Type 3 Flashcards
What should be done to reduce refrigerant loss from a purge unit on a R-123 chiller?
A. Leak test and repair the chiller.
B. Seal the purge unit discharge line.
C. Pipe purge unit back into the low side.
D. Pipe purge unit back into recovery unit.
A. Leak test and repair the chiller.
Leak testing a low pressure refrigeration system with nitrogen in excess of 10 psig could cause which of the following to fail? A: CONDENSER TUBES. B: PURGE UNIT SHELLS. C: EVAPORATOR D: Rupture Disc
D: Rupture Disc
What precaution should be taken prior to recovering refrigerant from a chiller suspected of having tube leaks
A. Drain the water sides of the evaporator and condenser
Industrial process refrigeration when the leak rate exceeds
D: 30%
What must a system owner do once the threshold leak rate has been exceeded on any low pressure system using an ozone depleting refrigerant?
D: Repair the applicance enough to bring the leak rate below the threshold, retrofit, or retire the applican
passed the initial verification leak test, when must a follow-up verification test be conducted
C: within 10 days
A typical setting for the high pressure cut-out control on a recovery unit used for evacuating the refrigerant from a low pressure chiller is
C: 10 psig
Refrigenant removal from a low-pressure system starts with
B: Liquid removal
Why should the oil be removed from a low-pressure system at 103’F
B: Less refrigenant will be contained in the oil at the higher temperature
A rupture disc on a recovery vessel for low-pressure refrigeants relieves at
C: 15psig
What is the result of raising the tempurature of the room in which a low-pressure chiller is located?
B: Faster refrigerant recovery
What is a typical advantage of a water cooled recovery unit?
Faster recovery of large quantities of refrigerant
Charging liquid R-245fa into a low-pressure refrigeration system under a vacuum greater than 18 inches. Hg vacuum can cause the
C: System water to freeze
Which of the following statements is true for recycling and recovery equipment?
It must be equiped with low-loss ball valves and flare fittings
to pressurized an R-1233zd system for the purpose of opening the system for a non-major repair?
Warming the liquid refrigerant in the system
What evacuation level must technicians recover refrigerant to before disposing a low-pressure applicane?
25mm of Hg absolute
require purge unit
These system operate below atmospheric pressure
reason to take oil sample
the unit has had a compressor burnout
prevent freezing by increasing pressure using a gas such as
Nitrogen
Pressure relief valves must NOT be installed
In series
which of the following statements about R-1233zd is FALSE
It is SNAP approved replacement for low-pressure centrifugal systems
Continuous excessive moisture collection in the purge unit of a low-pressure refrigeration system could indicate what condition?
The condenser or the chiller barrel tubes are leaking
ASHRAE Guideline 3, check for leak
1 mm Hg to 2.5mm Hg
Chillers belong to which EPA leak repair category
Comfort colling
After recovering liquid refrigerant
Recover the vapor refrigerant
What should be on/off during vapor removal from a chiller?
Water pumps, recovery compressor, recovery condenser warer should all be on
How do you determine when enough vapor has entered the refrigeration system before you charge refrigerant liqid
Refrigerant saturation temperature increases above 32’F
major
Replacement of Evaporator coil / Compressor /
R-123 at 14.7 PSIA will boil at
82’F
safety precautions should be adhered to for low-pressure systems
Use glove and safety goggles when working with liquid refrigerant
where should the discharge from a rupture disc be piped for venting
Outdoors
burst pressure for a rupture disc
15 psig
Place a leak detector probe to check gas leaks into the water box with water removed
In the drain valve opening
Which of the following CANNOT be used as a reason to extend the applicance leak repair deadline
Necessary repair parts are unavailable
The use of severly oversized vacuum pump could
Cause trapped water to freeze
lowest access point on a low-pressure centrifugal air-conditioning appliance
Evaporator charging valve
indicates air in a low-pressure system
High head pressure
refrigerant go after it leave the purse unit of a low-pressure centrifugal system
The evaporator
AHREA Standard 15-2013 requires the use of sensors and alarms to detect
All refrigerant safety groups
Excessive running of a purse unit
Leaking sysstem
replacement appliance used a refrigerant exempt from the venting prohibition
18 months
where is refrigerant added to a centrifugal machine
Evaporator charging valve
activate an alarm and mechanical ventilation
when the TLV-TWA Threshold Limit Value - Time Weighted Average is exceeded
