I have an 8 gpm 3500 psi hot water pressure pro machine hot water with 350 hrs on it. Recently I have began to notice that a good bit of water is going back through the bypass hose back into my water tank even when I have the trigger on the wand pressed. This is obviously causing me to lose a good bit of water volume. Do I need to replace the unloader or is something else causing the problem? My pump is a general ts-2021.