Common Faults And Solutions For Closed-Circuit Cooling Towers

Common Faults and Solutions for Closed-Circuit Cooling Towers

During operation, closed-circuit cooling towers are exposed to complex environments with alternating water, air, and temperature changes, making various faults inevitable. Timely detection and correct handling of these issues are key to ensuring long-term stable operation of the equipment.

Below are the most common types of faults in closed-circuit cooling towers and their corresponding solutions.

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I. Reduced Cooling Efficiency - High Outlet Water Temperature

This is the most frequently reported issue by customers.

Fault Symptoms:

Reduced temperature difference between inlet and outlet water, persistently high outlet water temperature, failure to achieve designed cooling performance.

Possible Causes:

Coil Scaling. This is the most common fault. Scale layers hinder heat conduction, causing continuous decline in cooling efficiency. Once the heat exchange coils of a closed-circuit tower scale up, thermal resistance spikes and energy consumption doubles.

Spray System Blockage. Clogged spray nozzles or uneven water distribution leave part of the coils uncovered by spray water, reducing heat exchange area. Foreign matter in nozzles, detached nozzles, or insufficient water pressure can all cause uneven water distribution.

Fan Malfunction or Insufficient Airflow. Worn fan bearings, loose belts, or damaged blades reduce ventilation and impair heat dissipation.

Insufficient Water Flow. Faulty circulating water pumps, blocked pipes, or partially closed valves can all lead to inadequate water flow.

Clogged or Aged Fill. Scale buildup or aging of fill layers blocks airflow and reduces air-water contact area.

Solutions:

Coil Descaling: Use chemical cleaning or physical cleaning methods to remove scale and impurities from coil surfaces. Softened water treatment systems can be used in daily operation to reduce scaling at the source.

Clean Spray System: Dismantle and clean spray nozzles, flush spray piping to ensure even water distribution without blockages. Install pre-filters at spray system inlets.

Inspect Fans: Check fan bearings for wear and replace damaged parts promptly; adjust belt tension to ensure fan speed meets requirements; remove obstructions from air ducts to ensure smooth airflow.

Inspect Pumps and Piping: Check pump operating status and pipe blockages, clean impurities from pipes to ensure adequate water flow.

Replace Fill: Replace fill promptly if aging, deformation, or blockage is found.

Oasis Bingfeng's Approach:

Internal circulation uses softened water to prevent scaling at the source; fully covered spray system design ensures no dry spots - no dry spots means no scale; 304 stainless steel coils clean easily with a high-pressure water jet. Every tower undergoes performance testing on the test platform before shipment - flow rate, temperature difference, and heat exchange capacity are all measured, and only qualified units are shipped.

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II. Abnormal Noise or Excessive Vibration

Fault Symptoms:

Unusual sounds or vibrations during fan operation, affecting the surrounding environment.

Possible Causes:

Worn or Poorly Lubricated Fan Bearings. Bearings support blade rotation - poor lubrication reduces speed, affects airflow, and may produce abnormal noise.

Unbalanced or Damaged Fan Blades. Deformed, broken, or improperly installed blades cause unbalanced operation.

Loose Mounting Bolts. Unstable foundation or loose bolts cause resonance.

Blocked Air Ducts. Clogged intake screens or debris in air ducts.

Solutions:

Inspect fan bearings, add lubricating grease promptly or replace worn bearings.

Replace deformed or broken blades and rebalance dynamically.

Retighten loose bolts, check and correct impeller installation deviations.

Clean intake screens and remove debris from air ducts.

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III. Spray System Malfunction

Fault Symptoms:

Uneven spraying, no water output, dry spots appearing on coil surfaces.

Possible Causes:

Clogged Spray Nozzles. Impurities or scale in water block nozzles.

Spray Pump Failure. Pump running dry, impeller blockage, or motor damage.

Scaled or Leaking Spray Piping.

Low Water Level in Collection Basin.

Solutions:

Dismantle and clean spray nozzles; replace severely clogged ones.

