©SIRJOEL EXAM SOLUTIONS
11/3/2024 10:54 PM
Local 94 School - 475 terms to know for the
RMO written Exam Questions With 100%
Verified Answers
How do automatic expansion valves work? - answer✔Evaporator pressure closes the valve and
spring pressure opens the valve.
When will a faulty check valve cause the most damage? - answer✔On startup.
What will happen if a TEV'S sensing bulb insulation wears off of the suction line in an 85 F
Degree room? - answer✔You will flood the evaporator.
What can a clogged pump strainer cause? - answer✔A reduction or loss in water flow which will
lead to high condenser head pressure.
What part of the Refrigeration system is the solenoid valve part of? - answer✔The pump down
cycle (Thermostat - Solenoid Valve - Low Pressure Controller).
What is the proper machine start up procedure? - answer✔Check oil, start chilled water pump,
start condenser water pump, start tower fans and start up machine.
, ©SIRJOEL EXAM SOLUTIONS
11/3/2024 10:54 PM
How does a reciprocating machine cycle compressors on and off? - answer✔Through the use of
the low pressure control.
What refrigerant has the best Refrigeration effect and highest latent heat? - answer✔Ammonia
(R-717) / ASHRE Classification is B2.
What is the leaving water temperature of an induced draft cooling tower that is operating
efficiently? - answer✔At some temperature between the dry and wet bulb temperature.
What could a sudden reduction in the supply flow of the cooling tower water result in? -
answer✔An increase in head pressure.
How do reciprocating compressor unloaders operate? - answer✔By keeping the compressor
suction valves open.
Which side of the compressor is R-22 vapor charged into? - answer✔The suction side.
What should the percentage of lubricant circulated through a well designed system be? -
answer✔Lubricant should not exceed 10%.
What is oil foaming in the compressor a result of? - answer✔Liquid refrigerant in the crankcase.
What is the main reason for installing an oil separator on the discharge line? - answer✔To return
oil back to the compressor crank case.
, ©SIRJOEL EXAM SOLUTIONS
11/3/2024 10:54 PM
What causes the foaming of oil in a reciprocating compressor using the splash system for
lubrication? - answer✔A rapid decrease in pressure.
What is the purpose of oil in a refrigerant compressor? - answer✔It reduces ware and friction.
What is a filter dryer used to remove? - answer✔Moisture, particles and contaminants.
Where in a refrigeration system is the oil separator located? - answer✔On the discharge line as
far from the compressor as possible.
If a motor has 4 belts and 1 of the 4 belts are worn, how many belts should be replaced? -
answer✔All of the belts should be replaced.
Does a solenoid valve vary or control the flow of refrigerant? - answer✔No.
What accessory meters and controls the flow of refrigerant into the evaporator? - answer✔The
TEV (Metering Device).
What will occur if you use an automatic expansion valve with a variable load? - answer✔You
will starve the evaporator.
What does an automatic expansion valve do? - answer✔It maintains a constant evaporator
pressure.
What could cause the evaporator to not respond to the adjustments of the TEV? - answer✔Oil
logged on the low side.
, ©SIRJOEL EXAM SOLUTIONS
11/3/2024 10:54 PM
What can non-condensible's cause? - answer✔High head pressure.
When will compressor motor horsepower increase? - answer✔It will increase as the head
pressure increases.
When will compressor motor horsepower decrease? - answer✔As the suction pressure increases.
When using a brine solution in a system what can be used to prevent rusting? - answer✔Di-
Chromate Tablets.
What would cause a Halide torch flame to turn yellow? - answer✔A clogged sample tube.
What is the purpose of having 2 compressors in a cascade system? - answer✔To operate and
very low temperatures and avoid high compression ratio.
Why is a pressure relief valve better than a fusible plug? - answer✔Because it can be re-seated
and is cost efficient.
What could cause compressor knocking? - answer✔Liquid refrigerant slugging the compressor.
What would occur if a TEV'S spring were to break? - answer✔It would flood the evaporator and
raise the suction pressure because a TEV uses spring pressure as its closing force. Thus, if the
spring does not close the TEV refrigerant will constantly be metered into the evaporator.
What is the purpose of the TEV equalizer line? - answer✔It compensates for the pressure drop in
the evaporator. Simply put, it equalizes pressure drop lost across the evaporator.
