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Closed Loop Systems

How can I tell if I have leaks in a closed loop system?

If leaks are suspected, installation of an inexpensive totalizing water meter in the make-up line will provide early detection. Regular testing of the water can also detect leaks.

Why does a closed loop system need a filter?

The fluid in a closed system usually contains a suspension of fine, abrasive particles which are harmful to equipment (i.e. pump seals), and leads to unscheduled shutdowns and increased maintenance. There are various sources of these particles, mostly resulting from corrosion. Side stream filtration and scheduled filter changes are necessary to minimize the risk of damage.

Do we require a different treatment program for boilers that contain aluminum?

Yes. Boilers manufactured with aluminum or stainless steel heat exchangers are extremely sensitive to the high pH levels used in traditional closed loop treatments. Typical closed loop treatments inhibit corrosion using pH buffering, and it is not uncommon to operate at values from pH 9.0 to 10.5. Aluminum starts to degrade rapidly at pH values above 8.5 and stainless steel at pH values above 9.0. Consult with your Pace Technical Representative for the specific corrosion inhibitor treatment recommended for your heating systems with aluminum or stainless steel metallurgy.

Should the water be clear in a closed loop system?

Closed loop water should be almost clear and colourless. Dark brown or black water indicates a serious corrosion problem. There should be very few solid particles collecting at the bottom of the sample container. Consult with a Pace Technical Representative in your area for further analysis to determine the water quality.

Legionella & Legionnaires Disease

What is Legionella?

Legionella pneumophila is a very common organism, capable of being present in appreciable numbers in almost all ground and surface water sources. Legionella tend to grow in biofilms or slime on the surfaces of lakes, rivers and streams and very adaptively, within water distribution systems such as cooling towers and evaporative condensers. The mere presence of Legionella does not by itself result in infectious disease. However, when certain Legionella multiply, (increase in population density) and transmit to a susceptible human host, they can cause Legionellosis infections.

Can proper treatment eliminate the risk of Legionella?

No, treatment will not eliminate the risk but it can certainly minimize the risk of legionella. Small amounts of legionella pneumophila can be present in the water supply so chemical treatment alone cannot completely eliminate all risk. Treatment is designed to minimize the risk by preventing legionella from multiplying within the cooling tower, decreasing the likelihood of transmission to people.

Do we need to test our cooling tower for Legionella?

Yes it is recommended. Sampling and testing for Legionella is useful in helping assess risks and in determining whether or not preventative and corrective measures are working. Having an action plan based upon results of Legionella sampling can alert you to increased risks and whether or not decontamination procedures should be implemented. There is no risk for Legionnaires Disease if there is no Legionella. The only practical way to know if you have Legionella is to test for it.

As per the Public Works and Government Services Canada (PWGSC) Document MD 15161 2013, Pace recommends that Legionella sampling and testing should be done monthly, or more frequently if the weekly TBC bacterial counts are excessively high or if heavy biofouling is evident in the cooling tower system.

Pace utilizes an independent CALA Accredited and CDC Elite Certified Laboratories for Legionella Analysis using ISO 11731 methodology for culture testing method.

Additionally, Pace provides real-time DNA testing services for Legionella using qPCR ISO 12869 methodology, which can be particularly beneficial to detect the immediate presence of Legionella bacteria. The qPCR testing method is also recommended following the cleaning/sanitization and decontamination procedures.

What water systems can Legionella grow in?

According to the Centre for Disease Control, Legionella can become a health concern when it grows and spreads in human-made building water systems like;

  • Showerheads and sink faucets
  • Cooling towers (structures that contain water and a fan as part of centralized air cooling systems for building or industrial processes)
  • Hot tubs that aren’t drained after each use
  • Decorative fountains and water features
  • Hot water tanks and heaters
  • Large plumbing systems
Do we need a Water Management Plan (WMP) for our building?

The CDC recommends the development and implementation of a Water Management Plan to minimize the spread of legionellosis for all applicable water systems in a building. This includes buildings that have water systems such as;

  • Domestic hot water tank and system
  • Hot tubs and spas
  • Ornamental fountains
  • Humidifiers, Misters, air washers
  • Other non-potable water systems
  • Cooling tower systems

To determine what water systems in your building should be included in your Building Water Management Plan, click on our ASHRAE 188-2021 Summary Technical Bulletin which outlines the applicable systems by conducting a survey of the building’s risk factors.

