few things you should NOT do when deploying Office Web Apps Server

“First, here are a few things you should NOT do when deploying Office Web Apps Server.

• Don’t install any other server applications on the server that’s running Office Web Apps Server. This includes Exchange Server, SharePoint Server, Lync Server, and SQL Server. If you have a shortage of servers, consider running Office Web Apps Server in a virtual machine instance on one of the servers you have.

• Don’t install any services or roles that depend on the Web Server (IIS) role on port 80, 443, or 809 because Office Web Apps Server periodically removes web applications on these ports.

http://technet.microsoft.com/en-us/library/jj219435%28v=office.15%29.aspx