Resideo ZD16X18TZ Damper 321894-709 5" mounting footprint makes this

5" mounting footprint makes this a versatile replacement for many OEM configurations

When diagnosing a cracked heat exchanger or assessing soot accumulation

What is the purpose of the CB suffix in the part number

then thread the new operator onto the existing valve base

Engineered with a durable porcelain bushing and a high-grade iron core construction

Resideo ZD16X18TZ Damper 321894-709 5" mounting footprint makes thisThe Resideo ZD16X18TZ is a robust 16" Wide X 18" High parallel blade zone damper engineered for precision airflow control in residential and light commercial HVAC zoning applications. Built with a high grade extruded aluminum frame and blades, this unit is designed for long term durability and low leakage performance. The synchronous motor is a 24Vac power closed spring return open actuator, ensuring a fail safe normally open position during power