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EPA 608 Core Exam·Substitute Refrigerants & Oils

Why must POE oil be handled carefully?

  1. AIt is flammable
  2. It absorbs moisture rapidly from the atmosphere
  3. CIt is toxic
  4. DIt evaporates quickly

Correct answer

It absorbs moisture rapidly from the atmosphere

Why

POE oil is highly hygroscopic (absorbs moisture rapidly). Exposure to air should be minimized to prevent moisture contamination.

The concept behind this question

Substitute refrigerants have to be evaluated as a system with their lubricant, not swapped in isolation. Mineral oil works with CFCs and HCFCs but does not circulate properly with most HFCs, which is why HFC systems generally use polyolester (POE) oil — and POE is strongly hygroscopic, so it absorbs atmospheric moisture fast when left open. Substitutes must also be approved for the specific end use under EPA's SNAP program, and newer A2L refrigerants are mildly flammable, which changes the handling and equipment rules that apply.

More questions on this topic

Exam-style practice question. Not an official EPA exam question.