Q-01 FDNY
A 10-ton refrigeration unit has a capacity of
A) 2,000 btu per minute
B) 12,000 btu per hour
C) 20,000 btu per minute
D) 144,000 btu per day - ------------ANS: A) 2,000 btu per minute
A compressor may lose oil if
(A) there is air in the system
(B) the velocity of refrigerant in the risers is too low.
(C) there are medium pressure drops in the evaporator.
(D) There are small load variations in the system. - ------------ANS: (B) the velocity of
refrigerant in the risers is too low.
A constant-pressure expansion valve is opening under a fluctuating load. Under a
heavy load, this valve will
A) starve the evaporator.
B) starve, then flood the evaporator.
C) flood the evaporator.
D) increase suction pressure. - ------------ANS: A) starve the evaporator.
A desirable property of ammonia refrigerant oil is
(A) high paraffin content.
(B) being free of water.
(C) very low flashpoint.
,(D) all of the above. - ------------ANS: (B) being free of water.
A desireable property of ammonia refrigerant oil is
A) high paraffin content
B) being free of water
C) very low flash point
D) all of the above - ------------ANS: B) being free of water
A desired chemical refrigerant characteristic is
(A) it mixes readily with oil
(B) stability
(C) it can easily change from a liquid to a vapor and back
(D) all of the above - ------------ANS: (B) stability
A direct expansion (bare) coil evaporator is used to maintain a meat storage space
at 28 to 30° F. The last coil has no frost. It can be said that this system is
A) condition is acceptable to maintain a high plant efficiency
B) is a direct indication of air in the system
C) indicates moisture in the refrigerant
D) is a direct indication that the coil is being starved - ------------ANS: D) is a direct
indication that the coil is being starved
A dryer is generally installed with other equipment in a commercial Freon
compressor system. The recommended location of this dryer is on the
A) high-pressure line between condenser and reciever
B) suction line between evaporator and compressor
,C) discharge line between compressor and condenser
D) liquid line between receiver and expansion valve - ------------ANS: D) liquid line
between receiver and expansion valve
A large refrigeration plant has three compressors with synchronous motor drives and
seven compressor with squirrel cafe induction motors. One important reason for this
arrangement is
A) provide some refrigeration capacity in the event of an AC power failure.
B) allow some variation in capacity, since synchronous motors can easily be run at
various speeds.
C) correct the overall power factor.
D) stabilize the overall plant demand factor. - ------------ANS: C) correct the overall
power factor.
A pressure or temperature response mechanism for automatically stopping the
operation of the pressure-imposing element is the
A) pressure-limiting device
B) pressure-relief valve
C) pressure-imposing device
D) pressure-relief device - ------------ANS: A) pressure-limiting device
A pressure or temperature response mechanism for automatically stopping the
operation of the pressure-imposing element is the
A) Pressure-limiting device
B) Pressure-relief valve
C) Pressure-imposing device
D) Pressure-relief device - ------------ANS: A) Pressure-limiting device
, A reciprocating refrigeration compressor is controlled in response to the water
temperature leaving the water chiller. If the thermostat is used for compressor control
did not have a wide enough differential, the probable result would be
A) inadequate time for oil to return to the compressor
B) stop on high-pressure cutout
C) stop on low-pressure cutout
D) a very long operating cycle - ------------ANS: A) inadequate time for oil to return to
the compressor
A refrigerant overcharge would
A) increase head pressure
B) decrease head pressure
C) decrease solution-side pressure
D) decrease discharge-side pressure - ------------ANS: A) increase head pressure
A wound-rotor induction motor with external resistance is a
A) multispeed motor
B) constant-speed motor
C) single-speed motor
D) waterproof cover - ------------ANS: A) multispeed motor
A wound-rotor induction motor with external resistance is a
A) Multispeed motor
B) Constant-speed motor
C) Single-speed motor
D) Waterproof cover - ------------ANS: A) Multispeed motor
A 10-ton refrigeration unit has a capacity of
A) 2,000 btu per minute
B) 12,000 btu per hour
C) 20,000 btu per minute
D) 144,000 btu per day - ------------ANS: A) 2,000 btu per minute
A compressor may lose oil if
(A) there is air in the system
(B) the velocity of refrigerant in the risers is too low.
