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Flashcards in HEAT Test Deck (100)
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1

A slight glass would normally be located:

A) in the liquid line, ahead of the metering device
B) in the suction line, ahead of the compressor
C) either A or B
D) neither A or B

A) in the liquid line, ahead of the metering device

2

Bubbles in a sight glass could be an indication of:

A) an overcharged of refrigerant
B) a Low refrigerant charge
C) a restriction in the filter-drier (if the sight glass is after the filter-drier)
D) either B or C

D) either B or C

3

A clear sight glass could indicate:

A) all liquid refrigerant
B) no refrigerant
C) either a or b
D) neither a or b

C) either a or b

4

Which of the following is TRUE of a solenoid in a pump down system?

A) it is located after the metering device
B) it is located before the metering device
C) it is located after the evaporator
D) it is used instead of a metering device

B) it is located before the metering device

5

A Low pressure cut-off switch is used to:

A) establish a minimum operating pressure in the evaporator
B) prevent condensing pressure from reaching dangerously high levels
C) sense oil pressure in the lower portion of the compressor
D) all of the above

A) establish a minimum operating pressure in the evaporator

6

A good description of a how bi-metal fan switch operates the blower motor on a gas furnace is:

A) temperature on-time off
B) time on-temperature off
C) temperature on-temperature off
D) time on-time off

C) temperature on-temperature off

7

Redundant gas valves used on gas furnaces will shut down if the 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

D) 13.5 in W.C

8

Burning one cubic foot of Liquefied Petroleum gas will completely produce approximately _________ BTU's

A) 2000-2500
B) 1500-2000
C) 1200-1500
D) 900-1100

A) 2000-2500

9

What is the purpose of a spoiler screw located on a burner, or adjustable-shutters?

A) mix combustion and dilution air
B) mix primary and secondary air
C) mix primary air and gas
D) mix dilution and excess air

C) mix primary air and gas

10

Furnace limit switches are wired in series with:

A) low speed fan
B) high speed fan
C) gas valve
D) heat anticipator

C) gas valve

11

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 valve to the furnace off
D) all of the above

D) all of the above

12

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

A) 3.5 in W.C

13

LP gas has a specific gravity of:

A) .4-.8
B) 1.0-1.1
C) 1.5-2.0
D) 2.5-3.0

C) 1.5-2.0

14

All condensing furnaces manufactured after 1992 must have an AFUE rating of at least:

A) 80%
B) 86%
C) 90%
D) 96%

A) 80%

15

The proper chemical name for natural gas is:

A) methane
B) propane
C) butane
D) octane

A) methane

16

A furnace nameplate specifies a temperature rise of 40-70 degrees. Temperature measurements indicate a rise of 80 degrees. The most appropriate action is to:

A) decrease fan speed
B) adjust the gas pressure regulator
C) increase fan speed
D) reduce burner size

C) increase fan speed

17

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

B) one degree Fahrenheit

18

Gas piping must be installed with a pitch of:

A) 1" per 15' of run
B) 1/2" per 15' of run
C) 1/3" per 15' of run
D) 1/4" per 15' of run

D) 1/4" per 15' of run

19

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

B) male threads less two end threads

20

A technician is installing a copper elbow on LP gas line; what type of solder is recommended?

A) rosin core solder
B) 95/5 solder
C) 0% silver
D) 15% silver

D) 15% silver

21

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

B) 10 cu ft

22

Air that is mixed with natural gas in the burner is called:

A) primary air
B) combustion air
C) excess air
D) dilution air

A) primary air

23

A natural gas furnace is operating properly. How many cubic feet 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

D) 30 cu ft

24

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

C) allow the heat exchanger to warm up

25

A technician needs to run the 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

B) 18 AWG

26

A good thermocouple should read approximately________on a D.C. meter.

A) 12 volts
B) 24 volts
C) 18 milli-volts
D) 250 milli-volts

C) 18 milli-volts

27

What is current flow?

A) flow of voltage in a circuit
B) the impedance of a circuit
C) the inductive reactance of the circuit
D) the flow of electrons in the circuit

D) the flow of electrons in the circuit

28

What is impedance?

A) opposition to alternating current flow
B) electrical pressure
C) amperage
D) voltage applied to the circuit

A) opposition to alternating current flow

29

Any material that will readily release electrons is called?

A) an insulator
B) a conductor
C) a resistance
D) a neutron

B) a conductor

30

The symbol for current is:

A) E
B) I
C) R
D) W

B) I