Many cooling towers start-up in the spring and you need your cooling equipment to work reliably during the hot summer months. Unexpected outages are very expensive, and clean heat transfer surfaces contribute directly to your bottom line energy savings. A little effort spent getting your cooling tower ready in the spring will pay big dividends throughout the summer cooling season. Follow these steps to reduce equipment failure, minimize corrosion and prevent the potential for dangerous Legionella bacteria outbreaks.
Prior to start-up, physically clean the tower basin. Use shovels, brooms, hoses, or whatever is necessary to remove debris and dirt. Clean out strainers and filters.
Lubricate fans and motors, and perform any other annual mechanical maintenance recommended in the equipment manuals. Be sure to remove any excess lubrication – oils and greases can be future food for bacterial growth.
Replace sacrificial anodes on chiller heads.
Re-passivate both the steel and copper metal cooling surfaces. The metal has been exposed to air and humidity during the off season, and protective coatings are thin or lost entirely. Rebuilding them takes more than the normal chemical maintenance dosage. There are a few ways to achieve the proper results.
Option #1: Fill the cooling system. Add U.S. Water's TowerClean 819 to achieve 1600 ppm as product, and circulate without heat load for 24-48 hours. Either drain and refill, or blowdown heavily as you bring up the heat load and start regular chemical feed. TowerClean 819 is designed to passivate both steel and copper surfaces.
Option #2: Start the cooling system under low load, and feed double the normal scale and corrosion inhibitor for 72-96 hours. This is not as effective as the TowerClean 819 treatment, so it takes a little longer. However, if your plant operates under an NPDES permit, this may be your best approach.
Remove biofilm and kill bacteria. Be especially thorough with stagnant lines or dead legs. While circulating the initial cooling system fill water (with TowerClean or start up chemical dosage) add oxidizing biocide to achieve 0.5-1.0 ppm free residual. Shock the system with 1.5 times normal dose of your non-oxidizing biocide, and add a biodispersant (CWT 405 at 60-100ppm).
Check to make sure if you keep reagents and testing solutions on site that they are not past their expiration date. If they are, order new ones.
Get coupons on order to have them available for use once a full load has been reached on the towers.
Order new Head (KOP) kits for chemical feed pumps coming on line. U.S. Water can help provide quotes for pump kits, repair kits and replacement parts.