answers A+ 2025\2026
On low-pressure chillers, moisture most frequently enters the system through;
a. air leaks in the rupture disc assembly.
b. tube leaks in the evaporator.
c. leaks from areas with gaskets or fittings.
d. leaks from the charging service valve.
- correct answer c. leaks from areas with gaskets or fittings.
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 continue.
b. Run the circulating pumps.
c. Be certain the purge unit is operating.
d. Open the condenser vents.
- correct answer a. Drain the water sides of the evaporator and continue.
Continuous excessive moisture collection in the purge unit of a low-pressure refrigeration system could
indicate what condition?
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 adjustment is not set properly.
- correct answer b. The condenser or chiller barrel tubes are leaking.
Which of the following CANNOT be used as a reason to extend the appliance repair deadlines?
,a. Requirements of federal, state, or local regulations make the repair within 30 days impossible.
b. The appliance is located in an area that is subject to radiological contamination.
c. Necessary repair parts are unavailable
d. A certified service technician is not available.
- correct answer d. A certified service technician is not available.
What is the best method to determine a chiller's normal charge for leak rate calculations?
a. Determine from the maximum power consumption.
b. Determine from the compressor horsepower.
c. Determine from the dimensions of the chiller.
d. Use the charge stated on the equipment nameplate.
- correct answer d. Use the charge stated on the equipment nameplate.
Approximately how much refrigerant vapor is left in an average 350-ton R-123 chiller at 0 psig once all
the R-123 liquid has been removed?
a. Trace amount
b. 50 pounds
c. 75 pounds
d. 100 pounds
- correct answer d. 100 pounds
A rupture disc on a recovery vessel used for low-pressure refrigerants relieves at;
a. 5 psig
b. 10 psig.
c. 15 psig
d. 20 psig
- correct answer c. 15 psig
Charged low-pressure refrigeration machines may be most efficiently leak checked by;
a. adding dry nitrogen to increase the pressure.
, b. adding refrigerant leak detection tracer dye.
c. adding heat with circulated hot water or heating blankets.
d. operating the purge system to see how much air comes out.
- correct answer c. adding heat with circulated hot water or heating blankets.
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 the purge unit back into the low side.
d. Pipe the purge unit back into the recovery unit.
- correct answer a. Leak test and repair the chiller.
According to ASHRAE Guideline 3, the system should be checked for leaks if during a standard vacuum
test the pressure in a system rises from 1 mm Hg to a level above;
a. 1.5 mm Hg
b. 2.0 mm Hg
c. 2.5 mm Hg
d. 3.0 mm Hg
- correct answer c. 2.5 mm Hg
A chiller with a charge of 200 pounds has passed the initial verification leak test. When must a follow-up
verification test be conducted?
a. The same day.
b. The next day.
c. Within 10 days.
d. Within 30 days.
- correct answer c. Within 10 days.
What is a typical advantage of a water-cooled recovery unit?
a. Higher pressure at the recovery compressor's discharge
b. Higher pressure in the recovery tank