Both of the two central vac units that I have owned -
diffferent makes - had an additional inlet at the machine -
if yours does - you coulld check IT for suction - carry your
hose to the garage.. and listen to the motor..
Also - if IT doesn't have suction - ta-da.


Inlets?
I never noticed if there is an additional "inlet".
I'll look later on today when it gets light and see what I can see.


Inlet - referred to as a utility valve by Beam :

http://www.beamvac.com/Productcatalo...ies/Beam-275C/

A little flapper door covers a suction point where your hose
can be inserted. ... your vacuum hose, that is.
John T.