EPA 608 609 - EPA Refrigerant Handling Certification EPA 608 Type III Practice Test 1 — Questions and Answers
Question 1: Which refrigerant is most commonly found in older low-pressure centrifugal chillers that require Type III EPA 608 certification?
- R-22
- R-11 (Correct answer)
- R-134a
- R-410A
Correct answer: R-11
R-11 (trichlorofluoromethane) is the classic CFC refrigerant used in older low-pressure centrifugal chillers. It operates well below atmospheric pressure at typical chiller conditions, which is the defining characteristic of Type III equipment. R-22 and R-410A are high-pressure refrigerants, and R-134a is a medium-pressure refrigerant.
Question 2: Under EPA Section 608 regulations, to what level must a technician recover refrigerant from a Type III low-pressure appliance before opening the system for service?
- 0 psig (atmospheric pressure)
- 25 mm Hg absolute pressure (Correct answer)
- 150 psig
- 29.92 in Hg vacuum
Correct answer: 25 mm Hg absolute pressure
EPA regulations require recovery from low-pressure appliances (Type III) to 25 mm Hg absolute pressure. This is a specific absolute pressure measurement — not a gauge pressure — reflecting that the system is already operating well below atmospheric. Recovering to 0 psig would still leave significant refrigerant in the system.
Question 3: How do technicians most reliably detect leaks in a Type III low-pressure chiller system during operation?
- Looking for ice or frost formation on refrigerant fittings
- Monitoring for a rise in system pressure caused by air infiltration (Correct answer)
- Pressurizing the system with nitrogen and checking for bubbles
- Using an ultrasonic detector tuned for high-pressure refrigerant escape
Correct answer: Monitoring for a rise in system pressure caused by air infiltration
Because Type III systems operate under vacuum, any leak allows atmospheric air to enter rather than refrigerant to escape. This air infiltration raises the internal pressure above the normal operating vacuum. Technicians watch for unexpected pressure rise as a primary leak indicator. Nitrogen pressurization is used for some leak checks but is not the primary operational detection method.
Question 4: What is the annual leak repair trigger rate established by EPA regulations for comfort cooling low-pressure chillers containing more than 50 pounds of refrigerant?
- 35% of the refrigerant charge per year
- 15% of the refrigerant charge per year
- 10% of the refrigerant charge per year (Correct answer)
- 5% of the refrigerant charge per year
Correct answer: 10% of the refrigerant charge per year
EPA regulations set the leak repair trigger rate for comfort cooling equipment (which includes Type III centrifugal chillers) at 10% of the total charge per year. Once leak rates exceed this threshold, the equipment owner must repair the leaks within 30 days. Commercial refrigeration and industrial process equipment have higher trigger rates.
Question 5: When non-condensable gases such as air accumulate in a Type III low-pressure chiller, what is the primary operational consequence?
- Evaporator temperature drops below the design setpoint
- Refrigerant charge increases beyond system capacity
- Condensing pressure rises and system efficiency decreases (Correct answer)
- The purge unit shuts down automatically to protect the compressor
Correct answer: Condensing pressure rises and system efficiency decreases
Non-condensable gases like air do not condense in the condenser and therefore occupy space, causing condensing pressure to rise above normal. This elevated condensing pressure increases the work the compressor must do, reduces system capacity, and degrades overall efficiency. The purge unit is designed specifically to remove these gases and restore normal condensing pressure.
Question 6: A Type III chiller's purge unit is activating far more frequently than normal. What is the most likely cause?
- The refrigerant charge has been overfilled
- The compressor is operating at higher-than-rated speed
- Air is leaking into the system at an abnormal rate (Correct answer)
- The condenser water temperature is too cold
Correct answer: Air is leaking into the system at an abnormal rate
The purge unit removes non-condensable gases (primarily air) that infiltrate the system because it operates under vacuum. Abnormally frequent purge activation means more air than usual is entering the system, which is a strong indicator of a leak in the vacuum-side components such as shaft seals, flanges, or fittings. This is an important diagnostic signal unique to low-pressure equipment.
EPA 608 609 - EPA Refrigerant Handling Certification EPA 608 Type III Practice Test 1
Which refrigerant is most commonly found in older low-pressure centrifugal chillers that require Type III EPA 608 certification?