Topics: All categories in the pool
1: What is the purpose of a surge capacitor on a contactor?
- to protect low voltage equipment
- to provide smoother start/stops
- to balance the sine waves
- to keep the contactor pulled in
2: R22 and 410A operate at the same range of condensing and evaporating temperatures
- true
- false
3: The main purpose of a refrigerant detector in a machinery room is to
- inform there is a refrigerant leak int he system
- detect toxins in the air caused by a refrigerant leak
- to set off an alarm when there is refrigerant present inside the room
- all of the above
4: What refrigerant were phased out in 2004?
- R-12
- R-134a
- R-11
- R-22
5: Heat that changes the physical state of a substance without effecting a change in its temperature is known as
- latent heat
- specific heat
- sensible heat
- lost heat
6: Total heat of a substance is considered
- empathetical
- enthalpy
- sensible heat
- specific heat
7: How many flammability classifications are refrigerants in?
- 3
- 5
- 7
- 2
8: When systems are protected by a high pressure relief device, the compressor's pressure limiting device shall be set at or below ____ % of the operating pressure of the high side relief device.
- 90
- 100
- 80
- 110
9: An example of direct system is
- rooftop unit
- chiller
- absorber
- none of the above
10: Capacity control on a centrifugal compressor is accomplished by the
- post-rotational guide vanes
- slide vanes
- pre-rotational guide vanes
- check valves
11: Suction line oil traps should be installed when the condenser is
- in the basement and the evaporator is on the third floor
- located outside the operates in temperatures below 35F
- more than 100' away from the evaporator
- on the third floor roof and the evaporator is in the basement
12: How much refrigerant can be stored in a mechanical room outside of the system?
- 150
- 200
- 330
- 100
13: Low-side system leaks in a low-pressure chiller will often result in
- air being pulled into the system
- system refrigerant leaking from the system
- water being pulled into the system
- nitrogen leaking out of the system.
14: Gauge pressure is
- Barometric pressure
- Force of pressure above that of atmosphere
- Atmospheric pressure
- Absolute pressrue
15: When a receiver is greater than 3 cubic feet but less than 10 cubic feed, what is the minimum relief device required?
- fusible plug
- relief valve
- rupture disc
- all of the above
16: All low-pressure chillers use which type of compressor?
- Reciprocating
- Scroll
- Centrifugal
- Rotary
17: Lithium-bromide, Li-Br, is best characterized as a
- salt
- sugar
- soil
- sand
18: When releasing a hydrogenated hydrocarbon refrigerant to the atmosphere, ample ventilation must be provided and
- explosion precautions must be taken
- gas masks must be worn
- the owner shall be informed
- no flames shall be permitted
19: Sublimation occurs when
- gas is formed directly from a solid
- ice melts and turns to water
- gas is formed from a liquid
- liquid is formed from a gas
20: Absolute pressure is
- Gauge Pressure
- Atmospheric Pressure
- Gauge + Atmospheric Pressure + Pi
- none of the above
21: A 50 VA control transformer with a 25 volt control output would be rated for _________ amps.
- 2.5
- There isn't enough information to answer.
- 1250
- 2
22: Fusible plugs shall not be used with pressure vessels of
- 15 square feet or less
- 3 cubic feet or more
- 3 cubic feet or less
- 15 cubic feet or more
23: What would be the classification of a prison?
- Large mercantile
- Institutional
- Industrial
- Place of assembly
24: When an A/C system is excessively low on refrigerant
- it can become contaminated with water
- there can be nuisance trip outs
- the suction line may be too hot to touch
- All of the above
25: Indirect systems using Group II refrigerants
- shall be used for mechanical equipment only
- shall be used in refrigeration system in excess of 1,000 lbs
- shall have all refrigerant containing parts except piping, installed in a Class T machine room
- shall be used in refrigeration system less than 1,000 lbs