FDNY Z51 RMO EXAM QUESTIONS WITH CORRECT ANSWERS LATEST UPDATE 2026/2027
the efficiency of the refrigerant cycle is affected by the operation of the condenser. Of the
following, a more efficient centrifugal compressor operation results from - Answers lowering
the condenser pressure
In most semi hermetic compressors, the suction vapor is used for - Answers cools the motor
The amount of refrigerant that flows through the orifices of an economizer is determined by the
- Answers difference between the high side and the low side pressure
the instalation of an inline refrigerant cleaning system is advisable - Answers to remove
impurities from the system
a refrigerant engineer verifies that a condenser pump is cavitation of the following the most
likely cause for this condition is: - Answers a faulty cooling tower water level controller
when an expansion valve is operating properly, at the end of the evaporator will contain -
Answers only superheated vapor
a centrifugal water pump is considered to be fully primed when - Answers the pump is full of
liquid
A refrigeration compressor has failed to turn on. the engineer on duty verifies the electrical
circuit to the motor, including all switches and circuit breakers is complete, according to
recomended service practice, the next item to be checked would likely be the: - Answers
temperature and pressure controls
Refrigerants are characterized by their physical properties including Flashpoint, refrigeration
effect and others, of the refrigerants in commercial and industrial the highest latent heat and
refrigerant effect is: - Answers ammonia
which of the following ashrae refrigerant safety classification is the most toxic - Answers b3
which of the following ashrae refrigerant safety classification is the most flammable - Answers
a3
in q indirect refrigeration system,of the following, the one that would not be used as a cooling
medium for building spaces being cooled is - Answers r 22 (cooling medium= glycol or any brine
solution)
the primary way of achieving capacity control of a an centrifugal compressor is by: - Answers
adjustment to the inlet impeller pre rotation vanes
regarding the functioning of a steam turbine, why is it advisable to keep moisture in the inlet low
as possible - Answers keeps turbine blades wear to minimum
, a water chiller is equipped with a reciprocating compressor, a thermostatic expansion valve and
a an air cooled condenser. A restriction in the refrigerant line would result in - Answers high
suction super heat
the process by which refrigerant is extracted and cleaned for reuse without requirements for
reclamation is called - Answers recycle
the purpose of wear rings in a centrifugal pump is to - Answers prevent wearing of the pump
housing and impeller
a centrifugal compressor is in operation with suction pressure is 3 psig and the discharge is
10psi what is the atmospheric pressure is 14.7 which is the ratio closest to - Answers 1.39
electrical current us measured in - Answers amperage
how would you put an additional pump online - Answers open suction valve, open discharge
valve gradually
of the following, the major advantage of a shell and coil condenser is - Answers there is less
danger of developing leaks
an engineer needs to vary the flow of refrigerant in a refrigeration system, which operation in the
flow of the system does not include - Answers solenoid valve
thermal bull is attached to the suction plate between the evaporator cokl and the compressor by
an insulated line. assume that the machine room is 85deg f . break down of the insulation
results in: - Answers flood the evaporator
water and moisture is serious problem in a refrigerant system how to avoid - Answers proper
evaluation at the charging of the system
while on duty a refrigeration engineer notic That the suction line to the compressor and part of
the compressor itself is frosted over the following the most likely reason for this condition
would be - Answers There is not enough Refrigerant in the system
While doing a routine inspection the engineer notices the bulb of the TXV on the floor. The
refrigerant engineer should have attached a bulb at the - Answers The outlet end of the coil
A refrigerant engineer verifies that a chilled water pump is cavity to of the following the most
likely cause for this condition is - Answers Water leaks through the mechanical seals
The only refrigerant/temperature chart available to a refrigeration engineer lists the temperature
ﾟ ﾟ
In C if the chart indicates a Celsius temperature of 4 this is equivalent to - Answers 39.2 ﾟ
The use of oil in the refrigeration machine is to - Answers Reduce wear and friction in the
