Other unwanted elements can consist of minerals and bacteria in lower temperature systems, as well as other organic or inorganic debris. Recirculating water carries water and any unwanted debris throughout the system. Once the undesirable debris is present in the closed system, they can wreak havoc if not properly maintained. Heating/Cooling transfer surfaces, pipes, tubes, and seals become coated with rust, microbial growth, scale deposits, and sludge which may affect the efficiency of the system. Another misconception is that adding inhibited glycol to a water system is efficient system water treatment alone. However, if glycol is added to dirty system water, the glycol will not be able to effectively protect the system. Recognizing the signs and symptoms a system may exhibit when needing cleaning and chemical treatment, along with regular systems checks is crucial.
Signs may include:
- Appearance of dark, cloudy water with sediment at the bottom of water samples taken, indicating possible corrosion
- Dissolved Iron or Total Iron test of system water resulting in significantly higher levels compared to the make-up water quality
- Amount of sediment build-up found during inspection of filters
- Deterioration of components—visually or mechanically
- Loss of heat/cool transfer efficiency
- Increased system run time
- Apparent leaks
If several of these signs have been recognized, the system may need to be cleaned, flushed, and chemically treated. A full system maintenance on a closed loop system every 2 years or so, will vastly improve the system’s performance and efficiency. Usually, it is recommended that chemical treatment occurs after the system is cleaned first. Cleaning the system would consist of removing the dirty water, a complete flush to remove sludge, rust deposits, and scale build up, with addition of a purging compound such as PURGEX L-24, to assist this process. Film forming corrosion inhibiting treatment is important to coat the internal surfaces of piping and equipment with a protective, monomolecular film that will protect the system metallurgy and enhance the efficiency of heating and cooling system. PACE BAR COR CWS series of corrosion inhibitors is recommended for all closed systems.
Finally, routine maintenance throughout the year consists of checking the pH of system water and glycol to ensure the fluid has not become acidic which needs to be done at least 2-4 times per year. Filter changes can be done monthly or quarterly for a clean system; weekly on systems that are known to be dirty. Regular visual inspection of equipment for leaks and installing an inexpensive totalizing water meter in the make-up line will help provide early detection of leaks. Lastly, it is important to check corrosion inhibitor concentrations regularly to ensure appropriate levels are being maintained for system protection.
Understanding misconceptions about closed loop systems will help to recognize signs and symptoms of a system that needs to be cleaned and chemically treated. Regular system maintenance consisting of filter changes, checking system fluid and inhibitors, and visual checks, will aid in preventing build up within the system and prolong the need for total system maintenance. PACE Chemicals has been servicing western Canada for 35 years and have AWT trained water treatment specialists in Vancouver, Calgary, Edmonton, Saskatoon, and Regina, as well as Certified Water Technologists (CWT) in each province. Contact us today for an inspection, cleaning, and chemical water treatment for closed loop boiler and chiller systems.
By: Glenn Strelau, Sr. Vice President, CWT, AScT, LEED GA
Co-Written by: Bri Dearwester