A technician is charging an R-410A system that uses a near-azeotropic blend. To keep the blend's composition correct, how should refrigerant be removed from the cylinder during charging?
Explanation
Zeotropic and near-azeotropic blends like R-410A must be charged as liquid so all components leave the cylinder in the correct proportion; removing vapor would fractionate the blend. Liquid is typically drawn from an inverted cylinder or a liquid valve and metered or flashed to vapor before it reaches the compressor to prevent slugging. Charging vapor from the top can change the blend's composition.
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