It just powered up suddenly with no hose attached to activate it.
How did you turn it off?
!. While it is working, map out the entire circuit that includes the vac. Generally the vac is on a dedicated
circuit. If that is the case, you have issues with more than one circuit and go ro #3
2. If the central vac is one with other lights/receps, you need too understand that the circuit takes a path thru several receps, switches and maybe even light jboxes to get to the vac location. The circuit can fail at any junction point along that route. Map the circuit, turn off power and start pulling out receps and switches looking for loose/bad/burned connections likely
in the back
of a recep. A bad connection can "reconect" temporarily.
3. If the vac is on a dedicated circuit, look in the panel and see if the wire coming from the breaker goes into a 3 wire cable. A 3 wire cable will have both a black
and a red
"hot" wire along with the white and bare as opposed to just a black/white. If so, go to #5
4. If the vac is on a dedicated circuit and other receps/lighte were affected and it is not a 3 wire cable, the problem will be in the panel or the wres feeding the panel.
5. If it's a 3 wire cable, you need to check the white wire at the panel and at the jbox(whever it may be) where it splits off.
Actually....forget it....just call somebody