507DR85 – 5” Start Collar w/ Damper

507DR85 5 Inch Start Collar with Damper is an HVAC air-distribution fitting designed to create a connection between compatible ductboard and 5-inch round ductwork. The integrated damper provides a convenient way to adjust airflow through the connected duct branch during system setup and balancing.

This start collar is identified as model 507DR85 and is designed for use with compatible 1½-inch or 2-inch ductboard. Before ordering, confirm the ductboard thickness, required duct diameter, planned connection location, and airflow requirements of the HVAC system.

507DR85 5 Inch Start Collar with Damper Features

The 507DR85 5 Inch Start Collar with Damper combines a 5-inch round duct connection and an airflow-control damper in a single component. It can be used when connecting a compatible round duct branch to a ductboard plenum or trunk.

• Model number: 507DR85
• Nominal connection diameter: 5 inches
• Designed for compatible 1½-inch ductboard
• Also designed for compatible 2-inch ductboard
• Integrated damper for airflow adjustment
• Suitable for HVAC air-distribution applications
• Connects compatible round duct to ductboard
• Useful for new installations and replacement projects

The collar forms the transition from the ductboard surface to the round duct branch. Correct installation helps create a stable connection and reduces the possibility of unwanted air leakage around the opening.

Integrated Airflow Damper

The damper included with the 507DR85 5 Inch Start Collar with Damper allows the airflow through the connected branch to be adjusted. This feature can support HVAC system balancing when different rooms or zones require different quantities of supply or return air.

A damper should not be used to compensate for incorrectly sized ductwork. The connected duct, collar, register, and other fittings must be selected according to the airflow requirements and static-pressure limits of the complete HVAC system.

Damper position should be adjusted by a qualified HVAC professional during system startup or balancing. Excessive restriction can increase static pressure, reduce delivered airflow, and contribute to unwanted operating noise.

After adjustment, verify that air continues to move properly through the connected branch. The technician should also confirm that the damper mechanism does not interfere with the flexible or rigid duct connected to the collar.

Compatible Ductboard Applications

The 507DR85 5 Inch Start Collar with Damper is listed for compatible ductboard measuring either 1½ inches or 2 inches thick. Confirm the actual thickness of the ductboard before cutting the installation opening.

Ductboard must be in suitable condition to support the collar and connected duct. Do not install the fitting on damaged, wet, deteriorated, or structurally weak material. A compromised surface may prevent the collar from remaining secure and properly sealed.

The opening should be accurately located and sized before cutting. Consider the position of existing duct connections, seams, reinforcements, equipment panels, and structural supports. Avoid placing the collar too close to an edge or another opening.

Installing the 507DR85 Start Collar

Before installing the 507DR85 5 Inch Start Collar with Damper, verify the planned position and make sure there is enough clearance for the collar, damper, connected duct, insulation, and fastening materials.

Mark the opening carefully using the correct template or installation dimensions for the fitting. Cut the ductboard with tools appropriate for the material and remove loose particles from the surrounding area.

Position the collar evenly in the prepared opening. Secure it according to the fitting and ductboard installation requirements. The connection should remain stable without crushing, tearing, or excessively compressing the ductboard.

Seal the complete perimeter of the collar using an approved HVAC sealing product compatible with ductboard. An airtight connection helps prevent conditioned-air loss and keeps unfiltered air from entering the duct system.

Follow applicable mechanical codes and approved ductboard installation practices. The exact fastening and sealing method may vary according to the ductboard construction, system application, and local requirements.

Connecting Round HVAC Ductwork

The 5-inch outlet on the 507DR85 5 Inch Start Collar with Damper is intended for compatible 5-inch round ductwork. Verify the actual dimensions and condition of the duct before completing the connection.

When installing flexible duct, pull the inner core completely over the collar and secure it using an approved clamp or fastening method. Seal the inner connection before returning the insulation and vapor barrier to their proper positions.

Flexible duct should follow a smooth and direct route without sharp bends, excessive sagging, twisting, or compression. These conditions can increase resistance and reduce airflow through the 5-inch branch.

When connecting rigid round duct, align the components correctly and fasten them using approved mechanical fasteners. Seal the entire joint with HVAC-approved mastic, sealant, or listed tape as required by the installation.

Airflow and System Compatibility

A 5-inch duct connection is not suitable for every HVAC application. The required diameter depends on airflow demand, duct length, number of fittings, blower performance, static pressure, and the purpose of the connected room or area.

The 507DR85 5 Inch Start Collar with Damper should be selected as part of a complete duct design. Do not determine compatibility only by comparing the collar diameter with an existing duct.

A qualified HVAC professional can calculate the required airflow and confirm whether a 5-inch branch is appropriate. The technician can also adjust the damper while measuring airflow and system static pressure.

Inspection and Maintenance

Inspect the start collar during routine HVAC maintenance. Check for loose connections, damaged ductboard, deteriorated sealant, air leakage, unusual vibration, and obstructions around the damper.

Whistling or excessive airflow noise may indicate a restriction, air leak, incorrect damper position, or duct-sizing problem. These conditions should be evaluated before making additional damper adjustments.

Keep the damper mechanism accessible whenever possible. Do not permanently cover the adjustment area with materials that prevent inspection or future airflow balancing.

Professional Installation Recommended

Professional installation is recommended to ensure that the 507DR85 5 Inch Start Collar with Damper is properly positioned, supported, fastened, sealed, and adjusted. Correct installation protects the ductboard and supports dependable HVAC airflow.

This product includes the start collar and integrated damper. Round duct, flexible duct, clamps, fasteners, sealants, insulation, and other installation materials may be sold separately. Verify all required components before ordering.

Browse more fittings and air-distribution products in the Xpress Supply Ducting & Venting category. For general heating, cooling, and energy-efficiency information, visit the U.S. Department of Energy Energy Saver.