Why Your Business Needs Closed Loop Water Treatment

Cleaning is an essential part of the water treatment program for closed heating and cooling water loops. This applies to new and existing piping. If piping is not properly cleaned, the below factors can help to form deposits on heat exchange surfaces and plug control valves,

 while interfering with corrosion control measures and preventing waterside problems from being kept under control.

  • Oil
  • Grease
  • Dirt
  • Mill scale
  • Corrosion by-products
  • Microbiological fouling
  • Other common debris

At NCH Asia Pacific, we know that hot water, chilled water, tempered water, process water and glycol filled closed loops are often ignored when considering a water treatment program. These systems can cause significant corrosion damage if they’re not properly treated, resulting in unwanted costs.

They can also cause corrosion, while wasting water and energy. NCH Asia Pacific has the product line and technical expertise to recommend the appropriate treatment for the metallurgy in any closed loop system and continue to monitor it after treatment is applied.

Closed loop cleaning also requires specialized skills, and NCH’s experienced and professionally trained team has the necessary expertise to ensure it is done properly.

Closed Loop Cleaning Achieves Reliable and
Efficient System Operation

It is important to keep the piping of closed loop systems clean to allow them to operate efficiently. This also greatly reduces the potential for deposits to use more valuable energy than they need to. Passivation helps to rapidly form a protective corrosion inhibitor film on the cleaned metal surfaces, but only once the piping has been properly and thoroughly cleaned. The immediate addition of one or more inhibitor products to the cleaned and passivated system keeps corrosion under control. This results in an energy-efficient system operation that you and your business can be proud of.

The Main Benefits of Chem-Aqua’s Closed Loop Water Treatment

Regular closed-loop cleaning and passivation help to:

  • Remove debris to keep systems clean and operate at maximum efficiency
  • Minimize energy and service costs
  • Improve corrosion control measures
  • Extend system life

Hot Water Systems


Hot water closed loop heating systems are often heated by high efficiency boilers with aluminum heat exchangers. These aluminum heat exchangers can’t tolerate the high pH levels created by common closed loop treatment products. Special corrosion inhibitors for these systems must be incorporated to protect these heat exchangers and the rest of the system metals from corrosion.

Hot water systems that are leaking bring in fresh water that contains oxygen—oxygen pitting corrosion can quickly damage these systems when they develop leaks, so appropriate treatment to deal with this oxygen must be applied until the leak can be eliminated.

 Chilled Water Systems

Chilled water closed loop inhibitors must provide good protection for steel, copper, and any copper alloys that are in the system. Chilled water systems require treatment to prevent corrosion of the metals within the system. The most common metals are steel, copper, and copper alloys. If copper corrodes, the copper ions in the water quickly plate out on the steel in the system, causing galvanic corrosion of the steel.

Tempered Water Systems

Tempered water systems found in heat pump applications have the same treatment requirements and potential problems as both chilled and hot water systems, depending on whether the system is in the heating or cooling mode.

Process Water Open and Closed Systems

Process water open and closed systems often have the same treatment requirements and potential problems as chilled and hot water systems. However, some processes have very small cooling water channels, so filtration becomes critical to the successful performance of these systems. Point-of-use filters on incoming cooling water to each machine in addition to system-wide side stream filters are often required to maintain the suspended solids at an acceptable level in the cooling water. These systems often have dead legs causing significant problems.

Glycol Solutions

Glycol solutions are frequently used to fill closed systems. Uninhibited glycol is extremely corrosive to system metals, so the glycol fluids being used must be inhibited with the appropriate corrosion inhibitors. NCH Asia Pacific recommends that only inhibited glycol fluids be used in these systems. Trying to treat uninhibited glycol with conventional closed loop inhibitors will NOT provide adequate protection from corrosion in these systems.

The glycol must be maintained at the appropriate level (usually 25-30% of the fluid) to provide adequate protection from corrosion and freezing. Special glycol feeders must be used to add fluid to the system when needed. Low glycol levels can allow microbiological growth and corrosion that can quickly cause damage to the system.


NCH Asia Pacific boasts over 100 years of expertise and experience, making our Chem-Aqua Closed Loop Water Treatment offering the best choice for your water solutions. We can help to improve your system reliability, accuracy, and safety. Our advanced technology, innovative products, and solutions keep us ahead of the rest.

Contact NCH today about creating a custom water treatment program for your business. Our team of NCH experts are always happy to help.

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