HWM-407CH-IOM (09/13)
Page 13
•
Drain some water from the system to provide enough volume for the calculated
amount of fluid.
•
Add the correct amount of fluid and any water needed to completely refill the
system, allowing for liquid expansion due to operating temperature.
•
Circulate the inhibited propylene-glycol antifreeze solution for at least 24 hours to
ensure complete mixing. Check the liquid concentration to assure that the correct
mixture is obtained.
C. Water Quality
Water quality in hydronic systems is important to the life and efficiency of the system.
Water of poor quality can cause a decrease in heat transfer ability and cause leaks.
Ensuring proper quality water is a key step in the installation of the hydronic water module
(HWM) and circulating water system.
Water quality parameters and the recommended ranges are listed in Figure 8a. The
antifreeze manufacturer’s water quality requirements take precedence over the ranges
listed in Figure 8a.
Parameter
Optimal Conditions
Comments
Glycol Freeze Protection
20% to 50%
Below 20% can promote the growth of bacteria. Concentrations
higher than 50% will dramatically reduce the heat transfer
ability. Glycol seepage can occur at o-rings and seals.
Corrosion inhibitor
Molybdate inhibitor
or
Nitrite inhibitor
100-150ppm
800-1200ppm
Without the addition of Nitrite or Molybdate inhibitors, corrosion
of the metallic components will begin and eventually lead to
leaks.
pH
9-10.5 pH units
A pH below 9.0 will allow the corrosion of steel and above 10.5
will allow the corrosion of brass and copper.
Conductivity
700-3200µS/cm
Conductivity above 3500µS/cm will cause the water to become
physically abrasive and damage the o-rings. Addition of
chemicals to the water will raise the conductivity.
Hardness
100-300ppm
Artificially soft water can be aggressive to the system. The use
of unsoftened water is recommended. Do not use distilled or
purified water.
Bacteria/Mold
No Bacteria or
Mold
The growth of bacteria will cause erosion of seals and the
deposit of a bacterial slime will clog the system. Bacteria can
attack the o-rings and cause premature failure. Glycol above
20% will kill any bacteria.
Figure 8a. Hydronic System Water Quality Parameters
