Why can warming the appliance help when recovering R-22 from a cold rooftop unit in winter?
Recovery techniques · EPA 608 Type II. The correct answer, and the reasoning behind it.
Recovering liquid first, speeding recovery, and avoiding cross-contamination.
The question
Why can warming the appliance help when recovering R-22 from a cold rooftop unit in winter?
- It raises the refrigerant pressure in the applianceCorrect answer
- It lowers the boiling point of the oil
- It makes the refrigerant easier to separate from air
- It lets system-dependent equipment be used
Why “It raises the refrigerant pressure in the appliance” is correct
Heating the appliance, or the vessel refrigerant is being removed from, raises its refrigerant pressure. A higher source pressure pushes refrigerant toward the recovery cylinder faster.
Source: EPA: Test Topics
Why the other answers are wrong
- It lowers the boiling point of the oil — Heating does not lower the oil's boiling point.
- It makes the refrigerant easier to separate from air — Warming does not separate air from refrigerant.
- It lets system-dependent equipment be used — The 15-pound limit on system-dependent equipment applies regardless of temperature.
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