Massachusetts Refrigeration Tech/Contractors practice quiz
Refrigeration RT/RC Prep Quiz
Topics: All categories in the pool
1: Refrigerant is metered into the evaporator on a large centrifugal chiller thru the
low side of the system
high side float assembly
cap tube
none of the above
2: If a low-pressure chiller has a low-side leak, which of the following will most likely result?
Low head pressure and high suction pressure
Low suction pressure and low discharge pressure
High suction pressure and high discharge pressure.
High head pressure and low suction pressure
3: Cooling tower lowers condenser water temp by
running water thru a secondary heat exchanger
running fans at 100%
condensation
evaporative cooling
4: The critical temperature of a refrigerant gas occurs when
any increase in pressure will not liquefy the gas
the gas returns to a liquid
any decrease in pressure will cause condensation
the gas is no longer saturated
5: What do you need to do when you install a new system?
Have it inspected
Document the superheat and subcooling reading
Insulate the suction line before you take a superheat reading
Add refrigerant
6: What percentage of amperage difference is allowable phase to phase on a HVAC circuit phased to phase?
25%
4%
2%
1%
7: Machinery rooms shall be vented to _____________ and utilizing mechanical ventilation.
the mechanical room housing the refrigeration system
Machinery rooms need not be vented
the return air ducted system
the outdoors
8: What is the minimum size wire you can use on a 30 amp circuit?
10 AWG
14 AWG
12 AWG
16 AWG
9: A chiller entering and leaving temperature difference is?
5 degrees F
10 degrees F
20 degrees F
50 degrees F
10: Single compound Refrigerants are classified by what two criteria?
Flammability and toxicity
Weight and color
Temperature range and hazardousness
Flammability and temperature range
11: 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.
3.0, 3.5
2.5, 3.0
6.6, 6.6
2.5, 2.5
12: Booster compressors connect to the ____ side of the compressor
vapor
oil side
low side
liquid
13: Liquid level gauges must be provided with what?
A relief valve
A red line
A low level mark
Automatic shut-offs
14: Pressure limiting devices are not required for systems containing less then ________ refrigerants.
22 lbs
6.6 lbs
13.9 lbs
44 lbs
15: Calculate the voltage in a series circuit when the total amperage is 10 amps and the resistors have values of: R1=12 ohms, R2=8 ohms, R3=4 ohms
24.0 volts
240 volts
2.40 volts
2,400 volts
16: Three-phase motors have what type of windings?
three run windings
one start winding and one run winding.
three run windings and 3 start windings
three start windings
17: Name an HCFC refrigerant(s):
R-22
R-123
R-11
both a & b
18: Suction valve unloaders afford an effective means of
superheat control
refrigerant control
capacity control
evaporator control
19: The gauge thickness required on a CO2 tank construction is
5/16"
3/32"
1/8"
1/16"
20: Dew point is
the temperature of air of 50% RH
the temperature below which water vapor in the air will start to condense
the temperature below which water vapor in the air will start to evaporate
the temperature above which water vapor in the air will start to condense
21: What type of voltage causes the winding in a potential relay to open?
BEMF (Back Electro-Motive Force)
24V control voltage from the thermostat
120V line voltage
None of the above
22: Two systems using separate refrigerants that are superimposed upon one another is called
single stage
booster
indirect
cascade
23: R-22 is classified as a ____ refrigerant on the safety matrix.
B-2
B-1
A-2
A-1
24: A motor starter contains a thermal overload and a
contactor
solenoid
3-way relay
transformer
25: A room having machinery but no flame producing apparatus permanently installed and operated is considered a