Common Water Treatment Questions

What is cycles of concentration?

You may have heard from your Pace Technical Representative that your cooling tower system is bleeding off too much water, or your steam boiler system requires more blowdown. This is all related to the cycles of concentration of the water system.

Cycles of concentration is one of the most important concepts in cooling water and boiler water treatment. It measures the amount of impurities in the makeup water that have cycled up in the recirculating water of your steam boiler or cooling tower. The higher the cycles ratio, the more impurities in the makeup water are being cycled up in the water system.  An easy way to check the cycles of concentration is to divide the conductivity of the system water by the conductivity of the makeup water. The cycles of concentration will increase due to the process evaporation of water, leaving the impurities behind where they will continually increase with the additional impurities that enter the system via the makeup water.

Systems that operate at excessive cycles have the potential for fouling, sludge and scale deposits, which means they require more bleedoff/blowdown. Systems that operate at too low cycles are wasting water and treatment and should reduce the bleedoff/blowdown.

Your Pace Technical Representative will provide the recommended cycles of concentration for your water system based upon the makeup water supply quality and the application at your site.

Why is elevating the temperature of the steam boiler feedwater so important?
Firstly, to avoid damage to the steam boiler itself. The boiler undergoes thermal shock when cold water is introduced to the hot surfaces of the boiler wall and its tubes. The hotter the feedwater means there will be a lower temperature difference when it enters the boiler system, and therefore a less risk of thermal shock and rupturing of the boiler tubes.
Secondly, the boiler feedwater normally consists of fresh makeup water plus the returned condensate, where it is heated in the deaerator to full saturation temperature corresponding to the steam pressure.  This is extremely beneficial as it scrubs and carries away the dissolved gases via the atmospheric vent of the feedwater tank. This removal of gases, particularly dissolved oxygen, is imperative in preventing oxygen pitting attack in the boiler and feedwater system. This will also reduce the demand for oxygen scavenger treatment.
If a steam boiler has a water softener treating the makeup water, does it still need treatment additives?

Yes, absolutely. Water softeners are a great pre-treatment method to remove water hardness (calcium & magnesium) before it enters the boiler system, however, most softeners will allow some leakage of hardness. A well designed treatment program will include additives to prevent this hardness from leading to boiler scale formation. Additionally, water softeners do not remove corrosive dissolved oxygen from the feedwater. Oxygen pitting and general corrosion of metals are accelerated in the presence of softer water, therefore the treatment program must also consist of oxygen scavenging treatments.

Pace RemoteLink™ Remote Monitoring Service

Top 10 Questions on the Pace RemoteLink Remote Monitoring Service

Endotherm Energy Saving Additive

How does EndoTherm work?

EndoTherm® reduces the surface tension of system water by 60% which increases heat transfer. The increase heat transfer improves system efficiency.

How long is the simple payback from adding EndoTherm?

The average payback is 18 months. Results vary based on cost of energy, energy demand, and system design.

Is EndoTherm safe on HVAC components like copper, aluminum, mild steel, plastics etc?

Yes, EndoTherm has been independently verified to be safe on all materials used in traditional HVAC systems.

Do I have to drain my system before adding EndoTherm®?

Draining is not required for most systems with good water quality. It is always recommend to have balanced water treatment for peak energy efficiency.

What types of buildings can use EndoTherm®?

EndoTherm can be used in any type of building including residential, institutional, commercial, industrial, health care, military etc.

Can EndoTherm be used with traditional water treatment for corrosion prevention or freeze protection?

Yes, EndoTherm is non-ionic, meaning it can be used in parallel with traditional corrosion inhibitors and glycol.

Can EndoTherm reduce gas consumption in high efficiency boilers?

Yes. EndoTherm impacts the heat transfer capability of the system water therefore will save energy in all types of hydronic boilers. High efficiency boilers specifically benefit from the colder return water found in EndoTherm® treated systems.

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