Michigan Mechanical Heating Service Practice Exam

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• Oil nozzles are rated based on gallons per minute at a standard test pressure of
• Oil nozzles are based on gallons.
• What is the correct sequence for a gas fired furnace with a flame sensor?
• Which statement best describes combustion air and its supply in a residential space?
• What drives the oil pump on an oil-fired furnace?
• Which statement is true about a manual shutoff valve on the gas supply line?
• The minimum pitch for horizontal steam mains and dry returns in 10 feet is?
• What is the light sensitive material used in a cad cell?
• What license is required to perform a CSD-1 on a boiler that has an input rating of 1.7MBTU?
• Which device is used to indicate the water level in a steam boiler?
• In a steam boiler system, no heat call with hot supply and cold return, most likely cause is?
• A gas space heater that operates with no external power source would be operating on _____
• What is the primary purpose of a vent connector on a gas appliance?
• The bimetallic strip in a thermostat is made of copper and which metal alloy?
• What constitutes proper vent termination on the outside of a building?
• What is the function of an aquastat in a boiler system?
• The ignition system of an oil system must raise the oil temperature to _____.
• Which entity conducts inspections after heating system work?
• Why do permits for heating system work exist under Michigan practice?
• The pressure regulator on an LP gas system is set at which pressure?
• What is venting clearance and why is it important near doors or windows?
• In a hydronic system, what does a properly designed primary/secondary piping arrangement help to maintain?
• Poor electrical contact can cause circuit resistance to do what?
• Which option is not a typical gas shutoff valve used on appliances?
• In order for oil to burn it is passed through a nozzle to ______.
• What is a draft regulator and when is it typically used?
• Which formula converts Celsius to Fahrenheit?
• In a scenario where the ignition transformer steps up from 120 V AC to approximately 10,000 V, this demonstrates that the secondary voltage is which relative to the primary?
• Which of the following is a potential cause of low LP regulator outlet pressure in extreme cold?
• What is the maximum safety dropout time for a thermocouple?
• Name a common control used to modulate boiler firing rate.
• In the ignition system, which substance is ignited by the high voltage produced by the ignition transformer?
• What is the function of the circulator pump in a hydronic heating system?
• Which statement is NOT a reason to obtain a permit for heating system work?
• The valve closing time for boilers 2.5M BTU/hr or greater is?
• In typical air, what percentage by volume is oxygen?
• What type of fittings should never be used on oil lines?
• Which device is specifically used on natural-draft appliances to maintain proper venting pressure?
• No part of an electrode inside an oil burner shall be closer than _____ to any metal part.
• The ignition transformer input uses what type of electrical current?
• The ignition transformer on an oil furnace converts 120V AC to approximately how many volts to ignite the oil droplets?
• Cold air returns in bathrooms should be omitted.
• What is backdrafting and why is it dangerous?
• Which vent pipe type is specified as acceptable for installations: Single wall or Type B?
• A redundant gas valve has two or three valve operators physically in series but wired in parallel with one another. This built-in safety feature allows any operator (pilot or main) to block.
• A yellow flame on a gas burner signals what combustion condition?
• What is the primary function of relay controls in a heating system?
• A psychrometer is a _____?
• A psychrometer measures atmospheric humidity by comparing readings from its wet-bulb and dry-bulb thermometers; what property is determined from their difference?
• What is the purpose of a manometer in gas piping work?
• What is a common method to purge air from a heating loop?
• What is the minimum clearance between an oil burner electrode and metal parts?
• A flame rectification system is an electrical process that causes a low-level DC current to be conducted from the flame rod through the flame, and back to ground.
• What device controls automatic recycling on an oil burning appliance?
• Why is a combustion analysis performed on an in-service furnace?
• Which device is designed to stop gas flow if there is no flame detected in a furnace safety system?
• What vent piping materials are commonly used for exhaust and intake on high-efficiency (condensing) gas furnaces?
• What operates the heat anticipator in a low voltage thermostat?
• 28 degrees Celsius is equivalent to _____ degrees Fahrenheit. Use formula F=(Cx9/5)+32.
• In an oil-fired burner, which component is responsible for creating the ignition arc by increasing line voltage?
• What is a common symptom of a malfunctioning flame sensor or ignition system?
• What is a typical requirement for vent termination regarding openings and obstructions?
• What is a typical sign of vent joint deterioration that would prompt replacement?
• In a hydronic system, which component absorbs water expansion and helps maintain pressure as temperature rises?
• What would cause low propane pressure on the outlet of an LP gas regulator during extreme cold temperatures?
• A limit control is located in which voltage portion of the electrical circuit?
