EPA 608 PRACTICE EXAM TIPS QUESTIONS AND ANSWERS
GUARANTEE A+
✔✔A centrifugal chiller's rupture disk is connected to the chiller's: ________.
a) condenser
b) evaporator
c) liquid line
d) economizer - ✔✔b) evaporator
✔✔When charging a chiller, refrigerant vapor is introduced into the system before
charging with liquid. That is because: ___________.
a) vapor charging increases pressure slowly, preventing failure of the rupture disc
b) vapor charging is faster than liquid charging
c) liquid charging is more difficult to control than vapor charging
d) liquid charged into a deep vacuum will cause the refrigerant to boil and lower
temperatures enough to freeze the water in the tubes - ✔✔d) liquid charged into a deep
vacuum will cause the refrigerant to boil and lower temperatures enough to freeze the
water in the tubes
✔✔To determine how much vapor to charge into an evacuated chiller, you should
charge with vapor until: __________.
a) the system pressure corresponds to a refrigerant saturation temperature of 36
degrees F
b) the recovery unit liquid level drops
c) you have charged with vapor for 15 minutes
d) the recovery unit pressure drops - ✔✔a) the system pressure corresponds to a
refrigerant saturation temperature of 36 degrees F
✔✔When there is excessive moisture collecting in the purge unit of a low pressure
refrigeration system, this indicates that: _________.
a) the system was charged with contaminated refrigerant
b) the condenser or chiller barrel tubes are leaking
c) the purge unit is not operating properly
d) the purge unit needs adjustment - ✔✔b) the condenser or chiller barrel tubes are
leaking
✔✔During chiller evacuation, water is circulated to: _________.
a) speed up the recovery process
b) prevent loss of refrigerant to the atmosphere
c) prevent freezing of the water
,d) maintain constant refrigerant pressure - ✔✔c) prevent freezing of the water
✔✔A system does not have to be evacuated all the way to the required level when:
__________.
a) the repair is major
b) the repair is followed by an evacuation of the appliance to the environment
c) the appliance is being disposed of
d) leaks in the appliance make evacuation to the prescribed level unattainable - ✔✔d)
leaks in the appliance make evacuation to the prescribed level unattainable
✔✔What is meant by the term "high efficiency purge unit"?
a) Those purge units which discharge a high percentage of refrigerant with the air which
they remove.
b) Those purge units which discharge a low percentage of refrigerant with the air which
they remove.
c) Those purge units which draw very little electrical power.
d) None of the above. - ✔✔b) Those purge units which discharge a low percentage of
refrigerant with the air which they remove.
✔✔The maximum test pressure for leak testing a low pressure centrifugal is: ________.
a) 0 psig
b) 10 psig
c) 25 psig
d) 50 psig - ✔✔b) 10 psig
✔✔When recharging a refrigeration system with R-11, what vapor pressure is
necessary in the shells before charging with liquid?
a) 21.1 inches of Hg vacuum
b) 19.7 inches of Hg vacuum
c) 18.1 inches of Hg vacuum
d) 16.9 inches of Hg vacuum - ✔✔d) 16.9 inches of Hg vacuum
✔✔During the evacuation of a system containing large amounts of moisture, you can
prevent freezing of this moisture by increasing the pressure with ______ gas.
a) nitrogen
b) R-22
c) air
d) oxygen - ✔✔a) nitrogen
✔✔Both CFC-11 and HCFC-123 chillers require purge units because: ___________.
, a) the purge units remove moisture
b) the system operates below atmospheric pressure
c) purge units remove refrigerant from the oil sump
d) purge units remove CFCs from the chiller - ✔✔b) the system operates below
atmospheric pressure
✔✔If you are going to remove oil from a low pressure system, you should heat the oil
because: __________.
a) you can warm your hands on the container
b) less refrigerant will be contained in the oil at the higher temperature
c) warmer oil has a lower viscosity and flows more easily
d) it shows that the heater is working - ✔✔b) less refrigerant will be contained in the oil
at the higher temperature
✔✔Refrigerant is added to a centrifugal machine through the: _________.
a) float valve
b) compressor service valve
c) condenser charging valve
d) evaporator charging valve - ✔✔d) evaporator charging valve
✔✔If you leak test a low pressure chiller with nitrogen in excess of 10 psig you could
cause the _______ to fail.
a) condenser tubes
b) purge unit shells
c) evaporator tubes
d) rupture disc - ✔✔d) rupture disc
✔✔To remove ice from sight glasses or viewing glasses, use: _________.
a) R-11 refrigerant
b) an alcohol spray
c) water
d) a screw driver of flat file - ✔✔b) an alcohol spray
✔✔What steps may be taken to prevent air accumulation into an idle low pressure
refrigeration system?
a) Leave the purge unit on-line at all times.
b) System pressure should be maintained slightly above atmospheric.
c) Open the air vents on the condenser.
