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The Goodman B1789882 Piston Kit is a genuine OEM metering device (fixed-orifice restrictor) supplied for Goodman GMP125-4 series equipment. The piston meters refrigerant into the coil at the precise rate the system was engineered for — the correct orifice is essential for rated capacity and efficiency.
Piston bore size is model-specific. An OEM B1789882 guarantees the exact orifice diameter matched to the coil, protecting superheat, subcooling, and capacity. A mismatched aftermarket piston can cause flooding, starving, or a compressor that never reaches rated performance — the small savings are not worth the risk.
Advanced — the refrigerant circuit must be recovered, opened, and evacuated. This is EPA Section 608 work and should be performed only by a certified technician. Recover refrigerant properly; do not vent.
Verify the required piston bore against the equipment charging chart before installing.