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NORA REVIEW EXAM | QUESTIONS &
ANSWERS (VERIFIED) | LATEST UPDATE |
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In a typical oil burner, the motor drives: Correct answer: Both the fuel unit and the fan The key final adjustment for most oil burners is: Correct answer: Combustion air High static air pressure burners: Correct answer: Enable boilers and furnaces to have tighter more efficient heat exchanger passages Dirt or lint build-up on the burnerfan blades will: Correct answer: Reduce the amount of combustion air One gallon of #2 oil contains approximately: Correct answer: 140,000 BTU's All petroleum products are chemical compounds of:
Correct answer: Hydrogen and Carbon The pour point of #2 oil is: Correct answer: The lowest temperature at which oil will flow Flash point of a fuel is an indication of: Correct answer: The maximum temperature at which it can be safely stored and handled without serious fire hazard The pour point of #2 oil can be reduced by: Correct answer: Blending it with kerosene As heating oil gets colder its viscosity (thickness): Correct answer: Increases A tank without a vent alarm: Correct answer: Should not be filled Oil lines that contact concrete or dirt should be: Correct answer: Coated or sleeved in plastic pipe with no fittings below the floor What is the most common source of water in oil tanks? Correct answer: Condensation
If the operating vacuum reading is significantly above the calculated vacuum you probably have: Correct answer: A clogged oil filter It is best to connect fuel units as a one-pipe system instead of two-pipe because: Correct answer: One pipe leads to longer filter life and eliminates worries about leaking return lines If a nozzle is dirty or plugged it should be: Correct answer: Replaced What keeps a nozzle from overheating while the burner is running? Correct answer: The amount of air and oil traveling past it The flow rate stamped on the nozzle is based on: Correct answer: 100 psi The purpose of an oil burner nozzle is to: Correct answer: Atomize and meter the oil Nozzle after-drip can be caused by: Correct answer: Thermal expansion of the oil in the drawer assembly after shut down
To reduce combustion problems caused by cold oil: Correct answer: Increase the pump pressure and reduce the nozzle size Increasing the fuel pump pressure will: Correct answer: Increase the flow rate Generally, the end of the burner air tube should be: Correct answer: Be flush with the face of the chamber or recessed approximately ¼" The draft regulator can: Correct answer: Decrease the draft A draft regulator is required because: Correct answer: The draft produced by the chimney needs to be controlled The most important draft measurement is: Correct answer: Over the fire To get accurate results, a combustion test should be performed: Correct answer: When the unit reaches steady state operation Excessive draft drop through the heat exchanger indicates: Correct answer: Heavy soot and scale deposits in the heat exchanger
Correct answer: Create soot that insulates heat exchanger surfaces and lowers efficiency To help ensure carbon monoxide does not enter buildings: Correct answer: Adjust burners properly and be sure the venting system safely removes all the combustion byproducts The hole in the flue pipe for combustion testing should be:: Correct answer: As close to the breech of the heating unit as possible 02 or CO2 measurements are used to calculate: Correct answer: The amount of excess air in the combustion gases Before using an electronic combustion analyzer you must: Correct answer: Perform a smoke test to be sure you are burning at a zero to trace smoke The electric force or potential (pressure) is: Correct answer: Volts The electrical current flowing in a circuit is measured in: Correct answer: Amps
Resistance to the flow of electricity in a circuit is measured in: Correct answer: Ohms Materials that allow electric current to flow through them with little resistance are: Correct answer: conductors What is an insulator at 120 volts but a conductorat 10,000 volts? Correct answer: Air A device that uses electricity to perform useful work is a: Correct answer: Load In a series circuit there is only one: Correct answer: Path for current through the loads Oil heating systems should be: Correct answer: Wired on their own separate circuit A voltmeter: Correct answer: Can be used on live circuit as it allows very little electric current to flow through it The clamp-on ammeter:
The primary control must be capable of reactingto: Correct answer: The presence and absence of flame Before pushing the reset button on a primary control be sure to: Correct answer: Check to be sure that the chamber is not saturated with oil In oil burner circuits the high limit must be: Correct answer: Line voltage and wired in series with the primary control What limit controls should be tested during a preventive maintenance call? Correct answer: All limit controls What happens to the electrical resistance through the cad cell as the light it sees gets brighter? Correct answer: Decreases The function of a switching relay is to: Correct answer: Control a line voltage load with a low voltage thermostat The fan and limit control on a warm air furnace is used to: Correct answer: Start and stop the blower at predetermined temperatures 12 pounds of pressure in a hot water boiler will push water up a pipe:
