Compressor Safety Components
The primary purpose of refrigerant oil is to ______.
A. cool the motor windings
B. help refrigerant flow more easily
C. lubricate the mechanical parts of a compressor
D. prevent refrigerant from forming clumps
C. lubricate the mechanical parts of a compressor
The US governmental body charged with enforcing the regulations of the Clean Air Act is the _____.
A. ASHRAE
B. DOT
C. EPA
D. SNAP
C. EPA
Which of the following measurements is the equivalent of atmospheric pressure at sea level?
A. 1 torr
B. 25.4 mm Hg
C. 29.92 in. Hg
D. 25,400 microns
C. 29.92 in. Hg
Most manufacturers recommend pulling a vacuum pressure of _____ before recharging a system.
A. 500 in. Hg
B. 500 microns
C. 500 mm Hg
D. 500 torr
B. 500 microns
The primary purpose of a metering device’s orifice is to produce _____.
A. equal distribution
B. a pressure drop
C. smooth flow
D. turbulent flow
B. a pressure drop
Why should refrigerant entering a compressor be all vapor and not liquid?
A. Compressing liquid refrigerant would damage the refrigerant oil circulating with it.
B. Liquid refrigerant carries too much heat content so that the system would reach its set point too quickly and in a short cycle.
C. Liquid slugging can damage the compressor.
D. None of the above.
C. Liquid slugging can damage the compressor.
Section _____ of the Clean Air Act requires that all technicians have certification to service HVACR equipment.
A. 8
B. 9
C. 179
D. 608
D. 608
When a system is running in normal operation, a service valve should be _____.
A. back seated
B. cracked open
C. front seated
D. in mid-position
A. back seated
The purpose of oil in a vacuum pump is to act as a lubricant for the pump and also as a(n) _____.
A. aid in pressure measurement
B. fluid seal between air, gases, and contaminants entering the pump
C. system leak detection method
D. All of the above
B. fluid seal between air, gases, and contaminants entering the pump
Capillary tubes are used extensively in _____ systems.
A. chiller
B. motor vehicle
C. refrigerator and window ac unit
D. VFR
C. refrigerator and window ac unit
If the moving parts within a compressor are not lubricated, it will most likely ______.
A. create sparks that ignite the oil in the system
B. friction weld the piston to the cylinder
C. have no short-term or long-term effect whatsoever
D. produce small metal chips that will damage the system
D. produce small metal chips that will damage the system
Which type of refrigerant has the highest ozone depletion potential?
A. CFCs
B. HCFCs
C. HFCs
D. HFOs
A. CFCs
When a service valve blocks the fl ow of refrigerant through the valve by closing off its regular passageway, it is _____.
A. back seated
B. cracked open
C. front seated
D. in mid-position
C. front seated
True or False?
Recovered refrigerant can be sold to a new owner once it has been recycled.
False
True or False?
The limited amount of refrigerant allowed to pass through a metering device into the evaporator is at high pressure.
False
Devices that specifi cally provide overcurrent protection for compressors are ______.
A. circuit breakers and fuses
B. crankcase pressure regulators
C. discharge line thermostats
D. head pressure controls
A. circuit breakers and fuses
HFCs have an ozone depletion potential of _____.
A. 0
B. 1.5
C. 11
D. 22
A. 0
To reduce the amount of refrigerant released into the atmosphere when connecting hoses, _____ fittings can be used.
A. fusible plug
B. free air displacement
C. quick-connect
D. retarder
C. quick-connect
Before repairing a leak, all of the refrigerant in a system must be _____.
A. recovered
B. recycled
C. reclaimed
D. resold
A. recovered
True or False?
The flow rate through fixed metering devices is relatively constant when the compressor is running.
True
A crankcase pressure regulator protects a compressor from high pressure in ______.
A. ambient air
B. the conditioned space
C. the high side of the system
D. the low side of the system
D. the low side of the system
A refrigerant’s global warming potential (GWP) is based on the ratio of its warming effect compared to the warming effect of _____.
A. ammonia
B. carbon dioxide
C. oxygen
D. R-11
B. carbon dioxide
Which of the following corresponds to the positions of a gauge manifold’s valves during system evacuation?
A. Both valves closed
B. Both valves open
C. High-side valve open, low-side valve closed
D. Low-side valve open, high-side valve closed
B. Both valves open
10.7
Recovery/recycling machines must be certified to comply with AHRI Standard _____.
A. 210/240
B. 340-360
C. 410
D. 740
D. 740
True or False?
Because moTruedulating metering devices can change refrigerant flow based on load, they operate more efficiently than fixed metering devices
True