Inspect spray pump, clean strainers, and repair impellers.

Flush spray piping, check for damage or leaks.

Check the water make-up system to ensure normal water level in the collection basin.

Oasis Bingfeng's Approach:

The spray system features a full-coverage design to ensure no dry spots on the coil exterior. Spray water is pre-cooled through fill before being sprayed onto the coils, minimizing water evaporation and scaling at the coil surface. Regular cleaning of spray filters effectively prevents blockages.

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IV. Water Leakage

Fault Symptoms:

Water accumulation around equipment, spray water overflow, or cooling medium leakage.

Possible Causes:

Corrosion Perforation of Heat Exchange Coils. Carbon steel coils are prone to pitting corrosion; stainless steel coils may also suffer intergranular corrosion in chloride-containing or acidic/alkaline water conditions.

Cracking of Tower Structure. FRP tower bodies may crack due to UV exposure or sudden temperature changes; metal tower weld seams may corrode and detach.

Poor Sealing at Pipe Connections. Aged or detached flange gaskets, defective weld seams.

Damaged Drift Eliminators. Wear or aging from long-term use causes water drift.

Solutions:

Minor Coil Leaks: Shut down, drain cooling water from coils, repair with argon arc welding (for stainless steel coils), and perform hydrostatic testing after repair.

Severe Coil Corrosion: If corrosion area exceeds 30% or multiple leaks appear, replace the entire coil bundle, preferably with 316L stainless steel material.

Tower Structure Repair: For FRP towers, fill with specialized resin and reinforce with fiberglass cloth; for metal towers, grind off rust and weld reinforcing plates.

Replace Seals: Replace aged flange gaskets with temperature-resistant and corrosion-resistant rubber/fluororubber gaskets.

Oasis Bingfeng's Approach:

The casing uses magnesium-aluminum-zinc coated sheets, providing over fifteen years of corrosion resistance; coils are standard 304 stainless steel with a normal service life of over ten years without leakage; all bolts are 304 stainless steel, never rusting. Material selection eliminates corrosion and leakage risks at the source.

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V. Electrical Control System Faults

Fault Symptoms:

Motor overheating, abnormal control panel display, or equipment failure to start.

Possible Causes:

Motor Overload. Long-term overload operation or bearing seizure.

Poor Electrical Connections. Loose or corroded wiring.

Temperature Probe Failure. Faulty sensors or controller damage.

Reduced Insulation Due to Moisture.

Solutions:

Inspect motor grounding and electrical connections, repair poor contact points.

Calibrate or replace temperature probes.

Regularly maintain motor bearings and replenish lubricating oil.

Reinforce waterproof sealing of electrical control cabinets.

Ensure stable voltage and clean motor heat dissipation channels.

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VI. Winter Freezing and Crack Damage

This is the most troublesome issue for northern customers.

Fault Symptoms:

Internal freezing of the cooling tower, coil cracking and leakage.

Possible Causes:

Failure to Drain Residual Water During Shutdown. Residual water in coils and pipes freezes and expands at low temperatures, causing coil rupture.

Blocked Air Intake. Snow or debris blocking intake vents restricts airflow.

Antifreeze Not Added.

Solutions:

Drain During Shutdown: Close inlet and outlet valves, open vent and drain valves to completely drain fluid from coils. Use compressed air to blow out residual water from the internal circulation system.

Add Antifreeze: During winter operation, add antifreeze to circulating water to prevent freezing.

Install Electric Heat Tracing: Install electric heat tracing cables on pipes and coils for automatic heating at low temperatures.

Clear Air Intake: Promptly remove snow and debris from air intakes.

Increase Inspections: Conduct at least two inspections daily during winter, focusing on insulation integrity, normal water circulation, and signs of ice formation.

Oasis Bingfeng's Approach:

Equipment can be equipped with electric heat tracing systems and antifreeze solutions. Northern projects receive targeted design to ensure safe winter operation.