FDNY Z51 RMO EVALUATION 2026 QUESTIONS AND
ANSWERS RATED A+
✔✔Cooling tower water requires the addition of chemical additives in order to: -
✔✔Reduce the formation of scale and algae
✔✔In the picture below describes the equipment's function: - ✔✔Remove non-
condensables from the condenser
✔✔The viscosity of lubrication oil is described by a number. A low viscosity number
describes oil that: - ✔✔Flows easily
✔✔The most likely reason for refrigeration engineer to use a psychrometer is to
measure: - ✔✔Relative humidity level of the atmosphere
✔✔The most important reason to use at least two compressors in a cascade system is
to: - ✔✔Avoid very high compression ratio for each compressor
✔✔The suction service valve of a reciprocating compressor is front seated and the
compressor runs until the low pressure cut out shuts the compressor off. When the
machine is stopped, the refrigeration engineer notices that the suction pressure
increases rapidly. The most probable cause of this pressure rise is: - ✔✔Malfunction of
a compressor valve
✔✔Regarding the functioning of a steam turbine, why is it advisable to keep moisture in
the inlet low as possible? - ✔✔Keeps turbine blades wear to minimum
✔✔According to the attached Material Safety Data Sheet, R-134 is a: - ✔✔Clear,
odorless liquid and vapor
✔✔Under normal conditions, the refrigerant enters the compressor as a: - ✔✔Low
pressure, super-heated vapor and leaves as a high pressure vapor
, ✔✔While operating an R-22 single acting compressor system, the refrigeration engineer
noticed oil foaming in the crankcase. This condition most likely, would have been
caused by a: - ✔✔Sudden drop in the crankcase pressure
✔✔Assume that an engineer is able to observe refrigerant water and oil together. The
fluids would settle in the container from top to bottom as follows: - ✔✔Oil, water,
refrigerant
✔✔What is the function of the vacuum breaker in the steam turbine? - ✔✔To achieve a
faster cost down cycle
✔✔An equalizer line on a TXV is used to: - ✔✔Compensate for the pressure drop
across the evaporator coil
✔✔If R-134 accidentally touches a refrigerant engineer's skin, what first aid should be
applied from the MSDS? - ✔✔Promptly flush the skin with water until all chemical is
removed
✔✔In a multi-stage centrifugal compressor, each stage: - ✔✔Is identical in volume to
the other stages
✔✔A refrigeration engineer notices excessive cycling of the temperature control for a
reciprocating compressor refrigeration unit. The crankcase temperature is high, the
compressor discharge temperature is low, the suction line temperature is high. Of the
following, the one that may cause this set of condition is? - ✔✔Faulty compressor
valves
✔✔On an operating centrifugal compressor refrigerant unit, the refrigeration engineer
notices that the compressor is short cycling. The unit is using a low side float valve as a
metering device. Of the following requirements, this would indicate that: - ✔✔The
system is undercharged with refrigerant
✔✔The vessel depicted below may used in connection with - ✔✔Refrigerant recovery
✔✔A refrigeration system uses jet ejector to raise settled oil mixed with refrigerant to
the oil pump. If a restriction in the refrigerant flow to the jet ejector develops: - ✔✔There
may be insufficient head to lift the oil
✔✔An indirect, low temperature refrigerant system frequently uses glycol, instead of salt
brine as the intermediate cooling medium. An advantage of this choice is: - ✔✔The
elimination of corrosion
ANSWERS RATED A+
✔✔Cooling tower water requires the addition of chemical additives in order to: -
✔✔Reduce the formation of scale and algae
✔✔In the picture below describes the equipment's function: - ✔✔Remove non-
condensables from the condenser
✔✔The viscosity of lubrication oil is described by a number. A low viscosity number
describes oil that: - ✔✔Flows easily
✔✔The most likely reason for refrigeration engineer to use a psychrometer is to
measure: - ✔✔Relative humidity level of the atmosphere
✔✔The most important reason to use at least two compressors in a cascade system is
to: - ✔✔Avoid very high compression ratio for each compressor
✔✔The suction service valve of a reciprocating compressor is front seated and the
compressor runs until the low pressure cut out shuts the compressor off. When the
machine is stopped, the refrigeration engineer notices that the suction pressure
increases rapidly. The most probable cause of this pressure rise is: - ✔✔Malfunction of
a compressor valve
✔✔Regarding the functioning of a steam turbine, why is it advisable to keep moisture in
the inlet low as possible? - ✔✔Keeps turbine blades wear to minimum
✔✔According to the attached Material Safety Data Sheet, R-134 is a: - ✔✔Clear,
odorless liquid and vapor
✔✔Under normal conditions, the refrigerant enters the compressor as a: - ✔✔Low
pressure, super-heated vapor and leaves as a high pressure vapor
, ✔✔While operating an R-22 single acting compressor system, the refrigeration engineer
noticed oil foaming in the crankcase. This condition most likely, would have been
caused by a: - ✔✔Sudden drop in the crankcase pressure
✔✔Assume that an engineer is able to observe refrigerant water and oil together. The
fluids would settle in the container from top to bottom as follows: - ✔✔Oil, water,
refrigerant
✔✔What is the function of the vacuum breaker in the steam turbine? - ✔✔To achieve a
faster cost down cycle
✔✔An equalizer line on a TXV is used to: - ✔✔Compensate for the pressure drop
across the evaporator coil
✔✔If R-134 accidentally touches a refrigerant engineer's skin, what first aid should be
applied from the MSDS? - ✔✔Promptly flush the skin with water until all chemical is
removed
✔✔In a multi-stage centrifugal compressor, each stage: - ✔✔Is identical in volume to
the other stages
✔✔A refrigeration engineer notices excessive cycling of the temperature control for a
reciprocating compressor refrigeration unit. The crankcase temperature is high, the
compressor discharge temperature is low, the suction line temperature is high. Of the
following, the one that may cause this set of condition is? - ✔✔Faulty compressor
valves
✔✔On an operating centrifugal compressor refrigerant unit, the refrigeration engineer
notices that the compressor is short cycling. The unit is using a low side float valve as a
metering device. Of the following requirements, this would indicate that: - ✔✔The
system is undercharged with refrigerant
✔✔The vessel depicted below may used in connection with - ✔✔Refrigerant recovery
✔✔A refrigeration system uses jet ejector to raise settled oil mixed with refrigerant to
the oil pump. If a restriction in the refrigerant flow to the jet ejector develops: - ✔✔There
may be insufficient head to lift the oil
✔✔An indirect, low temperature refrigerant system frequently uses glycol, instead of salt
brine as the intermediate cooling medium. An advantage of this choice is: - ✔✔The
elimination of corrosion
