Lochinvar & A.O. Smith 100233421 Damper

The Lochinvar & A.O. Smith 100233421 Damper is a critical 5-inch automatic flue damper designed for the Lochinvar RBN090 boiler and A.O. Smith water heaters. This 24V motor-actuated damper serves as a direct replacement for the legacy Lochinvar DRH2935, ensuring peak combustion efficiency by managing exhaust gas flow. When the burner cycle is in standby, the assembly closes to minimize standby heat loss, maintaining a higher energy factor and stabilizing internal temperatures. As a genuine OEM replacement part, it is also listed as compatible with CWN399PM and CWN500PM models. Engineered to hold up under high-duty cycles, this flue vent damper integrates seamlessly with existing HVAC control boards to verify draft before allowing ignition, preventing hazardous roll-outs. For field techs, the 100233421 ensures the venting system meets specific back-pressure requirements for the commercial heating units it services.

• Optimized Energy Efficiency: Seals the flue pipe during standby to prevent residual heat from escaping through the vent stack.
• Direct OEM Compatibility: Replaces Lochinvar DRH2935 and fits RBN090 and CWN series units for high-tolerance exhaust gas management.
• Enhanced Equipment Longevity: Reduces cyclic thermal stress on heat exchangers by maintaining stable internal conditions between firing cycles.
• Reliable Standby Control: Features a high-torque 24V damper motor for consistent opening and closing operation in demanding environments.

Is the 100233421 a direct replacement for the DRH2935?
Yes, the 100233421 is the official manufacturer-designated replacement for the obsolete Lochinvar DRH2935 5" damper.

Will a failing flue damper prevent the RBN090 from firing?
Technicians frequently find that if the damper end switch fails to prove it is open, the ignition control will lock out the sequence for safety.

Does this assembly include the actuator motor?
This is a complete automatic flue damper assembly, comprising the 5-inch galvanized steel housing and the pre-installed 24V actuator.

This item is not eligible for free shipping.

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.