compressor parts
the efficiency of the refrigerant cycle is affected by the operation of the condenser. Of the
following, a more efficient centrifugal compressor operation results from - Answers lowering
the condenser pressure
In most semi hermetic compressors, the suction vapor is used for - Answers cools the motor
The amount of refrigerant that flows through the orifices of an economizer is determined by the
- Answers difference between the high side and the low side pressure
the instalation of an inline refrigerant cleaning system is advisable - Answers to remove
impurities from the system
a refrigerant engineer verifies that a condenser pump is cavitation of the following the most
likely cause for this condition is: - Answers a faulty cooling tower water level controller
when an expansion valve is operating properly, at the end of the evaporator will contain -
Answers only superheated vapor
a centrifugal water pump is considered to be fully primed when - Answers the pump is full of
liquid
A refrigeration compressor has failed to turn on. the engineer on duty verifies the electrical
circuit to the motor, including all switches and circuit breakers is complete, according to
recomended service practice, the next item to be checked would likely be the: - Answers
temperature and pressure controls
Refrigerants are characterized by their physical properties including Flashpoint, refrigeration
effect and others, of the refrigerants in commercial and industrial the highest latent heat and
refrigerant effect is: - Answers ammonia
which of the following ashrae refrigerant safety classification is the most toxic - Answers b3
which of the following ashrae refrigerant safety classification is the most flammable - Answers
a3
in q indirect refrigeration system,of the following, the one that would not be used as a cooling
medium for building spaces being cooled is - Answers r 22 (cooling medium= glycol or any brine
solution)
the primary way of achieving capacity control of a an centrifugal compressor is by: - Answers
adjustment to the inlet impeller pre rotation vanes
regarding the functioning of a steam turbine, why is it advisable to keep moisture in the inlet low
as possible - Answers keeps turbine blades wear to minimum
, a water chiller is equipped with a reciprocating compressor, a thermostatic expansion valve and
a an air cooled condenser. A restriction in the refrigerant line would result in - Answers high
suction super heat
the process by which refrigerant is extracted and cleaned for reuse without requirements for
reclamation is called - Answers recycle
the purpose of wear rings in a centrifugal pump is to - Answers prevent wearing of the pump
housing and impeller
a centrifugal compressor is in operation with suction pressure is 3 psig and the discharge is
10psi what is the atmospheric pressure is 14.7 which is the ratio closest to - Answers 1.39
electrical current us measured in - Answers amperage
how would you put an additional pump online - Answers open suction valve, open discharge
valve gradually
of the following, the major advantage of a shell and coil condenser is - Answers there is less
danger of developing leaks
an engineer needs to vary the flow of refrigerant in a refrigeration system, which operation in the
flow of the system does not include - Answers solenoid valve
thermal bull is attached to the suction plate between the evaporator cokl and the compressor by
an insulated line. assume that the machine room is 85deg f . break down of the insulation
results in: - Answers flood the evaporator
water and moisture is serious problem in a refrigerant system how to avoid - Answers proper
evaluation at the charging of the system
while on duty a refrigeration engineer notic That the suction line to the compressor and part of
the compressor itself is frosted over the following the most likely reason for this condition
would be - Answers There is not enough Refrigerant in the system
While doing a routine inspection the engineer notices the bulb of the TXV on the floor. The
refrigerant engineer should have attached a bulb at the - Answers The outlet end of the coil
A refrigerant engineer verifies that a chilled water pump is cavity to of the following the most
likely cause for this condition is - Answers Water leaks through the mechanical seals
The only refrigerant/temperature chart available to a refrigeration engineer lists the temperature
ﾟ ﾟ
In C if the chart indicates a Celsius temperature of 4 this is equivalent to - Answers 39.2 ﾟ
The use of oil in the refrigeration machine is to - Answers Reduce wear and friction in the
compressor parts
