EPA 608 609 - EPA Refrigerant Handling Type II High-Pressure Systems Questions and Answers 2 — Questions and Answers
Question 1: EPA Section 608 Type II certification covers which category of refrigeration and air conditioning equipment?
- Small appliances with hermetically sealed compressors and less than 5 lbs of refrigerant
- High-pressure systems other than small appliances (Correct answer)
- Low-pressure systems using refrigerants below atmospheric pressure
- Motor vehicle air conditioning systems
Correct answer: High-pressure systems other than small appliances
Type II certification under EPA Section 608 covers high-pressure systems other than small appliances. This includes most commercial and industrial refrigeration equipment, large split systems, rooftop units, and other high-pressure systems that contain refrigerants such as R-22, R-410A, R-404A, and similar refrigerants that operate above atmospheric pressure.
Question 2: Which refrigerant is classified as a high-pressure refrigerant and commonly used in commercial refrigeration Type II systems?
- R-11 (low-pressure)
- R-113 (low-pressure)
- R-404A (high-pressure) (Correct answer)
- R-123 (low-pressure)
Correct answer: R-404A (high-pressure)
R-404A is a high-pressure HFC refrigerant blend commonly used in commercial refrigeration, supermarket display cases, and transport refrigeration (Type II systems). R-11, R-113, and R-123 are low-pressure refrigerants that operate below atmospheric pressure at room temperature, requiring Type III certification to service.
Question 3: What is the normal operating suction pressure range for an R-410A air conditioning system at a 45°F evaporator saturation temperature?
- Approximately 30 psig
- Approximately 68 psig
- Approximately 102 psig (Correct answer)
- Approximately 130 psig
Correct answer: Approximately 102 psig
R-410A has significantly higher operating pressures than older refrigerants. At a 45°F saturated suction temperature (typical for comfort cooling), R-410A has a saturation pressure of approximately 102 psig. This is roughly twice the pressure of R-22 at the same temperature, which is why R-410A systems require higher-rated components and service equipment.
Question 4: Before opening a high-pressure refrigerant system for service, what must a certified technician always do first?
- Add a dye tracer to locate any existing leaks
- Recover the refrigerant charge to meet EPA requirements (Correct answer)
- Increase system pressure to test for leaks before opening
- Drain the oil from the compressor crankcase
Correct answer: Recover the refrigerant charge to meet EPA requirements
Before opening any refrigerant system for service (such as replacing components), the technician must first recover the refrigerant charge using EPA-certified recovery equipment. Venting refrigerant to the atmosphere is prohibited. Only after recovering the refrigerant to the required level may the system be opened safely.
Question 5: R-410A is a zeotropic blend refrigerant. What does this mean for technicians during leak and recharge situations?
- It must always be charged as a liquid because its blend components can fractionate (Correct answer)
- It can be charged as either vapor or liquid without affecting its composition
- It is an azeotropic blend that behaves like a single-component refrigerant
- It separates into its components at temperatures above 100°F
Correct answer: It must always be charged as a liquid because its blend components can fractionate
R-410A is technically near-azeotropic, but as a blended refrigerant it should be charged as a liquid (from the liquid valve on the cylinder) to maintain proper blend composition. If charged as vapor, the two components (R-32 and R-125) may fractionate — meaning lighter components escape first — altering the blend ratio and reducing system performance. Always charge blended refrigerants as liquid.
Question 6: What is the purpose of a liquid line filter-drier in a high-pressure refrigeration system?
- To reduce refrigerant velocity entering the expansion device
- To remove moisture, acid, and particulates from the refrigerant (Correct answer)
- To separate oil from refrigerant on the high-pressure side
- To prevent refrigerant from flowing backward through the compressor
Correct answer: To remove moisture, acid, and particulates from the refrigerant
The liquid line filter-drier serves two critical functions: it contains a desiccant (typically molecular sieve or silica gel) to absorb moisture from the refrigerant, and it contains a filter element to trap particulates such as metal shavings and system debris. Moisture forms acid with refrigerant oils, causing corrosion and compressor failure, so drier maintenance is essential.
