Download NORA Bronze Exam Study Guide: Questions and Solutions and more Exams Mechanical Engineering in PDF only on Docsity!
NORA BRONZE STUDY GUIDE
QUESTIONS WITH COMPLETE
SOLUTIONS
“How many BTU's does one gallon of #2 fuel contain? - CORRECT
ANSWER 139,000"
"When the viscosity of fuel entering the nozzle increases the_____________
increases: - CORRECT ANSWER The flow rate also increases"
"Dirt or lint build up on fan blades or air inlet will: - CORRECT ANSWER
Reduce the amount of combustion air"
"High static pressure produced by oil burners: - CORRECT ANSWER
Allow manufacturers to create tighter heat exchangers for increasedefficiency"
"High static pressure burners have been developed to: - CORRECT
ANSWER to push the products of combustion through the heat exchanger
of high efficiency appliances" "How far from any open flame or fuel burning appliance must an oil tank be
installed? - CORRECT ANSWER 5'"
"Can cast iron fittings be used on oil tank piping? - CORRECT ANSWER
No"
"When nozzles are dirty or plugged, they should be: - CORRECT
ANSWER Replaced"
"Nozzles are normally cooled by: - CORRECT ANSWER The air & fuel
travelling past or through them" "The burner air tube should be installed ________________ back fromthe inside
wall of the combustion chamber. - CORRECT ANSWER ¼""
"Nozzle after drip can be caused by: - CORRECT ANSWER Bad pump
shutoff (PRV), air in nozzle line"
"Fuel must burn completely in suspension without touching what? -
CORRECT ANSWER The crown sheet, chamber floor or walls"
"True or false, ideally combustion chambers should be designed to both heat
up and cool off quickly: - CORRECT ANSWER True"
"If a chamber is too small, or the nozzle is too close to the chamber floor there
will be: - CORRECT ANSWER Impingement"
"With no insulating material between the heat exchanger and the hot flue
gasses, heat transfer to the water is - CORRECT ANSWER Better"
"Combustion tests give us the "steady state" efficiency of the unit. We test: -
CORRECT ANSWER The composition of the gasses (excess air), smoke
concentration,temperature of the gasses, draft through the unit" "True or False, the more efficient the appliance the higher the
stacktemperature will be: - CORRECT ANSWER False"
"What is "steady state"? - CORRECT ANSWER At steady state there are
no changes in the combustion gases. The unit has thoroughly warmed-up and will maintain constant conditions as long as the burner runs."
"Proper location of the hole in the flue pipe for combustion testing is: -
CORRECT ANSWER In the flue pipe near the appliance outlet (the
breech)."
"How many strokes are necessary when performing a smoke test? -
CORRECT ANSWER 10 full strokes"
"An electrical load is a device which converts electrical energy into: -
CORRECT ANSWER Another form of energy to perform "work""
"Step-down transformers have more: - CORRECT ANSWER Primary
coils than secondary coils and reduce voltage"
"Interrupted Ignition is: - CORRECT ANSWER Spark remains on for a
short time at the beginning of each cycle, then isturned off once flame is established" "When the light intensity on the cad cell increases (gets brighter) the
resistance (OHMS): - CORRECT ANSWER decreases"
"Before pressing the reset on a primary control: - CORRECT ANSWER
Check for oil in the chamber"
"What is Pre purge (Valve delay on) on a primary control: - CORRECT
ANSWER It lets the burner get up to speed and deliver full combustion air
before introducing oil, cleaner starts"
"What is Post purge (Valve delay off) on a primary control: - CORRECT
ANSWER It allows all combustion gasses and excess heat to dissipate,
cleaner shutdowns"
"Odor, soot, smoke, puff-back. What could cause it? - CORRECT
ANSWER Ignition issue, plugged chimney base, whole house fan."
