Testing And Maintenance Of Water Quality - Watts AERCO Modulex EXT Series Technical Application Manual

Modulex EXT Series Piping
BOILER QUALITY AND MAINTENANCE
cause harm to the boiler, pumps, piping, and other components of the hydronic boiler system.

2.2. TESTING AND MAINTENANCE OF WATER QUALITY

Water in the installation should be checked, monitored, and treated for the following:
• Hardness – High hardness of the available water is measured in grains of hardness and indicates the
quantity of minerals (mostly calcium and magnesium) which are dissolved in the water. Hardness
substantially contributes to the formation of scaling, which is highly undesirable. The total hardness
must be less than 200 ppm (11.7 grains/gallon).
• Artificial Softness – Do NOT use artificially softened water. Artificial softening agents generally use
salt, which creates a chloride water chemistry, a major contributor to the corrosion of the types of
metals used in hydronic systems. Elevated salt levels also contribute to higher conductivity levels,
another undesirable characteristic in hydronic systems.
• Chloride – Chloride salts result from the combination of chlorine gas with a metal and are
instrumental in accelerating corrosion in the types of metals used in hydronic systems. Chlorides may
be introduced into the water naturally. Concentrations of chlorides in system water should be less than
150 ppm.
• Conductivity – Dissolved metals and minerals increase the conductivity of water and indicate not only
the presence of undesired corrosive agents, but also contribute to the transfer and migration of ions
and charged particles in the water that contribute to fouling of sensors, valves, and other devices used
in the system. Additionally, high conductivity contributes to galvanic corrosion, in which one metal will
preferentially corrode when in contact with another type of metal, when both are in contact with an
electrolyte. Conductivity should be less than 3000 μS.
• pH – The pH, a measure of the acidic, neutrality, and alkalinity of the water, MUST ALWAYS BE
WITHIN 6.5 AND 8.0 FOR BOILERS USING ALUMINUM ALLOYS, such as the Modulex boiler
system.
• Oxygen – All precautions should be taken to avoid the formation and localization of oxygen in the
water of a heating system. Water that is low in minerals (soft water) absorbs oxygen much more
readily than mineralized (hard) water. For this reason it is necessary that in heating systems using
floor radiant heating, the plastic pipes used be impermeable to oxygen.
• Scale and Corrosion – The use of an inhibitor is advisable to treat feed and make-up water and to
protect heating systems against scale, corrosion and microbiologic growth. To prevent freezing, an
anti-freezing agent is advisable. Qualified companies can also provide boiler de-scaling.
• Total Solids – preferably less than 500 ppm, but a requirement of less than 1000 ppm.
• Water treatment is also advisable in the following cases:
o Very large heating systems
o High quantities of replenished water due to leakages or maintenance work
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10.07.2010
Application Guide
AERCO International, Inc. • 100 Oritani Dr.
Phone: 800-526-0288
Blauvelt, NY 10913 TAG-0099