Answers Verified 100% Correct
Desirable characteristics of a refrigerant:
A) High __________
B) Low __________ - ANSWER -A) High critical point
B) Low freezing point
Centrifugal Feed Water Pump
A) Start-up procedure
B) Shut-down procedure - ANSWER -A) Start-up procedure
1) Lock-out, tag-out
2) Close discharge valve
3) Open suction valve
4) Turn on
5) Open discharge valve
B) Shut-down procedure
1) Lock-out, tag-out
2) close suction valve
3) close discharge valve
In order to vary the capacity of an absorption plant, you should regulate the.. -
ANSWER -Flow of the water to the condenser
600,000 btu per hour equals how many tons of refrigeration?
A) 300
B) 3,000
C) 500
D) 50 - ANSWER -D) 50
Heat transfer takes place by
A) evaporation, conduction and condensation
B) radiation, conduction and convection
C) condensation, evaporation and radiation
D) sublimation, evaporation and convection - ANSWER -B) radiation, conduction
and convection
Refrigerant recovery is defined as
,A) Removing the refrigerant from a system and storing it in an external container,
with the lowest emissions possible.
B) Reprocessing a refrigerant into a new product that can be reused in another
system.
C) The process of cleaning a refrigerant of dirt and contaminates, such as oil, acid,
foreign material and non condensibles.
D) None of the above. - ANSWER -A) Removing the refrigerant from a system
and storing it in an external container, with the lowest emissions possible.
A 10-ton refrigeration unit has a capacity of
A) 2,000 btu/minute
B) 12,000 btu/minute
C) 20,000 btu/minute
D) 144,000 btu/day - ANSWER -A) 2,000 btu/minute
In an absorption system, the medium normally used to vaporize refrigerant and
increase its temperature is
A) water
B) propane
C) ethylene
D) steam - ANSWER -D) steam
Any water present in the refrigerant side of a Freon refrigerating system causes a
A) clogged oil trap
B) frozen discharge valve
C) clogged scale trap
D) frozen expansion valve - ANSWER -D) frozen expansion valve
The subcooling effect of the liquid refrigerant just before the expansion valve
causes increased
A) horsepower
B) refrigeration effect
C) expansion valve capacity
D) refrigerant flow - ANSWER -B) refrigeration effect
In a flooded evaporator using an accumulator and float valve, flash gas
A) passes directly into the evaporator
B) passes directly into the suction line
C) does not occur
D) stays in the receiver - ANSWER -B) passes directly into the suction line
, According to Title 49 CFR Section 173.34(e), cylinders and tanks must be
hydrostatically retested
A) once a year by visual inspection
B) a minimum of every 5 years
C) every six months
D) a minimum of once every 2 years - ANSWER -B) a minimum of every 5 years
The minimum required rate discharge capacity of the pressure-relief device or
fusible plug for a refrigerant-containing vessel is determined by the following
formula: C = Fd1. What is "C" equal to?
A) btu/minute
B) Refrigerant pressure
C) Air in pounds/minute
D) Cubic feet/minute - ANSWER -C) Air in pounds/minute
According to the provisions of the rule, a soldered joint is a gas-tight joint
obtained by the joining of metallic mixtures or alloys that melt below
A) 700° F and above 100° F
B) 800° F and above 200° F
C) 900° F and above 350° F
D) 1,000° F and above 400° F - ANSWER -D) 1,000° F and above 400° F
A pressure or temperature response mechanism for automatically stopping the
operation of the pressure-imposing element is the
A) pressure-limiting device
B) pressure-relief valve
C) pressure-imposing device
D) pressure-relief device - ANSWER -A) pressure-limiting device
CO2, Water, Oil —Which is on the top, in the middle and on the bottom
A) in the evaporator
B) in a recovery cylinder - ANSWER -A) Oil, CO2 & water, respectively
B) NH3, oil or CO2, oil or Oil, R-764
Explain capacitor-start, capacitor-run motors - ANSWER -During start-up, this
added capacitance in series with the start winding causes a greater phase angle
between the run and start winding, which gives the motor more starting torque.
When the start switch opens, the start capacitor is taken out of the circuit.
However, the run capacitor and start winding stay in the circuit. The run capacitor