Yes the sub woofer will go into power saving. The reason I put the gain down was to limit the sub to a very light work load. It was barely audible. This way I could see if it was just too much load on the amp the way I had it.

The sub eventually heated up like it was under load, and turned off. There is a little LED inside the amp, that you can see through the slits, and that turned red and the sub stopped. It took a few hours, but it definitely shut off.