ESCO HEATING 208 QUESTIONS WITH 100%CORRECT SOLUTIONS 2024-2025 LATEST UPDATED GRADED A+., Exams of Refrigeration and Air Conditioning

Download ESCO HEATING 208 QUESTIONS WITH 100%CORRECT SOLUTIONS 2024-2025 LATEST UPDATED GRADED A+. and more Exams Refrigeration and Air Conditioning in PDF only on Docsity!

ESCO HEATING 208 QUESTIONS

WITH 100%CORRECT SOLUTIONS

2024-2025 LATEST UPDATED

GRADED A+.

1. A gas furnace is to be installed in a garage. The burners and ignition sources must be located ______ above the floor. A: 6 inches B: 12 inches C: 18 inches D: 24 inches - Solution C: 18 inches
2. A good description of how hi-metal fan switch operates the blower motor on a gas furnace is: A: temperature on - time off. B: temperature on - time on. C: temperature on- temperature off. D: time on - time off. - Solution C: temperature on- temperature off
3. Redundant gas valves used on gas furnaces will shut down if gas pressure exceeds: A: 30.5 in. W.C. B: 60.5 in. W.C. C: 10.5 in. W.C. D: 13.5 in. W.C. - Solution D: 13.5 in. W.C.
4. Burning one cubic foot of Liquefied Petroleum gas completely will produce approximately ____BTU's. A: 2,000 - 2, B: 1,500-2. C: 1,200-1, D: 900-1,100 - Solution A

5. LP gas has a specific gravity of: A: .4-. B: 1.0-1. C: 1.5-2. D: 2.5 -3.0 - Solution C: 1.5-2.
6. What is the purpose of a spoiler screw located on a burner? A: Mix combustion and dilution air B: Mix primary and secondary air. C: Mix primary air and gas. D: Mix dilution and excess air. - Solution C: Mix primary air and gas
7. Furnace limit switches are wired in series with the: A: low speed fan B: high speed fan C: gas valve D: heat anticipator - Solution C: gas valve
8. A technician is using an extension ladder to work on roof top unit. The top of the ladder should extend beyond the support point. A: l foot B: 2 feet C: 3 feet D: 4 feet - Solution C: 3 feet 9.A technician determines that a natural gas furnace has a defective heat exchanger. The technician should: A: inform the homeowner. B: turn the thermostat off. C: turn the gas to the furnace off. D: All of the above. - Solution D: All of the above.
9. A natural gas (standing pilot) furnace usually requires ____gas pressure at the manifold and burners. A: 3.5 in- W.C. B: 4.2 in. W.C. C: 5.0 in, W.C. D: 7.0 in. W.C. - Solution A: 3.5 in- W.C.

11. The vent system for a condensing furnace is classified as ______by the National Field Gas Code. A: Category I B: Category II C: Category III D: Category IV - Solution D: Category IV
12. Type B vent pipe mast he kept at least _____from combustible materials. A: one eighth inch B: one quarter inch C: one half inch D: one inch - Solution D: one inch
13. All condensing furnaces manufactured after 1992 must have an AFUE rating ot at least: A: 80% B: 86% C: 90% D: 96% - Solution C
14. The ignition temperature of LP gas is: A: 500°F - 600°F B: 600°F-800°F C: 800dF - 1000°F D: 1000°F - 1200°F - Solution D
15. You have installed a Category IV two-pipe vent system that terminates through the roof of the residence. The elbow for the combustion air intake should: A: come straight out. B: point up. C: point down. D: have a rain cap. - Solution C
16. A fan motor is rated 1/3 HP at 120 volts. Approximately how many amps will the motor draw? A: B: 4 C: 6

