Does your unit blow when it should be sucking?

[0o0o0o0o0o0o0o0o0100]

that is cavitation of the rotors they are momentarily spinnig the air trapped in the vanes ,not good for the implellers ,the same if you block off 90% of the air intake of your home vacuum ,both not the best on the gear,

[nakedrednek]

all vac trucks do that its a safety so you dont blow up the blover vacume its just like the ball in a shop vac when its full the ball gets sucked up and kills the pressure thats what is happening here when the blower sucks the duct tape in its killing pressure then gives the pressure back hope that helps

[internetzwemmer]

that plate should not be on the vacuum arm !

[723meehan]

@internetzwemmer : There simulating the blower fully submerged and blocked in a working environment. I'm sure it's break-dancing across the pavement too.