Topics: All categories in the pool
1: A compressor in which the increase in vapor pressure is attained without changing the internal volume of the compression chamber is called
- non-positive displacement compressor
- negative displacement compressor
- neutral chamber-type compressor
- non-volumetric displacement compressor
2: Which of the following are considered inorganic refrigerants?
- R-717 and R-718
- 410A and R-407C
- R-500 and R-502
- None of the above
3: The maximum permissible amperage draw for a 40VA transfomer with a secondary voltage of 24V is
- 1.2
- .8
- .1
- 1.7
4: What type of relief valve is used on a CO2 system?
- fusible plug
- rupture disc
- glove disc
- gate valve
5: What device removes the start winding from the circuit of a split-phase motor once the motor reaches 75% of its rated load amps (RLA)?
- centrifugal switch
- duel-voltage switch
- motor starter
- printed circuit board (PCB)
6: The density of a gas refers to
- pounds per square foot
- pounds per cubic foot
- pounds per absolute pressure
- cubic feet per pound
7: Where must a refrigeration contractor's license number be displayed?
- Uniforms, checks, and invoices.
- Trucks, license plates, and uniforms
- Truck, office, every job, and on all equipment
- Trucks, invoices, and advertising
8: How many refrigerant classifications are there for flammability?
- 1
- 2
- 7
- 3
9: How many gallons of water per pound of ammonia do you need?
- 15
- 20
- 1
- 5
10: A single pole-double throw switch uses how many wires?(excluding the ground)
- 4
- 2
- 5
- 3
11: What is the refrigerant dichlorodifluoromethane?
- R-123
- R-134A
- R-22
- R-12
12: Pi equals approximately
- 3.14
- 3.41
- 12,000
- 746
13: Indirect systems using Group II refrigerants
- shall be used in refrigeration system in excess of 1,000 lbs
- shall be used for mechanical equipment only
- shall be used in refrigeration system less than 1,000 lbs
- shall have all refrigerant containing parts except piping, installed in a Class T machine room
14: In a refrigeration system, you open a valve from the condenser and collect some material on a clean white sheet of bond paper, which of the following would you most likely be testing for?
- checking the level of refrigerant in the system
- testing for oil in the system
- testing for moisture in the system
- none of the above
15: A self contained system
- is a unit system Group II refrigerants only
- is a complete factory made and tested system
- is any system or part of a system used to increase evaporation by expansion or vaporization
- is a unit system Group I refrigerants only
16: R-11 has the greatest corrosive effect on
- Bronze
- Copper
- Aluminum
- Magnesium
17: How many CFMs are required per square foot of commercial office occupied space
- .5 CFM
- 20 CFM
- 15 CFM
- 5 CFM
18: A normal operating evaporator temperature of R-22 for air conditioning is typically
- 58F
- 55F
- 45F
- 32F
19: What percentage of amperage difference is allowable phase to phase on a HVAC circuit phased to phase?
- 2%
- 25%
- 1%
- 4%
20: If the power element of an expansion valve should lose its charge the valve would
- go open
- overfeed the evaporator
- underfeed the evaporator
- go closed
21: When a refrigeration or air conditioning system is installed
- the form of certificate shall be authorized by the Department of Pubic safety
- a field inspection shall be made before it is put into service
- it shall be approved by the owner for proper operation.
- it shall not be operated below prescribed pressures
22: While water is evaporated in an evaporative condenser the impurities which were in the water are
- remain in the air
- accumulate in the sump water
- blown to the atmosphere by the fan
- washed out of the air by the spray pump
23: Which refrigerant replaced R-12?
- R-134A
- R-410A
- R-407A
- R-22
24: Can you use Ammonia in industrial applications?
- When mixed with R-718
- No, never
- Yes, Under certain condidtions
- Yes, always
25: Bubbles in the liquid line sight glass could be caused by
- leaking discharge valves in the compressor
- overcharge of oil
- plugged drier
- bad low pressure switch