Air Conditioning and Refrigeration
After disconnecting the refrigerant cylinder during leak troubleshooting it is replaced with a cylinder
of what type of inert gas? - ANSWER-Nitrogen
After how many hours of initial use it is recommended to renew the dehydrator charge in a new or
newly charged refrigeration system? - ANSWER-12-15
Air conditioning hydraulic hoses are hydrostatically tested at how many month intervals? - ANSWER-
60
Can refrigerant gases ever be mixed? - ANSWER-No
Compressor suction valves are working satisfactorily when checking them for proper operation if the
compressor can hold a minimum of how many inches of vacuum with the line stop valve shut? -
ANSWER-20" Hg
Cooling coils must be deefrosted when the average frost thickness reaches how many inches? -
ANSWER-3/16"
How are refrigerant leaks detected? - ANSWER-Electronic tester or soapsuds
How is chill water piping color coded? - ANSWER-Striped light blue and dark green
How many hours at a minimum must the system hold system pressure for with no pressure loss after
all refrigerant leaks have been found and corrected? - ANSWER-6
How many personnel must be present when charging a refrigeration system? - ANSWER-2
How often are air conditioning lube oil samples submitted to NOAP? - ANSWER-Quarterly
How often are machinery resilient mounts inspected? - ANSWER-Annually
How often at a minimum are operating refrigeration plant moisture indicators inspected? - ANSWER-
Weekly
How often at a minimum is it recommended to test the air conditioning control system for proper
operation? - ANSWER-Quarterly
How often at a minimum is the lube oil checked via the crackcase sight glass during operation? -
ANSWER-Daily
How often at a minimum must refrigerant usage logs be reviewed? - ANSWER-Monthly
How often is testing of refrigerant systems for leaks accomplished IAW PMS? - ANSWER-Semi
annually
If vapor bubbles can be noticed when viewing the flow of refrigerant through a sight flow indicator it
could indicate an inadequate supply of what? - ANSWER-Refrigerant
Inspecting solenoid coils, cleaning valves, or which other action must be taken if you suspect the
thermostatic cooling-coil magnetic valve is not operating? - ANSWER-Adjust pilots
Lithium bromide absorption along with which other type of chilled-water air conditioning system are
used aboard ships? - ANSWER-Vapor compression
Refrigerant usage logs must be kept when the refrigeration plant holds how many or more pounds of
refrigerant? - ANSWER-50
, Air Conditioning and Refrigeration
Taking care of thermal expansion of the water, making up for small losses and ensuring that a
positive water pressure exists at the highest water coil are the two functions of what component? -
ANSWER-Expansion tank
The condenser must be immediately cleaned IAW which NSTM if it is discovered that the condenser
has greater than 10% of its tubes blocked in one pass? - ANSWER-254
The refrigerant liquid strainer is designed to protect what? - ANSWER-Solenoid valves and TXV
TXV valves are set to maintain a superheat range of how many degrees at the cooling coil outlet? -
ANSWER-4 - 12 F
Under normal conditions, what percentage of the full refrigerant load should the refrigerant charge
be with the compressor stopped under normal conditions? - ANSWER-85%
What actuates the compressor capacity control valve? - ANSWER-Oil pressure
What can be used to determine leak locations in a leaking air conditioning plant refrigerant system in
which the location of the leaks cannot be determined? - ANSWER-Fluorescent dye
What controls the capacity of a refrigerant compressor? - ANSWER-Cylinder loading and unloading
What is installed in condenser heads to protect the condenser from corrosion? - ANSWER-Zinc
What is not permitted in the vicinity of performing recovery of refrigerant? - ANSWER-Hot work
What is the allowable monthly leakage rate of the total air conditioning charge minus reported
accidental or unintentional releases? - ANSWER-15%
What is the allowable monthly leakage rate of the total refrigerant charge minus the reported
accidental or unintentional releases? - ANSWER-35%
What is the first indication of a refrigerant shaft seal failure? - ANSWER-Oil leakage
What is the max moisture content of an oil sample drawn from a centrifugal compressor? - ANSWER-
100 PPM
What is the maximum allowable crankshaft oil seal leakage criteria on a reciprocating compressor? -
ANSWER-Less than 1 drop every 5 mins
What is the maximum percentage of condenser tubes that can be plugged in a refrigerant system? -
ANSWER-10%
What is the maximum seawater temperature that all R-134a reciprocating air conditioning and
refrigeration plants are designed to operate with? - ANSWER-85 F
What is the maximum temperature that refrigerant bottles should be exposed to? - ANSWER-130 F
What is the problem if while conducting a compressor discharge valve test, the discharge pressure
drops at a rate in excess of 3 pounds a minute and the crackcase pressure rises? - ANSWER-
Compressor discharge valve leakage
What is the service life of air conditioning hoses? - ANSWER-Indefinite
What is the setting of the condenser water regulating valves on an R-134 system? - ANSWER-130 -
