On Tue, 4 Apr 2017 08:31:37 -0400, Art Todesco opined:

You have
to use another vacuum to clean the dumb thing.

Two years ago when I asked here how to debug why my central vac didn't have
much suction, I didn't have extra vacuum cleaners.
https://groups.google.com/d/msg/alt....w/C-a-6iiVHrMJ

Now that I have four vacuum cleaners, I might plug one each into four
outlets, and see if anything comes out.

Or should I suction from the garage where the motor is?