{"product_id":"weil-mclain-381-800-474","title":"Weil McLain 381-800-474 Vent Damper","description":"\u003cp\u003eThe \u003cstrong\u003eWeil McLain 381-800-474 Vent Damper Assembly\u003c\/strong\u003e is the factory \u003cstrong\u003e4-inch automatic vent damper\u003c\/strong\u003e for the \u003cstrong\u003eWeil-McLain CG-25-3, CGa-25, CGa-3 and CGx-3\u003c\/strong\u003e gas-fired cast iron boilers. Weil-McLain's own \u003cstrong\u003eCGa Series 1 and 2\u003c\/strong\u003e replacement parts list shows the \u003cstrong\u003e4-inch vent damper assembly\u003c\/strong\u003e as \u003cstrong\u003e381-800-474\u003c\/strong\u003e for the \u003cstrong\u003eCGa-25 and CGa-3\u003c\/strong\u003e and cross-references it to the \u003cstrong\u003eField Controls GVD-4\u003c\/strong\u003e and the \u003cstrong\u003eEffikal RVGP-KS-4BKF\u003c\/strong\u003e damper models. An \u003cstrong\u003eautomatic vent damper\u003c\/strong\u003e is a motor-driven damper blade that sits in the \u003cstrong\u003eflue connection\u003c\/strong\u003e. It closes the vent while the boiler is idle so that heated room air is not drawn up the chimney between cycles, and it opens fully on a call for heat before the burners are allowed to light. On a system of this type that \u003cstrong\u003eopen-before-fire interlock\u003c\/strong\u003e makes the damper a combustion safety device, not just an efficiency accessory.\u003c\/p\u003e\n\n\u003cp\u003eVent dampers are \u003cstrong\u003ediameter-specific\u003c\/strong\u003e, and the \u003cstrong\u003e381-800-474\u003c\/strong\u003e is the smallest of the Weil-McLain gas boiler damper family. The \u003cstrong\u003eCGa Series 1 and 2\u003c\/strong\u003e parts list pairs each boiler size with its own damper: the \u003cstrong\u003e381-800-474\u003c\/strong\u003e (\u003cstrong\u003e4-inch\u003c\/strong\u003e) for the \u003cstrong\u003eCGa-25 and CGa-3\u003c\/strong\u003e, the \u003cstrong\u003e381-800-475\u003c\/strong\u003e (\u003cstrong\u003e5-inch\u003c\/strong\u003e) for the \u003cstrong\u003eCGa-4\u003c\/strong\u003e, the \u003cstrong\u003e381-800-476\u003c\/strong\u003e (\u003cstrong\u003e6-inch\u003c\/strong\u003e) for the \u003cstrong\u003eCGa-5 and CGa-6\u003c\/strong\u003e, and the \u003cstrong\u003e381-800-477\u003c\/strong\u003e (\u003cstrong\u003e7-inch\u003c\/strong\u003e) for the \u003cstrong\u003eCGa-7 and CGa-8\u003c\/strong\u003e. The same parts list shows the \u003cstrong\u003event damper harness 591-391-795\u003c\/strong\u003e and the \u003cstrong\u003event damper actuator 510-512-337\u003c\/strong\u003e as separate service parts, which matters when the damper body is sound and only the harness or actuator has failed. The \u003cstrong\u003e381-800-474\u003c\/strong\u003e is the \u003cstrong\u003ecomplete assembly\u003c\/strong\u003e: as pictured, a \u003cstrong\u003estainless-steel damper body\u003c\/strong\u003e stamped with a \u003cstrong\u003erotation marking\u003c\/strong\u003e, the \u003cstrong\u003emotor and actuator housing\u003c\/strong\u003e mounted on top with a short \u003cstrong\u003eflexible metal conduit\u003c\/strong\u003e, a \u003cstrong\u003emulti-color wire lead\u003c\/strong\u003e ending in a \u003cstrong\u003eplug-in connector\u003c\/strong\u003e, and \u003cstrong\u003etwo small loose mounting pieces\u003c\/strong\u003e packed alongside.