Applying coatings in HVAC systems is becoming more common and accepted in the industry. In many cases coating is called for in the specifications on fire restoration projects, mold restoration projects and projects that have internally lined ductwork or ductboard.
Choosing the right tools to apply coatings in HVAC systems can go a long way to help maximize coating productivity and quality. Unfortunately, no one tool can do everything so let’s look at the tools normally required to apply coatings in HVAC systems.
1. Coatings. A coating is not an application tool but it does have an affect what tools you do use. There are many coatings on the market with a wide range of viscosity and fiber content. This can dictate what size of airless sprayer you use.
2. Application Tools.
Commercial airless sprayers are the primary application tool for applying coatings in HVAC systems. They work very well when applying coatings in air handlers and large duct work that you can get inside. You simply spray like you were paint a wall in your house. They do not work well in smaller ductwork (ductwork you cannot get inside) because you would need to cut an access opening every 5-10 feet so you can reach inside with the handle held spray gun (sometimes with extension wands) and spray. This is very time consuming and not very productive.
When selecting and airless sprayer (renting or buying) you need a commercial unit not a typical home owner sprayer. Your local commercial painting contractor supply house typically would have the type and size sprayer you need applying coating in HVAC systems. The coating you are applying will dictate the size of airless sprayer you need. Thicker coatings will require a larger/more powerful airless sprayer than thinner coatings. Average viscosity coatings need an airless sprayer that has 1.4 hp motor and a .7 gpm pump while a thicker viscosity coating will need an airless spray that has 2.0 hp motor and a .95 gpm pump. An undersized airless sprayer is one of the most common problems on coating projects.
Cart spray systems are used with an airless sprayer to apply coatings in smaller HVAC ductwork. The liquid line from the airless sprayer is connected to the back of the cart spray system. The airless sprayer pump then pumps the coating through the liquid line, through the cart spray system and out the spray nozzle(s) to coat the interior of the ductwork. You typically place the cart spray system at the far end of the duct you want to coat and pull back on the push/pull rods or liquid line as you spray. Some systems use 360 degree spray nozzles. These systems work will for ductwork under 20” high and some systems have rotating or spinning spray nozzles. These systems work well for ductwork from 20” to 36” high. Cart spray systems range in price from $400 to $1,800.
Robotic spray systems are used with an airless sprayer to apply coatings in smaller HVAC ductwork. The liquid line from the airless sprayer is connected to the back of the robotic vehicle. The airless sprayer pump then pumps the coating through the liquid line, through the robotic spray system and out the spray nozzle(s) to coat the interior of the ductwork. You typically drive the robotic spray system to the far end of the duct you want to coat and drive in reverse as you spray. Some systems use 360 degree spray nozzles (for smaller ductwork) and some use a rotating or spinning spray nozzles for medium to large ductwork). Robotic spray systems range in price from $6,200 and up.
If you want more information on coating HVAC systems we offer a link to our Introduction to Coating HVAC Systems Guidelines and our Super Cart Spray System Family. Also, please feel free to call me at 800-597-3955 or 952-808-1619 if you have any questions about coatings, airless sprayers and cart/robotic spray systems.