Zonefirst SPRD-12 Damper

Modern forced-air zoning requires precise management of air velocity to prevent equipment damage and audible noise. The Zonefirst SPRD-12 is a professional-grade 12-inch round barometric static pressure regulating damper designed to bypass excess supply air directly into the return plenum as individual zone dampers close. Built with a heavy-duty 22-gauge galvanized steel shell, this single-blade unit utilizes a counter-balanced weighted arm to automatically respond to static pressure fluctuations without the need for electronic controls or complex wiring. By maintaining a constant CFM volume, the SPRD-12 protects the evaporator coil from freezing and prevents furnace high-limit tripping, ensuring the system operates within its engineered specifications. The adjustable weight can be calibrated for bypass air requirements up to 1,000 CFM, providing a reliable mechanical solution for total system balancing and enhanced contractor-level airflow control in both horizontal and vertical duct orientations.

• Automatic Static Control: Self-regulating blade responds instantly to duct pressure increases to maintain balanced airflow.
• System Protection: Critical for preventing short-cycling and preserving HVAC blower motor longevity in multi-zone configurations.
• Field Adjustability: Features an easy-to-calibrate weighted arm for precise setpoint tuning based on the specific external static pressure of the system.
• Heavy-Duty Construction: The 10-inch length sleeve and rigid blade design withstand high-velocity industrial and residential environments.
• Noise Reduction: Effectively eliminates the "whooshing" or air whistling common in zoned ductwork when only the smallest zone is calling.

How do I size this bypass damper for my system?
Subtraction is the standard method: take the total system CFM and subtract the CFM capacity of your smallest zone. The SPRD-12 is rated for approximately 1,000 CFM, making it suitable for 2.5 to 3-ton systems depending on the duct configuration.

Can this be mounted in a vertical duct?
Yes. Unlike rectangular models, the round SPRD series is designed for both horizontal and vertical installation. When mounting vertically, the counter-balanced arm must be adjusted to account for gravity acting on the blade weight.

Does this require a power source?
No. As a barometric relief damper, it is purely mechanical. It operates based on air pressure differentials across the blade, reducing the need for 24V wiring or static pressure switches.

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.