GUARANTEE A+
✔✔A centrifugal chiller's rupture disk is connected to the chiller's: ________.
a) condenser
b) evaporator
c) liquid line
d) economizer - ✔✔b) evaporator
✔✔When charging a chiller, refrigerant vapor is introduced into the system before
charging with liquid. That is because: ___________.
a) vapor charging increases pressure slowly, preventing failure of the rupture disc
b) vapor charging is faster than liquid charging
c) liquid charging is more difficult to control than vapor charging
d) liquid charged into a deep vacuum will cause the refrigerant to boil and lower
temperatures enough to freeze the water in the tubes - ✔✔d) liquid charged into a deep
vacuum will cause the refrigerant to boil and lower temperatures enough to freeze the
water in the tubes
✔✔To determine how much vapor to charge into an evacuated chiller, you should
charge with vapor until: __________.
a) the system pressure corresponds to a refrigerant saturation temperature of 36
degrees F
b) the recovery unit liquid level drops
c) you have charged with vapor for 15 minutes
d) the recovery unit pressure drops - ✔✔a) the system pressure corresponds to a
refrigerant saturation temperature of 36 degrees F
✔✔When there is excessive moisture collecting in the purge unit of a low pressure
refrigeration system, this indicates that: _________.
a) the system was charged with contaminated refrigerant
b) the condenser or chiller barrel tubes are leaking
c) the purge unit is not operating properly
d) the purge unit needs adjustment - ✔✔b) the condenser or chiller barrel tubes are
leaking
✔✔During chiller evacuation, water is circulated to: _________.
a) speed up the recovery process
b) prevent loss of refrigerant to the atmosphere
c) prevent freezing of the water
,d) maintain constant refrigerant pressure - ✔✔c) prevent freezing of the water
✔✔A system does not have to be evacuated all the way to the required level when:
__________.
a) the repair is major
b) the repair is followed by an evacuation of the appliance to the environment
c) the appliance is being disposed of
d) leaks in the appliance make evacuation to the prescribed level unattainable - ✔✔d)
leaks in the appliance make evacuation to the prescribed level unattainable
✔✔What is meant by the term "high efficiency purge unit"?
a) Those purge units which discharge a high percentage of refrigerant with the air which
they remove.
b) Those purge units which discharge a low percentage of refrigerant with the air which
they remove.
c) Those purge units which draw very little electrical power.
d) None of the above. - ✔✔b) Those purge units which discharge a low percentage of
refrigerant with the air which they remove.
✔✔The maximum test pressure for leak testing a low pressure centrifugal is: ________.
a) 0 psig
b) 10 psig
c) 25 psig
d) 50 psig - ✔✔b) 10 psig
✔✔When recharging a refrigeration system with R-11, what vapor pressure is
necessary in the shells before charging with liquid?
a) 21.1 inches of Hg vacuum
b) 19.7 inches of Hg vacuum
c) 18.1 inches of Hg vacuum
d) 16.9 inches of Hg vacuum - ✔✔d) 16.9 inches of Hg vacuum
✔✔During the evacuation of a system containing large amounts of moisture, you can
prevent freezing of this moisture by increasing the pressure with ______ gas.
a) nitrogen
b) R-22
c) air
d) oxygen - ✔✔a) nitrogen
✔✔Both CFC-11 and HCFC-123 chillers require purge units because: ___________.
, a) the purge units remove moisture
b) the system operates below atmospheric pressure
c) purge units remove refrigerant from the oil sump
d) purge units remove CFCs from the chiller - ✔✔b) the system operates below
atmospheric pressure
✔✔If you are going to remove oil from a low pressure system, you should heat the oil
because: __________.
a) you can warm your hands on the container
b) less refrigerant will be contained in the oil at the higher temperature
c) warmer oil has a lower viscosity and flows more easily
d) it shows that the heater is working - ✔✔b) less refrigerant will be contained in the oil
at the higher temperature
✔✔Refrigerant is added to a centrifugal machine through the: _________.
a) float valve
b) compressor service valve
c) condenser charging valve
d) evaporator charging valve - ✔✔d) evaporator charging valve
✔✔If you leak test a low pressure chiller with nitrogen in excess of 10 psig you could
cause the _______ to fail.
a) condenser tubes
b) purge unit shells
c) evaporator tubes
d) rupture disc - ✔✔d) rupture disc
✔✔To remove ice from sight glasses or viewing glasses, use: _________.
a) R-11 refrigerant
b) an alcohol spray
c) water
d) a screw driver of flat file - ✔✔b) an alcohol spray
✔✔What steps may be taken to prevent air accumulation into an idle low pressure
refrigeration system?
a) Leave the purge unit on-line at all times.
b) System pressure should be maintained slightly above atmospheric.
c) Open the air vents on the condenser.
