Gas and Electric Heat Written Final Review
For each watt of electrical power, _____________________ Btu/h are generated
3.413
A direct ignition furnace A. electronically lights the main burner B. electronically lights a pilot each time there is a call for heat C. requires the pilot to be lit manually D. automatically relights the pilot in the event of a pilot outage
A
A furnace with a vertical air flow through the heat exchanger and the blower compartment beneath the heat exchanger is called a(n) _________. A. upflow B. downflow C. low boy D. horizontal
A
Air that is pulled into the burner to mix with the gas prior to combustion is called A. primary air B. secondary air C. excess air D. dilution air
A
Auxiliary limit switches are typically located A. in the return air stream B. in the supply air stream C. around the burners D. near the draft hood
A
Burning one cubic foot of natural gas will produce approximately A. 1000 Btus B. 1500 Btus C. 2500 Btus D. 3200 Btus
A
During perfect combustion of natural gas, the carbon dioxide percentage produced is A. 11.7% to 12.2% B. 14.0% to 14.3% C. 8.0% to 9.5% D. 13.2% to 13.7%
A
Electric baseboard heaters are classified as _______. A. natural-convection heaters B. forced-convection heaters C. forced-draft conductors D. radiant heaters
A
For every 1 lb of water vapor that is condensed into liquid A. 970 Btus are released B. 1050 Btus are released C. 2500 Btus are released D. 3200 Btus are released
A
High-efficiency furnaces are designed with which of the following? A. A draft diverter B. Ribbon or slotted burners C. A condensing heat exchanger D. A natural draft heat exchanger
A
If too much air flows across a heat exchanger during the heat cycle, ________________. A. the flue gas will become too cool and may condense in the furnace and flue pipe B. the blower motor will operate in an overload condition C. flame rollout may occur D. the high limit switch may open to shut down the gas valve
A
In an intermittent ignition system, the flame sensor proves A. the pilot flame B. the main burner flame C. both the pilot flame and main burner flame D. the high voltage spark
A
In order to achieve combustion, _______________ are needed. A. heat, fuel, and oxygen B. heat, fuel, and natural gas C. heat, fuel, and propane D. fuel and oxygen
A
Primary air adjusters on atmospheric type gas burners are usually ________. A. butterfly shutters B. sliding sleeves C. spoiler screws D. all of the above
A
Solenoid, diaphragm, and heat motor are all types of A. gas valves B. pilot safety devices C. flame rectification D. pressure regulators
A
The component on which the spuds and burners are mounted to is the A. manifold B. gas valve C. heat exchanger D. draft diverter
A
The horizontal run of the flue pipe on gas-burning furnace should be sloped A. 1/4 in. rise per foot B. 1/4 in. rise per 10 feet C. 1/2 in. rise per foot D. 1/2 in. rise per 10 feet
A
The pressure at the manifold for LP is typically A. 10.5 to 11 in. WC. B. 10.5 to 11 psig. C. 8 in. WC. D. 3.5 in. WC.
