Chapter 11 Flashcards
Refrigeration systems are purged to:
A) Release excess refrigerant
B) Rid the system of non-condensable gases
C) Rid the system of moisture
D) Lower the system pressure
E) Lower the evaporator pressure
B
Pressure limiting devices should be provided on a refrigeration system with more than _____ of refrigerant.
A) 9 kg
B) 1 kg
C) 3 kg
D) 7 kg
E) 5 kg
A
When using ____________ as a refrigerant, moisture corrosion will not usually be a problem.
A) Propane
B) R-12
C) Ammonia
D) R-22
E) Carbon dioxide
A
The starting and stopping of the compressor is normally done automatically by means of:
A) Either a temperature actuated control or a pressure actuated control
B) A pressure limiting device
C) A rheostat
D) A heat sensor in the evaporator
E) An automatic low-pressure cut-out
A
Which of the following oil separators, used in a refrigeration system, consists of a series of baffles through which the oil-laden refrigerant must pass?
A) I.G.F.
B) Oil still
C) Cyclone
D) Inverted trap
E) Impingement
E
Before admitting any refrigerant, the entire refrigeration system is put ___________________.
A) Well above atmospheric pressure
B) Under a slight vacuum
C) Under a high vacuum
D) Above the dew point
E) Slightly above atmospheric pressure
C
The low-side float valve is controlled by:
A) The refrigerant level in the condenser
B) The refrigerant level in the receiver
C) The brine level
D) A float connected to/or in the evaporator
E) Evaporator pressure
D
A low pressure control in a refrigerating system can be used:
A) To start and stop the compressor
B) For purging non-condensable gases
C) To keep the receiver pressure from getting too high
D) For evaporator pressure control
E) For condenser pressure control
A
An oil pressure failure switch is used to:
A) Prevent damage to the compressor due to inadequate lubrication
B) Prevent damage to the condenser due to an inadequate oil level
C) Add oil automatically to the compressor
D) Warn the operator of low oil
E) Close the expansion valve if the oil pressure gets low
A
Moisture in refrigeration systems can be removed by:
A) Purging
B) Making the oil more absorbent
C) Blowing down the system
D) Using a dehydration device or strainer drier
E) Heating the refrigerant
D