"The best burner adjustment is one that allows for a smokeless operation with
a minimum of excess air, typically: - CORRECT ANSWER 25% - 35%"
how many btus does one gallon of #2 fuel contain? - CORRECT ANSWER
139,000 BTU's"
"pour point - CORRECT ANSWER lowest temp fuel will flow"
"cloud point - CORRECT ANSWER The temperature at which wax
crystals first start to form"
"fire point - CORRECT ANSWER The lowest temperature fuel will ignite
at"
"using additives can? - CORRECT ANSWER lower pour point and cloud
point"
"flash point - CORRECT ANSWER lowest temp a fuel can be safely
stored/handled"
"sulfur exists in? - CORRECT ANSWER varying degrees in all fossil
fuels"
"why is heating oil red? - CORRECT ANSWER to differentiate fuels (tax
reasons)"
"what is bioheat a blend of? - CORRECT ANSWER #2 fuel and B
biodiesel"
"pulsating fuel pressure can be caused by? - CORRECT ANSWER partial
clog, air, slipping coupling, or high vacuum" "(for vacuum) if the gauge reading is significantly above the calculated
reading it could be? - CORRECT ANSWER plugged filter/line, kink in
line." "NORA recommends that fuel lines that have blockages be cleared with what?
- CORRECT ANSWER hand pump to pull it out" "If the gauge reading is significantly below the calculated reading it could be? - CORRECT ANSWER Air leak in suction line, air leak on strainer gasket."
"How do you calculate the approximate operating vacuum of a fuel unit? -
CORRECT ANSWER 1" Hg filter, 1" Hg 10' of horizontal and 1" Hg 1'
vertical"
"why is 1 pipe preferred over 2 pipe systems? - CORRECT ANSWER
extended filter life, return line leak" "what is recommended by NORA whenever fuel tank is higher than the fuel
unit? - CORRECT ANSWER oil safety valve"
"T or F, fuel unit rotation is opposite of burner motor rotation - CORRECT
ANSWER True"
"T or F, the more efficient the appliance the higher the stack temp will be. -
CORRECT ANSWER false"
"what is "steady state"? - CORRECT ANSWER no changes in
combustion gases, unit warmed, maintain constant conditions while burner is on"
"proper location of the hole in the flue pip for combustion testing is? -
CORRECT ANSWER 1 flue pipe diameter away from damper, 2
diameters from breach or elbow"
"how many strokes are necessary when preforming a smoke test? -
CORRECT ANSWER 10"
"before using electronic analyzer, you must? - CORRECT ANSWER
Perform a smoke test."
"it's important to set smoke to trace or zero because? - CORRECT
ANSWER over air or to much smoke leads to soot"
"when a new appliance is installed, manufacturing residue often causes
temporarily elevated ___ levels. - CORRECT ANSWER CO/ Carbon
monoxide"
"electrical force or potential is measured in? - CORRECT ANSWER
Volts"
"a voltmeter measures? - CORRECT ANSWER potential difference"
"a series circuit has how many paths? - CORRECT ANSWER 1"
"a parallel circuit has how many paths? - CORRECT ANSWER multiple"
"step down transformers have more ___ - CORRECT ANSWER primary
coils"
"step up transformers have more - CORRECT ANSWER secondary coils"
"In residential systems, high limit controls are? - CORRECT ANSWER
line voltage - are activated by temp or pressure, wired in series with primary control"
"the fan and limit control on a warm air system is used - CORRECT
ANSWER To turn the burner and the blower on/off at set temperatures."
"Average warm air limit settings? - CORRECT ANSWER 200°F high
Limit, 140°F Fan = On, 110°F Fan = Off" "What commonly causes a burner on a warm air system to go off on high limit?
- CORRECT ANSWER clogged filter, broken blower belt, fan motor"
"High limit aquastats prevent? - CORRECT ANSWER Boiler water
temperature rising to unsafe levels."
"Low limit (operating) aquastats prevent? - CORRECT ANSWER boiler
water dropping below set point"
"switching relays allow control of? - CORRECT ANSWER line voltage
with a low voltage control (like a thermostat)."
