{"product_id":"weil-mclain-381800478-8-inch-vent-damper-assembly","title":"Weil-mclain 381800478 8 Inch Vent Damper Assembly","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\u003cp\u003eThe Weil-McLain 381800478 is an 8 inch vent damper assembly designed for use in residential and light commercial heating systems. Vent dampers are critical components in gas-fired boilers and furnaces. They mount in the flue or vent pipe and automatically open when the burner fires. When the burner shuts off, the damper closes. This prevents heated air inside the building from escaping up the flue stack when the heating system is idle. The result is improved system efficiency and lower energy consumption over the heating season. HVAC technicians and boiler service professionals rely on properly functioning vent dampers to meet equipment efficiency standards and maintain safe, code-compliant installations. The 381800478 is a direct replacement part sourced from Weil-McLain, a manufacturer with a long history of producing cast iron boilers and hydronic heating equipment. Using an OEM-matched damper assembly ensures the replacement component integrates correctly with existing wiring, linkage, and control circuits. This 8 inch diameter damper assembly is sized for larger residential or small commercial vent pipe runs. The assembly includes the damper blade, actuator motor, and housing needed to restore full functionality. It fits into standard round vent pipe and connects to the system control board to receive open and close signals. Technicians performing boiler maintenance, tune-ups, or component-level repairs will find this damper assembly straightforward to install with standard hand tools. Proper replacement of a failed vent damper restores fuel savings and prevents nuisance lockouts caused by faulty proving switches that detect damper position. Always verify vent pipe diameter and boiler model compatibility before installation.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e8 inch diameter damper assembly for residential and light commercial boiler vent systems\u003c\/li\u003e\n\u003cli\u003eAutomatic open and close operation tied to burner demand, reducing standby heat loss\u003c\/li\u003e\n\u003cli\u003eOEM Weil-McLain replacement part for accurate fit and reliable control circuit integration\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eProduct Highlights\u003c\/h4\u003e\u003cp\u003eThe Weil-McLain 381800478 vent damper assembly is a direct OEM replacement for 8 inch flue vent applications, restoring efficiency and safe operation to Weil-McLain heating systems. Its automatic actuator-driven design reduces standby heat loss and supports fuel savings throughout the heating season.\u003c\/p\u003e\u003ch3\u003eProduct Information\u003c\/h3\u003e\u003ch4\u003eStandard Information\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand\u003c\/strong\u003e: WEIL-MCLAIN\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: 381800478\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eItem Type\u003c\/strong\u003e: Vent Damper Assembly\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDamper Diameter\u003c\/strong\u003e: 8 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLength\u003c\/strong\u003e: 14 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWidth\u003c\/strong\u003e: 9.75 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeight\u003c\/strong\u003e: 8.5 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 9 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC\u003c\/strong\u003e: 672619115590\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"WEIL-MCLAIN","offers":[{"title":"Default Title","offer_id":51121035247922,"sku":"672619115590","price":483.74,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/41ljgR3vX5L_9323db71-271e-433e-b73a-3710bf083c87.jpg?v=1777746584","url":"https:\/\/voomisupply.com\/products\/weil-mclain-381800478-8-inch-vent-damper-assembly","provider":"Voomi Supply","version":"1.0","type":"link"}