135 PSIG
After disconnecting the refrigerant cylinder during leak troubleshooting it is replaced with a cylinder
of what type of inert gas? - ANSWER-Nitrogen
After how many hours of initial use it is recommended to renew the dehydrator charge in a new or
newly charged refrigeration system? - ANSWER-12-15
Air conditioning hydraulic hoses are hydrostatically tested at how many month intervals? - ANSWER-
60
Can refrigerant gases ever be mixed? - ANSWER-No
Compressor suction valves are working satisfactorily when checking them for proper operation if the
compressor can hold a minimum of how many inches of vacuum with the line stop valve shut? -
ANSWER-20" Hg
Cooling coils must be deefrosted when the average frost thickness reaches how many inches? -
ANSWER-3/16"
How are refrigerant leaks detected? - ANSWER-Electronic tester or soapsuds
How is chill water piping color coded? - ANSWER-Striped light blue and dark green
How many hours at a minimum must the system hold system pressure for with no pressure loss after
all refrigerant leaks have been found and corrected? - ANSWER-6
How many personnel must be present when charging a refrigeration system? - ANSWER-2
How often are air conditioning lube oil samples submitted to NOAP? - ANSWER-Quarterly
How often are machinery resilient mounts inspected? - ANSWER-Annually
How often at a minimum are operating refrigeration plant moisture indicators inspected? - ANSWER-
Weekly
How often at a minimum is it recommended to test the air conditioning control system for proper
operation? - ANSWER-Quarterly
How often at a minimum is the lube oil checked via the crackcase sight glass during operation? -
ANSWER-Daily
How often at a minimum must refrigerant usage logs be reviewed? - ANSWER-Monthly
How often is testing of refrigerant systems for leaks accomplished IAW PMS? - ANSWER-Semi
annually
If vapor bubbles can be noticed when viewing the flow of refrigerant through a sight flow indicator it
could indicate an inadequate supply of what? - ANSWER-Refrigerant
Inspecting solenoid coils, cleaning valves, or which other action must be taken if you suspect the
thermostatic cooling-coil magnetic valve is not operating? - ANSWER-Adjust pilots
Lithium bromide absorption along with which other type of chilled-water air conditioning system are
used aboard ships? - ANSWER-Vapor compression
Refrigerant usage logs must be kept when the refrigeration plant holds how many or more pounds of
refrigerant? - ANSWER-50
, Air Conditioning and Refrigeration
Taking care of thermal expansion of the water, making up for small losses and ensuring that a
positive water pressure exists at the highest water coil are the two functions of what component? -
ANSWER-Expansion tank
The condenser must be immediately cleaned IAW which NSTM if it is discovered that the condenser
has greater than 10% of its tubes blocked in one pass? - ANSWER-254
The refrigerant liquid strainer is designed to protect what? - ANSWER-Solenoid valves and TXV
TXV valves are set to maintain a superheat range of how many degrees at the cooling coil outlet? -
ANSWER-4 - 12 F
Under normal conditions, what percentage of the full refrigerant load should the refrigerant charge
be with the compressor stopped under normal conditions? - ANSWER-85%
What actuates the compressor capacity control valve? - ANSWER-Oil pressure
What can be used to determine leak locations in a leaking air conditioning plant refrigerant system in
which the location of the leaks cannot be determined? - ANSWER-Fluorescent dye
What controls the capacity of a refrigerant compressor? - ANSWER-Cylinder loading and unloading
What is installed in condenser heads to protect the condenser from corrosion? - ANSWER-Zinc
What is not permitted in the vicinity of performing recovery of refrigerant? - ANSWER-Hot work
What is the allowable monthly leakage rate of the total air conditioning charge minus reported
accidental or unintentional releases? - ANSWER-15%
What is the allowable monthly leakage rate of the total refrigerant charge minus the reported
accidental or unintentional releases? - ANSWER-35%
What is the first indication of a refrigerant shaft seal failure? - ANSWER-Oil leakage
What is the max moisture content of an oil sample drawn from a centrifugal compressor? - ANSWER-
100 PPM
What is the maximum allowable crankshaft oil seal leakage criteria on a reciprocating compressor? -
ANSWER-Less than 1 drop every 5 mins
What is the maximum percentage of condenser tubes that can be plugged in a refrigerant system? -
ANSWER-10%
What is the maximum seawater temperature that all R-134a reciprocating air conditioning and
refrigeration plants are designed to operate with? - ANSWER-85 F
What is the maximum temperature that refrigerant bottles should be exposed to? - ANSWER-130 F
What is the problem if while conducting a compressor discharge valve test, the discharge pressure
drops at a rate in excess of 3 pounds a minute and the crackcase pressure rises? - ANSWER-
Compressor discharge valve leakage
What is the service life of air conditioning hoses? - ANSWER-Indefinite
What is the setting of the condenser water regulating valves on an R-134 system? - ANSWER-130 -
135 PSIG
