ZoneFirst AOBD-20X10 Damper 328140-751 and gaskets eventually fail under

and gaskets eventually fail under thermal cycling

Engineered with a durable cast iron body and a 2-inch NPT connection

this is an automatic reset switch

Is this part suitable for high-pressure 250 lbs valves

Precision-fit geometry ensures the paddle interfaces correctly with the microswitch actuator

ZoneFirst AOBD-20X10 Damper 328140-751 and gaskets eventually fail underThe ZoneFirst AOBD 20X10 Damper is a professional grade automatic opposed blade damper engineered for precision bypass and zone control in high demand residential and commercial ductwork. This 20" wide by 10" high unit features an anodized extruded aluminum frame and blades, ensuring a low profile footprint that fits into 3 inch slots for streamlined side mount installation. Each blade is connected via a stainless steel draw bar and nickel plated