Water Treatment; Important Installation Warnings; Oxygen Levels In The System Water Warning; Antifreeze Compatibility Warning - Watts AERCO EXT Installation, Operation & Maintenance Manual

Modulex EXT Commercial Series
CHAPTER 4: Installation Instructions

4.15 Water Treatment

The chemical/physical composition of the heating system's water is fundamental to the boiler's correct
operation and safety. Among the problems caused by poor quality of feed water, the most frequent
and most serious is the buildup of deposits on boiler thermal exchange surfaces.
A less frequent (but still serious) problem is the buildup of deposits on the water circulating piping
surfaces caused by improperly treated water. Because of the low thermal conductivity of mineralization
deposits, thermal exchange efficiency may be seriously reduced and cause dangerous overheating.
NOTE: Never use water that has been treated by reverse osmosis, deionization, mineralization, or
distillation to fill the heating system.
AERCO suggests treating and conditioning feed water for the heating circuit:
•
When the hardness of the water is higher than 9 grains per gallons (gpg).
•
For cold/hot water installations with large water content.
•
Renewal of the water system due to uncontrolled leakages.
•
Subsequent refilling of the system due to maintenance work on the installation.
•
Presence of different metals in the water circuit.
Properly treated system and feed water will eliminate or substantially reduce lime scale deposit,
corrosion sludge, deposits, and microbiological growths (molds, bacteria etc.).
An appropriate treatment of the supply water will prevent the above stated problems and will maintain
the correct operation and efficiency of the boiler over time.
In order to properly treat water for use in a hydronic boiler heating system, the following
physical/chemical characteristics must be addressed.
Sediment: If sediment is present in the system, use a sediment filter or other device.
Water pH: If water has a pH above 8 or below 5 then the water must be treated to provide a medium
pH of between 5 and 8.
The system water to be judged for water characteristics should be taken from the return pipe of the
primary circuit downstream of the circulating pump.

4.16 Important Installation Warnings

4.16.1 Oxygen Levels in the System Water Warning

All necessary precautions must be taken for preventing the formation and localization of oxygen in the
system's water. For this reason, ensure that the plastic piping used in under-floor heating systems is
impermeable to oxygen.

4.16.2 Antifreeze Compatibility Warning

If any anti-freeze solutions are used ensure that they are compatible with aluminum and any other
boiler components and materials.

4.16.3 Lime Scale and Corrosive Water Damage Warning

Any damage caused to the boiler due to the formation of lime scale or by corrosive water will not be
covered by the warranty. Appropriate steps must be taken to ensure the indirect tank water heater
does not become plugged by scale caused by hard water or sediment. If the indirect tank water heater
becomes plugged by either scaling from hard water or sediment it is not the responsibility of AERCO
International.
OMM-0160_A • DRAFT Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
Page 35 of 117