Which statement about refrigerant blends is correct?
Substitute refrigerants and oils · EPA 608 Core. The correct answer, and the reasoning behind it.
Why there are no true drop-in replacements, and fractionation in blends.
The question
Which statement about refrigerant blends is correct?
- Blends may always be topped off after a leak without concern
- Zeotropic blends never change composition when they leak
- All blends have a single boiling point at a given pressure
- Azeotropes behave much like a single refrigerantCorrect answer
Why “Azeotropes behave much like a single refrigerant” is correct
Azeotropic blends (the R-500 series) behave much like one refrigerant. Zeotropic blends (the R-400 series) have components that boil at different temperatures, so they show temperature glide and can fractionate when they leak.
Source: EPA: Test Topics
Why the other answers are wrong
- Blends may always be topped off after a leak without concern — After a leak a zeotropic blend may have shifted, so topping off can leave the wrong mix.
- Zeotropic blends never change composition when they leak — Zeotropic blends are the ones that can change composition when they leak.
- All blends have a single boiling point at a given pressure — Zeotropic blends boil across a temperature range, not at one point.
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