air duct machine vs Carpet machine

Again this week I've seen another furnace bite the dust because of some air duct cleaners blowing all the crap down into the main chamber and fan.

I really believe that Carpet cleaning truck mount could do a better job....

just because it's all suction baby

naw carpet is way over priced...... and if your good you can get your price... I make money

MR. STEAMER wrote: Again this week I've seen another furnace bite the dust because of some air duct cleaners blowing all the crap down into the main chamber and fan. I really believe that Carpet cleaning truck mount could do a better job.... just because it's all suction baby

Any competent air duct cleaner will block off the furnace before the blowing and suction begins.  By the way, the coils and furnace need to be cleaned too (remember to cut off the power first).

To Do a Proper Air Duct Cleaning Job with "Negative Air" it takes a minimum of 4000 CFM.  Anything less does not do the job and you wont get dirt out of the vents, you will be wasting your money.  You also really need two people to do the job and the proper way is with Bladder bags to section off the vents.  The Labor is twice as expensive, that is why people us the portables.  But it does do a good job.   Negative air is called the "Push \ Pull " method because you have to hook a vacuum up to the main, block off all the vents and put bladders to section of areas.  So that (Vacuum) is the "Pull", The Push is you need either a skipper ball or mechanical brush to push sweep the dirt, that's the "Push".  So it is like sweeping, you Push the Brush\skipper ball down the vent, the light dirt flows all the way back to the vacuum while the heavier dirt travels X amount of feet then falls to the base of the Vent.  You then Push the Brush\skipper ball down farther the vent,  and repeat the process untill the dirt gets to the Main.   So if you have a Negative air machine with 4,000 CFM, your Lift is probably only 5 Inches.  In the Rotobrush, you have 160-180 CFM and about 80 inches of lift and in the DuctBrush you have 200 CFM and 100 inches of lift.  The movement is a fluid just like water.  If you have a fire hydrant and you open it, alot of volume of water comes out, but shoots only a short distance.  If you restrict the water flow like with a hose nozzel, a tenth the water will have 100 times the pressure and shoot much farther.   The Rotary Air Duct cleaning machines clean at the source just like a standard vacuum or Carpet cleaning machine.  Rotary source duct cleaning machines require much less CFM and more Lift.  Where the opposite is true for Negative air, it needs High CFM (Because the source of the vacuum is at the other side of the home) and less lift.  How the DuctBrush or Rotobrush work is that in it rotates a brush at the source.  Behind the brush is a vacuum nozzle that catches the disrupted dirt.  There are some comments about larger vents, and it is true that there is problems with larger Main returns becuase they are larger than the brush, however the same holds true with a negative air brush.  The difference is many negative air systems use Skipper Balls (Air Balls with Compressor) to agitate the dirt in the larger vents when this problem arises.  This Can't be done with the Rotobrush, but the Skipper Ball can be used with the DuctBrush becuase it uses a Compressor.  And it does a good job.  The best source for skipper balls is www.Skipperballs.com  , and the equipment at  www.Shaftway.com or www.Rotobrush.com .  Many Techs use the Rotary Air duct cleaning machines becuase it takes half the time and labor.  That is why they can advertise at much cheaper prices.  I realize that other people's intentions are good, but it is the man behind the machine that counts.