Also integral to the Dampp-Chaser system, with regard to grand pianos, are the string cover and underbelly covers. The string cover adds an enclosed additional area above and around the strings, where
RH levels can be kept low, while also keeping the salt air off the
strings and dust out of the piano. Click here for more info about
string covers and see a few pictures.
The underbelly cover keeps the area underneath the piano
enclosed to prevent the rush of moving air from interfering with
the system. Think about those nice breezes that
blow through the house when the windows are open. The
movement of the air will quickly remove the dry air under your
piano. Also available is a rear cover for vertical pianos and some
player pianos. These covers will help to solve this if your piano is
in an open area.