Put on protective equipment.
Shut down the cooling tower and turn off the heat source. Turn off fans if installed.
Close the blow-down valve in the bottom of the tower tank.
Turn off the automatic blow-down controller if installed and open the make-up water valve.
Turn on the fluid circulating pumps.
Add a low-foaming chlorine- or bromine-based bio-dispersant in the circulating fluid system. Add chlorine or bromine-based detergent compound to the circulating system.
Check that the system achieves a free residual chlorine (FRC) or free residual bromine (FRB) level of at least 10 mg/L.
Maintain the same FRC and operate the system for one hour. Maintain the pH between 7.0 and 7.6. Record the pH and FRC/FRB levels every 15 minutes.
Open the blow-down valve for 15 seconds during the circulation process to remove scale and sludge.
Repeat the blow down if required further.
Turn off the circulating system and shut down all circulating valves. Close the incoming water supply valve and open the drain valve to empty the cooling tower tank and tubes.
Check all water contact areas for scale, sludge and sediments. Clean the area with a brush and a water hose or pressure cleaner. Clean the fan screens and drift eliminators.
Clean the basin, sump, spray nozzles and pipe fittings with a high-pressure cleaner. Clean the cooling tower tubes.
Remove any loose deposits from the tower tank and sump with a wet vacuum cleaner.
Replace the tower components if removed.
Open the feed water supply valve and fill the cooling tower with water. Run the circulating system.
Add chlorine- or bromine-based detergent compound to the circulating system. Achieve FRC/FRB level of 10mg/L.
Run the circulating system for one hour. Perform a blow down and flush the entire system. Ensure the water is free from turbidity. Close the blown valve and drain valves.
Open the air intake valves and automatic blow-down controller closed previously.
Fill the cooling tower with fresh feed water and run the system.