When a central vacuum continues to run without a hose plugged into a vacuum wall port then there is a short in the system. Be sure to unplug the central vacuum unit to stop the vacuum from running and then follow these steps to determine where the short is and what to do about it.
If the central vacuum will not stop running you can find more detailed help here, or you can find a local dealer or give us a call. There is always a way to get your central vacuum to stop running and to work properly. We even have remote control products that will bypass the low voltage wire system.