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The brush is just round with soft bristles, check it out in the dryer vent section next time you're at homers.

The brush I use is just a dryer vent brush they sell at home cheapo. It has flexible rods that screw together, and you can put it in your drill, unfortunately the brush only comes in one size but it's better than nothing, I run it through the ducts while the neg pressure machine is going. If you could get different sized brushes it would actually work perfectly, it goes through flex pretty well. Kind of something I came up with on my own since the company won't buy me a Rotobrush, lol.

Originally Posted by greenhorn520

Well there's the rotobrush long vac hose with brush on the end of it. And then there is also large vacuums you can hook up to a supply and put the whole system under neg pressure. The brush I use hasn't done any harm to flex and the vac is not powerful enough to crush the flex either. I personally think the rotobrush would be more efficient if it can go through flex, but you can actually use the 2 types of vacs in conjunction.

Are the brushes you use the full round type or the collapsable flaps?
What I have for a neg air machine is probably what you have. It reminds me of the Air Care in the design but maybe an early model before they got kind of fancy. But the filter sizes are the same. I think 2500 cfm is about what it pulls on a good day.

Well there's the rotobrush long vac hose with brush on the end of it. And then there is also large vacuums you can hook up to a supply and put the whole system under neg pressure. The brush I use hasn't done any harm to flex and the vac is not powerful enough to crush the flex either. I personally think the rotobrush would be more efficient if it can go through flex, but you can actually use the 2 types of vacs in conjunction.

Originally Posted by greenhorn520

I was also wondering does the Rotobrush work well on flex? How do you run it through a 3" bathroom duct? Wish I had one, I have to use an old beat to hell HEPA 2500, and I have a long flexible brush that hooks into a drill, it's actually for drier vents but it works pretty well on flex.

I am wondering in general how brushes work on flex. Some act like a brush will or can tear flex up. Some brushes claim that they won't catch screws. And also I am wondering if variable speed is necessary on a duct machine, specifically to lower rpm for flex duct.

I was also wondering does the Rotobrush work well on flex? How do you run it through a 3" bathroom duct? Wish I had one, I have to use an old beat to hell HEPA 2500, and I have a long flexible brush that hooks into a drill, it's actually for drier vents but it works pretty well on flex.

Originally Posted by powderedtoastman

We go through Air Care, out of Las Vegas. I don't know how their prices compare, but their equipment has lasted us pretty well. Their technician that fixes our rotobrushes always tries to sell us crap when we order new bristles and chemicals...

Are you using the brushes on flex duct?

This is 100% correct. We just did a two story 5 ton zoned with 22 duct runs plus return. We pulled the blower, cleaned the coil, registers, and all ducts. We were there from 8:30 this morning until 4pm. We didn't take a lunch.

Originally Posted by drk

Don't agree. It's either clean or dirty. If it's still dirty it needs to be cleaned again. It takes 2 guys around 7 hours to clean it correct Cleaning all duct pulling the blower cleaning the coil cleaning the AHU. It takes time to do it correctly.

We go through Air Care, out of Las Vegas. I don't know how their prices compare, but their equipment has lasted us pretty well. Their technician that fixes our rotobrushes always tries to sell us crap when we order new bristles and chemicals...

Well drk I actually agree with you. If you're not going to do it right, then don't do it at all, exactly my point. Why offer some half ass duct clean that can't possibly net a good profit? Unfortunately it's not my company or my call, but I would really like to question them. It's just my foot in the door to become an HVAC Tech, in between duct cleans I get to help people change parts and do installs so I take it as it comes.

Don't agree. It's either clean or dirty. If it's still dirty it needs to be cleaned again. It takes 2 guys around 7 hours to clean it correct Cleaning all duct pulling the blower cleaning the coil cleaning the AHU. It takes time to do it correctly.

Most of them seem happy but I don't think they know any better. I guess you can't expect too much for 200$ but i don't like performing a BS service but i gotta do what I gotta do to have a job. To me duct cleaning is one of those things where you can spend 3 hours doing it or 13, just depends on what you want to invest in it.

Originally Posted by greenhorn520

I work for a small resi company who offers duct cleaning and it's a joke as far as I'm concerned. All we do is seal off all the registers, hook up an old Hepa 2500 vac to one of the supply ducts, while the vac is running we clean the registers one by one, maybe blow some air through the duct. It only costs about 200 and takes a couple hours but I'm pretty sure it does absolutely nothing. Not to mention the Hepa 2500 is huge and bulky and we have to bring it in the house, the vac hose (about 8" diameter) is a PITA to hook up. In my opinion you'd get much better draw from a 4" hose and it would be easier to hook up. Either way the service is a joke and I wish we didn't even offer it. Of course I understand a more legitimate duct clean would probably take a whole day and cost a lot more.

But how do the customers feel about the service? What kind of response and expressions do you get from them?

I work for a small resi company who offers duct cleaning and it's a joke as far as I'm concerned. All we do is seal off all the registers, hook up an old Hepa 2500 vac to one of the supply ducts, while the vac is running we clean the registers one by one, maybe blow some air through the duct. It only costs about 200 and takes a couple hours but I'm pretty sure it does absolutely nothing. Not to mention the Hepa 2500 is huge and bulky and we have to bring it in the house, the vac hose (about 8" diameter) is a PITA to hook up. In my opinion you'd get much better draw from a 4" hose and it would be easier to hook up. Either way the service is a joke and I wish we didn't even offer it. Of course I understand a more legitimate duct clean would probably take a whole day and cost a lot more.