• A gas drip leg must _____?
• A psychometric chart is a _____?
• On a low-pressure residential steam boiler, the relief device opens at?
• In this context, which gauge wire is specified to carry the most current?
• When venting clearances near doors or windows are not maintained, what risk increases?
• What is a typical shutoff device on the gas supply line that can be manually used to stop gas flow to the appliance?
• What would be the most likely cause of a furnace direct drive blower motor that failed for 3 consecutive years and had to be replaced?
• Which boiler rating threshold is associated with a 4-second flame failure response time?
• Which are two common types of gas shutoff valves used on appliances?
• In gas heating, a standing pilot burns how?
• Oil burners use a ______ to prove a flame is present.
• Which statement correctly describes what a yellow flame in a gas burner indicates?
• What letter is found in the center of the Water Boiler Certification symbol?
• Which description best defines a psychometric chart?
• The term BTU/hr in boiler specifications refers to:
• The thermostat range refers to which settings?
• For boilers 2.5M BTU/hr or greater, the maximum valve closing time is which of the following?
• Which statement best describes combustion?
• What is a key difference between a boiler and a furnace?
• What is the purpose of a balancing valve or flow control in a hydronic system?
• The range of carbon dioxide in oil burner flue gas is _____.
• Which electrical wire will carry the most current?
• The sight glass installed mid-point on a boiler is used for what purpose?
• What safety mechanism shuts off the fuel supply if combustion fails to start or goes out?
• The location of outside air exhaust and intake openings shall be located a minimum of how many feet from lot lines or buildings on the same lot?
• Duct shall be supported at intervals of which standard or guideline?
• Standards governing controls and limit devices on steam boilers?
• What is the primary purpose of the International Fuel Gas Code (IFGC) in heating installations?
• A fast acting type of gas valve is the which valve?
• The carbon dioxide content in typical oil burner flue gas is within which range?
• What is essential to check when performing service on gas equipment located in a confined space?
• Compared to natural gas with the same BTU/h rating, the orifice opening in an LP gas fired furnace is which of the following?
• Why is lockout/tagout important when servicing heating equipment?
• A typical sign of a blocked flue or vent is:
• Which device blends two streams to a single temperature in a hydronic system?
• The bimetallic strip used in thermostats is copper and which alloy?
• A fuel oil furnace in a commercial application operates in which pressure range?
• Which statement about direct-vent furnaces is true?
• What is the resistance of a cad cell in the absence of light?
• Which statement best describes the role of a balancing valve in a hydronic system?
• If a vent is blocked, what issue is likely to occur?
• What is the typical purpose of a vent damper, and when might it be used?
• The flame failure response time for boilers 400k BTU/hr or greater is?
• Total heat is composed of which two components?
• The secondary voltage of the ignition transformer is approximately how many volts?
• On an oil-fired burner, which component condition is specifically noted as important to inspect during a service call?
• In a gravity warm air furnace, the limit control setting shall not exceed how many degrees?
• The air for combustion in a building must be at least one square inch per which BTU/h value?
• In a hydronic heating system, what is the primary purpose of a primary/secondary piping arrangement?
• The ignition system of an oil burner must raise the oil temperature to approximately which value?
• What is the formula used to calculate a forced air furnace supply and return air duct sizing?
• What is the purpose of a pressure switch on draft-inducing appliances?
• What describes the flame rectification system?
• What is the purpose of lockout/tagout procedure during service?
• What percentage of oxygen is in the air?
• The safety loop that prevents boiler water from draining if a leak develops in return piping is called the?
• What should you consult to determine the minimum clearance from combustibles for a specific furnace model?
• Where is an appliance-mounted shutoff valve located?
• Which statement best describes the primary purpose of a vent damper?
• The high voltage from the ignition transformer is used to ignite which substance?
• Which component is primarily responsible for delivering high voltage in this ignition system?
• Low pressure type oil burners operate at pressures of _____.
• A hand shut-off valve in a gas line is used to turn gas on and off to which components?
• An instrument described as a U-shaped tube partially filled with liquid, used to indicate the pressure on the instrument, is called a(n) ______.
• What indicates proper duct balancing across rooms?
• The documentation notes a measurement of 1.4 inches per foot for a certain installation parameter. Which option correctly represents this value?
• A thermostat that cycles too often or not enough indicates which condition?
• A boiler pressure relief valve that is dispensing intermittently is most likely caused by which condition?
• Total heat is equal to which of the following?
• If a boiler relief valve is discharging intermittently, the most likely cause is what?
• Per CW-410, a gas-fired boiler rated at 150,000 BTU requires which limit control configuration?
• What is the role of a combustion blower on some gas appliances?
