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Hot water, chilled water, tempered water, process water, and glycol filled closed loops are often ignored when considering a water treatment program, which can be a costly mistake. Closed loops that are not properly treated can cause significant corrosion damage. Closed loops that are leaking can waste water and energy while causing corrosion. These systems must be checked on a regular basis to confirm proper treatment level and system integrity. Chem-Aqua has the product line and technical expertise to recommend the appropriate treatment for the metallurgy in any closed loop system and monitor it after treatment is applied.

Hot Water Systems
Hot water closed loop heating systems are often heated by high efficiency boilers with aluminum heat exchangers. These aluminum heat exchangers cannot 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. See the Owner’s Manual for specific treatment requirements for these boilers.

Hot water systems that are leaking bring in fresh water that contains oxygen, so oxygen pitting corrosion can quickly damage the system when it develops a leak. Appropriate treatment to deal with this oxygen must be applied until the leak can be eliminated.

Chilled Water Systems
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 the copper is allowed to corrode, the copper ions in the water quickly plate out on the steel in the system, causing galvanic corrosion of the steel. Chilled water closed loop inhibitors must provide good protection for steel, copper, and any copper alloys that are in the system.

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 Closed and Open Systems
Process water closed and open systems often have the same treatment requirements and potential problems as both 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 that can cause significant problems.

Glycol Solutions
Glycol solutions are frequently used to fill closed systems. Uninhibited glycol is very corrosive to system metals, so the glycol fluids being used must be inhibited with the appropriate corrosion inhibitors. Chem-Aqua 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 to 30 percent 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.

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