HVAC EPA Questions with Correct Answers
Graded A+
where does the refr. go after it leaves the purge unit of a low pressure centrifugal system?
the evaporator
when evacuating a system, the use of a large vacuum pump could: cause trapped water to
freeze
with a low pressure chiller, what must you do after recovering the liquid refrigerant?
recover the vapor ref.
a rupture disc on a recovery vessel for low-pressure refr. relieves at: 15psig
what should be done to reduce ref. loss from a purge unit on a CFC-11 chiller? leak test
and repair the chiller
continuous excessive moisture collection in the purge unit of a low pressure ref. system could
indicate what condition? the condenser or chiller barrel tubes are leaking
,refrigerant is added to the centrifugal machine through the evaporator charging valve
a hydrostatic tube test kit will: determine if a tube leaks
leak testing a low pressure ref. system with nitrogen in excess of 10 psig could cause what to
fail? rupture disc
excessive running of a purge system on a low pressure chillder indicates what condition?
system is leaking
what precaution should be taken prior to recovering ref. from a chiller suspected of having tube
leaks? drain the water sides of the evaporator and condenser
on a centrifugal system, the purge unit takes its suction from the: top of the condenser
when recharging a ref. system with R-11, what vapor pressure is necessary in the shells before
charging with liquid? 16.9 Hg vacuum
,after system servicing, why is refrigerant vapor re-introducted to the ref. system before liquid?
liquid charged into a deep vacuum will boil and may lower temps. enough to freeze water
in the tubes
water must be circulated through a chiller during ref. evacuation in order to: prevent
freezing of the water
when leak testing a low pressure centrifugal with nitrogen, what is the maximum test pressure?
10 psig
EPA regulations require that all applicances containing *more than 50lb of ref - EXCEPT for
commercial and industrial eq.* be repaired when the leak rate exceeds: 15% per year
what is the typical design burst pressure for a rupture disk on a low pressure centrifugal air
conditioning system? 15psi
how do you determine when enough vapor has entered the ref. system before you charge ref.
liquid? ref. saturation temp. increases to 36 F
, a typical setting for the high pressure cutout control on a recovery unit used for evacuating the
ref. from a low pressure chiller is: 10psig
when removing oil from a low pressure system, the temp should be 130 degrees because:
less ref. will be contained in the oil at the higher temp.
during vapor removal from a low pressure ref. system... the system water pumps, the
recovery compressor, and the recovery condenser water should ALL be on
pressure relief valves must not be installed: in series
when using recovery and recycling eq. manufactured AFTER 11/15/93, techs must evacuate low-
pressure appliances to the following level: 25mm of Hg ABSOLUTE
which component is particularly susceptible to leaks in low pressure ref. systems with open-drive
type compressors? shaft seal
on low pressure chillers, moisture most frequently enters the system through: tube leaks
Graded A+
where does the refr. go after it leaves the purge unit of a low pressure centrifugal system?
the evaporator
when evacuating a system, the use of a large vacuum pump could: cause trapped water to
freeze
with a low pressure chiller, what must you do after recovering the liquid refrigerant?
recover the vapor ref.
a rupture disc on a recovery vessel for low-pressure refr. relieves at: 15psig
what should be done to reduce ref. loss from a purge unit on a CFC-11 chiller? leak test
and repair the chiller
continuous excessive moisture collection in the purge unit of a low pressure ref. system could
indicate what condition? the condenser or chiller barrel tubes are leaking
,refrigerant is added to the centrifugal machine through the evaporator charging valve
a hydrostatic tube test kit will: determine if a tube leaks
leak testing a low pressure ref. system with nitrogen in excess of 10 psig could cause what to
fail? rupture disc
excessive running of a purge system on a low pressure chillder indicates what condition?
system is leaking
what precaution should be taken prior to recovering ref. from a chiller suspected of having tube
leaks? drain the water sides of the evaporator and condenser
on a centrifugal system, the purge unit takes its suction from the: top of the condenser
when recharging a ref. system with R-11, what vapor pressure is necessary in the shells before
charging with liquid? 16.9 Hg vacuum
,after system servicing, why is refrigerant vapor re-introducted to the ref. system before liquid?
liquid charged into a deep vacuum will boil and may lower temps. enough to freeze water
in the tubes
water must be circulated through a chiller during ref. evacuation in order to: prevent
freezing of the water
when leak testing a low pressure centrifugal with nitrogen, what is the maximum test pressure?
10 psig
EPA regulations require that all applicances containing *more than 50lb of ref - EXCEPT for
commercial and industrial eq.* be repaired when the leak rate exceeds: 15% per year
what is the typical design burst pressure for a rupture disk on a low pressure centrifugal air
conditioning system? 15psi
how do you determine when enough vapor has entered the ref. system before you charge ref.
liquid? ref. saturation temp. increases to 36 F
, a typical setting for the high pressure cutout control on a recovery unit used for evacuating the
ref. from a low pressure chiller is: 10psig
when removing oil from a low pressure system, the temp should be 130 degrees because:
less ref. will be contained in the oil at the higher temp.
during vapor removal from a low pressure ref. system... the system water pumps, the
recovery compressor, and the recovery condenser water should ALL be on
pressure relief valves must not be installed: in series
when using recovery and recycling eq. manufactured AFTER 11/15/93, techs must evacuate low-
pressure appliances to the following level: 25mm of Hg ABSOLUTE
which component is particularly susceptible to leaks in low pressure ref. systems with open-drive
type compressors? shaft seal
on low pressure chillers, moisture most frequently enters the system through: tube leaks
