B10C1(4) - CH126 Compression
Refrigeration Pre-Start Up Procedures
Exam Questions and Answers
Ammonia leaks may be traced with a wetted test paper treated with:
a. Caustic soda
b. Potassium chromate indicating liquid
c. Potassium iodide-iodate
d. Litmus solution
e. Sulphuric acid. - Answer-D
A sulphur candle is a test for what:
a. Freon leaks
b. Ammonia leaks
c. Air leaks
d. Vacuum seal
e. CFC leaks. - Answer-B
Before charging a system which of the following needs to be done?
a. The interlocks need to be tested
b. The sequence of controls must be tested
c. The controls need to be set
d. The required valves need to be opened
e. All of the above - Answer-E
The initial refrigerant charge is given where on the system?
a. The high side of the system
b. The low side of the system
c. The evaporator
d. The expansion valve
e. The heat exchanger - Answer-A
Which of the following statements about Manual Purging Systems is false?
a. Gas being vented into the atmosphere must pass through a beaker filled with water.
b. The receiver and condenser should be purged separately.
c. Purging rids the system of non-condensable gases.
d. Refrigerant vapour in the purger is always expelled with the
non-condensable gases.
e. They must be operated on a regular schedule. - Answer-D
When initially charging a refrigeration system:
a. It must be done with the liquid line shutoff valve open
b. It is done with a liquid refrigerant
, c. It must be done after the unit is shut down
d. It must be done at the compressor suction
e. Water should be added to dilute the refrigerant. - Answer-B
Higher than normal head pressure is undesirable for all of the following reasons except:
a. It increases power consumption
b. It decreases condenser capacity
c. It reduces compressor capacity
d. It over stresses compressor parts
e. It is detrimental to compressor lubrication. - Answer-B
Which of the following is not a recommended step for the procedure in which dry
nitrogen is used for a system leak test?
a. Remove controls and relief valves that may be damaged by
the test pressure.
b. Set the pressure, reducing valve for the minimum design
pressure of the high side.
c. Close the liquid line shut-off valve.
d. Open the cylinder shut-off valve and disconnect the nitrogen
cylinder.
e. Connect the nitrogen cylinder to the system, charging valve. - Answer-D
The chilling coil in an automatic purger has a primary function to:
a. Separate refrigerant vapour from the non-condensable gases
to be purged.
b. Keep the system cooling while being purged.
c. Increase the efficiency of the system.
d. Keep discharge through the coil at the lowest available suction
pressure.
e. Lower the operating temperature of the purger. - Answer-A
Before commencing to operate a new plant, or one in which piping alterations have
been made, the refrigerant system must be tested for:
a. High pressure
b. Vacuum control
c. Excessive oil consumption
d. Excessive vibration
e. Leaks. - Answer-E
Frost formation on the suction line indicates what?
a. Moisture in the system
b. "Copper-Plating" on the bearings and compressor exhaust valve
c. Overcharging the system
d. Thermostat controlled solenoid deterioration
e. Inadequate levels of refrigerant in the system. - Answer-C
Refrigeration Pre-Start Up Procedures
Exam Questions and Answers
Ammonia leaks may be traced with a wetted test paper treated with:
a. Caustic soda
b. Potassium chromate indicating liquid
c. Potassium iodide-iodate
d. Litmus solution
e. Sulphuric acid. - Answer-D
A sulphur candle is a test for what:
a. Freon leaks
b. Ammonia leaks
c. Air leaks
d. Vacuum seal
e. CFC leaks. - Answer-B
Before charging a system which of the following needs to be done?
a. The interlocks need to be tested
b. The sequence of controls must be tested
c. The controls need to be set
d. The required valves need to be opened
e. All of the above - Answer-E
The initial refrigerant charge is given where on the system?
a. The high side of the system
b. The low side of the system
c. The evaporator
d. The expansion valve
e. The heat exchanger - Answer-A
Which of the following statements about Manual Purging Systems is false?
a. Gas being vented into the atmosphere must pass through a beaker filled with water.
b. The receiver and condenser should be purged separately.
c. Purging rids the system of non-condensable gases.
d. Refrigerant vapour in the purger is always expelled with the
non-condensable gases.
e. They must be operated on a regular schedule. - Answer-D
When initially charging a refrigeration system:
a. It must be done with the liquid line shutoff valve open
b. It is done with a liquid refrigerant
, c. It must be done after the unit is shut down
d. It must be done at the compressor suction
e. Water should be added to dilute the refrigerant. - Answer-B
Higher than normal head pressure is undesirable for all of the following reasons except:
a. It increases power consumption
b. It decreases condenser capacity
c. It reduces compressor capacity
d. It over stresses compressor parts
e. It is detrimental to compressor lubrication. - Answer-B
Which of the following is not a recommended step for the procedure in which dry
nitrogen is used for a system leak test?
a. Remove controls and relief valves that may be damaged by
the test pressure.
b. Set the pressure, reducing valve for the minimum design
pressure of the high side.
c. Close the liquid line shut-off valve.
d. Open the cylinder shut-off valve and disconnect the nitrogen
cylinder.
e. Connect the nitrogen cylinder to the system, charging valve. - Answer-D
The chilling coil in an automatic purger has a primary function to:
a. Separate refrigerant vapour from the non-condensable gases
to be purged.
b. Keep the system cooling while being purged.
c. Increase the efficiency of the system.
d. Keep discharge through the coil at the lowest available suction
pressure.
e. Lower the operating temperature of the purger. - Answer-A
Before commencing to operate a new plant, or one in which piping alterations have
been made, the refrigerant system must be tested for:
a. High pressure
b. Vacuum control
c. Excessive oil consumption
d. Excessive vibration
e. Leaks. - Answer-E
Frost formation on the suction line indicates what?
a. Moisture in the system
b. "Copper-Plating" on the bearings and compressor exhaust valve
c. Overcharging the system
d. Thermostat controlled solenoid deterioration
e. Inadequate levels of refrigerant in the system. - Answer-C
