{"product_id":"oem-goodman-piston-kit-for-wghp4348aaa-heat-pump-b1789878","title":"OEM Goodman Piston Kit for WGHP4348AAA Heat Pump — B1789878","description":"\u003cp\u003eThe \u003cstrong\u003eGoodman B1789878 Piston Kit\u003c\/strong\u003e is a genuine OEM refrigerant metering device for \u003cstrong\u003eWGHP4348AAA\u003c\/strong\u003e heat pump systems. The piston — a fixed-orifice flowrator — sets refrigerant flow into the coil to maintain correct superheat and rated capacity. The larger-capacity WGHP4348AAA requires its specific orifice size, so using the matched B1789878 ensures the system meets its factory efficiency and cooling specs.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eOEM Part Number: B1789878\u003c\/li\u003e\n\u003cli\u003eCompatible Model: WGHP4348AAA\u003c\/li\u003e\n\u003cli\u003eType: Fixed-orifice piston \/ flowrator metering device\u003c\/li\u003e\n\u003cli\u003eBrand: Goodman\u003c\/li\u003e\n\u003cli\u003eApplication: Heat pump refrigerant control\u003c\/li\u003e\n\u003cli\u003eFit: Direct OEM exact-fit replacement\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eOEM vs. Generic\u003c\/h3\u003e\u003cp\u003eOur \u003cstrong\u003eOEM B1789878\u003c\/strong\u003e is bored to the exact factory orifice for the WGHP4348AAA, guaranteeing proper metering for this unit's tonnage. Generic universal pistons require manual orifice selection and can mis-meter refrigerant, risking floodback or starvation. For matched-system and warranty work, the OEM piston is the reliable choice.\u003c\/p\u003e\u003ch3\u003eInstallation Difficulty\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eModerate\u003c\/strong\u003e — requires refrigerant recovery, opening the coil or line set, and EPA 608 certification. Recommended for licensed HVAC technicians.\u003c\/p\u003e","brand":"Goodman","offers":[{"title":"Direct Replacement","offer_id":63032347033971,"sku":"B1789878-GEN","price":14.95,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048293777779,"sku":"B1789878","price":19.43,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-piston-B1789878.jpg?v=1782949990","url":"https:\/\/nationalhvacparts.com\/products\/oem-goodman-piston-kit-for-wghp4348aaa-heat-pump-b1789878","provider":"National HVAC Parts","version":"1.0","type":"link"}