Type II — High-PressureQuestion 150 of 240
A technician replaces a leaking evaporator on an R-410A system and must protect the new POE oil during the repair. Why is POE oil handling important?
a.It absorbs moisture fast; keep it sealed
b.POE oil is flammable at room temperature and must be kept frozen
c.POE oil never needs a vacuum because it repels water
d.POE oil can be mixed freely with mineral oil with no effect
Explanation
Polyolester (POE) oil used with R-410A is very hygroscopic, meaning it absorbs moisture from the air rapidly, so the system should be left open as briefly as possible and evacuated to a deep vacuum. Excess moisture can cause acid formation and system damage. POE and mineral oil are not freely interchangeable, which matters during retrofits and repairs.
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