Refrigeration RT/RC Prep Quiz

Topics: All categories in the pool

Quiz Result Settings

1: Refrigerant is metered into the evaporator on a large centrifugal chiller thru the

  • low side of the system
  • high side float assembly
  • cap tube
  • none of the above

2: If a low-pressure chiller has a low-side leak, which of the following will most likely result?

  • Low head pressure and high suction pressure
  • Low suction pressure and low discharge pressure
  • High suction pressure and high discharge pressure.
  • High head pressure and low suction pressure

3: Cooling tower lowers condenser water temp by

  • running water thru a secondary heat exchanger
  • running fans at 100%
  • condensation
  • evaporative cooling

4: The critical temperature of a refrigerant gas occurs when

  • any increase in pressure will not liquefy the gas
  • the gas returns to a liquid
  • any decrease in pressure will cause condensation
  • the gas is no longer saturated

5: What do you need to do when you install a new system?

  • Have it inspected
  • Document the superheat and subcooling reading
  • Insulate the suction line before you take a superheat reading
  • Add refrigerant

6: What percentage of amperage difference is allowable phase to phase on a HVAC circuit phased to phase?

  • 25%
  • 4%
  • 2%
  • 1%

7: Machinery rooms shall be vented to _____________ and utilizing mechanical ventilation.

  • the mechanical room housing the refrigeration system
  • Machinery rooms need not be vented
  • the return air ducted system
  • the outdoors

8: What is the minimum size wire you can use on a 30 amp circuit?

  • 10 AWG
  • 14 AWG
  • 12 AWG
  • 16 AWG

9: A chiller entering and leaving temperature difference is?

  • 5 degrees F
  • 10 degrees F
  • 20 degrees F
  • 50 degrees F

10: Single compound Refrigerants are classified by what two criteria?

  • Flammability and toxicity
  • Weight and color
  • Temperature range and hazardousness
  • Flammability and temperature range

11: A pressure vessel having an inside diameter of 6” or less shall be sufficient to withstand ____times the pressure of the saturation temperature of the refrigerant or ____times the critical pressure of the refrigerant, whichever is less.

  • 3.0, 3.5
  • 2.5, 3.0
  • 6.6, 6.6
  • 2.5, 2.5

12: Booster compressors connect to the ____ side of the compressor

  • vapor
  • oil side
  • low side
  • liquid

13: Liquid level gauges must be provided with what?

  • A relief valve
  • A red line
  • A low level mark
  • Automatic shut-offs

14: Pressure limiting devices are not required for systems containing less then ________ refrigerants.

  • 22 lbs
  • 6.6 lbs
  • 13.9 lbs
  • 44 lbs

15: Calculate the voltage in a series circuit when the total amperage is 10 amps and the resistors have values of: R1=12 ohms, R2=8 ohms, R3=4 ohms

  • 24.0 volts
  • 240 volts
  • 2.40 volts
  • 2,400 volts

16: Three-phase motors have what type of windings?

  • three run windings
  • one start winding and one run winding.
  • three run windings and 3 start windings
  • three start windings

17: Name an HCFC refrigerant(s):

  • R-22
  • R-123
  • R-11
  • both a & b

18: Suction valve unloaders afford an effective means of

  • superheat control
  • refrigerant control
  • capacity control
  • evaporator control

19: The gauge thickness required on a CO2 tank construction is

  • 5/16"
  • 3/32"
  • 1/8"
  • 1/16"

20: Dew point is

  • the temperature of air of 50% RH
  • the temperature below which water vapor in the air will start to condense
  • the temperature below which water vapor in the air will start to evaporate
  • the temperature above which water vapor in the air will start to condense

21: What type of voltage causes the winding in a potential relay to open?

  • BEMF (Back Electro-Motive Force)
  • 24V control voltage from the thermostat
  • 120V line voltage
  • None of the above

22: Two systems using separate refrigerants that are superimposed upon one another is called

  • single stage
  • booster
  • indirect
  • cascade

23: R-22 is classified as a ____ refrigerant on the safety matrix.

  • B-2
  • B-1
  • A-2
  • A-1

24: A motor starter contains a thermal overload and a

  • contactor
  • solenoid
  • 3-way relay
  • transformer

25: A room having machinery but no flame producing apparatus permanently installed and operated is considered a

  • Class T machinery room
  • Class M machinery room
  • Class B machinery room
  • Class A machinery room