Massachusetts Refrigeration Tech/Contractors practice quiz
Refrigeration RT/RC Prep Quiz
Topics: All categories in the pool
1: A single pole-double throw switch used how many wires excluding the ground wire?
five
three
four
two
2: How are safety controls wired in a circuit?
Either series or parallel
Parallel
Series/parallel
Series
3: Which of the following is a drop-in for R-22
R-410A
R-134A
R407C
None of the above
4: Pressure vessels with an internal volume of 3 cubic feet or less
shall use pressure relief devices or fusible plugs
do not need pressure relief protection
shall use fusible plugs
shall use pressure relief devices
5: The actual expansion curve of compressor follows most nearly which one of the following
Adiabatic
Isothermal
Pressure-Temperature
Volume
6: Defined process piping by code CMR (528)
Any piping that conveys a solid, liquid or gas that is not part of the plumbing or fire protection system
Any piping in an industrial space
Any piping in an industrial or commercial space
All of the above
7: The Department that certifies the transportation of refrigerant is the
EPA
EPO
RSES
DOT
8: The level of voltage caused by back electromagnetic force that opens the contacts of a potential relay in order to take the start capacitor out of the circuit is
boost voltage
run voltage
lift voltage
pick-up voltage
9: Which of the following is an example of an azeotropic refrigerant?
R-410A
R-134A
R-500
R-404A
10: What happens to copper joints when overheated?
nothing
joint becomes oxidized and ditorted
copper becomes harder
none of the above
11: An oil pressure safety switch should be set at
5 to 10 psi below low side pressure
10-15 psi above low side pressure
5 to 10 psi above low side pressure
10 to 15 psi below low side pressure
12: What pipe can not be used for refrigeration?
N
M
K
L
13: A check valve is a device
designed to allow the flow of refrigerant gas in both directions
that is always spring loaded
with a pressure drop
found on high pressure steam systems
14: Atmospheric pressure is equal to
29.92" Hg
14.7 psia
14.7 psig
both a & b
15: To determine the pump size needed for an open cooling tower system, the following must be known,
GPM and friction head
GPM and balanced head and friction head
GPM and unbalanced head and friction head
GPM, pipe size, and equivalent head.
16: 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
17: How does a centrifugal compressor create the pressure differential needed to move refrigerant through the system?
Rotating vanes
Fan-like action
Suction and discharge valves
Nesting scrolls
18: Liquid shall not occupy more than ____ of the volume when the temperature of the refrigerant is 90F.
75%
100%
90%
80%
19: When a refrigeration or air conditioning system is installed
a field inspection shall be made before it is put into service
it shall be approved by the owner for proper operation.
the form of certificate shall be authorized by the Department of Pubic safety
it shall not be operated below prescribed pressures
20: What must be done to refrigerant pipes before being buried?
Leaked checked
Encased
Certified
Coated
21: Electricity involves the movement of electrons in atoms
True
False
22: Low temperature systems should have what?
High pour point
Low pour point
High viscosity
None of the above
23: 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)
institutional occupancy
commercial occupancy
public assembly occupancy
illegal occupancy
24: 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
sight glass, weight, paper method, and frost line.
sight glass, weight, pressure, and dipstick
Buss-eye, weight, pressure, and frost line
25: If the suction pressure is low and the evaporator temperature high, the cause will be a?