A
The principal of flame rectification is based on the fact that A. a flame can conduct electricity B. flames are always grounded C. a flame can generate small amounts of voltage D. flame has a very low resistance
A
___________________ is composed of about 95% Methan, has a specific gravity 0.60, and produces about 1050 Btu per cubic foot when burned. A. Natural gas B. Butane C. Liquified petroleum D. Propane
A
A component that consists of two dissimilar metals that are fused together at one end that will generate a small voltage when heated it called A. flame sensor B. thermocouple C. bimetallic safety device D. liquid-filled remote bulb pilot safety device
B
A condensing gas furnace uses ________ from a condensing type heat exchanger to increase the furnace efficiency A. sensible heat B. latent heat C. superheat D. subcooling
B
A low-mass boiler A. heats up quickly and cools down slowly B. heats up quickly and cools down quickly C. heats up slowly and cools down slowly D. heats up slowly and cools down quickly
B
A multipoise furnace A. requires an auxiliary vent fan motor when installed in the upflow position B. may require some components to be relocated depending on the installation position C. is no longer manufactured and should be replaced when encountered in the field D. may require the spuds (orifices) to be changed when installed in the downflow position
B
Air that is pulled into combustion area to support combustion is called A. primary air B. secondary air C. tramp air D. dilution air
B
An electric heating unit that utilizes ductwork to distribute the heated air is classified as a _________. A. natural-convection heater B. forced-convection heater C. forced-draft conductor D. radiant heater
B
As excess air decreases, A. dew point decreases B. dew point increases C. gas pressure increases D. gas pressure decreases
B
Boilers that operate with efficiencies over 90% are classified as A. conventional boilers B. condensing boilers C. conversion boilers D. compensating boilers
B
Combination gas valves have A. 120-V pilot solenoids B. built-in pressure regulators C. external pressure regulators D. dual gas outlets
B
Flame current is measured in ______________. A. AC volts B. DC microamps C. DC volts D. DC millivolts
B
In a direct ignition system, the flame sensor proves A. the pilot flame B. the main burner flame C. both the pilot flame and main burner flame D. the high voltage spark
B
In a two-stage furnace, the typical manifold pressure in low-fire is A. 3.5 in. WC B. 1.75 in. WC C. 10.5 in. WC D. 1.0 in. WC
B
In an intermittent pilot (IP) ignition system A. the pilot must be manually lit and will remain lit indefinitely B. the pilot is lit electronically each time there is a call for heat C. the pilot must be lit manually each time there is a call for heatn an intermittent pilot (IP) ignition system D. the pilot is used to heat the bimetal fan switch
B
In the liquid-filled remote bulb pilot safety device, the liquid is usually A. water B. mercury C. refrigerant D. liquefied propane
B
Radiant heat is transferred by _______. A. ultraviolet rays B. infrared rays C. ionization D. refraction
B
The ________________ is usually made of silicone carbide or silicone nitride, operates at 120 V, and is used to ignite the main burner. A. flame sensor B. hot surface igniter C. spark electrode D. thermocouple
B
The first step in systematically troubleshooting a furnace with an integrated furnace control (IFC) is to A. turn off the power and gas supply to the furnace B. obtain the wiring diagram for the furnace being serviced C. rewire the furnace from scratch to ensure proper electrical connections D. try to determine the age of the system
B
The maximum allowable undiluted carbon monoxide level in the flue gas of a furnace is A. 50 PPM B. 400 PPM C. 1000 PPM D. 2500 PPM
B
The orifice is a precisely sized hole in the __________. A. manifold B. spud C. burner tube D. combustion chamber
B
The three things needed for combustion are A. air, fuel, and oxygen B. fuel, air, and heat C. fuel, air, and water D. air, carbon, and fuel
B
Which of the following is most likely true with regards to rooms that are zoned together? A. A living room and a bedroom will very likely be zoned together B. A garage, kitchen, and dining room will very likely be zoned together C. A garage, dining room, and bedroom will very likely be zoned together D. All of the bedrooms in a house will very likely be zoned together
B
Zoning a hydronic heating system is beneficial because this strategy saves energy by A. overheating the areas of the structure that are not occupied B. only heating the spaces that need to be heated at any given time C. underheating the areas of the structure that are occupied D. preventing the boiler from operating when occupied space gets too cold
B
