Massachusetts Refrigeration Tech/Contractors practice quiz
Refrigeration RT/RC Prep Quiz
Topics: All categories in the pool
1: A Lithium-bromide system is an absorption system that
uses ammonia as a refrigerant and lithium bromide as an absorbent
uses water 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
2: When should a relief valve start to function?
Before the purge station discharges
Two times it's working pressure
10 psi before it's set pressure
At it's set pressure
3: A rule of thumb in air conditioning is ____ CFM per ton?
400
600
100
500
4: Laten heat is associated with a change in state of a refrigerant but not temperature
True
False
5: Halo-carbon refrigerants cannot be used with what material?
Aluminum
Stainless Steel
Copper
Magnesium alloy
6: The most common type of motor starter is
duel-winding starter
across the line starter
part winding starter
delts-wye starter
7: A micron is
one thousandths of a millimeter
one millonths of a centimeter
a larger unit of measurement than Hg
one millonths of a micrometer
8: Which of the following is NOT a positive displacement compressor?
scroll
screw
reciprocating
centrifugal
9: A premise or that portion of a premise where large numbers of people congregate and from which occupants cannot quickly vacate the space such as auditoriums, ballrooms, classrooms, passenger depots, restaurants, and theaters is considered a(n)
commercial occupancy
illegal occupancy
institutional occupancy
public assembly occupancy
10: Clearance volume
has no effect on compressor capacity
is the same on all compressors
affects compressor capacity
varies depending on compressor speed
11: Ammonia can come in contact with _______ ?
Aluminum
Copper tubing
Brass
Copper
12: The 4 basic methods of determining whether the proper amount of refrigerant is being introduced into the system are
sight glass, weight, pressure, and frost line
Buss-eye, weight, pressure, and frost line
sight glass, weight, pressure, and dipstick
sight glass, weight, paper method, and frost line.
13: How do you find net oil pressure on a compressor?
discharge pressure - suction pressure
gross oil pressure - suction pressure
gross oil pressure - discharge pressure
all of the above
14: All electrical work done on refrigeration systems must comply with
OSHA
NEC and Massachusetts Modifications
Department of Energy
ASHREA-15 Section 9.2.1
15: If a low-pressure chiller has a low-side leak, which of the following will most likely result?
High suction pressure and high discharge pressure.
Low suction pressure and low discharge pressure
Low head pressure and high suction pressure
High head pressure and low suction pressure
16: Volts x amps equals
Ohms Law
Impedance
Watts
Inductance
17: R-717 is
ammonia
trichloromethane
water
carbon dioxide
18: Large vessels containing refrigerant ______________________ from using two or more pressure-relief devices in parallel to obtain the required capacity.
containing R-11, R-123 & R-717 exclusively shall not be prohibited
of Group B2 refrigerant shall be prohibited
shall not be prohibited
shall be prohibited
19: 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
licensed technician
competent welder
welder qualified
licensed welder
20: What is used to check very low air pressures in air conditioning duct?
Vacuum gauge
Barometer
Anemomter
Manometer
21: Three-phase motors have what type of windings?
three start windings
three run windings and 3 start windings
one start winding and one run winding.
three run windings
22: 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
23: 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.
6.6, 6.6
2.5, 3.0
2.5, 2.5
3.0, 3.5
24: What is the typical air conditioning operating pressures for 410A?
60 psi suction, 210 psi discharge
25 psi suction, 125 psi discharge
105 psi suction, 350 psi discharge
None of the above
25: How much refrigerant can be stored in a mechanical room outside of the system?