Closed Circulating Loops
Closed loops are the most common and widely used HVAC hydronic systems around. Nearly every facility has a few. These are designed to be tight and operate with little to no make-up. No special controllers, pumps or blowdown are typically needed, so, operators and treatment personnel can often overlook these, “out of site out of mind”. The fact is these are usually some of the largest water systems at a facility, and they can circulate through miles of piping, valves and controls. We want to be sure these have good protection as well.
Typical problems that can occur in closed loops are:
1) Inadequate or no start-up chemical cleaning. Construction materials of any HVAC system will have a certain amount of oils, mil scale, and debris associated with shipping or installation. These must be chemically cleaned to remove all loose debris, oils, etc. that could be, or attract a foulant. Failure to do so may lead directly to under deposit cell corrosion or galvanic attack.
2) Uncontrolled water losses: A facility can lose thousands of gallons annually due to leaking coils, bad regulators, or pop off valves. Installing water meters on the dedicated make-up water to the loop can be a great tool for finding losses. As designed these should have little to no scale issues as the dissolved solids in the water do not water cycle up. Excess water loss, particularly in heating water loops, can cause scale at points of heat exchange
.
3) Misapplied, or No Chemical Treatment: A testing and corrosion inhibition program must be in place. Those systems with little to no passivation can suffer from localized attack such as oxygen corrosion. Some treatment designed to protect well in tight systems can actually be detrimental in systems with excessive make-up. Borate Nitrite compound can, oxidize and breakdown to a non-protective nitrate with potential for proliferation of de-nitrifying bacteria. Choosing the correct product for your situation is important.
4) Proliferation of microbiological organisms: Microbiological growth can occur in systems lacking treatment, or that have depleted inhibitors. These organisms can expel gases that are acidic. A low (below 8.5) or dropping pH can be an indicator. Left un-tended microbiological proliferation can do costly damage through fouling and high potential for corrosion.
Water Consultants of Texas has the experience needed to identify and address these issues. Every situation is different, but you can be assured once we do an evaluation we can develop the best course of action to correct existing problems or prevent many of the common failures these systems encounter.
Typical problems that can occur in closed loops are:
1) Inadequate or no start-up chemical cleaning. Construction materials of any HVAC system will have a certain amount of oils, mil scale, and debris associated with shipping or installation. These must be chemically cleaned to remove all loose debris, oils, etc. that could be, or attract a foulant. Failure to do so may lead directly to under deposit cell corrosion or galvanic attack.
2) Uncontrolled water losses: A facility can lose thousands of gallons annually due to leaking coils, bad regulators, or pop off valves. Installing water meters on the dedicated make-up water to the loop can be a great tool for finding losses. As designed these should have little to no scale issues as the dissolved solids in the water do not water cycle up. Excess water loss, particularly in heating water loops, can cause scale at points of heat exchange
.
3) Misapplied, or No Chemical Treatment: A testing and corrosion inhibition program must be in place. Those systems with little to no passivation can suffer from localized attack such as oxygen corrosion. Some treatment designed to protect well in tight systems can actually be detrimental in systems with excessive make-up. Borate Nitrite compound can, oxidize and breakdown to a non-protective nitrate with potential for proliferation of de-nitrifying bacteria. Choosing the correct product for your situation is important.
4) Proliferation of microbiological organisms: Microbiological growth can occur in systems lacking treatment, or that have depleted inhibitors. These organisms can expel gases that are acidic. A low (below 8.5) or dropping pH can be an indicator. Left un-tended microbiological proliferation can do costly damage through fouling and high potential for corrosion.
Water Consultants of Texas has the experience needed to identify and address these issues. Every situation is different, but you can be assured once we do an evaluation we can develop the best course of action to correct existing problems or prevent many of the common failures these systems encounter.
