Q-01 FDNY COMPLETE ACTUAL EXAM /
QUESTIONS AND CORRECT ANSWERS 2024/2025
LATEST VERSION.
Rupture members, when used in parallel with a relief valve, are not to exceed _____%
above designed working pressure - 20%
Butterfly valve: where can it be used? - Can be used on the inlet and outlet of a water
pump
What electrical motor protection device automatically resets itself? - The thermal
protector
746 watts equals how many kilowatt hours? - .746 kilowatt hours
What position is the liquid line service valve normally in? - Back-seated
In an operating evaporator, oil stays on top of which refrigerant? - Carbon dioxide, R-
744
At what pressure does the relief valve blow on a high pressure machine? - 300 psi
What would indicate a restriction (such as dirt or scale) in the liquid line? - Frost
immediately after the restriction
What does solubility mean? - The ability of a refrigerant to mix with other substances
Charging Vapor —In a compression system, where do you charge the vapor? - Suction
side of the compressor at the Suction Service Valve
When comparing a brine with s PH of 8 to one with a PH of 10, its alkalinity is: - 100
times greater (ex. PH 8 to PH 9 is 10 times greater)
In an efficiently operating induced draft cooling tower, the leaving water is between: -
Dry bulb and wet bulb temperature
To produce the desired evaporator temperature, the power input is reduced by keeping
head pressure... - Head pressure as low as possible & suction pressure as high as
needed
,The accumulator is usually between the... - Compressor and evaporator
An oiling system in a large centrifugal system should consist of at least... - Reservoir,
pump and distribution lines
In an evaporator that chills brine, the greatest cooling effect on the brine results from
the... - Boiling of low pressure liquid
The flow of weak liquor to the absorber is controlled by
A) gas pressure
B) throttling device
C) float valve
D) pressure of the strong liquor pump - B) throttling device
The best way of detecting ammonia brine is by using
A) CO2 gas
B) potassium of lime
C) Nessler reagent
D) carbonate of soda - C) Nessler reagent
The best time to purge an ammonia plant with 250 lbs. of ammonia is
A) during shut-down, because you will lose ammonia
B) while charging the plant
C) during operation
D) none of the above - C) during operation
What will make the strong liquor in the absorber decrease?
A) expansion valve open too much
B) A decrease in evaporator load
C) An increase in evaporator load
D) Too much steam on the generator - B) A decrease in evaporator load
Which of the following statements is incorrect?
A) A service valve is a key-operated shut-off valve used during shipment, installation
and repairs
B) Brine is a liquid cooled by refrigeration and used for the transmission of heat
C) A fusible plug has a set-temperature fusible member to relieve pressure
D) A rupture member automatically ruptures at a predetermined temperature - D) A
rupture member automatically ruptures at a predetermined temperature
Oil in a refrigerant should
A) have a high pour point
B) have a low flash point
C) have a high viscosity
D) not contain moisture - D) not contain moisture
, In an NH3 dry expansion evaporator with TXV and bulb clamped properly on the outlet
of the evaporator, the superheat is
A) 7 to 10° F
B) 5 to 9° F
C) 20 to 30° F
D) 1 to 2° F - A) 7 to 10° F
The setting of a fusible plug is
A) 280° F
B) 300° F
C) b380° bF
D) b300 bpsig. b- b bA) b280° bF
If bthe binsulation bwas bremoved bfrom bthe bbulb bof bthe bexpansion bvalve, bwhat bwould
bhappen? b- b bFlooded bevaporator b—the bTXV bbulb bopens bin ba brange bfrom b45 bto b85° bF. bIf
bthe binsulation bwas bremoved, bthe bbulb bwould bsense bthe btemperature bin bthe bmachine
broom band bkeep bthe bTXV bopen, bthus bflooding bthe bevaporator.
On bthe bmost bcommon bthree-phase, bfour-wire bservice, bthe bvoltage bbetween bany bphase
band bneutral bshould bbe
A) b105 bvolts
B) b120 bvolts
C) b208 bvolts
D) b220 bvolts b- b bB) b120 bvolts
A brefrigerant bovercharge bwould
A) bincrease bhead bpressure
B) bdecrease bhead bpressure
C) bdecrease bsolution-side bpressure
D) bdecrease bdischarge-side bpressure b- b bA) bincrease bhead bpressure
A bdryer bis bgenerally binstalled bwith bother bequipment bin ba bcommercial bFreon bcompressor
bsystem. bThe brecommended blocation bof bthis bdryer bis bon bthe
A) bhigh-pressure bline bbetween bcondenser band breciever
B) bsuction bline bbetween bevaporator band bcompressor
C) bdischarge bline bbetween bcompressor band bcondenser
D) bliquid bline bbetween breceiver band bexpansion bvalve b- b bD) bliquid bline bbetween breceiver
band bexpansion bvalve
R-22 b—What bdoes bit bsmell blike? b- b bOdorless
Desirable bcharacteristics bof ba brefrigerant:
A) bHigh b__________
B) bLow b__________ b- b bA) bHigh bcritical bpoint
B) bLow bfreezing bpoint
QUESTIONS AND CORRECT ANSWERS 2024/2025
LATEST VERSION.
