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The Goodman B1789865 Piston (Orifice) Kit is the genuine OEM metering device for ASH130301AC heat pump systems. The fixed-orifice piston controls the precise rate at which liquid refrigerant flows into the coil, setting the pressure drop that governs cooling and heating capacity. A correctly sized piston is essential for proper superheat, subcooling, and rated efficiency.
OEM pistons are drilled to the exact bore diameter specified for your ASH13 unit's capacity. An incorrectly sized generic piston will flood or starve the coil, hurting efficiency and risking compressor damage. At this price point, the genuine OEM part is always the smart choice.
Difficulty: Advanced (Professional Recommended). The system must be recovered and opened at the liquid line/coil connection to swap the piston, then evacuated and recharged. Requires EPA certification and refrigerant-handling tools.