Flushing & General Cleaning of Cooling Towers: A Necessary Investment for Optimal Performance
Cooling towers are the workhorses of industrial cooling systems. Just like vehicles that require regular tune-ups, cooling towers also need periodic maintenance to ensure they continue to perform optimally. Two key terms in this maintenance are Flushing and General Cleaning.
Although they sound similar, they have different purposes, methods, and frequencies. Understanding the differences is very important for planning effective and efficient maintenance.
Part 1: Flushing New Cooling Towers - A Crucial First Step
Why Do New Cooling Towers Need to Be Flushed?
Many people assume that new equipment is ready to use right away. However, for cooling towers, this assumption can have fatal consequences. Flushing new cooling towers is a must for several reasons:
Cleaning Manufacturing Residues
Metal Burrs: During the fabrication and cutting process, small metal burrs or shavings can remain in the system.
Glue, Oil, and Grease: Components such as fans, gearboxes, and joints are often lubricated or assembled using materials that can wash off and contaminate the water.
Construction Dust and Debris: During transport and installation, cooling towers can be exposed to dust, sand, and other debris.
Protecting Sensitive Equipment
Physical contaminants such as metal shavings and sand can cause severe erosion on expensive pumps, seals, and heat exchanger tubes.
Oil and grease deposits can reduce heat transfer efficiency and interfere with the action of corrosion inhibitors and biocides.
Preparing a Clean Base for Chemical Programmes
Water treatment programmes are designed to work on clean metal surfaces. If the surface is contaminated from the outset, chemical programmes will fail to achieve their effectiveness, leading to rapid corrosion and scale formation.
New Cooling Tower Flushing Procedure:
Fill the basin with clean water.
Run the circulation system without adding chemicals.
Perform repeated blowdown and refilling (dump and fill) until the water appears clear and free of obvious physical impurities.
Only after flushing is complete, use the chemical programme Bowen co alkaline cleaner and Passivation
Part 2: General Cleaning of Cooling Towers - Thorough Cleaning Process
Why is General Cleaning Necessary?
While flushing for new cooling towers is a ‘once in a lifetime’ event, General Cleaning is vital routine maintenance for cooling towers that are already in operation. This process is more intensive and aims to clean accumulated dirt that cannot be removed by daily chemical programmes alone.
The main reasons for performing General Cleaning:
Removing Biofilm and Microbiological Control
Biofilm is a slimy layer produced by bacteria, which sticks strongly to the surface of the fill, basin, and pipes. Biofilm acts as a highly effective heat insulator, drastically reducing the efficiency of the cooling tower.
Within the biofilm, harmful bacteria such as Legionella can multiply safely from the attack of ordinary biocides. Mechanical general cleaning is the best way to break down and remove this biofilm.
Overcoming Stubborn Scaling
Over time, hard minerals (calcium carbonate, calcium phosphate) can settle and form hard crusts, especially on fill packs and heat exchangers. These crusts reduce air and water flow and inhibit heat transfer.
General cleaning with chemical cleaning (descaling) dissolves this scale and restores thermal efficiency.
Reducing System Workload and Saving Energy
Fill packs clogged with biofilm, scale, and sludge cause fans and pumps to work harder to achieve the desired cooling capacity. This leads to significant waste of electrical energy.
Clean surfaces ensure smooth and efficient operation.
Extending Equipment Lifespan
The accumulation of dirt and microorganisms accelerates the rate of underdeposit corrosion. By maintaining internal cleanliness, you extend the lifespan of cooling towers, fill packs, and other related equipment.
Meeting Health and Safety Standards
Regular general cleaning is a key part of the Legionella control programme and ensures a safe working environment, especially around cooling towers.
When Should General Cleaning Be Performed?
Routinely: Recommended at least once or twice a year, depending on environmental conditions and operating load.
Based on Conditions: When there is a significant decrease in performance, an increase in differential pressure, or inspection results show severe dirt accumulation.
General Cleaning Process:
Shut-down and System Isolation.
Drainage: Emptying water from the basin and system.
Mechanical Cleaning: Spraying the fill pack, basin, and drift eliminator with high-pressure water jetting to remove adhering dirt.
Chemical Cleaning (Descaling): Use Bowen co descalling fluid to dissolve scale and biofilm.
Thorough Flushing: Remove all remaining dirt and chemicals with Bowen co neutralising agent
Re-assembly and Start-up: Fill the system with clean water and start the Bowen co Anti scalling chemical programme
Conclusion: Flushing and General Cleaning are the Two Main Pillars of Maintenance
These two processes complement each other and are equally crucial in the cooling tower life cycle:
Flushing for New Cooling Towers is an initial investment step to ensure the system starts clean, avoids early problems, and protects your investment.
Periodic General Cleaning is a long-term maintenance strategy to maintain efficiency, save energy, prevent costly damage, and ensure operational safety.
Neglecting both is inviting trouble: declining efficiency, inflated energy costs, costly repairs, and the risk of biological contamination.
By incorporating flushing and general cleaning into a structured maintenance plan, you are not only addressing issues but preventing them from occurring in the first place.
Need Professional Assistance with Your Cooling Tower Maintenance?
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