Massachusetts Refrigeration Tech/Contractors practice quiz
Refrigeration RT/RC Prep Quiz
Topics: All categories in the pool
1: On a centrifugal compressor, stationary diffuser vanes are needed to
increase the clearance space
convert velocity energy to pressure
stop gas flow
prevent high pressure on the packing
2: An example of an "Expendable Refrigerant" is
lithium bromide
ammonia
liquid oxygen
liquid nitrogen
3: The actual expansion curve of compression follows most nearly which one of the following curves?
Isothermal
Adiabatic
Volume Temperature
Pressure Temperature
4: If you have a motor of 2 HP or less and under 300V, you can use a single pole switch (light switch) with what rating?
2x FLA
4x FLA
5x FLA
3x FLA
5: R-410A can segregate in the system or chemically change its composition due to a leak.
True
False
6: According to the 522 CMR Board of Boilers, refrigerant detectors, alarms, and the refrigeration mechanical room ventilating systems shall be tested
annually
quarterly
regularly
bi-annually
7: Each machinery room shall contain
smoke and fire alarms as well as three means of egress and that egress must meet 528 CMR ventilation requirements
a refrigerant detector located in an area where the refrigerant from a leak will concentrate
high and low pressure controls
a toxicity detector where the presence of ammonia or lithium bromide from a leak will concentrate
8: What measures gas pressure?
Hydrometer
Hygrometer
Barometer
Manometer
9: Trichlorofluoromethane is the name of what refrigerant?
R-502
R-113
R-11
R-12
10: What refrigerant has zero ozone depletion
HFC
CFC
HCFC
None of the above
11: Mercury was used in thermometers primarily because it
was inexpensive
vaporizes at very high temperatures
expands uniformly
never freezes
12: If a condenser is on a roof and the temperature is 35F and dropping the capacity
decreases
run as designed with low ambient controls
doesn't change
increases
13: A multi-evaporator refrigeration system uses what type of valve to maintain evaporating temperatures?
CPR valve
EEV
Solenoid valve
EPR valve
14: Which creates more of a heat load?
50% RH
70% RH
90% RH
30% RH
15: "R" represents ___ in the Ohm's law formula
capacitance
resistance
voltage
amperage
16: All welding done on any refrigeration system or piping covered by 522 CMR 9.00 shall be performed by a according to Section IX of the ASME code
welder qualified
competent welder
licensed welder
licensed technician
17: Ammonia systems use ____ pressure to adjust oil pressure
discharge
liquid
air
stream
18: How many groups of refrigerants are there?
1
7
5
3
19: A micron is
a larger unit of measurement than Hg
one thousandths of a millimeter
one millonths of a micrometer
one millonths of a centimeter
20: 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.
2.5, 2.5
3.0, 3.5
2.5, 3.0
6.6, 6.6
21: A run capacitor is wired in series with the _____ windings.
start
start capacitor
common
run
22: When energized, a normally open relay will be
open
closed
noisy
depends on the type and class of the relay
23: Where is an EPR valve located on a multi-evaporator system?
Suction line prior to the accumulator of the lowest temperature system
Suction line of the coolest evaporator
Suction line at the compressor
Suction line of the warmest evaporator
24: In a system designed for sub-zero ambient temperatures, what must be added?
Infrared dye for leak identification
Nitrogen
Low-ambient kit
Booster compressor
25: On cooling towers, what causes the condenser water to drop