On Thu, 06 Apr 2017 12:25:58 -0400, opined:

The unit is already trying to suck that way- unsuccessfully so I'd
try sucking out the inlets.

Good idea. I just suctioned backward, all the in-house inlets but I didn't
get much by way of debris.

Here's basically what I got out of the more than half-dozen inlets:
http://i.cubeupload.com/1XHC3N.jpg

All but one seemed clean, where the one most used had a little bit of
debris I could hear hitting the vacuum container sides.
http://i.cubeupload.com/JGkKeB.jpg

It took a while to get the hoses right because they're all the same size on
the large end and the same size on the small end, where I needed to fit
together a large-to-large using this gasoline tube piping.
http://i.cubeupload.com/CrPUAN.jpg

I changed vacuum cleaners from the Eureka floor type to use the Costco
tin-can type with the air blowing out visibly, where it seemed that none of
the vacuum inlets is clogged because the air blew out pretty well.
http://i.cubeupload.com/QdwsYB.jpg