Deck 24: Gas Heat

Question 1

Gas pressure is measured in which unit of measure?

A) inches of mercury
B) inches of water column
C) cfm
D) psi

Answer 1

B

Question 2

Natural gas is a mixture of __________ to __________% methane and 5-40% other hydrocarbons.

A) 70, 95
B) 60, 95
C) 30, 60
D) 10, 60

Answer 2

B

Question 3

LP gas has a heat content of __________ Btu/cu.ft.

A) 1000
B) 1050
C) 3200
D) 5000

Answer 3

C

Question 4

What three elements bond together to form aldehydes?

A) carbon, hydrogen, and water vapor
B) carbon, nitrogen, and oxygen
C) carbon, hydrogen, and oxygen
D) carbon dioxide, hydrogen, and oxygen

Question 5

Which product of combustion is NOT present during complete combustion?

A) CO₂
B) water vapor
C) CO
D) nitrogen

Question 6

Natural gas has a heat content of __________ Btu/cu.ft.

A) 500
B) 1050
C) 3200
D) 5000

Question 7

Two-stage gas valves are used to provide different capacities as the heating requirements of the structure change.

Question 8

It is possible to set up or adjust the firing efficiency of a fossil-fuel heating appliance by sight or sound.

Question 9

Conventional 80% efficient gas furnaces have a flue temperature of __________ degrees F.

A) 100
B) 200
C) 400
D) 600

Question 10

Natural gas has a natural garlic-like smell.

Question 11

The spud orifice on a natural gas furnace is larger than the spud orifice on an LP gas furnace.

Question 12

Condensing gas furnaces are classified as Category __________ appliances.

A) I
B) II
C) III
D) IV

Question 13

LP gas is heavier than air.

Question 14

When a thermocouple is heated, a voltage of __________ is generated.

A) 30 volts dc
B) 30 millivolts
C) 30 volts ac
D) 30 microamps

Question 15

Which products of combustion are toxic?

A) carbon dioxide
B) aldehydes
C) carbon monoxide
D) both a and c
E) both b and c

Question 16

LP gas has a boiling temperature of __________ degrees at atmospheric pressure.

A) 0
B) -20
C) -40
D) -50

Question 17

Which instrument measures the pressure of flue gases in the furnace?

A) draft gauge
B) smoke tester
C) carbon dioxide tester
D) stack thermometer

Question 18

Natural gas is heavier than air.

Question 19

LP gas is also used as a refrigerant.

Question 20

Incomplete combustion occurs when there is a lack of __________ during the combustion process.

A) CO₂
B) CO
C) nitrogen
D) oxygen

Question 21

When troubleshooting a gas furnace, the technician reads 24 volts at the gas valve solenoid coil, but there is no burner during a call for heat. What is the most likely cause?

A) defective room thermostat
B) defective limit switch
C) defective gas valve
D) defective induced draft motor

Question 23

List four types of ignition on residential gas furnaces.

Question 25

What is the efficiency rating of a gas furnace with an input of 105,000 Btus and an output of 84,000 Btus?

Question 26

The __________ rating of fossil-fuel heating appliances is commonly used to evaluate the efficiency of the appliance. This rating represents the percentage of the energy in the fuel that __________.

Question 28

List and describe two common types of gas valves.

Question 29

When troubleshooting a gas furnace, the technician reads 0 volts at the gas valve solenoid coil during a call for heat. What would NOT be the problem?

A) defective gas valve
B) defective room thermostat
C) defective induced draft motor
D) open limit switch
E) defective blower motor

Question 30

__________ appliances draw in outside air for combustion and then exhaust the flue gasses directly back out of the structure.

Question 31

List the three items that are necessary for combustion.