Question 33Refrigeration & AC - 1st Asst/Chief

The correct answer is C) R-123. R-123 is normally classified as a low pressure refrigerant, as it operates at lower pressures compared to other refrigerants like R-12, R-22, and R-134A. This is due to R-123's chemical properties and its lower saturation pressure at typical refrigeration temperatures. The lower operating pressure of R-123 makes it a safer choice for certain applications, as high pressure refrigerants carry a greater risk of leaks or mechanical failures. The other answer choices, R-12, R-22, and R-134A, are classified as medium or high pressure refrigerants and operate at higher pressures than R-123, making them less suitable for low pressure refrigeration systems.