Sharepoint 2010 : Crawl issues - Search refiners
For troubleshooting managed property for search refiners : Type the <Managedpropertyname>=<the value> in the search box. If the search results return the searchresults filtered by the managed property, the managed property is available for search refiners. Managed properties also can be queried with the < (lesser than) , > (greater than) symbols. Happy Sharepointing!