I too had a similar problem. I think I have the 980 model but when nothing would go through the hose, I ended up taking the pump assembly apart. The problem I had was that a piece of paint "skin" (paint that has dried but is still in the paint can) got jammed where the 1/2" hose is joined to the 1/4" hose. After removing the clamps and taking out the junk then replacing everything, the power roller worked fine. I think it's a great time saver. Hope this helps with your problem.