D: 8 - Solution A

17. The reason heating thermostats have anticipators is to: A: reduce overshoot. B: increase overshoot. C: reduce lag. D: increase lag. - Solution A
18. Typical vent or stack temperature of a Category III furnace is: A: 450°F - 500°F B: 350°F - 450°F C: 280°F - 300°F D: 100°F - 120°F - Solution C
19. The proper chemical name for natural gas is: A: Methane B: Propane C: Butane D: Octane - Solution A
20. Burning one cubic foot of natural gas will produce _____BTU's A; 2000- B: 1,500 - 2. C: 1.200-1, D: 900-1,100 - Solution D
21. Natural gas has a specific gravity of: A: ,4-. B: 1.0 -1. C: 1.5-2. D; 2.5 -3.0 - Solution A
22. A BTU is the amount of heat required to raise the temperature of one pound of water: A: one degree centigrade. B: one degree Fahrenheit C: one degree Celsius. D: one degree Kelvin. - Solution B

23. Natural gas piping must be sized to prevent excessive pressure drops. The National Fuel Gas Code maximum pressure drop allowance is approximately: A: .20 in. W.C. B: .35 in. W.C. C: .50 in. W.C. D: 1.5 in. W.C. - Solution C
24. Gas piping must he installed with a pitch of: A; 1" per 15' run. B: 1/2" per 15'run. C: 1/3" per 15' run. D: 1/4" per 15' run. - Solution D
25. Pipe Joint compound should be applied to: A: male threads completely. B: male threads less two end threads. C: both male and female threads. D: female threads. - Solution B
26. A technician is installing a copper elbow on LP gas line; What type of solder is recommended? A: 60/40 solder. B: 95/5 solder. C: 0% stiver solder. D: 15% silver solder. - Solution D
27. To burn one cubic foot of natural gas completely; at least ____ of combustion air must be available. A: 5 cu ft. B: 10 cu ft. C: 15 cu ft. D: 20 cu ft. - Solution B
28. The ignition temperature of Natural Gas b A: 500°F - 600°F B: 600°F - 800°F C: 800°F - 1000°F D: 1000°F - 1200°F - Solution D

29. Air that is mixed with Natural Gas in the burner is called: A; primary air. B: combustion air. C; excess air. D: dilution air. - Solution A
30. A Natural Gas furnace is operating properly. How many cu. ft. of flue gas are needed for every one cu. ft. burned? A: 5 cu. ft. B: 10 cu. ft. C: 20 cu. ft. D: 30 cu. ft. - Solution B
31. The purpose of a flue baffle is: A: replace vent fans. B: control air to the burner C: slow down excess air. D: better furnace drafting. - Solution C
32. A redundant gas valve will have some type of vent limiting orifice. What is Its purpose? A: Decrease regulation pressure safety. B: Increase regulation pressure safety. C: Regulation and proper safe operation. D: Proper operation in high altitude locations. - Solution C
33. The LP gas pressure supplied to the gas valve should be: A: 2-4 in. W.C. B; 4-6 in. W.C. C: 7-9 in. W.C. D: 11-13 in. W.C - Solution D
34. An installed gas furnace should have a minimum of ____inches for service aceess. A: 12 B: 18 C: 24 D: 30 - Solution C

35. Which conditions listed below would cause the temperature limit safety switch to shut off the burner? A; High gas pressure. B: Low gas pressure. C: Vent fan or flue problem. D: Fan motor failure. - Solution D
36. The cut off plate is a component of the: A: ignition board. B: fan motor. C: draft diverter. D: blower housing. - Solution D
37. A "spud" or burner orifice: A: controls manifold pressure. B: controls air to burner. C: controls gas to burner. D: controls vent fan cycling. - Solution C
38. A good thermocouple should read approximately ___on a D.C. meter. A: 12 volts B: 24 volts C: 18 millivolts D: 250 millivolts - Solution C
39. Liquefied petroleum, (LP) gases are: A: butane and methane. B: propane and butane. C: butane, methane, and air. D; propane, methane, and air. - Solution B 40.Fan time/temperature delay switches are used on gas furnaces to: A: allow the vent to create proper draft. B: remove condensation from the manifold. C: allow the heat exchanger to warm up. D: Both "A" and "C" - Solution C
40. What instrument would a technician use to calculate return airflow to a furnace? A: Anemometer.

