FDNY Z51 RMO QUESTIONS AND ANSWERS
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
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
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)
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
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
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
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)
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
