Topics: All categories in the pool
1: A single pole-double throw switch uses how many wires?(excluding the ground)
- 4
- 5
- 3
- 2
2: What refrigerant is an inorganic compound?
- R-132A
- Ammonia
- R-22
- R-410A
3: A 24 volt transformer with a 240 volt primary can handle how many amps?
- There isn't enough information to answer.
- 20 amps
- 24 amps
- 10 amps
4: Machinery rooms must be vented to ______?
- outdoors
- unoccupied spaces
- basement
- neutralizing tank
5: The total amount of refrigerant stored in a machinery room in all containers not provided with relief valves shall not exceed
- 660 lbs
- 330 lbs
- 55 lbs
- 500 lbs
6: Starting relays for a single phase compressors are used to remove the starting circuit from operation when the motor reaches approximately ____ percent of its speed.
- 50
- 75
- 100
- 24
7: The normal operating evaporator temperature of R-410A for air conditioning is typically
- 155F
- 158F
- 45F
- 32F
8: Pipe identification labels are required when the system contains more than
- 110 lbs
- 65 lbs
- 55 lbs
- 120 lbs
9: What must be done to refrigerant pipes before being buried ?(8.10.4)
- Leak checked
- Insulated and installed in a pipe duct (Encased)
- Classifed
- Certified
10: The main purpose of the accumulator is to
- provide space for the accumulation of oil and containminants
- store liquid refrigerant
- provide space for vapor to accumulate
- prevent liquid slugs at the compressor
11: On a TXV, the purpose of an external equalizer is to?
- balance the evaporator load
- Increase the pressure on the top of the power head diaphragm
- compensate for a pressure drop across the evaporator coil
- allow a greater adjustment spam
12: When can 50/50 solder be used?
- in the low side
- in the high side
- liquid and suction lines
- none of the above.
13: Horizontal piping should be run level.
- Yes, if the condenser is located above the evaporator
- No, unless the supervisor on the job says so.
- True
- False
14: Foaming of oil in a compressor is most likely to occur
- when there is insufficient air across the condenser(i.e., dirty coil)
- when ambient temperature are low
- at start-up
- when the evaporator temperatures are below 32F
15: Group A2 refrigerants have a ______ toxicity rating than Group B1 refrigerants.
- there is no Group B1 refrigerants
- higher
- lower
- the same
16: Can you use Ammonia in industrial applications?
- Yes, Under certain condidtions
- No, never
- When mixed with R-718
- Yes, always
17: When air is ducted through a machine room that services occupied space, What must be done?
- Welded and seamed.
- Ducted and sealed
- Insulated and cross broke
- Flanged and gasketed
18: In an A/C unit, dirty filters will cause
- high discharge pressure
- low oil pressure
- low suction pressure
- high suction pressur
19: What pipe can not be used for refrigeration?
- K
- L
- N
- M
20: The maximum permissible amperage draw for a 40VA transfomer with a secondary voltage of 24V is
- 1.7
- .1
- 1.2
- .8
21: How many volts would you read on a 480V system phase to phase?
- 480
- 277
- 1/3 the voltage
22: The formula for Pure Power in a resistance circuit is
- Kw = volts X amps
- Watts X amps.
- Watts = volts X amps
- Watts X power factor
23: Which refrigerant class listed below is the most flammable?
- C3
- B2
- A3
- A2
24: Pressure-limiting device isn't required on a factory-sealed system containing less than ____ lbs.
- 22
- 18
- 50
- 33
25: Can ammonia be used on domestic system?
- yes
- no, unless there is proper ventilation system installed
- no
- yes, for systems under 10 tons