FDNY Z51 RMO ESSENTIAL STUDY QUESTIONS
AND ANSWERS
◉ In electrical circuits the conductor is always what color?
Answer: Green or Bare
◉ Unloaders are used for what?
Answer: To increase capacity
◉ Oil foaming in a crankcase is caused by what?
Answer: A sudden drop in crankcase pressure
◉ How would you test for acid in the refrigerant?
Answer: Spraying liquid refrigerant from a condenser or receiver on
to bond paper
◉ What is the function of a cylinder bypass?
Answer: To allow operation at different capacities
◉ The chilled water supply to the building is 55F. If the chiller is
being used for human comfort, should you be concerned about this,
and why?
,Answer: Yes. this temperature is too high for human comfort
purpose
◉ The packing gland of a centrifugal pump serves to:
Answer: The drip part of the packing gland gives evidence that there
is water in the pump
◉ Capacity control of a reciprocating hermetic compressor is
typically achieved through
Answer: Operation of the hot gas bypass valve
◉ The most important reason to sub-cool the refrigerant in the
condenser is to ensure that:
Answer: A pure liquid refrigerant will enter the metering device
◉ A refrigeration engineer is logging reading from a reciprocating
system. compressor discharge temperature have dropped
significantly and the suction line pressure is high. which of the
following that may be causing this set of condition.
Answer: An expansion valve that is open to wide
◉ A low side float valve is used to maintain:
Answer: The level of the refrigerant in the evaporator
,◉ Regarding fire safety, which ASHRAE refrigerant safety
classification indicates no flammability and lower toxicity?
Answer: A1
◉ All liquid has been recovered from a system to be overhauled, the
system
Answer: Should not be opened until all vapor has been recovered
◉ When a refrigerant engineer uses a portable compressor recovery
unit to remove vapor refrigerant from a refrigeration system the
removal rate of the refrigerant will gradually slow down because
Answer: The vapor density is decreasing
◉ You are the engineer running a 2000-ton (steam-driven turbine)
centrifugal refrigeration system, a refrigeration system supplies
chilled water to a college campus with multiple buildings. During the
course of making your rounds, you check the 9 cell cooling tower on
the roof. You note the water level in all of the cooling tower cells is
very low. Which one of the following immediate action would take?
Answer: Add additional make up water to cooling tower
◉ A rooftop water cooling tower is connected to a water pump in the
building basement with a 12 inches diameter pipe, with the pump
turn off, a pressure gauge at the pumps inlet show a pressure of 140
PSIG the height of the water column, in feet, would be closet to.
, Answer: 323
◉ What device protects the steam turbine from excessive speed?
Answer: Governor assembly
◉ A refrigeration compressor has failed to turn on. The refrigeration
engineer on duty verifies that the electrical circuit to the motor,
including all switches and circuit breakers, is complete according to
recommended service practice, the next item to be checked would
likely be the:
Answer: Temperature and pressure controls
◉ Refrigerants are characterized by their physical properties
included flashpoint, refrigeration effect, and others. Of the
refrigerants in commercial and industrial the highest latent heat and
refrigerant effect is:
Answer: Ammonia
◉ On what characteristics is ASHRAE refrigerant safety group
classification system:
Answer: flammability and toxicity
AND ANSWERS
◉ In electrical circuits the conductor is always what color?
Answer: Green or Bare
◉ Unloaders are used for what?
Answer: To increase capacity
◉ Oil foaming in a crankcase is caused by what?
Answer: A sudden drop in crankcase pressure
◉ How would you test for acid in the refrigerant?
Answer: Spraying liquid refrigerant from a condenser or receiver on
to bond paper
◉ What is the function of a cylinder bypass?
Answer: To allow operation at different capacities
◉ The chilled water supply to the building is 55F. If the chiller is
being used for human comfort, should you be concerned about this,
and why?
,Answer: Yes. this temperature is too high for human comfort
purpose
◉ The packing gland of a centrifugal pump serves to:
Answer: The drip part of the packing gland gives evidence that there
is water in the pump
◉ Capacity control of a reciprocating hermetic compressor is
typically achieved through
Answer: Operation of the hot gas bypass valve
◉ The most important reason to sub-cool the refrigerant in the
condenser is to ensure that:
Answer: A pure liquid refrigerant will enter the metering device
◉ A refrigeration engineer is logging reading from a reciprocating
system. compressor discharge temperature have dropped
significantly and the suction line pressure is high. which of the
following that may be causing this set of condition.
Answer: An expansion valve that is open to wide
◉ A low side float valve is used to maintain:
Answer: The level of the refrigerant in the evaporator
,◉ Regarding fire safety, which ASHRAE refrigerant safety
classification indicates no flammability and lower toxicity?
Answer: A1
◉ All liquid has been recovered from a system to be overhauled, the
system
Answer: Should not be opened until all vapor has been recovered
◉ When a refrigerant engineer uses a portable compressor recovery
unit to remove vapor refrigerant from a refrigeration system the
removal rate of the refrigerant will gradually slow down because
Answer: The vapor density is decreasing
◉ You are the engineer running a 2000-ton (steam-driven turbine)
centrifugal refrigeration system, a refrigeration system supplies
chilled water to a college campus with multiple buildings. During the
course of making your rounds, you check the 9 cell cooling tower on
the roof. You note the water level in all of the cooling tower cells is
very low. Which one of the following immediate action would take?
Answer: Add additional make up water to cooling tower
◉ A rooftop water cooling tower is connected to a water pump in the
building basement with a 12 inches diameter pipe, with the pump
turn off, a pressure gauge at the pumps inlet show a pressure of 140
PSIG the height of the water column, in feet, would be closet to.
, Answer: 323
◉ What device protects the steam turbine from excessive speed?
Answer: Governor assembly
◉ A refrigeration compressor has failed to turn on. The refrigeration
engineer on duty verifies that the electrical circuit to the motor,
including all switches and circuit breakers, is complete according to
recommended service practice, the next item to be checked would
likely be the:
Answer: Temperature and pressure controls
◉ Refrigerants are characterized by their physical properties
included flashpoint, refrigeration effect, and others. Of the
refrigerants in commercial and industrial the highest latent heat and
refrigerant effect is:
Answer: Ammonia
◉ On what characteristics is ASHRAE refrigerant safety group
classification system:
Answer: flammability and toxicity