B: Velometer. C: Draft gauge. D: Megger. - Solution A

42. A furnace with a hot surface igniter will not light. Before changing the igniter the technician should: A: check for cracks. B: check voltage to igniter. C: check for loose wires. D: All of the above. - Solution D
43. A technician starts a standing pilot furnace and notices, on main igntion, the flames "roll out". The technician suspects: A; high gas pressure. B; low gas pressure. C: insufficient combustion air, D: a faulty vent. - Solution D
44. A technician serv icing an LP gas furnace notices a tag stating it was converted from natural gas. He finds large amounts of soot in the heat exchanger. What could be the cause of this soot? A: Low gas pressure. B: Low air flow (CFM). C: Incorrect return air velocity. D: Orifice, (spud) too large. - Solution A
45. A customer tells a technician that his six month old furnace stops heating before the residence is warm. This happens only on very cold nights. The technician lights the furnace, and tries to adjust the gas valve, but the flames do not change. He suspects A: a defective ignition module. B: a defective gas valve regulator. C: incorrect heat anticipator setting. D: intermittent vent fan operation. - Solution B
46. A standing pilot furnace has a bi-metal fan control. What are the factory' settings? A: Fan on 125°F / Fan off 110°F / Limit cut out 200°F. B: Fan on 125°F / Fan off 80°F / Limit cut out 200°F. C: Fan on 95°F / Fan off 110°F / Limit cut out 250°F.

D: Fan on 95°F / Fan off 80°F / Limit cut out 250°F - Solution B

47. A gas furnace with an induced draft blower is classified as ___by the National Fuel Gas Code. A: Category I B: Category II C: Category III D: Category IV - Solution C
48. Type B Vent pipe is constructed with an inner pipe and outer pipe.The inner pipe is made of: A: stainless steel. B: galvanized steel. C: aluminum. D: black iron - Solution C
49. On a dedicated vent system, a fire stop support plate is located: A: after an adjustable elbow. B: between flashing and the vent cap. C: above Type B metal vent. D: where it passes through a ceiling. - Solution D
50. When venting Category I furnaces, it is sometimes necessary to increase the vent pipe size. The proper location to adapt to the larger vent is: A: at the furnace connection. B: one foot above the furnace connection. C: two feet above the furnace connection. D: three feet above the furnace connection. - Solution C
51. You are installing 1/2" and 3/4" black iron pipe to a natural gas furnace. What is the approximate number of threads to cut? A: 5- B: 7- C: 8- D: 10-11 - Solution B
52. The proper name of the tool used to cut the threads of a steel pipe is a: A: pipe cutter. B: reamer.

C: ratchet bead cutter. D: die head. - Solution D

53. The proper name of the tool used to clean the inside edge of steel pipe is a: A: pipe cutter. B: reamer. C: ratchet head cutter. D: die head. - Solution B
54. Clevis, ring and single hook are types of:. A: sealants B: anchors C: hangers to support gas piping D: tools - Solution C
55. You are installing two sections of a rectangular sheet metal duct to the main supply line. What connectors are used to secure sections of the trunk line? A: S connectors and end clips. B: S connectors and drive clips. C: Snap connectors and expansion sleeves. D: Snap connectors and wedge sleeves. - Solution B
56. Metal ductwork tends to transmit noise and fan vibratians to conditioned space in residential installations. What type of connectors are specified to control this? A: Damper eliminating brackets B. Plastic hangers C Vapor barriers D: Flex connectors. - Solution D
57. Duct wrap is used to insulate round metal ducts. What is the approximate R-value for one inch of this insulation? A: R-1. B: R-2. C: R-4. D : R-6.0 - Solution C: R-4.
58. A "Category 1" natural gus furnace has a typical air temperature rise of:

