Yes, of course it can. There are a lot different duct cleaners out there and most of them are little more con artists looking for quick buck. They can to do more harm than good. As I am writing this I thinking back to just this last week we were out to a home where the furnace was damaged by a ducting cleaning company. The duct cleaning company was trying to do the right thing. We were the third company out as the first two companies could not find out what was happening to the furnace. It turned out that the duct cleaning company broken some wires in the furnace which shorted out the circuit board and the induced draft motor on a very high end furnace. The damages come to about $1200.
Many duct cleaning machines have rotating brushes and these can become jammed and tear the flexible ducting up. I have seen duct cleaners clean asbestos ducts and release asbestos fibers into the air. There is a brand of ducting called Quiet-Flex that had a fabric inner liner. This liner can easily be torn by by a rotating brush. (The picture to the left is an attic duct that was torn apart by a rotating brush from improper duct cleaning. This transition was not installed properly to begin with.)
The majority of the time duct cleaning is perfectly safe for ducts and will not pose any problem whatsoever. When duct clean cleaning does harm ducts it is usually because the ducts are not attached very well. If your duct system in your home is over 10 years of age then chances are very good that your ducts are not attached very well.
Most air duct systems fall apart not from poor installation, but from code approved city inspected new construction systems. The reason is that there were a number of problems with the way ducts were made, sized and installed that were perfectly fine at the time, but proved to be disastrous with age.
Yep, it sucked. Nearly every brand of duct tape 10 years ago is drying out and falling apart. It is a fact and there is nothing anyone can do about it. No fix, just replacement. Brand after brand of cloth backed duct tape, in 90% of homes 10 years ago, is susceptible to drying out and fall apart. This leaves the ducting barely attached and often it comes apart from the metal fittings allowing massive amount of air to escape. Duct cleaning, agitating the inside of the ducts, helps to activate and enhance this condition leading to more problems after duct cleaning if the company doesn’t know what they are doing. (The picture to the upper right is some very dirty air ducts that need
The outer vapor of older ducting was not made to resist the deteriorating effects of sunlight on the outer nylon skin. It turns out that there is enough light going through an attic to cause the deterioration process to begin. As a result, we see flexible ducting literally falling apart in house after house. The new ducting is fine, but the old stuff should be replaced. Applying pressure in the ducting from a duct cleaning machine break it up if a thorough inspection is not performed before hand.