Massachusetts Refrigeration Tech/Contractors practice quiz
Refrigeration RT/RC Prep Quiz
Topics: All categories in the pool
1: If a liquid receiver is designed to receive the refrigerant charge during a pumpdown procedure, it shall have the capacity to
receive the pumpdown charge
Pumpdown procedures are not allowed with systems containing liquid recievers
release the charge when the pressure exceeds 310 psig or higher
hold up to 110% of the pumpdown charge
2: What happens to copper joints when overheated?
nothing
joint becomes oxidized and ditorted
copper becomes harder
none of the above
3: The outer portion of shell of the compressor used on low-pressure chillers is called the
volute
nozzle
suction
baffle
4: What type of relief valve is used on low pressure centrifugal compressor systems?
Spring-loaded relief valve
Rupture disc
Purge relief
None of the above
5: No open flames are allowed in the machinery room unless?
Approved by the authorized person
Only when combustion air is provided from outside of the machinery room
Never can be allowed
Approved by the installing contractor
6: Two capacitors are wired in parallel. One capacitor has a value of 15uf. The other has a value of 25uf. What is the total value supplied?
40 uf
25 uf
15 uf
20 uf
7: Increasing superheat will do what to your frost line?
Increasae
Decrease
Could either increase or decrease depending on the load conditions
Nothing
8: Low temperature systems should have what?
High pour point
Low pour point
High viscosity
None of the above
9: Name an HCFC refrigerant(s):
R-22
R-123
R-11
both a & b
10: An electrical circuit has a 208V power supply and draws 47 amps total, What would be the wattage of the circuit
.9776 watts
9,776 watts
977.6 watts
9.776 watts
11: The maximum permissible amperage draw for a 40VA transfomer with a secondary voltage of 24V is
1.2
.1
1.7
.8
12: _____ alloys shall not be used in contact with an halogenated refrigerants.
Magnesium
Zinc
Nickel
Copper
13: How many refrigerant classifications are there for flammability?
7
2
3
1
14: Starting relays for a single phase compressors are used to remove the starting circuit from operation when the motor reaches approximately ____ percent of its speed.
50
24
100
75
15: A rule of thumb in air conditioning is ____ CFM per ton?
100
600
500
400
16: A line voltage thermostat controls a 1,200 watt strip header at 120 volts. What must be minimum ampere rated of the stat be?
15 amps
20 amps
5 amps
10 amps
17: Three-phase motors have what type of windings?
three run windings
three run windings and 3 start windings
one start winding and one run winding.
three start windings
18: The purpose of an accumulator is to
store excess refrigerant from the reciver
reduce friction loss to the flow of refrigerant
filter out impurities from the system
assure no liquid returns to the compressor
19: With a 5/8" X 5/8" x 3/4" tee, what size is the center connection?
5/8"
3/4"
1/2"
3/8"
20: "R" represents ___ in the Ohm's law formula
amperage
resistance
voltage
capacitance
21: Which of the following is not an air velocity meter?
Anemometer
Velometer
Anemotherm
Hydrometer
22: The generator shell contains the
condenser and the generator
condenser and the absorber
condenser, the evaporator, and the generator
evaporator and the absorber
23: What refrigerant doesn't have to be classifted?
R-134a
R-718
R-717
R-711
24: On a large centrifugal system, what meters the flow to the evaporator?