Topics: All categories in the pool
1: A mercury bulb controller is not recommended for
- line or low voltage use
- line voltage use
- low voltage use
- use where vibration is severe
2: A halide torch is most useful with a freon compression system
- to sweat flanges on the refrigeration piping
- to remove from from TXV's and evaporator coils
- to release a sticking valve
- to detect refrigeration leaks in piping joints
3: How are safety controls wired in a circuit?
- Series
- Parallel
- Series/parallel
- Either series or parallel
4: A rule of thumb in air conditioning is ____ CFM per ton?
- 500
- 100
- 400
- 600
5: What do you need to do when you install a new system?
- Insulate the suction line before you take a superheat reading
- Add refrigerant
- Document the superheat and subcooling reading
- Have it inspected
6: R-718 is rated unlimited for refrigeration quantity contained in a system. Why?
- Because it's a non-flammable refrigerant
- R-718 is not rated unlimited because it's a dangerous refrigerant
- Because it's cheap
- Because it's water
7: Three-phase motors have what type of windings?
- three run windings
- three run windings and 3 start windings
- three start windings
- one start winding and one run winding.
8: Low-side system leaks in a low-pressure chiller will often result in
- air being pulled into the system
- nitrogen leaking out of the system.
- water being pulled into the system
- system refrigerant leaking from the system
9: What device measures the specific gravity of a substance?
- Hygrometer
- Thermometer
- Hydrometer
- Manometer
10: Machinery rooms shall be vented to _____________ and utilizing mechanical ventilation.
- Machinery rooms need not be vented
- the mechanical room housing the refrigeration system
- the outdoors
- the return air ducted system
11: What is the refrigerant dichlorodifluoromethane?
- R-134A
- R-22
- R-123
- R-12
12: What is used to check very low pressure?
- Hydrometer
- Hygrometer
- Manometer
- Velometer
13: The normal operating evaporator temperature of R-410A for air conditioning is typically
- 32F
- 158F
- 155F
- 45F
14: Fusible plugs shall not be used with pressure vessels of
- 3 cubic feet or more
- 3 cubic feet or less
- 15 cubic feet or more
- 15 square feet or less
15: 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, insulate
- make sure it's compatible, notify owner, notify A.H.J
- you can't change refrigerants
16: A Lithium-bromide system is an absorption system that
- uses ammonia as a refrigerant and lithium bromide as an absorbent
- uses salts as an absorbent and lithium bromide as a refrigerant
- uses water as a refrigerant and lithium bromide as an absorbent
- uses water as a absorbent and lithium bromide as a refrigerant
17: In designing duct work, pressure and ______ need to be considered
- length
- CFM
- duct sealant used
- all of the above
18: On a single phase motor, when does the start winding cut out?
- Start windings do no cut-out of the run cycle
- At 75% of its full rated speed
- At 25% of its full rated speed
- At 50% of its full rated speed
19: How many gallons of water per pound of ammonia do you need?
- 20
- 1
- 15
- 5
20: Megaohm meters can detect a ground in the
- up to 1,000 ohms
- up to 1,000,000 ohms
- 10,000,000 ohms or higher
- up to 10,000 ohms
21: Megaohm meter's main function is
- to detect weak motor winding insulation of a refrigeration or air conditioning compressor by creating high DC voltages to the compressor
- to detect very high resistances to ground of refrigeration or air conditioning compressors
- to test very high value capacitors for large 3-phase refrigeration compressors and blower motors.
- Both a and b are correct
22: A R-22 system running with a condensing temperature of 110F and a 40F evaporator temperature will read pressures of ____ on the high side and ____ on the low side.
- 226 psig, 68 psig
- 350 psig, 120 psig
- 257 psig, 77 psig
- 455 psig, 185 psig
23: Increasing superheat will do what to your system?
- Increase liquid flow
- Nothing
- Decrease liquid flow
- Increase gas flow
24: If the power element on an expansion valve should lose its charge, the valve would
- Over feed
- Under feed
- Stay open
- Close
25: An accumulator can be located between the
- first stage and second stage compressors
- condenser and evaporator
- evaporator and compressor
- compressor and condenser