Duct Cleaning Vacuum Modification


New Member
Mar 5, 2009
Real Name
John McTighe`
Business Location
United States
I thought this might be helpful for some of you that currently do carpet cleaning and perhaps are looking into duct cleaning as another service. I have done duct cleaning for about 9 years, using the Spin Vax System and Viper System for cleaning. I have used both styles of vacuum systems including the large size 8 inch negative air vacuum, along with the Spin Vax vacuum which amounts to a central vac unit with a long hose cleaning directly in the duct.

The frustration over the years for us has been the lack of suction power on the Spin Vax system, while the negative air machine vac is cumbersome and does not produce the results that the hose cleaning directly in the duct provides.

We are testing a different duct cleaning vacuum system, which I will update with results. We are outfitting an existing portable carpet extractor (the Namco Beast) with 2 1/2 inch cool cuffs with adapter, and using a 21/2 inch off the shelf plumbing rubber boot to attach to the inside of the machine. The opening in back fits a variety of large vacuum bags in our instance we are testing out the Kirby HEPA bags in our machine since they are large, thick and readily available via our partner vacuum store.

We will test a single opening with a 50 foot 2 1/2 inch vac hose with the use of a 20 foot 1 1/2 inch hose inside the duct openings. We may add another 2 1/2 inch port to the Beast and run another 50 feet to a Y connector, essentially 5 inch to the door.

The expectation is to gain in both lift and CFM since the current Spin Vax system produces about 100 inches of lift and ~180 CFM at 50 feet of hose. I cannot test the lift on the negative air machine but assume it is lower with the larger vac opening and CFM is rated at 2000 +. however the negative air machine vac hose is run into furnace only, causing issues with flex ducts and old homes.

Here is our modification:

The Stock 1 1/2 inch port has simply been plugged with a rubber stopper, while a 2 1/2 inch opening was drilled to install the cool cuff adaptor.

The rubber boot connects to the back of the adaptor, holding it very snug in place using hose clamps. The opening inside the machine fits Kirby vacuum bags perfectly and did not come off with the high suction. (Sorry the picture is dark).


I will update the results but the tests at the port run 280+ cfm and lift over 200 inches +. We will see if this is a good fit for cleaning directly inside the duct work and what the tests reveal at 70 feet+ I am assuming the power will be very good but if it results in faster cleaning times and a better end result is my main question.
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Premium VIP
Dec 21, 2009
Real Name
matt wood
Business Location
United States
I'm wanting to do something very similar to my rotobrush duct system. I want to bypass the two vacuum motors by hooking up my truck mount's vacuum hose to it.
I'm debating on whether or not I should use my old devastator with a dust downer hooked to it, or if I should put a bag similar to your kirby bag in my truck mount's waste tank.

I like the soft brush system in the rotobrush, but I despise the lack of suction it provides. It's a joke
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Henry Nelson

New Member
Mar 21, 2016
Real Name
Henry Nelson
For duct modification and installations we:

  • Install fire damper sensors
  • Install necessary duct supports
  • Install access doors
  • Extend exhaust duct through roof
  • Install ducting supports and transitions
  • All rigid ducting connections to be solder sealed for leak free operation
  • Supply and install fire retardant flexible drops
Ducting and vacuum tube cleaning includes:

  • Removing connections to dust producing equipment, dust collectors and hoppers
  • Fry brush clean the inside of vacuum line and dust collection line
  • Hand clean all connection ducting and vacuum tubing
  • Reinstall connections to dust producing equipment, dust collectors and hoppers