If the unit was just installed, the rust is probably not affecting the integrity, or life expectancy, of the base stainless steel material.  It is most likely foreign material on the surface that can be cleaned. 

So, where is the rust coming from?  The rust spots that show up on the surface of the unit are not signs of the base stainless steel material corroding.  Often, they are foreign material, such as welding slag, that has collected on the surface of the unit.  The rust spots will be located around areas on the unit where there has been welding.  It is not uncommon to find these spots around inlet and outlet connections of cooling towers, around coil connections of fluid coolers and condensers, around the cold water basin near the support steel, and around field-erected platforms and catwalks.  Another possibility is that there may be dirt or airborne contaminants that contain mineral content that has collected in or on the unit.  Given time and the right environment, this foreign material will rust and stain the surface of the stainless steel. 

Rust on Steel

What can be done to get rid of these rust spots?  A good cleaning should remove them.  The cleaners that EVAPCO recommends are either Naval Jelly or a good stainless steel cleaner, such as Mother's Wax.  Using a heavy-duty scouring pad, in conjunction with these products, will clean the surface of the stainless steel very well.  In most cases, these means of cleaning the unit will correct the problem.  It should be mentioned that maintenance of the unit's surface should be performed on a regular basis.  The unit is just like a car; the finish must be maintained on a regular basis to preserve its appearance. 

In areas where cooling towers are constantly exposed to a salty environment, rust spots may occur.  At these locations, the towers’ exterior may require rinsing or wiping down once or more each year to prevent rusting and staining of the steel.  There is also evidence that the presence of certain microorganisms/bacteria in system water may accelerate the breakdown of the steel surface if it is allowed to accumulate in the steel surface.  Ask your local EVAPCO sales representative about the available water treatment options for your location.