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Effective Closed Loop Water System Treatment 

Effective Closed Loop Water System Treatment

A closed loop water system often falls into the “fill it and forget it” mode of operation. The enclosed water circulates unexposed to outside elements or foreign contamination and doesn’t require extensive maintenance. While this type of system might not be subject to the debris and dirt an open cooling tower can accumulate, within a closed loop water system a slight change in the chemistry, differential pressure or flow rate can jump start the process of corrosion. If left unchecked, corrosion can damage critical equipment, requiring costly repairs or replacement. 

In addition, a slight buildup of fouling, just 1/100th of an inch, can reduce the efficiency of the water system by up to ten percent. Although the system is enclosed, minimal maintenance procedures and preventive measures can help safeguard this system against future damage. 

Assessing Potential Costs

Preventive maintenance and safeguards all come with a price tag. The price tag for not paying attention to this system can rack up bills much higher than any preventive treatment.  

First, think about a ten percent reduction in energy efficiency. Two forms of energy typically power the heating and cooling systems: gas and electricity, respectively. In the cooling system for example, fouling on the heat exchange surface will create a barrier to the metal’s ability to transfer heat. The unit has to work that much harder to transfer heat from one system to another. In order to achieve the requisite level of cooling, the energy usage rises correspondingly to provide that level of heat exchange. These additional energy costs don’t take long to add up.  

A secondary issue related to fouling that can occur inside a closed loop system is its impact on capital equipment. Fouling can easily cause a boiler or chiller, designed to last for 20-30 years, to fail in less than ten years instead, possibly even sooner. This drastic reduction in the lifespan of expensive equipment helps highlight the importance of preventive maintenance on a system easy to ignore.  

Prevalence of Closed Loop Systems

Many types of residential buildings, offices, hospitals and manufacturing facilities rely on a closed loop water system for controlling the temperatures through heating and cooling.  A power plant often will operate multiple closed loop systems.  

A closed loop system is not hermetically sealed but refers to a recirculating water system that measures negligible water loss ranging from 1% to 5% per day. A heat exchanger either heats or cools the water within hard piping constructed of carbon steel or other materials. The water, sometimes demineralized, can circulate within the system for weeks or years.   

The difference between a closed loop and an open cooling tower is the contamination factor. Dirt, debris, insects and foreign matter can get sucked into the cooling tower. Sun and bacteria also can cause separate issues.  

Issues that Impact Closed Loop Systems

While protected from outside elements, a closed loop system can still be subject to microbiological, corrosive and oxygen related problems. In fact, corrosion is inevitable in any system combining water and metal, on a microscopic scale.   

Microbiological activity will: 

  • Decrease heat transfer efficiency and
  • Increase corrosion by decreasing the effectiveness of a corrosion inhibitor 

While bacteria isn’t typically an issue in a closed-loop system, certain conditions can promote growth.. Existent bacteria that then proliferates creates what is called a “living” deposit. The acidic byproduct of bacterial respiration, which also consumes oxygen, causes the biofilm base to corrode the metal.  

Oxygen will: 

  • Lead to oxygen pitting 
  • Corrode heat exchangers, piping, valves and coils 

Oxygen pitting—Although enclosed, a closed loop system is not immune to oxygen intrusion. Sources of air seeping into the system can include valves, unions, elbows or pumps, for example.  

Corrosion will: 

  • Reduce heat transfer efficiency 
  • Cause wear on pump seals and impellors 
  • Increase plugging and fouling 
  • Cause erosion 

Treatment Combination Supplies Close to 100% Protection

Maintenance professionals have a few choices when it comes to prevention in a closed loop water system. These can involve chemicals alone, filtration alone or a combination of the two. One option for filtration is a side stream filter. A side stream filter operates by taking a small leg of pipe and having the pump pass the water flow through a filter. These contain a bag or cartridge type filter with varying levels of micron sizes, similar to a kitchen sink strainer that catches food particles before going down a drain. The cloth mesh bag that comprises the filter that has anywhere from 50 microns down to five microns, or particles not visible to the naked eye.  

This bag filtering however, leaves particles that are even smaller within the system. Over the course of time, if those microscopic <>5-micron particles are not captured, the constant wash of these abrasive particles within the system will erode pipes and other components.  


Magnetic Filtration 

However, side stream filters don’t capture all particles, specifically magnetite. ChemREADY can provide a combination of chemical protection and a Magstrainer™, a magnetic water filtration system, to capture microscopic ferrous particles, for an effectiveness that reaches close to 100% protection. Only magnetic filtration can remove this sub-micron magnetite from the system. 

The Magstrainer Protects Capital Equipment

The Magstrainer used in combination with a bag filter is designed to capture these microscopic particles and filter them away from the system, supplying long-term capital benefits. Cutting down on this erosion will reduce ongoing maintenance costs, lend a longer lifespan to the equipment meaning savings on capital expenditures for equipment replacement over time.  

The Magstrainer works with virtually any size piping, presenting an ideal solution for smaller commercial systems to the largest industrial systems for factories, hospitals, universities and residential housing complexes.  

The H1 model of the Magstrainer works as an equivalent to the bag filter, combining the features of a magnetic strainer with the capability to add chemicals into the water in the closed loop system. Some of the H1 combines three key filtration elements: 

  • A powerful magnet set 
  • A bag filter for larger particulate matter 
  • A chemical pot feeder for dosing and system maintenance 

It can connect with virtually any size pipe and removes nearly 100% of magnetite and other unwanted debris from hydronic systems.  

The H2 model offers magnetic filtration in line with the piping itself and is not considered a side stream filter. The H2 model:  

  • Captures existing contamination 
  • Prevents further buildup 
  • Increases system efficiency 
  • Protects boilers and ECM heat pumps 
  • Prevents “cold spots” in the systems 
  • Extends the long-term life of these systems 
  • Reduces maintenance overall 

For more information about water treatment or the Magstrainer specifically, visit www.getchemready.com/product/magstrainer/ or call ChemREADY at 800-229-6801. 

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