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The Goodman B1789882 is a genuine OEM piston (flowrator) restrictor kit designed as a direct-fit replacement for the GSC130481AD 13 SEER, 4-ton condensing unit. The piston is the refrigerant metering device that controls flow into the evaporator or condenser coil, maintaining the correct pressure drop and superheat for efficient cooling. A worn, clogged, or incorrectly sized piston causes poor cooling, icing, and high energy use—so using the factory-specified orifice is critical.
This factory-original Goodman piston is bored to the exact orifice diameter matched to the GSC130481AD's capacity and refrigerant charge. Generic pistons with even slightly different orifice sizing throw off superheat and subcooling, hurting efficiency and risking compressor damage. OEM guarantees the correct metering for this system.
Advanced. Replacing the piston requires recovering refrigerant, opening the liner/flowrator assembly, swapping the orifice, and recharging the system. EPA Section 608 certification is required. This job should be performed by a licensed HVAC technician.