(C) there are medium pressure drops in the evaporator.
(D) There are small load variations in the system. - ------------ANS: (B) the velocity of
refrigerant in the risers is too low.
A constant-pressure expansion valve is opening under a fluctuating load. Under a
heavy load, this valve will
A) starve the evaporator.
B) starve, then flood the evaporator.
C) flood the evaporator.
D) increase suction pressure. - ------------ANS: A) starve the evaporator.
A desirable property of ammonia refrigerant oil is
(A) high paraffin content.
(B) being free of water.
(C) very low flashpoint.
,(D) all of the above. - ------------ANS: (B) being free of water.
A desireable property of ammonia refrigerant oil is
A) high paraffin content
B) being free of water
C) very low flash point
D) all of the above - ------------ANS: B) being free of water
A desired chemical refrigerant characteristic is
(A) it mixes readily with oil
(B) stability
(C) it can easily change from a liquid to a vapor and back
(D) all of the above - ------------ANS: (B) stability
A direct expansion (bare) coil evaporator is used to maintain a meat storage space
at 28 to 30° F. The last coil has no frost. It can be said that this system is
A) condition is acceptable to maintain a high plant efficiency
B) is a direct indication of air in the system
C) indicates moisture in the refrigerant
D) is a direct indication that the coil is being starved - ------------ANS: D) is a direct
indication that the coil is being starved
A dryer is generally installed with other equipment in a commercial Freon
compressor system. The recommended location of this dryer is on the
A) high-pressure line between condenser and reciever
B) suction line between evaporator and compressor
,C) discharge line between compressor and condenser
D) liquid line between receiver and expansion valve - ------------ANS: D) liquid line
between receiver and expansion valve
A large refrigeration plant has three compressors with synchronous motor drives and
seven compressor with squirrel cafe induction motors. One important reason for this
arrangement is
A) provide some refrigeration capacity in the event of an AC power failure.
B) allow some variation in capacity, since synchronous motors can easily be run at
various speeds.
C) correct the overall power factor.
D) stabilize the overall plant demand factor. - ------------ANS: C) correct the overall
power factor.
A pressure or temperature response mechanism for automatically stopping the
operation of the pressure-imposing element is the
A) pressure-limiting device
B) pressure-relief valve
C) pressure-imposing device
D) pressure-relief device - ------------ANS: A) pressure-limiting device
A pressure or temperature response mechanism for automatically stopping the
operation of the pressure-imposing element is the
A) Pressure-limiting device
B) Pressure-relief valve
C) Pressure-imposing device
D) Pressure-relief device - ------------ANS: A) Pressure-limiting device
, A reciprocating refrigeration compressor is controlled in response to the water
temperature leaving the water chiller. If the thermostat is used for compressor control
did not have a wide enough differential, the probable result would be
A) inadequate time for oil to return to the compressor
B) stop on high-pressure cutout
C) stop on low-pressure cutout
D) a very long operating cycle - ------------ANS: A) inadequate time for oil to return to
the compressor
A refrigerant overcharge would
A) increase head pressure
B) decrease head pressure
C) decrease solution-side pressure
D) decrease discharge-side pressure - ------------ANS: A) increase head pressure
A wound-rotor induction motor with external resistance is a
A) multispeed motor
B) constant-speed motor
C) single-speed motor
D) waterproof cover - ------------ANS: A) multispeed motor
A wound-rotor induction motor with external resistance is a
A) Multispeed motor
B) Constant-speed motor
C) Single-speed motor
D) Waterproof cover - ------------ANS: A) Multispeed motor
