Hi, it sounds like someone converted the unit to a bag type. It was probably a long bag with a hole towards the top like with our Closed Microfilter Bags. And yes, all the accessories you see will fit your system. We highly suggest a new kit, they ALL fit. Compare our Electric Kits and our Air Driven Kits to find a solution that works best for you.
In the troubleshooting chart see the box that has the #4 solution attached to it. Follow the directions in that box to test your inlets. https://builtinvacuum.com/flowchrt.html