__________________ is pulled into the burner, prior to ignition, and mixes with the gas for combustion. A. Excess air B. Primary air C. Secondary air D. Dilution air
B
A 10 Kw heating element, operating on rated 240 V, will generate _________ Btu/h A. 29,319 B. 31,062 C. 34,130 D. 35,875
C
A common problem in direct spark ignition systems is A. a dirty pilot orifice B. improper pilot positioning C. an improper spark gap D. a defective bimetallic pilot safety device
C
A control's response to a specific number of unsuccessful trials for ignition is a (n) A. prepurge cycle B. interpurge cycle C. lockout D. timed fan delay
C
A gas valve that may incorporate a manual control, gas supply for a pilot, pilot safety features, a pressure regulator, and operating controls is referred to as a (n) A. solenoid valve B. combination gas valve C. automatic combination gas valve D. heat motor-controlled valve
C
A high-mass boiler A. heats up quickly and cools down slowly B. heats up quickly and cools down quickly C. heats up slowly and cools down slowly D. heats up slowly and cools down quickly
C
A hydronic system provides comfort heating by producing A. heated hot water B. steam C. heated hot water or steam D. neither heated hot water nor steam
C
A tool, which measures in inches of water column, that can be used to test gas pressure is a A. combustion analyzer B. microammeter C. digital manometer D. digital multimeter
C
After a gas piping system is assembled, it should be A. pressurized with oxygen and leak tested with a digital leak detector or bubble solution B. pressurized with nitrogen to 150 psig and left for 24 hours to test for leaks C. pressurized with gas and leak tested with a digital leak detector or bubble solution D. pressurized with gas and leak tested with a small open flame
C
Burning one cubic foot of propane will produce approximately A. 1000 Btus B. 1500 Btus C. 2500 Btus D. 3200 Btus
C
The component that separates the flue gas from the medium being heated is the A. burner B. flue pipe C. heat exchanger D. draft diverter
C
The fan switch, used to turn the blower on and off, can be controlled by _____________. A. pressure or temperature B. the thermostat C. temperature or a time delay D. temperature only
C
The horizontal run of gas piping should be sloped in the direction of flow. The recommended slope is A. 1/4 in. rise per foot B. 1/4 in. rise per 10 feet C. 1/4 in. rise per 15 feet D. 1/4 in. rise per 20 feet
C
The most common furnace configurations are A. upflow, bi-flow, and downflow B. upflow, horizontal, and bi-flow C. downflow, upflow, horizontal, and multipoise D. downflow, counterflow, bi-flow, and upflow
C
The proper color of a gas flame is A. sharp all blue B. lazy all blue C. blue with slight orange tips D. lazy with yellow tips
C
The resistance wire used in electric heating elements is usually _________. A. copper B. nickel steel C. nickel chromium D. aluminum
C
To cycle the blower motor during the heating sequence, an integrated furnace control (IFC) uses A. time on-time off B. time on-temperature off C. temperature on-time off D. temperature on- temperature off
C
To test the flame rectification circuit, digital multimeter should be placed A. across the flame sensor terminals to test microfarads B. around the flame sensor wire to test for amps C. in series with the flame sensor to test microamps D. in series with the flame sensor to test for DCmV
C
Which of the following elements is not a power-consuming device? A. The sequencer heater coil B. A magnetic solenoid that moves the armature in a contactor C. The contacts of a contactor D. The blower motor
C
A bimetal fan/limit switch cycles the blower using A. time on-time off B. time on-temperature off C. temperature on-time off D. temperature on- temperature off
D
A high-efficiency condensing furnace falls into which venting category? A. Category I B. Category II C. Category III D. Category IV
D
A servo pressure regulator reacts to changes in A. the temperature and pressure in the vent system B. the voltage to pilot valve coil C. the valve's inlet gas pressure D. the valve's outlet gas pressure
D
A thermopile typically generates A. 24 to 120 VAC B. 18 to 30 mVDC C. 1 to 25 DC microamps D. 500 to 750 mVDC
D
Any unit heater designed to have air forced across the element should not be operated without the ________ operating. A. fuse B. interlock C. element D. fan
D
Furnace efficiency is measured by A. Energy Efficiency Ratio (EER) B. Season Energy Efficiency Ratio (SEER) C. Heating Seasonal Performance Factor (HSPF) D. Annual Fuel Utilization Efficiency (AFUE)
D
Furnaces with serpentine-type heat exchangers typically use A. ribbon burners B. slotted burners C. cast-iron burners D. inshot or upshot burners
D
In a conventional gas furnace, the hot flue gases are __________. A. forced out a PVC vent with a blower B. recycled through a secondary heat exchanger and then vented through a draft diverter C. forced through a type B vent by a blower D. vented by natural convection
