What is the primary function of a refrigerant distributor at the outlet of a
thermostatic expansion valve?
a. Allow the evaporator to operate with proper superheat.
b. Feed the evaporator sufficient liquid to control the leaving air
temperature.
c. Decrease the pressure drop across the evaporator coil.
d. Evenly feed each evaporator circuit. – ANSWER- D
The voltage that controls the operation of the contact points in a
potential relay is:
a. Line voltage.
b. Run-winding voltage.
c. Back EMF.
d. Control voltage. – ANSWER- C
Refrigerant migration can be minimized by the use of a(n)
a. Oil separator.
b. Receiver tank.
c. Liquid line solenoid valve.
d. Crankcase pressure regulating valve. – ANSWER- C
A transformer rated at 40 VA at 24 volts output has a maximum capacity
of:
a. 0.625 A.
b. 0.960 A.
c. 1.240 A.
d. 1.667 A. – ANSWER- D
Using the illustration below, what is the pressure drop across the
refrigerant distributor and distributor tubes?
a. 2.5 psi.
b. 35 psi.
c. 71 psi.
d. 120 psi. – ANSWER- B
The current that opens the contacts in the current relay is the:
a. Start-winding current.
b. Run-winding current.
c. 24-volt applied voltage.
d. Back EMF. – ANSWER- D
The holding coil of the potential start relay is connected across:
a. The run-winding and common.
b. The start-winding and common.
c. Both run and start windings.
d. The line voltage. – ANSWER- B
In a pump-down refrigeration system, the compressor is cycled on and
off by the:
a. Temperature control.
b. Low pressure control.
c. Head pressure control.
d. Liquid solenoid valve. – ANSWER- B
Low ambient head pressure controls in a condensing unit function by
controlling flooding of liquid refrigerant in the:
a. Receiver.
b. Accumulator.
c. Evaporator.
d. Condenser. – ANSWER- D
As head pressure increases while suction pressure remains constant, the
compressor current:
a. Increases and capacity increases.
b. Decreases and capacity increases.
c. Increases and capacity decreases.
d. Increases and capacity remains constant. – ANSWER- B
On an inside 30 lb. receiver with a safety-pressure relief device, the
discharge of the safety device should be piped to the:
a. Inside compressor.
b. Outside condenser.
c. Outside atmosphere.
d. Inside evaporator. – ANSWER- C
On a new installation, the purpose of adjusting a thermostatic expansion
valve to maintain a low superheat is to ensure that:
a. The liquid refrigerant will boil off as quickly as possible in the
evaporator.
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