Part # STMPD (shown) Round Medium Pressure Damper designed for 5 ton and over systems - 1.75" w.c. max differential pressure.

Part # STMRTD W x H Rectangular Medium Pressure Damper designed for 5 ton to 7.5 ton systems - 1" w.c. max differential pressure.

Part # STCD W x H (shown)Rectangular Heavy Duty Damper designed for 7.5 ton and larger systems - 1.75" w.c. max differential pressure.

Zonex Systems zone dampers modulate to provide precise room by room zone control. Each zone damper is controlled by a zone thermostat. More than one damper can be controlled by one zone thermostat (slaving dampers).

Our medium pressure round and heavy duty rectangular Dampers are also used as Bypass Dampers.The Bypass Damper is a pressure relief valve placed between the supply and return ducts of the forced air duct work. As Zone dampers start closing, the bypass damper will open and divert some of the supply air to the return. This prevents a pressure buildup in the supply duct which can cause fan cavitation, excessive air velocities, and excessive zone damper blow-by.