Many cooling or heating systems use water in closed piping loops to transfer heat around a building. These loops are heated, or cooled, directly, or indirectly through a heat exchanger, by boilers, chillers, cooling towers, etc. The quality of the water inside of these closed loops drastically affects the performance and efficiency of your heating or cooling system.
Why Closed Loop Water Treatment Maintenance is Important
Poorly maintained loops will require more fuel/energy to transfer the heat, and will suffer from corrosion byproducts like sludge, mud and deposits building on the inside of the piping. These corrosion byproducts will bind together and settle in narrowed parts of the piping, at bends, and in the small and intricate spaces of the heat transfer surfaces. If unchecked, rampant corrosion will result in leaks, which further exacerbates corrosion and emergency repairs.
In closed loops related to cooling, in addition to the corrosion related concerns above, bacteria growth and proliferation can occur causing additional adverse conditions in the loops also quickly reducing efficiency, increasing fuel costs, and causing damage leading to costly repairs.
Chemistry Program for Closed Loop Water Treatment
A proper water treatment regimen should be designed specific to each building, but the chemistry goals should be:
- Prevent oxygen from attacking the metallurgy.
- Form a protective film on the internal metallic pipe surface to passivate and protect from the harmful effects of corrosion.
- Maintain pH at non-harmful levels.
- Target dissolved solids in the system to limit deposition.
Chemical Feed for Closed Loops
As important as the chemistry program, the method of chemical application is very important as well. As closed loops are 100% filled with liquid, and often pressurized, adding chemistry can be difficult. Over pressurizing a loop by forcing more liquid in can pop safety valves and cause leaks/floods.
Proper chemical application should be done through a bypass feeder. When this inexpensive “pot-feeder” is installed, a small amount of liquid can be released from the loop, making room for the matching amount of chemistry needed to be added.
For the best care of your closed loops, a bypass filter feed should be installed. This upgraded feeder not only allows for safe application of chemistry but has the added benefit of continuous side-stream filtration of the loop. The filter in the by-pass filter feeder catches the sludge, mud and deposits mentioned earlier. The minor additional cost to install a filter feeder versus a non-filter version is greatly outweighed by the benefits of filtration.
Routine Service for Closed Loops
Although in theory a closed loop should never lose water, in reality, due to leaks, and more frequently, but forgotten, repairs, they do lose water. Even just a 10% water loss would introduce more impurities and accelerate corrosion byproducts. Having a monthly water treatment service visit will ensure chemistry levels are maintained and will verify the levels of harmful impurities. Recommendations can be made on corrective actions and additional chemistry can be added if needed. Also, the filter in the filter feeder should be changed out each month to remove the sludge, mud and sediment captured.
In addition, a certified lab sample should be collected annually for a more thorough look into the conditions in your closed loop.
Closed Loop Cleaning
Loops, if not cared for and monitored properly, can change and foul quickly. If your loop is fouled and not transferring heat properly, a loop cleaning may be required to restore efficiency. A cleaning involves circulating an appropriate cleaning detergent, draining, and flushing the entire loop, refilling, and purging any trapped air.
Extended Lifespan of Closed Loop Systems
With affordable routine care, astute chemistry programs, proper chemical feed equipment, and filtration, your closed loops can run extremely efficiently and flawlessly for decades into the future.
If your closed loop contains glycol, see our previous post about specific care recommendations for glycol loops: Proper Care for your Glycol Loops Subject to Freezing
Metro Group has been the trusted source for building solutions since 1925. Contact us for free quote on all your closed loop water treatment needs.