9.13 - Practice Questions Set 2

Module: Type III Low-Pressure Appliances
Format: 25-question closed-book EPA 608-style Type III practice set
Regulatory basis: Module 9 material verified through August 13, 2026
Purpose: Provide a second complete Type III practice attempt covering all major examination areas through different service scenarios, diagnostic clues, and regulatory conditions.

Instructions

Select the one best answer for each question.

Read every choice before answering. Pay particular attention to words such as not, most, best, before, after, maximum, absolute, and required.

Complete this set without notes or the answer file if you are using it as a readiness check.

These are original EPA 608-style practice questions developed from Module 9 content and exam-style topic patterns. They are not actual, leaked, or official EPA or certifying-provider examination questions.

Question 1

A centrifugal chiller uses a refrigerant whose liquid-phase saturation pressure at 104°F is 190 psia. Which certification type is determined by this pressure condition for that appliance?

A. Type III because every centrifugal chiller is low pressure

B. Type II because the refrigerant is not in the low-pressure category

C. Type I because a centrifugal compressor is factory assembled

D. No Section 608 certification can apply to a chiller

Question 2

In a shell-and-tube low-pressure chiller, which statement correctly describes the normal water/refrigerant separation?

A. Refrigerant always flows through both water boxes

B. Water and refrigerant are intentionally mixed in the evaporator

C. Water flows through the heat-exchanger tubes while refrigerant occupies the shell side

D. The purge unit separates chilled water from condenser water

Question 3

A purge unit that previously operated occasionally now runs much more frequently. What should the technician suspect?

A. The chiller has become a very-high-pressure appliance

B. The evaporator charging valve is oversized

C. The recovery cylinder is overfilled

D. Air may be leaking into the chiller

Question 4

Unusually large amounts of moisture are being removed by a low-pressure chiller purge system. Which condition should be investigated?

A. A possible tube or water-side leak

B. A recovery vessel with too little refrigerant

C. An undersized refrigerant cylinder color label

D. A compressor operating above its motor voltage

Question 5

Why is a slight positive refrigerant-side pressure useful when leak checking a low-pressure chiller?

A. It makes air leak inward faster

B. It can reverse the leak direction so refrigerant or test gas moves outward at the leak

C. It eliminates the need for a leak detector

D. It converts a tube leak into an electrical fault

Question 6

After controlled heating, nitrogen is permitted for a low-pressure chiller leak test. While staying within the Type III 10 psig exam-preparation maximum, which nitrogen setup is appropriate?

A. Nitrogen cylinder connected directly with no regulator

B. Oxygen cylinder connected through a manifold

C. Regulated nitrogen with gauges and appropriate downstream pressure protection

D. Compressed shop air connected until the relief device lifts

Question 7

Which location is a classic leak point on a low-pressure chiller equipped with an open-drive compressor?

A. Condenser-water pump impeller only

B. Cooling-tower fan blade

C. Chilled-water balancing valve only

D. Shaft seal

Question 8

A 350-ton R-11 chiller has had all accessible liquid removed and is at 0 psig. Which Type III exam lesson is illustrated by the classic example for this condition?

A. About 100 lb of refrigerant vapor may still remain in the representative example

B. No refrigerant can remain at 0 psig

C. The recovery vessel must contain exactly 100 lb

D. The chiller may now be vented because only vapor remains

Question 9

A low-pressure recovery machine with the traditional 10 psig high-pressure cutout repeatedly trips during vapor recovery. Which condition should be checked first?

A. Whether the chiller is classified as Type I

B. Insufficient cooling-water flow through the recovery-machine condenser

C. Whether the evaporator water box is painted

D. Whether the purge unit has been removed

Question 10

The traditional Type III recovery-vessel rupture-disc value is 15 psig. What is the most important interpretation of that number?

A. It is the normal final evacuation pressure of the chiller

B. It is the oil-change opening pressure

C. It is a recovery-vessel protection value and not a universal chiller relief rating

D. It is the pressure at which every vapor charge must switch to liquid

Question 11

Why does freeze risk increase as a low-pressure chiller is pulled into a deeper vacuum during recovery?

A. Lower pressure always raises the refrigerant saturation temperature

B. Vacuum causes water to generate heat inside the tubes

C. The recovery machine stops removing latent heat

D. Lower refrigerant pressure lowers saturation temperature, so boiling refrigerant can cool tube surfaces enough to freeze water

Question 12

During normal recovery, the chiller water pump motor is running. What additional fact is important before assuming freeze protection is adequate?

A. Actual water flow through the required circuit must be verified

B. The recovery vessel must be exactly 15 psig

C. The purge unit must be disconnected

D. All service valves must be closed

Question 13

What causes oil foaming in a refrigeration system?