"when mounting a tstat it should be? - CORRECT ANSWER on a inside
wall, 5ft up, away from heat emitters, no windows or outside doors"
"the end switch on a zone valve is commonly wired to? - CORRECT
ANSWER T-T on the boiler controls"
"primary controls have three basic functions: - CORRECT ANSWER
responds to tstat, limits, controls running and stopping the burner"
"primary control accomplishes its functions by - CORRECT ANSWER
reacting to flame, managing start up and shutdown"
"Intermittent ignition is - CORRECT ANSWER igniter on entire run
cycle"
"Interrupted Ignition is? - CORRECT ANSWER igniter on set time"
"why is intermittent ignition considered to be worse? - CORRECT
ANSWER reduces life of electrodes and transformer, nox higher,
combustion problems maybe hidden"
"can you repair cracked ceramic insulators on electrodes? - CORRECT
ANSWER No"
"what is the purpose of a circulator? - CORRECT ANSWER creates
pressure difference to move more water"
"12 PSI "pushes" water how high? - CORRECT ANSWER 28ft approx, 1
PSI = 2.31 ft of water"
"a single pipe that goes from the boiler outlet through each piece of ___ -
CORRECT ANSWER Heat distribution unit (base boards, etc)"
"what makes a one pipe system different from a series loop system? -
CORRECT ANSWER series loop: less heat at end of HDU
one pipe: special tee configuration each Heat distribution unit sees approximately same temperature"
"residential hot water boiler relief valves are set to open at? - CORRECT
ANSWER 30 psi"
"No residential steam heating system should operate at more than? -
CORRECT ANSWER 2 psi"
"the LWCO on a steam system shuts down the burner when? - CORRECT
ANSWER water drops to unsafe level"
"On steam boilers the relief valve is set to open at? - CORRECT ANSWER
15 psi"
"all water heaters with storage capacity must have a? - CORRECT
ANSWER Temperature and pressure relief valve"
"how do you ensure the system is operating efficiently and reliably during a
preventative maintenance call? - CORRECT ANSWER Combustion test"
"what controls should be tested during a preventative maintenance call? -
CORRECT ANSWER all limit controls, primary control"
"NORA recommends that during a preventative maintenance call the oil tank
be checked for? - CORRECT ANSWER water and leaks"
"how should you approach a service call? - CORRECT ANSWER
systematically"
"Reset Pressed -Nothing Happens. What should be checked? - CORRECT
ANSWER Voltage, Cadcell (flame light) (dark: over 20,000 ohms) (light:
1,600 ohms)"
"on a no heat call: you press the reset and the burner runs. what do you do? -
CORRECT ANSWER Begin your testing routine, determine why it went
off, make all necessary repairs to correct the problem and to keep it from re- occurring."
"Odor, soot, smoke, puff-back. What could cause it? - CORRECT
ANSWER Ignition issues, chimney issues"
"temperature rise in a furnace is: - CORRECT ANSWER difference in
temp between the supply air and the return air"
"Using ultra low sulfur diesel (ULSD) all but eliminates: - CORRECT
ANSWER soot and scale formation"
"Codes require that oil-heat systems shall be wired: - CORRECT
ANSWER in dedicated circuits"
"Flash point is: - CORRECT ANSWER The maximum temp a fuel can be
safely stored & handled without serious fire hazard"
"Fire point is: - CORRECT ANSWER Ignition point is the lowest
temperature at which fuel vapor will initiate andsustain combustion"
"Pour point is: - CORRECT ANSWER The lowest temperature at which
fuel will flow"
"What is secondary air? - CORRECT ANSWER Air that exits through the
slots cause the air to spin enabling the best mix offuel and air"
"What is tertiary air? - CORRECT ANSWER Air that exits around the
outside of the flame retention ring and blankets the fuel with air to ensure clean combustion"
"The difference between fixed and adjustable heads: - CORRECT
ANSWER Fixed heads are attached and have a pre-set tertiary air opening,
an adjustable head is attached to the nozzle assembly and is moved to change the tertiary air opening"
"The key final adjustment for most burners is: - CORRECT ANSWER
Combustion air"
"Burner fan blades need to be clean of debris to ensure: - CORRECT
ANSWER Proper amount of combustion air is delivered"
"A tank without a functioning vent alarm should: - CORRECT ANSWER
Not be filled until the vent alarm is repaired or replaced"
"Tanks should be kept free of water because: - CORRECT ANSWER It
leads to corrosion and provides a home for harmful bacteria"
"Condensation in outdoor tanks can be reduced by: - CORRECT
ANSWER Setting it in an enclosure, painting it a light color"
"For normal residential use, what size oil line is recommended? -
CORRECT ANSWER 1/2" O.D. fuel lines (3/8" I.D.)"
