WF-06:   Water Filtration Why Clean Water Does Not Necessarily Mean Effective Water Filtration In the later 1970s, and even before, many design changes to air conditioning systems for high rise office buildings resulted in the installation of smaller diameter condenser water pipe.  Rather than large 18 in. pipe runs straight to and from the roof to the central chiller plant, smaller package A/C units and heat pumps were installed on each floor using 4 in. or smaller diameter pipe – and lots of it. Same Issue – Greater Impact While rust product and airborne captured particulates have always been a problem for open condenser water systems, their impact to individual A/C units has been far greater due to smaller diameter schedule 40 pipe of lesser wall thickness, threaded assembly in many cases, and extended horizontal runs. Moderate and even low corrosion activity significantly impacted the smaller pipe. Rust product generated anywhere throughout the system then had a tendency to settle out in low flow areas, and especially at the lower floor horizontal lines.  Package A/C units and heat pumps designed to shut…

WF-05:   Water Filtration A Worthless Expense, Or Highly Effective Benefit To Any HVAC System? The importance of water filtration is becoming known in terms of reducing corrosion activity as well as to improving heat transfer efficiency.  Even under the most effective chemical treatment control conditions producing lowest possible corrosion rates, steel pipe is still oxidized into producing potentially hundreds and even thousands of pounds of deposits or more over decades of service.  A 5 MPY corrosion rate acting against 12 in. schedule 40 pipe actually removes an astounding 64 pounds of steel per every 100 ft. per year.  Oxidized, that 64 lbs. of steel translates into 1.6 cu. ft. of iron oxide rust. This website offers overwhelming evidence to the reality of what corrosion activity produces in terms of internal deposits to any circulating system, and to a long term threat rarely seen or recognized until a failure occurs. Our other Technical Bulletins related to water filtration well illustrate common problems associated with water filtration systems – from inappropriate equipment choices to its wrong installation on the system.  In the overwhelming number of examples…

WF-04:   Volume vs. Size The Common Misunderstanding That Particle Size Retention Is Most Important To Filter Selection The major selling point to any water filtration unit is its particle retention size in microns.  One manufacturer will claim 0.8 micron, another 0.65 micron, and some to as low as 0.45 micron.  Filters that cannot capture 1 micron or less particles are often excluded.  Competition is intense to offer purer water than all other products, with an obvious loss of vision to the purpose of the unit and its intended application. Any water filter installed into an open condenser water system has a huge demand upon it.  Often, water filtration is in response to a corrosion problem that may or may not be defined in terms of severity or the volume of rust deposits present – thereby leaving the choice of filter type and size to sheer speculation.  Fouled heat exchangers, clogged pump strainers, and rust covered tower sump pans all drive the interest to remove such a tangible threat through filtration, at which time further thought regarding the problem is forgotten. Filtration experts drive the…

WF-03:   Improper Filter Installation Two Obvious Reasons Why Most High Cost Water Filtration Systems Fail To Perform Installing a water filter for any larger piping system is often a capitol decision costing $50,000 or more.  In most cases, it is in direct response to a recognized corrosion problem – where its function may play an even greater role in protecting millions of dollars of equipment, product, revenue, and/or infrastructure. For any heavily corroded system, substantial rust deposits will line the pipe interior to both eliminate any further benefit from the chemical treatment program, and to potentially interfere with system operation, mechanical equipment, and heat efficiency, etc.  From our experience, removing heavy rust deposits is an absolute necessity to reducing corrosion; with it impossible to slow corrosion otherwise.  Contrary to the claims of most chemical treatment suppliers, no protection is provided to the base steel beneath 1/2 in. or more of iron oxide tuberculation.  And as a result, corrosion continues unabated. While removing such internal deposits is the fundamental objective of all filtration systems, it is very rarely achieved due to a combination of some…

WF-02:   Misleading Indicators The Critical Mistake Of Assuming That Clean Water Circulation Means A Clean Piping System The effectiveness of any water filtering system is often promoted by their manufacturer, and viewed by most clients, in terms of water clarity produced.  With sand filters generally providing the highest particle removal efficiency, it is not unusual to see claims of sub-micron particle retention used as the major selling point. Although not an absolute rule, most corrosion fouled piping systems will show a higher than normal iron oxide content under a laboratory analysis – both in dissolved and suspended forms.  In its suspended form, the rust typically settles out in the lower floor piping and at other horizontal and lower flow areas – thereby causing notice in the form of lost heat transfer and clogged smaller lines.  It may also impart a brown or yellow tint to the water depending on particulate concentration, and dissolved iron content.  Condenser, process, or open water systems suffer the greatest deposit problems for the obvious reasons.  Originally dissolved, it may precipitate out into solid form, or be removed completely with…

WF-01:   Water Filtration Improving Heat Transfer Efficiency In Open And Closed HVAC Recirculating Systems One very common misconception about closed HVAC heating and cooling systems is that they are essentially corrosion and maintenance free.  Most building owners and operators feel that the absence of externally introduced dirt and debris, coupled with a traditionally low corrosion rate, eliminates concern over the type of fouling problems typically associated with condenser water piping and open water systems. This is far from true, however, since closed piping systems are still subject to all the same corrosive forces – just to a lesser degree.  While corrosion rates of under 1/2 mil per year (MPY) might have been reasonably expected 30 years ago, less effective chemicals, more corrosion susceptible pipe steels, along with other factors, have driven that rate significantly higher. Age is also an important element for many of today’s building properties.  Even a low corrosion rate, when extended over four decades or more, will produce a substantial volume of oxidized material if not regularly removed.  Chemical cleanouts, if they are performed at all, are often light dispersant cleanings…