Weil McLain 381-800-475 Assembly

The Weil McLain 381-800-475 Assembly is a 5" automatic vent damper and actuator kit engineered for high-performance flue gas management in gas-fired boiler systems. As a heavy-duty OEM replacement part, this assembly is the direct successor to the discontinued 510-512-345 and the Effikal RVGP-KS-5-BKF. Designed for precision, the galvanized steel damper body works in tandem with a 24 VAC motorized actuator to mitigate standby heat loss by sealing the vent during non-firing cycles. This HVAC vent damper assembly features an integrated wiring harness for plug-in compatibility with Weil McLain CGa, CG, and EG series boilers. By ensuring the motorized damper opens fully before burner ignition via end-switch feedback, this unit maintains combustion safety while optimizing thermal efficiency. For technicians servicing residential boilers, this 5-inch diameter assembly is essential for restoring proper sequence of operation and meeting ANSI safety standards for automated vent control.

• Reduced Standby Loss: Automatically seals the flue during off-cycles to retain residual heat within the heat exchanger.
• Direct OEM Compatibility: Verified replacement for Effikal RVGP-KS-5-BKF and Field Controls GVD-5 units.
• Integrated Safety Loop: Built-in end-switch ensures the damper is in the full-open position before the ignition control module initiates the pilot.
• Simplified Installation: Factory-installed wiring harness prevents wiring errors and reduces field labor during boiler repair.
• Durable Construction: Heavy-gauge galvanized steel provides reliable resistance against corrosive flue gases and thermal expansion.

Can I install just the motor if the damper blade is still intact?
While some technicians attempt motor-only swaps, the 381-800-475 is supplied as a complete actuator and damper assembly to ensure the mechanical linkage and electrical end-switches are perfectly calibrated for safe operation.

Will this damper fix an ignition lockout on a Weil McLain CGa boiler?
If your boiler fails to spark and the vent damper is stuck closed or failing to signal the "open" position to the control board, replacing this assembly typically resolves the interlock failure.

Is this compatible with 24V control circuits?
Yes, this is a standard 24 VAC component designed to interface directly with the factory boiler wiring harness and integrated ignition controls.

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Disclaimer: 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.