A: 40°F-50°F

B: 40°F-70°F

C: 60°F-100°F

D: 60°F-120°F - Solution C

59. A technician connects the electrical circuit to 80,000 BTU gas furnace with a 3-ton cooing system. The fan motor is rated 1/3 HP @ 120 VAC. What size copper conductor would normally be used? A: 10-12AWG B: 12-14AWG C: 14-16AWG D: 16-18AWG - Solution B
60. A GFCI circuit breaker detects: A: Current leaks to ground. B: voltage drop at the appliance. C. AC&DC voltages at the appliance. D: impedance at the appliance. - Solution A 61.The National Electrical Code Classification for thermostat wire is: A: NEC Class l B: NEC Class 2 C: NEC Class A D: NEC Class B - Solution B
61. A homeowner complained that his furnace makes a load bang upon ignition. The technician decides to check the gas pressure and finds 3.2 in. W.C. at the manifold. The technician should:; A: check supply gas pressure. B; check the vent system. C: check burner alignment D: All of the above. - Solution D 63.A How much current does a typical flame sensor produce? A: 1-30 microamps. B: 30 - 200 mtcroamps. C: 1 - 3 ptcoamps. D: 300 - 200 piccomps. - Solution A

64.Direct spark ignition systems have no pilot assembly. A flame sensor rod usually|verifies the furnace has fired. How long is the "trial for ignition" or "flame proving time" A: 1-3 seconds. B: 4-8 seconds. C: 9-12 seconds. D: 15 - 25 seconds. - Solution B 65.A typical vent stack temperature on a Category I furnace is; A: 450°F-550°F. B: 350°F-450°F. C: 280°F-300°F D: I00°F-120°F - Solution B 66.A customer complains that a 2-year-old gas furnace will not light. The technician determines that the furnace locks out while attempting to light, and reads 19 VAC at the gas valve. The technician concludes: A: the electronic board is faulty. B: the gas valve could have a short. C: the secondary of the transformer could be faulty. D: Both "B" and "C". - Solution C 67.The pilot assembly orifice of a spark Ignition furnace is completely clogged. The technician should: A: replace it. B; use an awl to clean it. C: soak it in a coil cleaning solution. D: soak it in penetrating oil - Solution A 68.Carbon monoxide is dangerous* What percentage of CO is acceptable in a sample of the flue gas? A:.8% B: 1.0% C: 20% D:.04% - Solution D

69. A technician starts up a 15 year old natural gas furnace. The main burner lights and after 60 seconds the blower fan comes on, but the burner flames wave in one comer. The technician suspects: A: faulty burners.

B: a faulty vent system. C: a faulty blower housing. D: a faulty heat exchanger. - Solution D

70. A technician lights a spark type ignition furnace.The main burners light, but the spark igniter continues to spark. After 60 seconds, the blower fan comes on and the burner goes out. The technician suspects: A: a faulty fan switch. B: a faulty ignition board C: a faulty pilot bi-metal. D; Either "A" or "C" - Solution B
71. A technician starts up a standing pilot furnace. The main burners light, but after 30 seconds the furnace cycles off. The blower did not come on. The technician suspects: A: a faulty fan switch. B: a faulty gas valve. C: a defective thermocouple. D: Either "A" or "C" - Solution A
72. The proper instrument for measuring carbon dioxide is a: A: manometer B: ananometer C: draft gauge. D: combustion analyzer. - Solution D
73. If voltage is applied across two speed terminals on a fan motor, the motor will: A: run too slow. B: run too last C: change rotation D: short out - Solution D 74.The maximun static pressure on a typical gas furnace blower system is: A: .1 -.2 in. W.C, B: .2-.3 in. W.C. C : .4-.5 in,W.C. D: .6-1.0 in. W.C. - Solution C
74. Induced draft furnaces have a vent safety switch that should open at

A: 80°F.

