Search - Minimum Characters
You can set the default minimum number of characters that
must be entered before a basic search is automatically invoked, by defining the
following statement in the
<appSettings> section of the web.config
configuration file. For example, you can set the minimum number of characters
that must be entered before a basic search begins, to 10, as illustrated below:
<add key="AW:QuickSearch:MinEntry" value="10" />