Ewc Controls ECLBD-12 Constant Load Bypass Damper 12 in

Product Description

The EWC CONTROLS ECLBD-12 is a round, non-motorized constant load bypass damper designed to maintain balanced static pressure in zoned HVAC duct systems. When zone dampers close and reduce airflow demand, this bypass damper opens to redirect excess supply air back to the return side, protecting the blower from pressure buildup. At 12 inches in diameter and 8 pounds, it is sized for residential and light commercial trunk duct installations. No motor or spring-return mechanism is required, making it a straightforward mechanical solution for pressure relief in variable-airflow zoning setups.

This bypass damper is used in forced-air zoning systems where multiple zone dampers operate independently and total system airflow can drop significantly when fewer zones call for conditioning. It mounts inline in a round duct bypass leg, typically between the supply plenum and the return plenum or main return trunk. HVAC technicians install it as part of a complete zoning control system to prevent excessive static pressure that can shorten blower motor life, generate noise, and reduce system efficiency. It is suited for residential new construction and retrofit zoning applications.

Key Features

• 12-inch round profile fits standard duct sizes common in residential zoning systems
• Non-motorized design eliminates wiring and reduces points of failure
• Non-spring-return operation allows the damper to respond passively to system pressure differentials
• 14-inch body length accommodates standard duct collar connections
• 8-pound unit weight supports straightforward field handling and single-technician installation

Compatibility

Designed as an OEM-style replacement or new-installation bypass damper for round-duct residential and light commercial forced-air zoning systems requiring constant load pressure relief.

Installation Notes

Installation is performed by licensed HVAC technicians as part of a zoned forced-air system. Power down the air handler or furnace at the disconnect before making any duct or control connections. The damper should be mounted in a dedicated bypass duct run between the supply and return plenums, sized and positioned per the zoning system manufacturer guidelines and local mechanical code requirements. Verify all duct connections are sealed with approved mastic or metal tape to prevent air leakage.

Technical Specifications

• Shape: Round
• Damper Type: Bypass
• Motorized: No
• Spring Return: Non-Spring Return
• Size: 12 inches
• Product Height: 12 inches
• Product Length: 14 inches
• Unit Weight: 8 pounds

Standard Information

• Brand: EWC CONTROLS
• Manufacturer Part Number: ECLBD-12