Massachusetts Refrigeration Tech/Contractors practice quiz
Refrigeration RT/RC Prep Quiz
Topics: All categories in the pool
1: After setting up a forward curved fan for the desired conditions, something happened to lower the total static pressure the fan had to operate against. Which would occur?
CFM and HP decrease
CFM and HP increase
CFM and RPM decrease
RPM and CFM increase
2: How many different groups of refrigerants are there?
3
15
11
7
3: Pairs of mating stop valves that allow sections of a system to be joined before opening these valves or separated after closing them are
companion or block valves
king valves
ball valves
gate or globe valves
4: Where are the three places that the discharge from an ammonia relief valve be piped?
atmosphere, tank containing water, where the A.H.J. indicates
underground, into drain, into mechanical room
to chemical neutralizing tank only
none of the above
5: In a horizontal shell & tube condenser, the ammonia is liquefied by
passing thru the tubes from top to bottom
removing the latent heat of vaporization
removing the latent heat of fusion
water sprayed over condenser
6: Which is the lowest vacuum?
5" hg
10 psia
5 psig
1,000 Microns
7: A compressor that increases vapor pressure by changing the internal volume of the compression chamber is called?
Non-positive displacement
Positive displacement
Low Pressure displacement
Pressure induced displacement.
8: Brazed joints melt at temperatures above
1,000F
500F
800F
1,200F
9: The dial of a pressure gauge, when installed on the high side of a system be graduated 1.2 times the designed pressure.
True
False
10: What refrigerant has zero ozone depletion
HFC
CFC
HCFC
None of the above
11: The discharge relief valve is located (9.4.6)
between the compressor and the stop valve
on top of the condensor
between the compressor and oil separator
between the compressor and reciever
12: Copper and its alloys shall not be used with ammonia
True
False
13: It takes how many BTU's of latent heat/hr to boil 1 lbs of water into steam?
970 BTU
144 BTU
12,000 BTU
24,000 BTU
14: A normal operating evaporator temperature of R-22 for air conditioning is typically
45F
55F
32F
58F
15: When is the space above a drop ceiling calculated as space for refrigerant limit quantities?
When there are sprinklers above
When there is a space 6' or more above it
When its white
When it's used as part of a supply or return air system
16: On a centrifugal compressor, stationary diffuser vanes are needed to
increase the clearance space
stop gas flow
convert velocity energy to pressure
prevent high pressure on the packing
17: Halogenated refrigerants cannot be used with what material?
Magnesium alloy
Stainless steel
Copper
Aluminum
18: What kind of system uses two different refrigerants in separate systems dependent on each other?
R-414B
Cascade
Low pressure
Simple
19: Ashrae states that the equipment on a building needs to conform to adjacent buildings classifications when within ____ feet from opening and intakes.
50
20
15
75
20: Liquid refrigerant flashing, or turning to vapor, in the liquid line may be due to
liquid line that is too small
shortage of refrigerant
liquid line that had too high vertical lift
All of the above
21: On an air cooled condenser, if the ambient air is 35F and dropping, what's its effect to the condensor?
it would make the condenser less efficient
it would have no effect on the condenser
it would cause the condenser to sweat
it would make the condenser more efficient
22: A halide torch is most useful with a freon compression system
to release a sticking valve
to detect refrigeration leaks in piping joints
to remove from from TXV's and evaporator coils
to sweat flanges on the refrigeration piping
23: Suction valve unloaders afford an effective means of
capacity control
evaporator control
superheat control
refrigerant control
24: What device removes the start winding from the circuit of a split-phase motor once the motor reaches 75% of its rated load amps (RLA)?
duel-voltage switch
motor starter
printed circuit board (PCB)
centrifugal switch
25: In a properly balanced system with valves open and properly adjusted, if the suction line is warm to the touch, its because of