Free EPA 608 Low Pressure Systems Practice Test (2026)

80 questions · 120 min · 70% to pass

80 Questions · 120 Minutes · 70% to Pass

Question 1 of 5

Sample Questions

Question 1

R-123 is classified under which category of refrigerants in terms of ozone depletion?

Answer: R-123 is classified as a Class II ozone-depleting substance (HCFC). It has a lower ozone depletion potential than R-11 but is still subject to phase-down regulations.

Question 2

What is the evaporator pressure of R-123 at a typical chiller operating temperature of 40°F?

Answer: R-123 operates at a pressure below atmospheric (in a vacuum) at 40°F, approximately 5.8 inches of mercury vacuum. This is why R-123 systems are considered low pressure systems.

Question 3

What type of compressor is almost exclusively used in low pressure refrigeration systems?

Answer: Centrifugal compressors are almost exclusively used in low pressure refrigeration systems. Their design is well-suited for handling the large volumes of low-pressure refrigerant vapor.

Question 4

What is the boiling point of R-123 at atmospheric pressure?

Answer: R-123 has a boiling point of approximately 82.2°F (27.9°C) at atmospheric pressure. This high boiling point means it operates below atmospheric pressure at typical chiller conditions.

Question 5

Which refrigerant was the primary low pressure refrigerant used in centrifugal chillers before being phased out as a Class I ozone-depleting substance?

Answer: R-11 (trichlorofluoromethane) was the primary low pressure refrigerant used in centrifugal chillers before its phase-out. It was replaced largely by R-123.