I've got a problem with a sticky valve somewhere. The machine has been powering up fine, shortly after power up, several minutes, I'd hear a rushing sound of air moving in the system. As of late it's been taking longer, at one point the tool changer faulted out. One time, the tool changer arm wouldn't move up when servo power was applied. Does anyone know which valve(s) I should be looking at? They look like they can be disassembled for cleaning.