What Causes High Conductivity in Cooling Tower Water

Maintaining proper water quality is essential for efficient cooling tower operation. One of the most common issues operators face is high conductivity in cooling tower water. But what does that mean, why does it happen, and how can you prevent it? Let’s break it down in a practical, easy-to-understand way.

Introduction to Conductivity in Cooling Tower Water

Simply put, conductivity measures how well water can conduct electricity, which depends on the concentration of dissolved ions like salts, minerals, and other impurities. In cooling towers, monitoring conductivity is a critical part of water management to prevent damage, inefficiency, and increased operating costs.

Why Monitoring Conductivity Matters

High conductivity can signal serious problems:

• Accelerated scaling and corrosion

• Reduced heat transfer efficiency

• Increased maintenance costs

• Shorter equipment lifespan

Regular monitoring helps operators catch issues early and maintain optimal cooling performance.

Basic Concepts of Water Conductivity

What Is Electrical Conductivity (EC)?

Electrical conductivity measures water’s ability to carry an electrical current. The more dissolved salts and minerals in the water, the higher the conductivity. High EC is a red flag indicating that water may become aggressive toward metals or cause scale formation.

Relationship Between TDS and Conductivity

TDS (Total Dissolved Solids) and conductivity are closely related. As TDS increases, conductivity rises. This is crucial because high TDS contributes directly to scaling, corrosion, and reduced cooling efficiency.

Factors Leading to High Conductivity

High conductivity rarely occurs by accident. Several factors contribute:

Concentration of Dissolved Minerals

As water circulates, minerals such as calcium, magnesium, and sodium accumulate. Over time, this naturally raises conductivity.

Poor Makeup Water Quality

Using water with high mineral content as makeup water adds directly to conductivity levels.

Evaporation Effects and Water Blowdown

Evaporation leaves behind minerals, increasing conductivity. Without proper blowdown, concentrations build up quickly.

Inadequate Water Treatment

Without proper chemical treatment—scale inhibitors, corrosion inhibitors, or biocides—mineral buildup accelerates, driving conductivity higher.

Contamination from System Materials

Rust, scale from pipes, or debris can release ions into water, further increasing conductivity.

Role of Evaporation and Cycles of Concentration

How Evaporation Increases Conductivity

Every time water evaporates, minerals stay behind. This concentrates dissolved solids, raising electrical conductivity over time.

Understanding Cycles of Concentration (COC)

COC measures how concentrated circulating water is relative to fresh makeup water. High COC without proper blowdown leads to excessive conductivity and potential scaling.

Effects of High Conductivity on Cooling Towers

Scaling and Mineral Deposits

High conductivity promotes scale formation on heat exchangers, fill media, and pipes, reducing heat transfer efficiency and increasing energy costs.

Corrosion Issues

Excessive ions accelerate corrosion, especially in metallic components, leading to costly repairs.

Reduced Heat Transfer Efficiency

Mineral deposits and scale act as thermal insulators, making chillers and HVAC systems work harder.

Methods to Control High Conductivity

Regular Water Testing

Use conductivity meters and TDS tests to monitor water quality daily or weekly. Early detection prevents major problems.

Blowdown Management

Controlled blowdown removes a portion of highly concentrated water, lowering conductivity to safe levels.

Proper Chemical Treatment

Use scale inhibitors, corrosion inhibitors, and biocides to maintain balanced water chemistry and reduce risks.

Using High-Quality Makeup Water

Low-mineral makeup water reduces the rate at which conductivity rises, minimizing the need for frequent blowdown.

Mach Cooling Solutions for Water Conductivity Management

At Mach Cooling (https://www.machcooling.com/), cooling towers are designed with water management in mind:

• Easy access for water testing

• Optimized blowdown systems

• Durable materials resistant to corrosion and scaling

• Custom solutions for industrial and commercial HVAC systems

Common Mistakes and Troubleshooting Tips

• Ignoring conductivity readings until problems occur

• Using hard water as makeup water

• Delaying blowdown and chemical adjustments

• Not inspecting pipes, fill media, or drift eliminators

Following a routine monitoring schedule prevents most conductivity-related issues.

FAQs About Conductivity in Cooling Towers

Q: What is a safe conductivity level?
A: Most HVAC towers operate safely below 2,500–3,500 µS/cm, depending on system design and water chemistry.

Q: Can high conductivity cause Legionella?
A: High conductivity itself doesn’t cause bacteria growth, but poor water management associated with high conductivity can increase microbial risks.

Final Summary

High conductivity in cooling tower water is primarily caused by mineral concentration, poor makeup water quality, evaporation, inadequate treatment, and contamination from system materials. Regular monitoring, proper blowdown, and chemical treatment are key to maintaining system efficiency and longevity. With engineered solutions from Mach Cooling, operators can minimize conductivity issues and ensure optimal cooling tower performance year-round.