Rupture members, when used in parallel with a relief valve, are not to exceed _____%
above designed working pressure - 20%
Butterfly valve: where can it be used? - Can be used on the inlet and outlet of a water
pump
What electrical motor protection device automatically resets itself? - The thermal
protector
746 watts equals how many kilowatt hours? - .746 kilowatt hours
What position is the liquid line service valve normally in? - Back-seated
In an operating evaporator, oil stays on top of which refrigerant? - Carbon dioxide, R-
744
At what pressure does the relief valve blow on a high pressure machine? - 300 psi
What would indicate a restriction (such as dirt or scale) in the liquid line? - Frost
immediately after the restriction
What does solubility mean? - The ability of a refrigerant to mix with other substances
Charging Vapor —In a compression system, where do you charge the vapor? - Suction
side of the compressor at the Suction Service Valve
When comparing a brine with s PH of 8 to one with a PH of 10, its alkalinity is: - 100
times greater (ex. PH 8 to PH 9 is 10 times greater)
In an efficiently operating induced draft cooling tower, the leaving water is between: -
Dry bulb and wet bulb temperature
To produce the desired evaporator temperature, the power input is reduced by keeping
head pressure... - Head pressure as low as possible & suction pressure as high as
needed
,The accumulator is usually between the... - Compressor and evaporator
An oiling system in a large centrifugal system should consist of at least... - Reservoir,
pump and distribution lines
In an evaporator that chills brine, the greatest cooling effect on the brine results from
the... - Boiling of low pressure liquid
The flow of weak liquor to the absorber is controlled by
A) gas pressure
B) throttling device
C) float valve
D) pressure of the strong liquor pump - B) throttling device
The best way of detecting ammonia brine is by using
A) CO2 gas
B) potassium of lime
C) Nessler reagent
D) carbonate of soda - C) Nessler reagent
The best time to purge an ammonia plant with 250 lbs. of ammonia is
A) during shut-down, because you will lose ammonia
B) while charging the plant
C) during operation
D) none of the above - C) during operation
What will make the strong liquor in the absorber decrease?
A) expansion valve open too much
B) A decrease in evaporator load
C) An increase in evaporator load
D) Too much steam on the generator - B) A decrease in evaporator load
Which of the following statements is incorrect?
A) A service valve is a key-operated shut-off valve used during shipment, installation
and repairs
B) Brine is a liquid cooled by refrigeration and used for the transmission of heat
C) A fusible plug has a set-temperature fusible member to relieve pressure
D) A rupture member automatically ruptures at a predetermined temperature - D) A
rupture member automatically ruptures at a predetermined temperature
Oil in a refrigerant should
A) have a high pour point
B) have a low flash point
C) have a high viscosity
D) not contain moisture - D) not contain moisture
, In an NH3 dry expansion evaporator with TXV and bulb clamped properly on the outlet
of the evaporator, the superheat is
A) 7 to 10° F
B) 5 to 9° F
C) 20 to 30° F
D) 1 to 2° F - A) 7 to 10° F
The setting of a fusible plug is
A) 280° F
B) 300° F
C) b380° bF
D) b300 bpsig. b- b bA) b280° bF
If bthe binsulation bwas bremoved bfrom bthe bbulb bof bthe bexpansion bvalve, bwhat bwould
bhappen? b- b bFlooded bevaporator b—the bTXV bbulb bopens bin ba brange bfrom b45 bto b85° bF. bIf
bthe binsulation bwas bremoved, bthe bbulb bwould bsense bthe btemperature bin bthe bmachine
broom band bkeep bthe bTXV bopen, bthus bflooding bthe bevaporator.
On bthe bmost bcommon bthree-phase, bfour-wire bservice, bthe bvoltage bbetween bany bphase
band bneutral bshould bbe
A) b105 bvolts
B) b120 bvolts
C) b208 bvolts
D) b220 bvolts b- b bB) b120 bvolts
A brefrigerant bovercharge bwould
A) bincrease bhead bpressure
B) bdecrease bhead bpressure
C) bdecrease bsolution-side bpressure
D) bdecrease bdischarge-side bpressure b- b bA) bincrease bhead bpressure
A bdryer bis bgenerally binstalled bwith bother bequipment bin ba bcommercial bFreon bcompressor
bsystem. bThe brecommended blocation bof bthis bdryer bis bon bthe
A) bhigh-pressure bline bbetween bcondenser band breciever
B) bsuction bline bbetween bevaporator band bcompressor
C) bdischarge bline bbetween bcompressor band bcondenser
D) bliquid bline bbetween breceiver band bexpansion bvalve b- b bD) bliquid bline bbetween breceiver
band bexpansion bvalve
R-22 b—What bdoes bit bsmell blike? b- b bOdorless
Desirable bcharacteristics bof ba brefrigerant:
A) bHigh b__________
B) bLow b__________ b- b bA) bHigh bcritical bpoint
B) bLow bfreezing bpoint
