and flows into an inverted bucket. |
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thermodynamic steam trap |
a single movable disc that raises to allow the discharge of air and cool condensate |
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natural gas |
colourless and odorless fossil fuel that consist primarily of methane, small amounts of ethylene and other gases |
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combustion controls what |
fuel supply, air supply, air to fuel ratio, and removal of gases of combustion |
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an on/off control system controls what? |
the amount of steam produced by starting and stopping the burner. |
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an on/off control system is commonly used on what? |
small package boilers and where the steam load allows the burner to start and stop as required |
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a flame safeguard monitors what |
burner start-up sequence and the main flame and controls the firing rate during normal operation |
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a flame safeguard programmer sequences burner function for what |
pre-purge, ignition trials, run period, and post-purge |
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a draft system is what |
a boiler system that regulates the flow of air to and from the burner |
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what is the cause of foaming |
formation of steam bubbles trapped below a film on the boiler water surface |
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boiler water pH must be between what |
7 and 10 |
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surge tank |
collects condensate before sending it to the deaerator |
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bypass feeder |
introduces feedwater treatment chemicals into a boiler at a predetermined and controlled rate |
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what is the FIRST thing that should be checked when entering a boiler room |
check the boiler water level |
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when blowing down a gauge glass what should happen |
water should enter the gauge glass quickly indicating that the lines are free of sludge, sediment, or scale build up |
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what is the function of try cocks on a water column? |
second method to check water level. |
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what is the purpose of a feedwater pump? |
boiler accessory to pump feed water to the boiler |
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how does a pressure control function to control the burner? |
a switch that shuts ON/OFF the burner based on steam pressure. |
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what is the purpose of a safety valve? |
prevent the boiler from going over the MAWP( maximum allowable working pressure) |
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how often should a safety valve be tested? |
every 30 days |
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what is a low water fuel cutoff on a boiler |
shuts off the boiler if it is low on water |
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what are two reasons for a bottom blowdown? |
1. remove sludge and 2. chemical concentration control |
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how does a safety valve operate to prevent the boiler from exceeding its MAWP |
opens until enough steam is released and there is a drop in pressure |
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how often should a low water fuel cutoff be tested? |
Daily |
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what is an aquastat |
a fitting that senses water temp in the boiler by starting and stopping the burner |
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what is a compression tank |
it absorbs water pressure |
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high and low fire of the burner is controlled by what |
aquastat |
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a fan located between the breeching and stack is what |
induced draft fan |
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a main steam stop valve would most likely be a |
os and y gate valve |
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complete combustion is what |
burning all the fuel with the theoretical amount of air |
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oxygen in the boiler causes what |
pitting |
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foaming of boiler water from floating foreign matter causes an increase in what? |
surface tension |
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a water column must be located where |
at the normal operating water level |
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a feed whater pump can become steambound from what |
feedwater temp too hot |
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the boiler vent is opened when |
warming the boiler and draining the boiler |
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the number of blowdowns required is determined by what |
feedwater analysis |
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annunciator |
an audible electronic alarm that alerts the boiler operator of a condition that needs immediate attention |
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back flow preventer |
a boiler accessory that prevents the flow of boiler water back to the city water |
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boiler cross tee |
a pope fitting with removable plugs that allow for cleaning inspection of piping |
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breeching |
a duct used for the transport of gases of combustion from the boiler to the stack |
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carryover |
a condition that occurs when small particles of boiler water are carried into the steam lines |
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compound gauge |
a pressure gauge that indicates vacuum in inches of mercury or pressure in PSI on the same gauge |
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conduction |
heat transfer that occurs when molecules in a material are heated and the heat is passed from molecule to molecule through the material |
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convection |
heat transfer that occurs when currents between warm and cool regions of a fluid |
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makeup water |
water added to the boiler to replace lost water from steam leaks, blowdown, and/or other losses in the system |
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package boiler |
a boiler that is preassembled at the factory |
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steam pressure gauge |
a boiler fitting that displays the amount of pressure in PSI inside the boiler |
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surge tank |
a water treatment accessory that is used to collect condensate before sending it to the deaerator |