B: l00°F. C: 120°F. D: 140°F. - Solution D

76. A technician shoald install a thermostat approximately______ inches above the floor. A: 44 B: 52 C: 70 D: 78 - Solution B
77. Thermostat wire comes in two standard gauges: A: 26 and 24 AWG B: 22 and 20 AWG C: 18 and l6 AWG D: 14 and 12 AWG - Solution C
78. A technician solders a spade connector to a wire. What type of solder should be used? A: rosin core. B: 60/40. C: 40/60. D: 95/5. - Solution A
79. A furnace blower motor is rated at 115 VAC. What is the allowable voltage variance? A; ±5 vote. B: ±10 volts.| C: +5vote. D: +10 volts. - Solution A
80. To change the speed of a belt driven blower, the technician should: A: adjust motor and blower wheel pulleys B: adjust blower wheel pulley. C: adjust motor pulley. D: change blower wheel. - Solution C
81. the formula (x= A: FPM

B: CFM

C: latent heat D: Sensible heat - Solution B

82. The most common burner used in induced draft furnace is: A: single port. B: ribbon C: inshot D:Potted - Solution C
83. A technician wraps a thermostst wire ten times around his clamp-on ampmeter and measures 5.5 amps between R and W on the thermostat sub-base. He should set the heat anticipator too: A: 5. B:. C:. D: .055 - Solution B
84. A gas valve with 100% shut off means: A: gas to main burner is shut-off B: gas to a pilot burner is shut off C: gas to the manifold is shut off D: gas to the regulator is shut off - Solution B
85. A gas furnace has an electric control board. How is the fan cycled during heating? A: heat relay B: cooling bi-metal C: temperature. D: time. - Solution D
86. Fuseable links used on furnace provide: A: Fan safety B: transformer protectiom C: gas valve regulation D: Flame rollout protection - Solution D
87. A gas furnace is installed in a closet. What is the minumum recommended clearance between the front of the furnace and the closet door?

A: 4 inches B: 6 inches C: 8 inches D: 10 inches. - Solution A

88. A primary cause of "Flashback" is: A: high manifold pressure. B: low manifold pressure. C: excessive primary air. D: excessive combustion air. - Solution B
89. The Maximum allowable temperature rise through a furnace heat exchanger is; A: 70°F. B: 80°F. C: 90°F. D: 100°F. - Solution A
90. The reason for a crossover on a gas burner is to: A: Prevent soot buildup B: prevent short cycling. C: provide smooth lighting af all burners. D: provide secondary air. - Solution C
91. A technician needs to run thermostat wire 75 feet. To avoid a voltage drop, the technician should use: A: # 16 AWG. B: # 18 AWG. C: # 20 AWG. D: # 22 AWG. - Solution A
92. A gas furnace has an induced draft fan. What switch must operate property before ignition sequence? A: fan limit. B: dilation air. C: rollout. D: differential air pressure. - Solution D

93. A technician reads 2 Ohms between the common and low speed wires oa a 120 VAC furnace motor. from this the technician determines that the winding is; A: grounded. B: open. C: shorted. D: OK. - Solution C
94. A technician reads infinity between the high and low speed wires on a 120 VAC furnace motor. A: grounded. B: open. C: shorted. D: OK. - Solution B
95. The "bonnet capacity" of a furnace is: A: furnace category rating. B: furnace venting category. C: furnace input BTU's. D: furnace output BTU's - Solution D
96. A gas furnace installed at altitudes above ______feet needs to have adjustments to operate properly. A: B: 1000 C: 1, D: 2,000 - Solution D
97. Failure to polarize a replacement low voltage transformer in a electronic ignition furnace will: A: cause no problems. B: short the PC board. C: ground tbe PC board. D: cause flame rectification problems. - Solution D
98. A spark ignitor operates at______VAC. A: 1, B: 5, C: 8, D: 7,500 and higher - Solution D

99. Which type of metallic conduit is recommended for indoor use only? A: EMT B: IMC C: PVC D: MCC - Solution A 100 A dedicated vent system: A; serves a combination of appliances. B: is the only vent for an appliance. C: is a manifold vent for an appliance. D: is a muIti-position vent for an appliance. - Solution B