Vacuum Cleaners Discussions

I am happy with my central but for some reason it has low suction and there are not any blockages and its the top of the line Beam System.  It had to be installed in the attic because thats the only place were the installers had enough space for installation, but that was the only down part of it, its not a problem going to the attic to dump the canister but why is the suction low.  I mean its has the suction of your typical run of the mill canister vacuum.  It uses 15amps of power but I may have it plugged into a lower voltage outlet.