Water quality
Warning
Water quality has a significant impact on the lifetime and performance of a boiler's heat exchanger.
Improperly prepared water in a heating circuit may cause damage to the heat exchanger through
fouling or corrosion. Repeated or uncontrolled water fills will increase the potential for damage.
High levels of dissolved solids or minerals may precipitate out of the fluid onto the hottest part of the
heat exchanger, impairing heat transfer and resulting in overheating and premature failure. The
amount of solids that may form on the heat exchanger will depend on the degree of hardness and
the total water volume in the system. A high water volume system with a low hardness count may
cause as much damage as a system with less volume and higher hardness, so it is recommended
to treat water so as to remove all dissolved solids. Other water chemistry allowable limits are as
follows:
Acidity pH is to be between 6.6 and 8.5
Chloride is to be less than 125 mg/l
Iron is to be less than 0.3 mg/l
Cu less than 0.1 mg/l
Conductivity is to be less than 400μS/cm (at 77°F [25°C])
Hardness is to be 7 Grains or less
Important
: Ensure that these limits are acceptable for the other water-side components in the
system.