"Fuel lines that contact concrete or dirt must be: - CORRECT ANSWER
coated or sleeved in plastic"
"In general, the right size tank is one that holds: - CORRECT ANSWER
About one-third (1/3) of the customer's annual fuel consumption"
"Pulsating fuel unit pressure can be caused by: - CORRECT ANSWER
Slipping coupling, excessive vacuum, partially clogged strainer, air leak"
"If the gauge reading is significantly above the calculated reading it could be:
- CORRECT ANSWER Plugged filter, plugged/kinked line, stuck check valve" "True or false, NORA recommends that pumping "clean" oil from an oldtank
into a new tank is ok: - CORRECT ANSWER False"
"NORA recommends that fuel lines that have blockages be cleared with: -
CORRECT ANSWER Hand pumps to pull blockages out"
"If the gauge reading is significantly below the calculated reading it could be:
- CORRECT ANSWER Clogged strainer, air leak in suction line, air leak around gasket"
"How do you calculate the approximate operating vacuum of a fuel unit? -
CORRECT ANSWER 1" Hg for every foot of vertical lift, 1" Hg for every
10' of horizontal run, ½"to 1" Hg for clean filter."
"Why is 1 pipe preferred over 2 pipe systems? - CORRECT ANSWER 1
pipe systems reduce the possibility of return line leaks and extend filter life" "What is recommended by NORA whenever fuel tank is higher than the fuel
unit? - CORRECT ANSWER Oil Safety Valves"
"True or False, Fuel unit rotation is opposite of burner motor rotation: -
CORRECT ANSWER True"
"What are the nozzle functions: - CORRECT ANSWER Atomize the oil,
provide a spray pattern, and deliver a fixed quantity ("meter the oil")" "The best burner adjustment is one that allows for a smokeless operationwith
a minimum of excess air, typically: - CORRECT ANSWER 25% - 35%"
"For proper installation of a nozzle heater, it must be wired in: - CORRECT
ANSWER Parallel with the limit control, not in series"
"Gallons per hour is clearly stamped on each nozzle and box and is based on:
CORRECT ANSWER A flow of 100 PSI."
"If 2 openings are provided into 1 chimney flue, they shall be at different
levels, what appliance would be at the higher level? - CORRECT
ANSWER The appliance with the lower firing rate shall enter at the higher
level"
"What is 1 cause of insufficient air for combustion? - CORRECT
ANSWER Less air leaks into modern buildings because of new construction
practices"
"What is the best solution for insufficient combustion air? - CORRECT
ANSWER Install isolated combustion a.k.a an outside air connection to the
burner" "True or False, a draft regulator can increase the draft from the chimney or
power venter. - CORRECT ANSWER False"
"Which factors cause variable draft and require draft regulators to maintain
steady draft? - CORRECT ANSWER Humidity, Barometric Pressure, Air
Temperatures"
"Natural draft is divided into two categories. What are they? - CORRECT
ANSWER Thermal and Currential"
"Draft for a direct vented appliance is produced by: - CORRECT
ANSWER The static pressure created by the burner fan"
"Air contains how much oxygen and nitrogen? - CORRECT ANSWER
21% oxygen and 78% nitrogen"
"# 2 Fuel is Approximately ______ % Carbon. - CORRECT ANSWER 85"
"To prevent CO from entering the home we will need to: - CORRECT
ANSWER Properly adjust the oil burner, ensure the venting system is
installed correctly"
"An 1/8" of soot on the heat exchanger can increase fuel consumption by: -
CORRECT ANSWER 8%"
"Carbon Monoxide is produced by incomplete combustion which can because
by? - CORRECT ANSWER Too little or too much combustion air"
"Before using electronic analyzer you must: - CORRECT ANSWER
Perform a smoke test"
"It's important to set smoke to a trace or zero because: - CORRECT
ANSWER Higher smoke settings lead to soot creation which insulates the
heatexchanger surfaces and lowers efficiency"
"As excess air is added: - CORRECT ANSWER CO2% goes down and the
02 goes up."