11/3/2024 10:54 PM
Local 94 School - 475 terms to know for the
RMO written Exam Questions With 100%
Verified Answers
How do automatic expansion valves work? - answer✔Evaporator pressure closes the valve and
spring pressure opens the valve.
When will a faulty check valve cause the most damage? - answer✔On startup.
What will happen if a TEV'S sensing bulb insulation wears off of the suction line in an 85 F
Degree room? - answer✔You will flood the evaporator.
What can a clogged pump strainer cause? - answer✔A reduction or loss in water flow which will
lead to high condenser head pressure.
What part of the Refrigeration system is the solenoid valve part of? - answer✔The pump down
cycle (Thermostat - Solenoid Valve - Low Pressure Controller).
What is the proper machine start up procedure? - answer✔Check oil, start chilled water pump,
start condenser water pump, start tower fans and start up machine.
, ©SIRJOEL EXAM SOLUTIONS
11/3/2024 10:54 PM
How does a reciprocating machine cycle compressors on and off? - answer✔Through the use of
the low pressure control.
What refrigerant has the best Refrigeration effect and highest latent heat? - answer✔Ammonia
(R-717) / ASHRE Classification is B2.
What is the leaving water temperature of an induced draft cooling tower that is operating
efficiently? - answer✔At some temperature between the dry and wet bulb temperature.
What could a sudden reduction in the supply flow of the cooling tower water result in? -
answer✔An increase in head pressure.
How do reciprocating compressor unloaders operate? - answer✔By keeping the compressor
suction valves open.
Which side of the compressor is R-22 vapor charged into? - answer✔The suction side.
What should the percentage of lubricant circulated through a well designed system be? -
answer✔Lubricant should not exceed 10%.
What is oil foaming in the compressor a result of? - answer✔Liquid refrigerant in the crankcase.
What is the main reason for installing an oil separator on the discharge line? - answer✔To return
oil back to the compressor crank case.
, ©SIRJOEL EXAM SOLUTIONS
11/3/2024 10:54 PM
What causes the foaming of oil in a reciprocating compressor using the splash system for
lubrication? - answer✔A rapid decrease in pressure.
What is the purpose of oil in a refrigerant compressor? - answer✔It reduces ware and friction.
What is a filter dryer used to remove? - answer✔Moisture, particles and contaminants.
Where in a refrigeration system is the oil separator located? - answer✔On the discharge line as
far from the compressor as possible.
If a motor has 4 belts and 1 of the 4 belts are worn, how many belts should be replaced? -
answer✔All of the belts should be replaced.
Does a solenoid valve vary or control the flow of refrigerant? - answer✔No.
What accessory meters and controls the flow of refrigerant into the evaporator? - answer✔The
TEV (Metering Device).
What will occur if you use an automatic expansion valve with a variable load? - answer✔You
will starve the evaporator.
What does an automatic expansion valve do? - answer✔It maintains a constant evaporator
pressure.
What could cause the evaporator to not respond to the adjustments of the TEV? - answer✔Oil
logged on the low side.
, ©SIRJOEL EXAM SOLUTIONS
11/3/2024 10:54 PM
What can non-condensible's cause? - answer✔High head pressure.
When will compressor motor horsepower increase? - answer✔It will increase as the head
pressure increases.
When will compressor motor horsepower decrease? - answer✔As the suction pressure increases.
When using a brine solution in a system what can be used to prevent rusting? - answer✔Di-
Chromate Tablets.
What would cause a Halide torch flame to turn yellow? - answer✔A clogged sample tube.
What is the purpose of having 2 compressors in a cascade system? - answer✔To operate and
very low temperatures and avoid high compression ratio.
Why is a pressure relief valve better than a fusible plug? - answer✔Because it can be re-seated
and is cost efficient.
What could cause compressor knocking? - answer✔Liquid refrigerant slugging the compressor.
What would occur if a TEV'S spring were to break? - answer✔It would flood the evaporator and
raise the suction pressure because a TEV uses spring pressure as its closing force. Thus, if the
spring does not close the TEV refrigerant will constantly be metered into the evaporator.
What is the purpose of the TEV equalizer line? - answer✔It compensates for the pressure drop in
the evaporator. Simply put, it equalizes pressure drop lost across the evaporator.
