Most cooling tower manufacturers recommend facilities clean their cooling towers quarterly, or at the very least, twice a year. OSHA suggests this maintenance be conducted prior to spring start-up and after fall shutdown. During the winter season, many cooling towers have been in layup mode, which provides a favorable environment for growth and incubation of organisms, including Legionella. Not only does cleaning your tower in spring flush bacteria and remove biofilm, but towers that are not properly cleaned before startup can also lead to a loss in efficiency.
The cooling tower basin is a large volume area where oxygen-rich water is tempered and pooled. Cleaning and disinfecting this area is extremely critical to reduce and remove biological activity and enhance your treatment program. Use shovels, brooms, hoses, etc. to remove any debris or dirt, and clean out all strainers and filters.
Cooling tower fan housings are often difficult areas for chemical treatments to prevent bacteria growth due to condensation, and can cause the spread of airborne pathogens and corrosion. Scrub and disinfect fan housing and lubricate fans and motors. Be sure to remove any excess oils and grease to eliminate future bacteria food sources. Replacing the system’s sacrificial anodes on chiller heads is also good practice in the spring.
Clogged distributors can reduce the cooling tower’s ability to cool water and increase energy usage. Normal system filtration may not always remove debris. Open and clean all distribution pans to ensure reliable water flow.
Metal cooling surfaces have been exposed to air and humidity during the off season, resulting in thin or lost protective coatings. There are a few different options to re-passivate both the steel and copper surfaces. This can be done by utilizing U.S. Water’s TowerClean 819 or, if your plant is operating under an NPDES permit, feeding double the normal scale and corrosion inhibitor to your cooling system. Contact U.S. Water to learn more about your facility’s options for rebuilding your system’s surface protection.
Condenser before and after cleaning.
Seasonal controller maintenance should also be incorporated into your spring routine. Many controller manufacturer’s recommend sensors to be replaced annually at a minimum. Calibrate, inspect and replace (if necessary) all controller sensors, especially pH and ORP sensors as they are more prone to failure.
Spring is also a great time to perform inspections on condenser water heat exchangers and steam boilers. U.S. Water’s borescoping inspection allows plant maintenance teams to visually inspect the inside of their chiller and evaporator tubes to determine the effectiveness of the water treatment program. Effective use of a borescope can visually determine if a water treatment program is preventing scale formation, copper corrosion and biological fouling. Early detection of issues allows for tubes to be replaced prior to starting equipment and preventing early tube failures. U.S. Water recommends scoping should be done yearly on condenser tubes and every two years on evaporator tubes. Contact U.S. Water for more information regarding our integrated solutions to help you maintain a clean system year-round.