Massachusetts Refrigeration Tech/Contractors practice quiz
Refrigeration RT/RC Prep Quiz
Topics: All categories in the pool
1: A capacitor in series with the start windings will do what?
Nothing
Increase run efficiency by 10% of its rating
Increase starting torque
Decrease the RLA to within 10% of its rating
2: A low oil switch is typically
automatic reset
non used on semi-hermetic compressors over 10 ton capacity
time-delay auto reset
manual reset
3: Class T machine room
shall have refrigerant leak detecting systems installed inside and outside the room
shall have remote controls to stop the action of the refrigerant compressor
has no flame producing apparatus permanently installed
shall include closets used for setting equipment
4: Joints in refrigeration piping must be _____ before being covered?
Leak tested
Insulated
Inspected
Pressurized
5: If the dry bulb temperature is 85F and the wet bulb temperature is 70F, the dew point temperature will be approximately (use psychometric chart)
77F
58F
70F
32F
6: How many forces operate a thermostatic expansion valve?
1
4
2
3
7: If a condenser is on a roof and the temperature is 35F and dropping the capacity
decreases
run as designed with low ambient controls
increases
doesn't change
8: If the compression ratio on a centrifugal compressor rises too high, the compressor will stop pumping and make a loud sound commonly referred to as a
merge
splurge
purge
surge
9: Which of the following is NOT a positive displacement compressor?
centrifugal
reciprocating
scroll
screw
10: Emergency shutdown procedures, including precautions to be observed in case of a breakdown or leak over 55 lbs of refrigerant charge, shall be displayed on a conspicuous card located as near as possible to the
compressor
outside the machinery room
boiler
evaporator
11: What was the main reason for enacting the no venting rule of July 1, 1992?
Ozone depletion
Green house effect
Global warming potential
All of the above
12: High pressure controls should be set no higher than
80% of set point
25% of set point
10% of set point
90% of set point
13: Electricity involves the movement of electrons in atoms
True
False
14: Heat transferred by conduction from one body to another is done via:
gas
liquid
solid
All of the above
15: When is the space above a drop ceiling calculated as space for refrigerant limit quantities?
When its white
When it's used as part of a supply or return air system
When there are sprinklers above
When there is a space 6' or more above it
16: On a single phase motor, when does the start winding cut out?
75% of its RLA speed
25% of its RLA speed
100% of its RLA speed
50% of its RLA speed
17: An oil pressure safety switch should be set at
10 to 15 psi below low side pressure
5 to 10 psi below low side pressure
5 to 10 psi above low side pressure
10-15 psi above low side pressure
18: Fractionation occurs when
the pressures increase as the heat load increases
when a fraction of refrigerant is added as the full charge
the pressures decreases as the heat load decreases
some of the blended refrigerant evaporates or condenses before the rest of the blend
19: Floc point testing on refrigeration oils are traditionally tested with a 10% oil and 90% refrigerant mixture.
True
False
20: When can recovered refrigerants be reused?
They can't
Only when used in original owner's equipment
Only if used in 30 days of recovery
None of the above
21: 746 watts is equal to
10 hp
Pi
100 hp
1 hp
22: The boiling point of a refrigerant is based on
Temperature
Heat content
a pressure-temperature relationship
None of the above.
23: A crankcase heater has a supplied voltage of 100 volts and is drawing 1.4 amps. What is the resistance?
104 ohms
27 ohms
71 ohms
80 ohms
24: All machine rooms must be outfitted with a detector that _______?
activates an audible alarm
activates a visual alarm
starts the ventilation system
All of the above
25: R-12. R-22, and R-40 are considered Group I refrigerants.