• What is the function of a draft hood in venting systems?
• Which device protects potable water from backflow in boiler systems?
• In a residential fuel oil furnace, the operating oil pressure is in which range?
• What is the proper action when a flame sensor fails to sense flame in a gas furnace?
• What safety device is used to shut fuel supply if combustion fails to start or goes out?
• Duct construction standards for metal and flexible ducts are published by which organization?
• Compared to propane burner orifices, natural gas burner orifices are larger in diameter.
• A mixing valve in a hydronic piping system allows for two separate fluids at different temperatures to enter the valve and be controlled so only a single set fluid temperature leaves the valve.
• Cold air returns in bathrooms should be which of the following?
• What is the minimum number of times the blower and electric motor bearings should be oiled during the heating season?
• All boilers shall have the potable water protected with which device?
• What type of shut off valve can be installed between a boiler and the low water cut off?
• Combustion is what type of process?
• How does duct leakage affect heating system efficiency?
• Which instrument uses a U-shaped tube partially filled with liquid to indicate pressure?
• What is the primary function of a furnace in a heating system?
• AFUE rating indicates what aspect of heating equipment?
• What test should be performed to verify that CO is not leaking into living spaces?
• Which formula converts Fahrenheit to Celsius?
• Which statement correctly describes the role of the low water cut off in a boiler system?
• What is the usual oil pressure at the nozzle in a high-pressure gun type oil burner?
• During combustion analysis, which metric is used to optimize burner performance?
• What is the main safety rationale for depressurizing a gas line before testing for leaks?
• The approximate secondary-to-primary voltage ratio of the ignition transformer (primary 120V, secondary about 10kV) is about...
• _____ is to exhaust unburned gas in a combustion chamber before ignition by exhausting so that gas explosion can be prevented.
• In Fahrenheit to Celsius conversion, what factor is multiplied after subtracting 32?
• Which statement best describes why a furnace flame might appear yellow instead of blue?
• What is a typical resistance value for a cad cell in darkness?
• What does AFUE measure?
• When venting gas appliances, what effect do long vent runs and multiple bends have on venting performance?
• In a combination boiler, which valve controls directing heated water to either the domestic hot water coil or the radiator circuit?
• What is the purpose of balancing an air duct system?
• The difference between the supply air temperature and return air temperature on a forced air furnace is known as _____
• Which component is commonly used to sense flame in an oil burner by producing a signal when the flame is present?
• All steam boilers must have which of the following?
• What is the primary purpose of a quick shutoff blowout valve in steam boiler piping?
• Which of the following would indicate a vent pipe replacement is needed?
• The piping feature at the top of a steam boiler used to balance pressure in the return line is called the?
• Which gauge assembly must be present on steam boilers to indicate water level and pressure?
• Why is vent length and number of bends important in venting gas appliances?
• How can you identify a CO hazard in a home?
• In a forced warm air furnace, what is the maximum belt movement allowed?
• A gas-fired furnace with a 6-inch common vent can have what other type of exhaust connected to the vent?
• The diverter valve is a mechanical valve used in combination boilers to divert flow between which two paths?
• Name two common methods to test gas piping for leaks after installation.
• What best describes an oil ignition transformer?
• Which pipe has the thickest walls?
• What size boiler requires gas pressure monitoring?
• Which of the following best describes how a standing pilot operates on a gas furnace?
• What type of license is required to install and repair commercial boilers?
• Which is not a type of electric resistance heating wire?
• Which material is commonly used for venting high-efficiency furnaces for both exhaust and intake?
• What is the maximum allowable play in the blower belt of a forced air furnace?
• Why is a CO detector required in sleeping areas in many jurisdictions?
• What is the primary purpose of performing a post-start combustion analysis after starting a gas appliance?
• What is one major difference between troubleshooting a gas appliance and an oil-fired appliance?
• 70 degrees Fahrenheit is equivalent to _____ degrees Celsius?
• Which component should be used to lock out energy sources during service work to prevent restart?
• The abbreviation 'CSD' stands for?
• CGV is the abbreviation for which device?
• To determine minimum clearance from combustibles for a furnace model, you should consult
• In a hydronic heating system, what is the purpose of an expansion tank?
• What is the purpose of a gas line pressure test and what safety precaution should be observed?
• If too much primary air is used, the flame will _____?
• Which device provides rapid shutdown of steam flow in an emergency?
• What distinguishes direct-vent from non-direct-vent gas furnaces?
• Which statement describes the purpose of permits in heating system work?
• The cad cell is used in gas burner safety circuits to detect what?
• Which valve described as fast acting is used for gas control in LP systems?