D
In an intermittent pilot system, the pilot is ______________ A. continuously lit, whether there is a call for heat or not B. larger than in other systems that utilize a pilot flame C. lit manually at the start of the heating season D. lit each time there is a call for heat by the thermostat
D
Modulating furnaces typically have A. long run cycles and lower combustion efficiencies B. short run cycles and high temperature swings C. short run cycles and very low temperature swings D. longer run cycles and very low temperature swings
D
Most gas furnaces and appliances use a(n) _________ burner. A. compressed B. hybrid C. pressurized D. atmospheric
D
Quartz and glass panel electric units are classified as ________. A. natural-convection heaters B. forced-convection heaters C. forced-draft conductors D. radiant heaters
D
The benefits of electric baseboard heating are that ________. A. each room can be controlled individually B. they are inexpensive to install C. they operate on a 24-V power supply D. Both a and b
D
The component that consists of several thermocouples wired in series to increase voltage output is the A. flame sensor B. thermocouple C. bimetallic safety device D. thermopile
D
The limit switch is used on the electric element assembly to __________. A. start the unit if the thermostat malfunctions B. ensure that the fan stops when the unit cools down C. start the unit prematurely on a cold day D. shuts off the unit if high temperature occurs
D
The pressure at the manifold for natural gas is typically A. 10.5 to 11 in. WC. B. 8 in. WC. C. 3.5 psig. D. 3.5 in. WC.
D
The silicon carbide hot surface igniter, used in many direct ignition systems, typically operates at A. 18 to 30 mVDC B. 750 mVDC C. 24 VAC D. 120 VAC
D
The specific gravity of natural gas is A. 0.08 B. 1.00 C. 0.42 D. 0.60
D
The three adjustable pointers on a fan/limit switch are used to set the temperatures for A. igniter on, igniter off, high limit B. combustion blower on, fan on, and high limit C. gas valve on, fan on, and high limit D. fan on, fan off, and high limit
D
When working on a pressure regulator, turning the adjustment screw counterclockwise will A. increase the inlet pressure B. decrease the inlet pressure C. increase the outlet pressure D. decrease the outlet pressure
D
Which of the following would cause a problem with the flame rectification circuit? A. An overfiring condition B. Furnace short cycling C. An improperly positioned thermostat D. A poor ground wire connection
D
A gas furnace designed for use with natural gas can be used with liquefied petroleum (LP) with no system modifications True or false
False
All electric furnaces use package sequencers True or False
False
Electric heating units provide almost instant heat. Therefore, anticipators are not needed in electrical heat thermostats True or False
False
When using a pipe thread compound, it should be applied to the female threads, less the two end threads. True or False
False
Three products of complete combustion of natural and LP gas are carbon dioxide, water vapor, and _________________
Heat
In order to provide time delay between stages of electric heat, the controls that are used are called ______________.
Interlock
Butterfly shutters and sliding sleeves are examples of _____________ and are used on atmospheric type gas burners
Primary air adjusters
Generally speaking, electric heat is very efficient but can be more expensive to operate compared to oil and gas True or False
True
High efficiency condensing furnaces operate below the dew point of the combustion gases to allow condensation to happen. True or False
True
If flue gases are not vented properly, carbon monoxide could result True or false
True
If the number two contact on a package sequencer fails to close, the number three contact can still close True or False
True
In the USA, natural gas supplies supply gas with a heat content of about 1,050 Btu/cu ft. True or false
True
Liquid petroleum (LP) is heavier than air and can cause suffocation if not handled properly True or false
True
One potential safety hazard that all technicians should be aware of when working on an electrical furnace is that there are many exposed electrical connections behind the inspection panels True or False
True
Some units may be designed to move enough air across the heating elements so that they do not glow. True or False
True
The gas flame will lift off the burner and be noisy if it receives too much primary air True or false
True
Radiant electric heating panels used for ceiling installation are often made of _________________ with wire heating circuits running throughout
gypsum board
The horizontal furnace is positioned on its side, and it is usually installed in locations where it takes ____________________.
no floor space