A. Condenser water mixing with nitrogen in the recovery vessel

B. Rapid boiling of refrigerant out of oil when pressure is suddenly reduced

C. The oil reaching 25 mm Hg absolute

D. A refrigerant monitor sensing oxygen

Question 14

After chiller oil has been heated to the Type III examination value of 130°F, why should the vapor released from the oil be recovered before the oil is removed?

A. To increase refrigerant venting during oil handling

B. To raise water-box pressure

C. To reduce refrigerant remaining in the oil and minimize release during removal

D. To eliminate the need for the final recovery endpoint

Question 15

What is the principal thermodynamic effect of the initial vapor charge in a deeply evacuated low-pressure chiller?

A. It lowers pressure and lowers saturation temperature

B. It removes moisture without a vacuum pump

C. It forces liquid refrigerant out through the rupture disc

D. It raises pressure and saturation temperature, reducing freeze risk

Question 16

A technician is looking for the correct charging connection on a centrifugal chiller. Which approach is best?

A. Use the manufacturer-designated evaporator charging valve

B. Use whichever fitting is physically closest to the floor

C. Use the rupture-disc outlet because it is connected to the refrigerant space

D. Use a water-box drain because it is a low point

Question 17

A technician reads a low-pressure recovery requirement as ‘25.’ Which unit/reference makes that current Type III value correct?

A. 25 psig

B. 25 mm Hg absolute

C. 25 in. Hg vacuum

D. 25 mm Hg above atmospheric pressure

Question 18

A normal low-pressure chiller has a 150-lb refrigerant charge. Another has a 500-lb charge. Under the current normal Table 1 low-pressure row, which statement is correct?

A. Only the 500-lb chiller uses 25 mm Hg absolute

B. The 150-lb chiller uses 4 in. Hg vacuum

C. Both use 25 mm Hg absolute

D. The 200-lb boundary changes the Type III endpoint to 15 in. Hg vacuum

Question 19

A service opening exposes more than 4 square inches of flow area for more than 15 minutes. How is the work classified under the current major-repair definition?

A. It is never major unless the compressor is removed

B. It is automatically a Type I repair

C. It is exempt from refrigerant recovery

D. It is major maintenance, service, or repair

Question 20

A qualifying non-major repair is being performed on a low-pressure appliance using a refrigerant with a boiling point at or below 85°F at standard atmospheric pressure. Which pressurization statement is correct?

A. A method requiring subsequent purging, such as nitrogen, must not be used for that procedure

B. Nitrogen must always be used to raise the appliance to 10 psig

C. Compressed air is preferred over heat

D. The appliance may be opened at 5 psig

Question 21

A low-pressure chiller has one leaking component and one non-leaking component that can be isolated. Which procedure correctly applies the current leak exception?

A. Leave both portions at 0 psig because one component leaks

B. Evacuate the non-leaking portion to the normal Table 1 level, and take the leaking portion to the lowest attainable level without substantial contamination, not above 0 psig

C. Pressurize both portions to 10 psig before opening

D. Vent both portions because the leak prevents normal recovery

Question 22

A low-pressure chiller reaches the required recovery vacuum, is isolated, and then the pressure rises. What is the BEST conclusion?

A. The pressure increase proves an external leak

B. The pressure increase proves the chiller is empty

C. Additional refrigerant may still be vaporizing from liquid or oil, so the condition must be evaluated

D. The recovery-machine condenser must be replaced immediately

Question 23

Why is simply installing two ordinary independent pressure-relief valves in series not proper redundant protection?

A. Two valves in series always lower pressure below absolute zero

B. The arrangement converts both valves to purge units

C. The arrangement is required on every low-pressure chiller

D. The downstream valve can restrict or interfere with the required relief flow

Question 24

Which atmosphere meets OSHA’s general-industry definition of oxygen deficient?

A. 19.4% oxygen

B. 20.9% oxygen

C. 20.0% oxygen

D. 19.5% oxygen or higher

Question 25

Before loosening a large water-box cover, which sequence is most appropriate?

A. Shut the pump off and immediately loosen the lowest bolts

B. Isolate the circuit, control applicable hazardous energy, relieve pressure, drain or vent as required, verify the condition, then open using the approved lifting procedure

C. Pressurize the refrigerant side to 15 psig to hold the cover in place

D. Run the pump while removing the cover so water cannot stagnate

Score

Score: _____ / 25

Readiness target: 22 / 25

Detailed answers and explanations for all three Type III practice sets will be provided in 9.15 - Answers and Explanations.md.