"Too much draft over the fire causes combustion gases to travel: -
CORRECT ANSWER Too rapidly through the heat exchanger"
"When a new appliance is installed, manufacturing residue often
causestemporarily elevated _____________________levels. - CORRECT
ANSWER carbon monoxide"
"Codes require that Oil-heat systems shall be wired: - CORRECT
ANSWER In dedicated circuits."
"Electrical force or potential is measured in: - CORRECT ANSWER
Volts"
"A voltmeter allows: - CORRECT ANSWER Very little current flow and
are used on "live" circuits to measure the difference in potential."
"A series circuit has __________ path. - CORRECT ANSWER 1"
"A parallel circuit has ___________ paths. - CORRECT ANSWER multiple"
"In an energized 120 VAC circuit, when a voltmeters leads are placed on both
sides of a toggle switch in the closed position, the reading will be: -
CORRECT ANSWER 0 VAC"
"Electrical "current" describes the amount or rate of electricity flowing
through a circuit, and it is measured: - CORRECT ANSWER Amperes
(amps)"
"A single pipe that goes from the boiler outlet through each piece of radiation
and back to the boiler inlet is what type of piping system? - CORRECT
ANSWER Series loop"
"What makes a one pipe system different from a series loop system? -
CORRECT ANSWER All of the sections of radiation are connected to the
single pipe main by these of a standard tee and a special tee that form a "branch" of the main circuit."
"Residential hot water boiler relief valves are set to open at: - CORRECT
ANSWER 30 PSI"
"No residential steam heating system should operate at more than: -
CORRECT ANSWER 2 PSI"
"The low water cut off on a steam system shuts down the burner when? -
CORRECT ANSWER The water drops to an unsafe level"
"On steam boilers the relief valve is set to open at: - CORRECT ANSWER
15 PSI"
"All water heaters with storage capacity must have a: - CORRECT
ANSWER Temperature and pressure relief valve"
"Temperature rise in a furnace is: - CORRECT ANSWER The difference
in temperature between the supply air and the return air." "How do you ensure the system is operating efficiently and reliably during a
preventative maintenance call? - CORRECT ANSWER Combustion test"
"What controls should be tested during a preventive maintenance call? -
CORRECT ANSWER The primary control and all limit controls to be sure
they function properlyand shut off the burner if a problem develops" "NORA recommends that during a preventative maintenance call the oil tank
be checked for: - CORRECT ANSWER Corrosion, leaks, and water"
"How should you approach a service call? - CORRECT ANSWER
systematically"
"Reset Pressed -Nothing Happens. What should be checked? - CORRECT
ANSWER Voltage, is primary control sensing flame, cad-cell leads might be
crimped, F-F circuit might be shorted, control might be defective" "On a No Heat Call: You press the reset & the burner runs. What do you do?
CORRECT ANSWER Begin your testing routine, determine why it went
off, make all necessary repairs to correct the problem and to keep it from re- occurring"
"What is combustion? - CORRECT ANSWER rapid reaction of
combustible material with oxygen involving the production of heat and light"
"3 things needed for combustion? - CORRECT ANSWER oxygen, fuel,
heat"
"what 3 electrical components does the primary control operate? -
CORRECT ANSWER burner motor, igniter and oil valve"
"what does the burner motor drive? - CORRECT ANSWER fan and fuel
unit"
"what's the fuel units' function? - CORRECT ANSWER moves fuel from
the tank, pressurizes it and delivers it to the nozzle, provides fast and complete cutoff of fuel on burner shutdown"
"primary air - CORRECT ANSWER air that exits through the center
opening"
"secondary air - CORRECT ANSWER air that exits through the slots,
causes the air to spin enabling the best mix of fuel and air"
"tertiary air - CORRECT ANSWER Air that exits around the outside of
the flame retention ring and blankets the fuel with air to ensure clean combustion."
"what's the difference between fixed and adjustable heads? - CORRECT
ANSWER fixed heads are attached and have a preset tertiary air opening.
