Download WGU D236 FINAL EXAM (Latest Update 2026 / 2027) Pathophysiology Questions with Correct Ans and more Exams Chemistry in PDF only on Docsity!
NORA Bronze (Latest Update 2026 / 2027)
Questions with Correct Answers {Grade A}
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When the burner on a furnace short cycles or shuts off on high limit, the most likely cause would be? - Correct answer A dirty air filter Limit controls that respond to steam pressure are called? - Correct answer Pressure Controls or Procurators Vapor-stats will operate on _______ of steam pressure. Ounces or Pounds? - Correct answer Ounces What is the purpose of the low water cut-off? - Correct answer To prevent the burner from operating if the water level is too low in the boiler. Hot water controls are called aquastats True or
False? - Correct answer True A reverse acting aqua stat is used in a hydronic system to do what? - Correct answer Stop the circulator when the boiler water temperature falls below the set point The switching relay's job is to do what? - Correct answer Control a line voltage load with a low voltage thermostat What two things must the primary control have to activate the oil burner? - Correct answer It must have both High Voltage (120 volts) and Low Voltage (24 volts) The primary control must be capable to reacting to what two things? - Correct answer The presence or absence of flame
allows what? - Correct answer The ability to view and monitor the flame When the cad cell is exposed to light, what happens to the resistance? - Correct answer It decreases What should you check before pushing a reset button? - Correct answer Check to see that the chamber is not saturated with oil What are the benefits to using Motor-Delay-Off (post-purge type technology)? - Correct answer This provides cleaner shutdowns and removes residual flue gases from the system. Besides the advantage of using less current, why do we use capacitor start motors? - Correct answer They provide greater starting torque
If a burner motor does not operate and the voltage to the motor is correct, you should first check what? - Correct answer The overload switch An 1/8" of soot can reduce the efficiency of a burner by how much? - Correct answer 8% What two types of overload switches are there? - Correct answer Automatic and Manual What is the advantage of PSC Motors over conventional split phase motors? - Correct answer They use less current What should we do before using an ohmmeter to test a capacitor start motor? - Correct answer Discharge (Deenergize) the capacitor What type of motor has a variable motor speed capability? - Correct answer ECM (Electrically Commutated Motors)
A furnace creates ________? that is distributed throughout the home/building. - Correct answer Warm Air What can be incorporated with a warm air furnace? - Correct answer Air Cleaners, Humidifiers, and Central Air Conditioning. Temperature rise in a warm air system refers to: - Correct answer The difference in temperature, at the furnace, between the supply air and the return air What are the three most common piping systems used to distribute the hot water the boiler has produced? - Correct answer Series Loop, One Pipe, Two Pipe What is the function of the pressure reducing valve (water feeder)? - Correct answer To reduce the pressure of the incoming water
and maintain boiler water and pressure. 12 pounds of pressure on a hot water boiler will push water up a pipe how many feet? - Correct answer 27.6 Feet (28 Feet) What device is used to prevent gravity circulation in a forced hot water system? - Correct answer Flow Control Valve (Flo- Check) The maximum steam pressure needed to operate a residential steam system is? - Correct answer 2 PSI What two things cause the relief valve on a water heater to open/discharge? - Correct answer High Pressure, High Temperature During a Proper Tune-Up Besides the Furnace or Boiler, What Else Does
What three things could cause a boiler relief valve to leak? - Correct answer Pressure reducing valve (water feeder) stuck open., A compromised expansion tank (to little air, torn bladder or to much water - cushion type tank), Domestic coil leaking into the boiler water. What may an oil film or drip in the burner housing be caused from? - Correct answer A leaking fuel pump seal. What is typically the cause of an odor, smoke, or soot call? - Correct answer Faulty or Delayed Ignition. Increasing the amount of excess air causes what Two things to happen? - Correct answer Increases stack temperature and decreases efficiency Why is the off cycle heat loss much greater for older