Unlike many of my competitors I rarely and I do mean rarely sanitize a system. Only slightly better than soot sealing, both when routinely offered are an expensive joke. I'm also honest with the customer - duct cleaning alone cannot possibly eliminate all of the dust in your home and one of the best reasons I can think of for why airborne particulates might be high after cleaning is the fact that we are often moving household items that have not been moved or cleaned under in months and sometimes years. Also in basements with unfinished ceilings there is often more dirt on top of the ducts than there is in them and it will be dislodged when the agitation tools pass below.

I connect a short section of 8” vacuum hose to the return side of the system. This is generally done at the base of the return plenum, filter or blower cabinet opening. It and one or more sections of 10” vacuum hose are then connected to my truck mounted vacuum. We remove and clean the vent covers and then using pneumatic cleaning tools on small 3/8” to ½” o.d. flexible rods go thru those openings to clean the smaller branch ducts. When all of the branch ducts are clean I access and clean the main return trunks, plenums, blower cabinet, furnace doors, etc. If dirty I will also remove, disassemble and clean the furnace blower which in turn gives me access to the secondary heat exchanger or the primary on older furnaces. I also clean washable filters, EAC’s, humidifiers, humidistats, sail switches, etc.

I own three, but have never found a brush system that works well. My pneumatic cleaning tools consist of whips 14” to 28" long with 3 to 8 tentacles each and these are used in conjunction with and as applicable either a forward or reverse air sweep. Operating pressures range between 150 and 200psi and each tool is chosen for its ability to safely/thoroughly clean the material the duct is made from. Multiple passes are made with each and continue until my video monitor clearly shows that all lighter potentially airborne particles have been removed from the duct being cleaned. If a vent opening is particularly dirty and I suspect that dirt will be blown back into the living space, I cover the opening with a bath towel (ours) before turning on the pressure to my cleaning tool. Camera placement is generally directly in front of the 8” suction hose and this enables me to see all of the dirt as it is leaving the system. When clean a final pass is made with an air sweep to remove any larger particles that may have been left behind. Whenever possible I also do a visual inspection of the main trunk to ensure that nothing has been left there and if seen those pieces are removed with air sweeps.

When the return side is finished, I repeat this process for the supply side of the system. Whenever possible access is gained directly above the indoor coil which allows me to protect it and later clean it. I also foil tape sheets of thermopan above the coil to prevent dirt from falling into and damaging the fins. If I suspect the underside of the coil to be caked with dirt or animal hair and I am unable to remove an end plate to clean it, I will suggest that the homeowner have an HVAC company remove the coil for cleaning.
I see many of my customers from time to time and always ask how the work went. To date I have not had a single complaint about dust. I’ve had a few complain about how long our cleaning took and one lady who was dead sure that we had missed the extremely dirty vent in her bathroom. I had to turn the switch on to prove to her it was an exhaust fan and no I do not clean those for a variety of reasons!

Early on I missed the occasional loose wiring connection and got called back for those. Also had a muskrat chew thru a condenser power cable and spent 4 hours looking for the problem before finally finding it dead under the garage. Unlike many we go the extra mile and if there’s any dirt anywhere on the floors near the vents or ductwork we use a Dyson to clean it up and that includes the dust bunnies under the furniture that hasn’t been moved in 20 years.

While I’m sure that I don’t know nearly as much as you, I do have associate degrees in both HVAC and IAQ.

There's a LOT more to controlling particulates that just the horsepower of a vacuum. That's almost like saying my air conditioner is better because its the biggest AHU on the market.

You still have your connections, condition and sizing/ kinks in hoses, etc. Also, what sort of mechanical brushing do you use?

I'm not calling you wrong but as one who does environmental sampling and very familiar with particulate soiling, the fact that you have not had a single "legitimate" complaint does not guarantee you haven't accidentally caused a problem--you just haven't been successfully sued for one yet apparently.

Just curious what would constitute a 'non-legitimate' complaint and how was it determined to be illegit?
TIA,

http://www.youtube.com/watch?v=SEBLt6Kd9EY

duck air pressure problems

While that may be true for those running glorified shop vacs or worse, my vacuum is powered by a 56HP turbo diesel and in my 11 years of cleaning, I've not had a single legitimate callback. I'm not the only company that uses quality equipment, but far too many companies looking to make a fast buck get suckered into buying glorified shop vacs and/or are unwilling to take the time to do it right.

duck cleaning

I think initially, it stirs up a lot of particulates esp. in the 10 and below micron range that std. filters do not catch. Much like asbestos mitigation where the airborne levels are worse than before they started.

Definitely need to use a high quality filter and change often. This would be one case where I'd recommend temporarily using a 16 MERV filter for a few days then replace it with an 8-10 MERV for maintenance.

http://www.youtube.com/watch?v=CWgbmgIzoT8

There haven't been any studies that I know of done in several years but like anything else the job is only as good as the people doing it. Those customers who are fortunate enough to find a company that invested in good equipment and more importantly take the time to do the job right will see a positive difference in air quality.