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Filtering Out The Problem

For any computer room operation, maintaining the proper humidity level is critical.  With virtually all environmental control unit manufacturers building humidification into their equipment, a common operating problem exists in the scale and other solid deposits left behind in the humidification pans as the water continually evaporates.  Hard water areas are mostly affected, although any hardness content will build-up after sufficient use.

Humidification pans will often become encrusted with deposits of calcium carbonate and magnesium carbonate minerals to the degree requiring their removal for chemical cleaning and/or scraping.  They also accumulate airborne particulates and microorganisms captured in the turbulence of the air flow.  While some manufacturers have built automatic rinsing mechanisms into their units, their effectiveness will vary – leaving the local water quality as the determining factor in many cases.

Eventually, the humidification pans must be replaced, as such deposits also accelerate pan corrosion and pitting.  The problem is directly proportional to the amount of humidification supplied, and the amount of calcium carbonate hardness and other impurities in the local water source.  Well water supplies having high hardness levels or low pH are typically the most troublesome.

• Secondary Concerns Exist

Aside from the regular maintenance which is required to physically remove these deposits, such nutrient rich conditions produce the ideal environment for bacteria and other microbiological organisms to grow.  Almost any microorganism type will thrive given the right environmental conditions and food source.

Loose and flaky contaminants from the humidification pan are then pulled into the fan system, easily penetrate the 40% efficient filtration media typically used, and are distributed throughout the breathing environment – creating a secondary problem of concern to human health and indoor air quality.  Airborne contaminants such as Legionella, Aspergillis, mold and other organisms, although rarely found, can thrive and propagate in such environments.

• Filter Out The Problem

By filtering out the dirt and hardness impurities carried by the make-up water prior to its introduction into the humidification pan, it is possible to dramatically reduce the degree of problems typically encountered in such systems by approximately 75 percent or more.  Essentially, this process operates in two stages:  The first stage involves pre-filtering the sediment and suspended particulates with 1-5 micron filtration. In the second stage, the majority of scale forming minerals are adsorbed or absorbed onto one or more specialty ion exchange resins.

While it is virtually impossible to prevent the migration of airborne bacteria into the humidification pan, bacterial growth will be dramatically reduced since their necessary nutrients, typically supplied by the make-up water, have already have been removed.  The supplemental use of commercially available biocide tablets in the humidification pan will generally suppress whatever limited bacterial growth may develop.

• Simple Installation

Such filtration equipment can be easily installed, setup, and operated by building personnel.  Cartridges are individually housed so that only those elements which have reached their maximum removal capacity can be changed – thereby reducing the number and cost of replacement elements.  A clear sediment pre-filter housing is typically supplied for visual observation of dirt loading.  An optional light indicator is available to signal filter changes of the mineral absorbing cartridge – which lowers maintenance requirements, and extends the life of the cartridge.

For most applications, one single filtering system can be installed on a common feed water line to two or more climate control units – further reducing installation and maintenance costs.  Although maintenance can still be expected, its frequency and severity is far less.

The below schematic flow diagram illustrates the basic layout of an effective particulate and calcium carbonate scale removal system as described above.

Scale forming deposits are a constant source of operating trouble for most A/C equipment types.  While not a total solution, filtering out the offending elements prior to their entering the humidification system will dramatically reduce this common maintenance concern.

© Copyright 2023 – William P. Duncan, CorrView International, LLC