\u003c\/p\u003e\n\n\u003cp\u003eA failed vent damper usually shows up in one of three ways: the boiler \u003cstrong\u003ewill not fire\u003c\/strong\u003e because the damper never proves open, the damper \u003cstrong\u003esticks closed or only partly open\u003c\/strong\u003e and the boiler locks out or spills flue gas, or the damper \u003cstrong\u003esticks open\u003c\/strong\u003e and the boiler loses efficiency between cycles. Before condemning the assembly, shut off power and gas, confirm the \u003cstrong\u003eblade turns freely by hand\u003c\/strong\u003e, check that the \u003cstrong\u003eharness plug is fully seated\u003c\/strong\u003e and the wires are not chafed or heat-damaged, and verify the boiler control is sending the damper its signal on a call for heat. If the blade is seized, the actuator is dead or the body is warped, replace the \u003cstrong\u003ecomplete 381-800-474 assembly\u003c\/strong\u003e. Install it with the \u003cstrong\u003erotation marking\u003c\/strong\u003e oriented as Weil-McLain's instructions show, secure it to the flue connection per the boiler manual, connect the harness, and run a full cycle to confirm the damper opens before ignition and closes after the burner shuts down. \u003cstrong\u003eNever bypass or wire around a vent damper\u003c\/strong\u003e: an inoperative damper on a gas boiler is a \u003cstrong\u003ecarbon monoxide hazard\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eKey Benefits\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFactory Weil-McLain Fit:\u003c\/strong\u003e The \u003cstrong\u003e4-inch\u003c\/strong\u003e assembly specified for the \u003cstrong\u003eCG-25-3, CGa-25, CGa-3 and CGx-3\u003c\/strong\u003e boilers, not a universal damper.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eComplete Assembly:\u003c\/strong\u003e \u003cstrong\u003eDamper body, actuator housing, flexible conduit and wire lead with plug\u003c\/strong\u003e in one part, so there is no piecing together a damper from separate components.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eRestores the Safety Interlock:\u003c\/strong\u003e A working \u003cstrong\u003eautomatic vent damper\u003c\/strong\u003e proves the vent is open before ignition and closes it when the boiler cycles off.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eEasy Cross-Reference:\u003c\/strong\u003e The parts list ties this assembly to the \u003cstrong\u003eField Controls GVD-4\u003c\/strong\u003e and \u003cstrong\u003eEffikal RVGP-KS-4BKF\u003c\/strong\u003e, so you can match it to the damper on the boiler now.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cstrong\u003eCommon Questions\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eWhich boilers does the 381-800-474 fit?\u003c\/strong\u003e It is the \u003cstrong\u003e4-inch\u003c\/strong\u003e vent damper for the \u003cstrong\u003eCG-25-3, CGa-25, CGa-3 and CGx-3\u003c\/strong\u003e boilers. Confirm against the boiler's model and serial number before ordering.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eCan I use the 381-800-475, 381-800-476 or 381-800-477 instead?\u003c\/strong\u003e No. Those are the \u003cstrong\u003e5-inch, 6-inch and 7-inch\u003c\/strong\u003e dampers for larger boilers. Match the damper to your boiler's flue connection diameter and model.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eWhat if only the harness or actuator is bad?\u003c\/strong\u003e Weil-McLain lists the \u003cstrong\u003event damper harness 591-391-795\u003c\/strong\u003e and the \u003cstrong\u003event damper actuator 510-512-337\u003c\/strong\u003e as separate service parts. Replace the full \u003cstrong\u003e381-800-474\u003c\/strong\u003e assembly when the body, blade or several components are damaged.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eDisclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.\u003c\/p\u003e","brand":"Weil McLain","offers":[{"title":"Default Title","offer_id":67725030785202,"sku":"381-800-474","price":463.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1838\/2375\/files\/381-800-474.jpg?v=1792091936","url":"https:\/\/www.gsistore.com\/en-ca\/products\/weil-mclain-381-800-474","provider":"GSIstore","version":"1.0","type":"link"}