less efficient units than new high efficiency ones? - Correct answer The old heat exchanger passes are wider, Old units are more likely to have air leaks in the heat exchanger, Old units need more excess air so the burner air bands are opened wider A heating unit that is closely matched in size to the building's heating requirements will provide what? - Correct answer The lowest off-cycle heat loss and highest efficiency What causes Infiltration losses? - Correct answer Cold outside air drawn into the building to replace the warm air going up the chimney To minimize on-cycle heat loss what Three things do we need to do? - Correct answer Adjust the burner properly, Keep heat exchanger surfaces clean, Replace inefficient burners, boilers, or furnaces
The definition of (pour point of #2 oil) is what? - Correct answer The lowest temperature at which oil will flow (21 F) The pour point of #2 oil can be lowered by what two methods? - Correct answer It can be lowered by blending with kerosene. It can be lowered with fuel additives (~1 F) The viscosity is the thickness of the fuel; viscosity will change depending on the temperature, as oil gets colder does the viscosity increase or decrease? - Correct answer Increases One gallon of heating oil contains how many BTU's? - Correct answer 139,000 BTU's Water in the bottom of the tank will lead to what two things? - Correct answer Sludge and ice
Ultra Low Sulfur Fuel (ULSD), all but eliminates what? - Correct answer Scale and soot formation on the heat exchanger surfaces. Why is #2 Heating Oil Dyed Red? - Correct answer #2 fuel used for heating and hot water purposes is dyed red to differentiate it from on-road diesel fuel for tax compliance reasons. Does evidence of the red dye on components indicate there's a problem? - Correct answer No, problems with the fuel are not indicated by the darkness of the color. Sludge is a combination of what three things? - Correct answer Water, Bacteria, Degraded Fuel and other contaminants What are the three basic parts of combustion? - Correct answer Oxygen (Air), Fuel, Ignition
burners is what? - Correct answer Combustion Air To Change the air ratio for different firing rates with an adjustable head burner, what do we adjust? - Correct answer The position of the drawer assembly in the air tube, by moving it against or away from the choke ring. One advantage of high static pressure burners is what? - Correct answer They enable boiler and furnace manufacturers to design tighter, more efficient heat exchangers Where does the bacteria live in an oil tank and what does it do? - Correct answer Bacteria lives on the oil/water line, It creates an acid that corrodes the metal in the tank. What are the three most common cause of water in the oil tank? - Correct answer Condensation, Loose or missing fill/vent caps, and failing to drain water from tank during installation.
How much of the customers annual fuel usage should the tank hold? - Correct answer 1/3 of their annual fuel usage What three locations are oil tanks typically installed? - Correct answer Outside, inside, or underground How should oil lines that come in contact with or are buried in concrete be installed? - Correct answer They should be sleeved in plastic or PVC pipe with no fittings below the floor When the oil tank is installed outside, should the line be Top or Bottom drawn? - Correct answer Top drawn When installing an oil tank, what are three things we should be sure to do? - Correct answer Make sure the fill and vent lines are pitched
vacuum, when should they be installed? - Correct answer When you have a high lift and long run The rule of thumb for calculating vacuum: - Correct answer 1" for every 1' rise and 1" for every 10' horizontal If the oil level in the tank is 4 foot below the fuel unit and 10 feet away, the approximate vacuum should be? - Correct answer ~4 to 6 inches What's the benefit to installing a fuel de-aerator? - Correct answer It eliminates the need for a return line back to the tank, it reduces the vacuum, removes air and conditions the fuel If the vacuum is below the anticipated calculated vacuum, you may have a what? - Correct answer Suction Line Leak
If the vacuum is higher than the anticipated calculated vacuum, you may have a? - Correct answer Suction Line Restriction such as a clogged oil filter or kinked line What is the best way to clear a clogged oil line? - Correct answer With a push-pull hand pump Is it ok to blow out an oil line with a CO2 kit? - Correct answer No, NORA recommends that fuel lines and tanks should NEVER be pressurized. This includes blowing out the line with a CO2 cartridge. Fuel pump strainers should always be checked and cleaned or replaced True or False - Correct answer True The rotation of the fuel unit must be _______ the burner motor and the speed must be _____ the burner
