Cooling tower Trouble Shooting
cooling tower trouble-shooting, structured from symptoms to causes and solutions.
Critical First Steps: Safety & Preparation
Before starting any troubleshooting:
- Lock Out / Tag Out (LOTO): Isolate all energy sources (electrical, pneumatic) to fans, pumps, and motors.
- Secure Hazards: Be aware of wet surfaces, chemical exposure, and confined spaces.
- Gather Data: Check recent maintenance logs, water treatment reports, and operating conditions (load, ambient wet bulb).
Symptom-Based Troubleshooting Guide
1. Symptom: Poor Cooling Performance (High Cold Water Temperature)
- Possible Cause:Insufficient Airflow
- Check: Loose or damaged fan belts, improper fan motor speed, dirty fan blades, clogged air intake louvers or fill.
- Fix: Tighten/replace belts, adjust VFD/speed, clean fan blades and louvers.
- Possible Cause:Poor Water Distribution
- Check: Clogged nozzles/sprays, broken/distribution arms not rotating (on crossflow towers), low water flow.
- Fix: Clean strainers and nozzles, ensure arms rotate freely, check for proper pump operation and system pressure.
- Possible Cause:Fouled Heat Exchange Surfaces
- Check: Scale, sludge, or biological growth in the fill (pack).
- Fix: Implement aggressive chemical cleaning (acid for scale, biocide for biofilms). Improve ongoing water treatment.
- Possible Cause:Excessive Load or Adverse Ambient Conditions
- Check: Is the process load above design? Is the ambient wet-bulb temperature unusually high?
- Fix: Reduce load if possible. Understand that approach temperature (cold water temp minus wet-bulb temp) widens under high load/humidity.
2. Symptom: Excessive Drift (Water Carryover)
- Possible Cause:Damaged or Missing Drift Eliminators
- Check: Eliminators are clogged, corroded, or broken.
- Fix: Clean, repair, or replace drift eliminators. This is critical to prevent water loss and chemical spread.
- Possible Cause:High Water Flow Rate / Air Velocity
- Check: Water flow above design, fan speed too high.
- Fix: Adjust flow to design specifications and check fan speed.
3. Symptom: High Vibration or Noise
- Possible Cause:Fan/Motor Imbalance
- Check: Loose set screws, ice/debris on fan, worn bearings, bent fan blades.
- Fix: Tighten hardware, clean fan, replace bearings, balance or replace fan assembly.
- Possible Cause:Misalignment
- Check: Misalignment between motor and gearbox or fan shaft.
- Fix: Realign couplings and driveshafts per manufacturer specs.
- Possible Cause:Structural Looseness
- Check: Loose bolts, degraded structural supports.
- Fix: Tighten all hardware, inspect and repair structure.
4. Symptom: Excessive Makeup Water Usage
- Possible Cause:Leaks
- Check: Visible leaks in basin, pipes, or valves. Overflow pipe running continuously.
- Fix: Repair leaks. Ensure basin level control is set correctly.
- Possible Cause:Excessive Blowdown (Bleed-off)
- Check: Improperly adjusted or stuck blowdown control (conductivity controller).
- Fix: Calibrate and adjust blowdown controller for proper cycles of concentration (CoC).
- Possible Cause: Drift (see Symptom 2)
5. Symptom: Corrosion or Wood Deterioration
- Possible Cause:Poor Water Treatment
- Check: Low or improper inhibitor chemical levels, low pH (acidic water).
- Fix: Test and adjust water chemistry immediately. Consult water treatment specialist.
- Possible Cause:Galvanic Corrosion
- Check: Dissimilar metals in contact (e.g., steel bolts in a copper sump).
- Fix: Install dielectric unions or replace components with compatible materials.
- Possible Cause:Microbiologically Influenced Corrosion (MIC)
- Check: Slimy deposits, pitting under biofilm.
- Fix: Shock treatment with biodispersant and biocide, then maintain a proper biocide program.
6. Symptom: Pump Cavitation or Low Flow
- Possible Cause:Clogged Suction Strainer
- Check: Strainer before pump is clogged with debris.
- Fix: Clean the strainer.
- Possible Cause:Air Leak in Suction Line
- Check: Leaking gaskets, fittings, or valves on the pump inlet side.
- Fix: Pressure test and repair suction-side leaks.
- Possible Cause:Insufficient NPSH (Net Positive Suction Head)
- Check: Basin water level too low, pipe restrictions.
- Fix: Raise basin level, check for closed valves or undersized pipes.
Proactive Maintenance Checklist (To Prevent Problems)
Regularly scheduled maintenance is the best troubleshooting.
| Component | Task | Frequency |
| Water Quality | Test/Adjust pH, Conductivity, Inhibitor, Biocide levels. | Daily/Weekly |
| Drift Eliminators | Inspect for damage and cleanliness. | Quarterly |
| Fill Material | Inspect for scaling, clogging, and deterioration. | Semi-Annually |
| Distribution System | Check nozzles for clogs, ensure even water flow. | Monthly |
| Fans & Motors | Check belt tension, bearing condition, alignment, vibration. | Monthly |
| Basin & Strainers | Clean of silt, algae, and debris. | Weekly/Monthly |
| Structure | Inspect for corrosion, loose bolts, and integrity. | Annually |
When to Call a Specialist
- Major structural repairs.
- Complex water chemistry issues (scale, severe corrosion, legionella risk).
- Large fan/motor/gearbox replacement or balancing.
- If the problem persists after basic checks.