Zonefirst SPRD-8 Damper

The Zonefirst SPRD-8 8" Round Barometric Static Pressure Regulating Damper is a critical component for maintaining system bypass airflow and duct integrity in multi-zone HVAC residential and light commercial applications. Constructed from 22-gauge galvanized steel, this barometric relief damper features a single-blade, counter-balanced weighted arm designed to respond automatically to fluctuating static pressure. As zone dampers close, the SPRD-8 offsets the resulting pressure spike by opening to bypass excess air, effectively reducing airflow noise and preventing equipment damage or coil freeze-ups. This model is rated for a maximum static pressure of 0.5" W.C. and handles a constant volume of 400 CFM, ensuring peak operational efficiency for the air handler. The 10-inch sleeve length provides a rigid, professional-grade housing with a crimped end for seamless ductwork installation. For technicians managing variable volume systems, the adjustable counterweight allows for precise field calibration to match specific pressure setpoints in both horizontal and vertical orientations.

• Controls duct static pressure automatically without the need for additional sensors or wiring.
• Minimized system noise and increased blower longevity by regulating bypass air requirements.
• Durable 22-gauge galvanized steel construction ensures high-performance handling of temperatures from 0°F to 180°F.
• Field-adjustable weighted control arm allows for custom pressure balancing based on the smallest zone capacity.
• In-line round design features a crimped end for rapid integration into existing 8-inch rigid or flex ducting.

How do I calibrate the SPRD-8 for vertical duct runs?
When installing in a vertical orientation, the weighted arm must be adjusted to neutralize the weight of the blade. Slide the weight along the shaft and tighten the set screw once the damper remains closed at normal system pressure but opens during high-pressure cycles.

What is the maximum CFM capacity of the 8-inch model?
The Zonefirst SPRD-8 is engineered to bypass approximately 400 CFM. If your total system CFM minus your smallest zone CFM exceeds this value, a larger diameter (e.g., SPRD-10 or SPRD-12) may be required.

Can this be used as a fresh air intake?
No, the SPRD is a barometric bypass damper designed for internal pressure relief. Standard motorized dampers or specific intake hoods should be used for fresh air ventilation.

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.