Topics: All categories in the pool
1: In a system designed for sub-zero ambient temperatures, what must be added?
- Booster compressor
- Nitrogen
- Infrared dye for leak identification
- Low-ambient kit
2: If the power element of an expansion valve should lose its charge the valve would
- underfeed the evaporator
- go open
- go closed
- overfeed the evaporator
3: A cross charged power element on an expansion valve would normally be used in what temperature range?
- 30F to 50F
- 0F-38F
- -100F to -40F
- -40F to 0F
4: What is NOT a positive displacement compressor.
- Reciprocating
- Centrifugal
- Scroll
- Rotary
5: A single pole-double throw switch uses how many wires?(excluding the ground)
- 2
- 4
- 5
- 3
6: Pressure vessels shall be provided with ___________in accordance with Section VIII of the ASME Boiler & Pressure Vessel Code
- Pressure vessels need no type of protection as long as it is hydrostatically tested every three months
- over pressure protection
- over pressure protection and a rupture disc
- over pressure protection as well as a temperature protection device
7: What type of oil is used in R-410A systems?
- mineral oil
- polyolester (POE)
- polyalkylene glycol (PAG)
- naphthene
8: Megaohm meters can detect a ground in the
- up to 1,000 ohms
- 10,000,000 ohms or higher
- up to 10,000 ohms
- up to 1,000,000 ohms
9: The actual expansion curve of compressor follows most nearly which one of the following
- Isothermal
- Pressure-Temperature
- Volume
- Adiabatic
10: Before you change the type of refrigerant in a refrigeration system, what three things must be done?
- Nothing must be done
- Place sign, check for leaks, and insulate suction line
- Make sure its compatible, notify owner, and notify AHJ.
- you can never change refrigerants
11: A micron is
- one thousandths of a millimeter
- one millonths of a micrometer
- one millonths of a centimeter
- a larger unit of measurement than Hg
12: The dial of a pressure gauge, when installed on the high side of a system be graduated 1.2 times the designed pressure.
- True
- False
13: What is potential measured in?
- Amps
- Volts
- Henrys
- Ohms
14: What is used to check very low air pressures in air conditioning duct?
- Anemomter
- Manometer
- Barometer
- Vacuum gauge
15: Pressure vessel having an inside diameter exceeding 6” with an internal pressure greater than 15psig shall be marked directly on or on the nameplate the letters _______________ signifying compliance with the ASME Boiler & Pressure Vessel Code.
- “UM” and “UV”
- “UL”
- “U” or “UM”
- “UV”
16: An air conditioning system rated for 36,000 BTU's is equivalent to
- 12,000 tons of cooling
- two tons of cooling
- one ton of cooling
- three tons of cooling
17: Who is permitted to access a refrigeration machine room?
- Contractors only
- Any employee
- Anyone, it's a completely safe area
- Authorized persons only
18: What will occur if the strong solution in an absorption chiller becomes too strong?
- The machine will stop cooling and solution will crystallize
- The machine will stop cooling and the solution will evaporate.
- The machine will cool excessively as the solution evaporates
- The machine will cool excessively as the solution crystallizes.
19: Thermodynamics is the branch of science that deals with
- state of energy
- energy due to motion
- molecular therory
- heat energy
20: Evaporators located ____inches of a heating coil shall be equipped whit a pressure relief device.
- 10
- 18
- 15
- 24
21: What should never be used in pressure testing refrigeration systems?
- Oxygen
- Compressed air
- Nitrogen
- Both a and b
22: A movie theater would be considered a
- mixed occupancy
- commercial occupancy
- public assembly occupancy
- institutional occupancy
23: It shall be the duty of the person in charge of the premises on which a refrigeration system containing more than ___ lbs of refrigerant is installed to provide a schematic drawing or panel giving directions for the operation of the system.
- 75
- 50
- 55
- 15
24: Adjusting the spring pressure on a TXV
- makes no difference
- changes subcooling
- adjusts the bulb charge
- changes superheat
25: 14.7 psia is equivalent to
- atmospheric pressure at seal level
- 29.92" Hg
- 0 psig
- All of the above.