Correct answer: 28 feet The maximum steam pressure needed to operate a residential one-pipe steam system is: Correct answer: 2 PSI During a proper tune-up you should: Correct answer: Perform a combustion efficiency test What does NORA recommend be done during the tune-up? Correct answer: Check the oil tank for leaks and water What problem does an oil film on the burnerfan blades typically indicate? Correct answer: Leaking fuel unit seal On an emergency midnight no-heat call, you press the reset button and the burner runs: Correct answer: Begin yourtesting routine to determine why the burner went off on safety What is typically the cause of an odor, smoke, or soot call? Correct answer: Faulty Ignition
Correct answer: corrosion inhibitors A weakening of metal caused by long-term corrosion is known as Correct answer: embrittlement The proper pH range for water in a hydronic heating system is Correct answer: between 7 and 10 The part of a circulating pump that moves water through a hydronic system is the Correct answer: impeller One side of an expansion tank is filled with water and connected to the hydronic system piping and the other side of the tank is filled with Correct answer: Air When charging an expansion tank, a technician should use a Correct answer: bicycle pump The purpose of an expansion tank is to maintain a stable _______ under varying operating conditions. Correct answer: pressure An expansion tank must be installed on the supply side of system piping and never
on the return side. Correct answer: True A _______ valve blends hot water from one inlet with cooler water from another inlet. Correct answer: Mixing Balancing valves are most often valves. Correct answer: globe or ball If the supply water leaving a boiler is not hot enough, the water will be Correct answer: recirculated through the boiler A mixing valve may be installed. Correct answer: in the return or supply water line A valve that adjusts the water flow to each terminal unit or zone so that heat is evenly distributer is called a Correct answer: balancing valve A valve installed in the makeup water line that adjusts the pressure of the water supply from the main to the operating pressure of the system is a valve. Correct answer: pressure-reducing
The type of air that consists of bubbles at the high points of the hydronic system is called Correct answer: free air Water's ability to hold dissolved oxygen increases as Correct answer: its temperature drops An air vent releases air to atmosphere by means of a Correct answer: float valve Devices that use a series of deflectors to collect and remove air from water in hydronic systems are Correct answer: air scoops Devices that use a wire mesh element to create a swirling motion to remove air from water in hydronic systems are Correct answer: air separators Splitting a series loop hydronic system into two smaller loops Correct answer: reduces the overall distance that the circulating water must travel A major difference between a series loop and a one-pipe system is that a one-pipe system has branch circuits.
Correct answer: True In a zoned hydronic system, a zone valve is most often controlled by Correct answer: a room thermostat Radiant hydronic systems often use. tubing. Correct answer: PEX In a radiant heating system, the loops of tubing warm the surfaces adjacent to them by conduction. Correct answer: True Dry underfloor radiant heating systems consist of tubing embedded in a conerete slab. Correct answer: False A radiant system traditionally distributes heat to conditioned spaces by Correct answer: piping enclosed in walls or floors In an oil - fired boiler, the atomized fuel spray is ignited by Correct answer: electrical sparks
An aquastat measures the temperature of boiler water and uses this information to Correct answer: turn on and off heating of the water The maximum temperature setting on an outdoor reset control should be set higher than the temperature setting on the boiler's high-limit control. Correct answer: False Outdoor reset control monitors the difference between indoor and outdoor temperatures in order to modify the Correct answer: operating temperature range of a hydronic system An indoor reset control is used to adjust Correct answer: boiler temperature to match the heating load An indoor or outdoor reset control should be wired to bypass a boiler's high-limit control Correct answer: never Eccentric reducer fittings are used to join tubing of different sizes in order to Correct answer: reduce the danger of air pockets forming When installing metal pipes, be certain to make allowance for. Correct answer: piping expansion
The heat difference between return water and supply water should be approximately Correct answer: 20°F (11°C) To protect valves and pump seals from dirt, sand, and other particulates when preparing a hydronic system for initial startup, a technician should Correct answer: clean the screens thoroughly before refilling the system When balancing a system during initial start-up, pressure gauges or flow meters are used to determine water flow rate in Correct answer: Gpm For steam heating systems, the ________ must slope down to the boiler. Correct answer: return piping A steam trap that uses a mixture of water and mineral spirits to trigger its valve is a(n) Correct answer: balanced pressure steam trap In a two-pipe system, the thermostatic radiator valve should be installed on the supply side of the radiator. Correct answer: True In a one-pipe system, the air vent should be installed on the
