UTB13 Air Conditioning Flashcards
What is the term used for the range of effective temperatures that most people feel comfortable in?
Comfort zone
(True or False) Using electricity to clean the air of large air-conditioning systems is the best method and the cheapest.
True
Which of the following is another name for a floor-mounted air-conditioning unit?
Package unit
What type of system is used for air conditioning large tonnage capacities?
Water chillers
(True or False) The lubrication of fan bearings should be done when the unit is running.
False
What type of cooling tower requires a completely open space because its performance depends on existing air currents?
Natural draft
Which of the following reciprocating compressors is driven by an external motor?
Open
What type of swash plate compressor uses a plate connected to a hinge pin that permits the swash plate to change its angle?
Five-cylinder variable
What type of suction pressure-regulating valve uses a sealed pressure element to maintain a constant pressure independent of the altitude of the vehicle?
Pilot operated absolute (POA) valve
Which of the following refrigerants has replaced R-113 as a primary flushing agent used for cleaning a system?
R-141b
What classification of air ducts takes air from the conditioned space and then distributes it back into the air conditioner system?
Conditioned air
Which of the following duct components is used to deliver a concentrated air stream into a room?
Registers
(True or False) A radial flow fan can be belt-driven or direct-drive.
True
What is the term given to the net effects of temperature, humidity, and air motion?
Effective temperature
(True or False) Electricity can be used to purify the air in some large air- conditioning systems.
True
Window-mounted air-conditioning units usually range from 4,000 to ______ Btu per hour in capacity.
36,000
(True or False) Flooded shell-and-tube coolers use less refrigeration than other systems of equal size.
False
What type of condenser is used for practically all water-cooled refrigeration systems?
Shell-and-tube
Cooling towers have been linked to the spread of what disease?
Legionnaire’s disease
How much Btu is required to evaporate 3 gallons of water?
1 pound of water = 8.3
- 3 x 3 = 24.9
- 9 x 1,000 = 24,900
What type of compressor is used in large air-conditioning systems that handle large volumes of refrigerants at low-pressure differentials?
Centrifugal
What air-conditioning control is an adjustable temperature-sensitive device that has contacts that open and close to control the operation of the air conditioner?
Thermostat
What type of automotive air-conditioning compressor changes rotary motion into reciprocating motion, and contains four pistons mounted 90 degrees from each other?
Scotch-yoke
What is the first step to be followed when performing diagnosis of an air- conditioning system?
Know the system and how the parts work together
According to the EPA, what refrigerant can now be used to replace R-12 refrigerant in air-conditioning systems?
R-134a
(True or False) When servicing HVA/R units, certification is not required for using or removing refrigerants.
False
What type of standard air-conditioning certification must a technician have to service or dispose of low-pressure appliances?
Type III
(True or False) Conditioned air ducts bring outside air into the air-conditioning system, then distributes it to the conditioned area.
True
What air-conditioning duct is the most efficient?
Round
Which of the following duct components controls the distance, height, and spread of air-throw, as well as the amount of air, but can also cause some resistance to airflow? A. Diffuser B. Register C. Grille D. Damper
C. Grilles
(True or False) Automatic fire dampers that are installed in vertical ducts must be inspected at least once a year to ensure they are working properly.
True
What type of air conditioner fan is also known as a squirrel cage fan?
Radial flow
What is the fourth step that a technician should follow when balancing the system?
Measure the “free” grille area.
