HEAT Test Flashcards
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
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
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
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
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
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
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
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
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
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
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
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
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
All condensing furnaces manufactured after 1992 must have an AFUE rating of at least:
A) 80%
B) 86%
C) 90%
D) 96%
A) 80%
The proper chemical name for natural gas is:
A) methane
B) propane
C) butane
D) octane
A) methane
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
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
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
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
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
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
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
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
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
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
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
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
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
Any material that will readily release electrons is called?
A) an insulator
B) a conductor
C) a resistance
D) a neutron
B) a conductor
The symbol for current is:
A) E
B) I
C) R
D) W
B) I
Electricity can produce:
A) heat
B) light
C) magnetism
D) all of the above
D) all of the above
The safety ground conductor is usually color coded:
A) red
B) black
C) green
D) white
C) green
An electron has:
A) no charge
B) a negative charge
C) a positive charge
D) extra charge
B) a negative charge
What is resistance?
A) opposition to current flow
B) electrical pressure
C) amperage
D) voltage applied to the circuit
A) opposition to current flow
How are fused sized?
A) amps
B) volts
C) watts
D) both A and B
D) both A and B
Capacitors are rated in:
A) amperes
B) microfarads
C) volts
D) both B and C
D) both B and C
One horsepower is equal to how many watts?
A) 3.416
B) 746
C) 1200
D) 208
B) 746
In a series circuit, the voltage drop across each resistance (load) will:
A) always add up to equal the source voltage
B) depend on the value of each resistor
C) depend on the current flow in the circuit
D) all of the above
D) all of the above
Which of the following statements about current is true?
A) current flow is the same as voltage
B) current flow will increase when voltage increases
C) current flow will increase when resistance increases
D) current flow will decrease when voltage increases
B) current flow will increase when voltage increases
Which of the following statements is the correct formula for determining wattage in an electrical circuit?
A) W=E times I
B) W=E/R
C) W=I/R
D) W=E times R
A) W=E times I