Topics: All categories in the pool
1: On a centrifugal compressor, stationary diffuser vanes are needed to
- stop gas flow
- prevent high pressure on the packing
- convert velocity energy to pressure
- increase the clearance space
2: What is an example of institutional occupancy?
- Hospital
- Shopping mall
- Football stadium
- Dorms
3: If a condenser is on a roof and the temperature is 35F and dropping the capacity
- doesn't change
- increases
- run as designed with low ambient controls
- decreases
4: If a liquid receiver is designed to receive the refrigerant charge during a pumpdown procedure, it shall have the capacity to
- hold up to 110% of the pumpdown charge
- receive the pumpdown charge
- release the charge when the pressure exceeds 310 psig or higher
- Pumpdown procedures are not allowed with systems containing liquid recievers
5: The first step in mechanical refrigeration is
- expansion
- compression
- evaporation
- condensation
6: In a horizontal shell & tube condenser, the ammonia is liquefied by
- removing the latent heat of vaporization
- passing thru the tubes from top to bottom
- removing the latent heat of fusion
- water sprayed over condenser
7: 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 not be operated below prescribed pressures
- it shall be approved by the owner for proper operation.
8: Which of the following is NOT a positive displacement compressor?
- scroll
- screw
- reciprocating
- centrifugal
9: On a day with low relative humidity, the two thermometers on a sling psychrometer will read
- 2F difference
- a ling psychrometer doesn't have two theremometers.
- far apart or greater difference
- nearly the same
10: A professional or office building would be considered what type of occupancy?
- business
- mercantile
- commercial
- public assembly
11: How many forces operate a thermostatic expansion valve?
- 2
- 3
- 1
- 4
12: How many refrigerant classifications are there for toxicity?
- 2
- 1
- 3
- 5
13: Foaming of oil in a compressor is most likely to occur
- when ambient temperature are low
- when there is insufficient air across the condenser(i.e., dirty coil)
- at start-up
- when the evaporator temperatures are below 32F
14: An accumulator can be located between the
- evaporator and compressor
- first stage and second stage compressors
- condenser and evaporator
- compressor and condenser
15: The outer portion of shell of the compressor used on low-pressure chillers is called the
- suction
- baffle
- nozzle
- volute
16: What is the amp draw of a 40 VA transformer at 24 volts
- 106 amps
- 1,000 amps
- 1.6 amps
- 1K amps
17: Which creates more of a heat load?
- 70% RH
- 50% RH
- 90% RH
- 30% RH
18: What refrigerant were phased out in 2004?
- R-22
- R-11
- R-134a
- R-12
19: Usually dry bulb temperature is
- not important and shall be ignored
- lower than dry bulb temperature
- higher than wet bulb temperature
- same as wet bulb temperature
20: A Lithium-bromide system is an absorption system that
- uses water as a refrigerant and lithium bromide as an absorbent
- uses ammonia as a refrigerant and lithium bromide as an absorbent
- uses water as a absorbent and lithium bromide as a refrigerant
- uses salts as an absorbent and lithium bromide as a refrigerant
21: Before you change the type of refrigerant in a refrigeration system, what three things must be done?
- place sign, check for leaks, insulate
- you can't change refrigerants
- make sure it's compatible, notify owner, notify A.H.J
- nothing must be done
22: The boiling point of a refrigerant is based on
- Temperature
- Heat content
- a pressure-temperature relationship
- None of the above.
23: If the power element on an expansion valve should lose its charge, the valve would
- Close
- Under feed
- Over feed
- Stay open
24: A split-phase motor has a ______ winding and a ____ winding
- start, common
- duel-run, duel-start
- run, start
- run, common
25: A total of all group A-2,B-2, A-3, and B-3 refrigerants shall not exceed ____ lb in the occupied areas and machinery rooms of institutional occupancies.
- 100
- 50
- 550
- 350