Massachusetts Refrigeration Tech/Contractors practice quiz
Refrigeration RT/RC Prep Quiz
Topics: All categories in the pool
1: Copper and its alloys shall not be used with ammonia
True
False
2: When an A/C system is excessively low on refrigerant
it can become contaminated with water
there can be nuisance trip outs
the suction line may be too hot to touch
All of the above
3: pressure relief valves must discharge to the atmosphere at a location not less than 15 feet from ground level and ____ feet from any window, ventilation opening, or exits of buildings.
20
10
15
25
4: A movie theater would be considered a
institutional occupancy
commercial occupancy
public assembly occupancy
mixed occupancy
5: 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
6: Fractionation occurs when
some of the blended refrigerant evaporates or condenses before the rest of the blend
the pressures decreases as the heat load decreases
when a fraction of refrigerant is added as the full charge
the pressures increase as the heat load increases
7: _____ alloys shall not be used in contact with an halogenated refrigerants.
Nickel
Zinc
Copper
Magnesium
8: A factory-sealed system containing less than 22lbs. of Group A1 refrigerant
does not require a pressure-limiting device
shall have a pressure limiting device installed on the high side of the system
shall be inspected by the Boiler of Inspectors bi-annually
shall have a pressure limiting device and a pressure relief valve installed
9: The principle used in continuous type absorption systems is
Dalton's Law
Ohm's Law
Boyle's Law
Charles's Law
10: 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
11: R-22 is considered a(n)
HCFC
CFC
HCFCH
HFC
12: A R-22 system running with a condensing temperature of 110F and a 40F evaporator temperature will read pressures of ____ on the high side and ____ on the low side.
257 psig, 77 psig
226 psig, 68 psig
455 psig, 185 psig
350 psig, 120 psig
13: If the power element on an expansion valve should lose its charge, the valve would
Under feed
Stay open
Close
Over feed
14: If a purge unit fails on a low pressure chiller, what are the symptoms?
high head pressure
increased capacity
low pressure chillers do not have purge units
low suction pressure
15: Insurance companies shall forward each inspection report of all refrigeration or A/C systems to the Chief of Inspections within
2 months
1 week
30 days
14 days
16: Before you change the type of refrigerant in a refrigeration system, what three things must be done?
you can't change refrigerants
nothing must be done
place sign, check for leaks, insulate
make sure it's compatible, notify owner, notify A.H.J
17: Liquid refrigerant R-22 enters an evaporator at 50.2 psig, 20F and leaves 37F, its pressure as it leaves will be
50.2 psig
66.1 psig
43.3 psig
70.8 psig
18: Systems containing more than 110 pounds must have stop valves located at the
compressor suction inlet
compressor discharge outlet
receiver inlet and outlet
All of the above
19: How many closing forces operate a thermostatic expansion valve?
3
4
2
1
20: What kind of system uses two different refrigerants in separate systems dependent on each other?
Cascade
R-414B
Low pressure
Simple
21: In a properly balanced system with valves open and properly adjusted, if the suction line is warm to the touch, its because of
not enough oil in the system
oil in evaporator
low head pressure
moisture in the system
22: What is absolute humidity?
the amount of moisture in the air per one pound of 50% RH air
the amount of moisture in the air in grains of cubic feet of volume
the amount of moisture in the air in grains of square feet of volume
none of the above
23: 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
24: 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.