Steam humidifier and Zone System

[crroda]

I am thinking about adding a steam humidifier to an existing two zone system. A concern I have is the steam condensing and corroding the URD dampers.

What is a safe distance between the humidifier and the zone dampers if the humidifier is in the main supply run upstream of the bypass and zone dampers?
-or-
Is it necessary to place the humidifier between the bypass branch and the zone branches so that the humidified air is not returned to the unit?
-or-
Should the humidifier be installed downstream of one the zone dampers and rely on the vapor pressure of the "wet" zone to humidify the "dry" zone?

Any application and/or installation hints are appreciated.

Thanks

[Eric K.]

The humidifier will not affect the zone dampers any more then it will you steel ductwork, there is no minimum distance requirement.

The humidifier should be placed upstream(before) of the zone dampers and downstream (after) of the bypass take off. When humidifying, the moist air will enter all zones if there is no demand for heat, and the calling zone(s) if there is a demand for heat. The humidity will migrate throughout the building.