FDNY Q01/Q99
FDNY Q01/Q99 Written Exam
Questions and Solutions
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
FDNY Q01/Q99
,FDNY Q01/Q99
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
FDNY Q01/Q99
,FDNY Q01/Q99
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
FDNY Q01/Q99
, FDNY Q01/Q99
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) 380° F
D) 300 psig. - A) 280° F
If the insulation was removed from the bulb of the expansion valve, what would happen?
- Flooded evaporator —the TXV bulb opens in a range from 45 to 85° F. If the insulation
was removed, the bulb would sense the temperature in the machine room and keep the
TXV open, thus flooding the evaporator.
On the most common three-phase, four-wire service, the voltage between any phase and
neutral should be
A) 105 volts
B) 120 volts
C) 208 volts
D) 220 volts - B) 120 volts
FDNY Q01/Q99
FDNY Q01/Q99 Written Exam
Questions and Solutions
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
FDNY Q01/Q99
,FDNY Q01/Q99
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
FDNY Q01/Q99
,FDNY Q01/Q99
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
FDNY Q01/Q99
, FDNY Q01/Q99
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) 380° F
D) 300 psig. - A) 280° F
If the insulation was removed from the bulb of the expansion valve, what would happen?
- Flooded evaporator —the TXV bulb opens in a range from 45 to 85° F. If the insulation
was removed, the bulb would sense the temperature in the machine room and keep the
TXV open, thus flooding the evaporator.
On the most common three-phase, four-wire service, the voltage between any phase and
neutral should be
A) 105 volts
B) 120 volts
C) 208 volts
D) 220 volts - B) 120 volts
FDNY Q01/Q99
