Cluster Renderer

I'm having issues getting my Feature Service to implement clustering. I'm using GE 4.2 /HTLM5 2.3 Viewer. I have publised a map service with Feature Access that has about 5 feature classes. I added the one feature layer to my site and configured the settings to enable clustering...nothing happens. I've tried changing the symbology, (originally used a character symbols and a classified legend), but that didn't work. I found one reference to get this to work by configuring the Site.xml but I think this is for an older GE (3.1x/HTML5 1.x). Anyone have any ideas?