54
ARTC-SVX007A-EN
Table 16. Water quality guidelines (continued)
Element/Compound/Property
Value/Unit
Free Chlorine
< 1.0 ppm
Ammonia (NH3) < 0.5 ppm
Sulphate (SO42–) < 100 ppm
Hydrogen Carbonate (HCO3– 60 – 200 ppm
(HCO3–) / (SO42–)
> 1.5
(Ca + Mg) / (HCO3–)
> 0.5
Chloride (Cl-) < 200 ppm
Notes:
1. Total Hardness/corrosion: Water with high hardness can cause corrosion problems due to its high ion content (Ca+2, Mg+2, Fe+2) which
also means a high electrical conductivity and a high total dissolved solid (TDS). For this reason, too high hardness values should be
avoided, not only due to higher risk of scaling, but also for corrosion risk. On the other hand, soft water, but not necessarily cation
exchange softened water, may in contrast have a low buffering capacity and so be more corrosive. If the hardness values are outside the
recommended range, other parameters such as oxygen content, conductivity, and pH values should be considered to evaluate the
corrosion risk.
2. Fe3+ and Mn4+ are strong oxidants and may increase the risk for localized corrosion on stainless steels in combination with brazing
material copper.
Monitor Water Quality
Maintaining water/glycol mixture quality and cleanliness is
critical to chiller health and maintainability. Water/glycol
mixture samples should be taken and tested by a
professional lab. The results will enable the accurate
adjustment of quality thereby increasing the operational life
of the chiller.
Note: Trane will not validate the chiller warranty if the
proper water/glycol mixture composition and quality
is not maintained.
Protect the chiller from freezing, particularly if the chiller
has a set point that is lower than the freezing point of the
water/glycol mixture in the chiller. The chiller is designed to
operate with a maximum propylene glycol concentration of
50%. See Table 17, p. 54, for the effects on the chiller
when operating with other glycol concentrations.
Table 17, p. 54 shows the capacity reduction and the
pressure drop that occurs when higher concentrations of
glycol are used.
Maintain Glycol Level
When the chiller has a water set point that is below the
freezing point of the water/glycol in use, take precautions
against freezing.
The glycol concentration should be based on the lowest
fluid design temperature. See Table 18, p. 55 provides
guidelines for adding propylene glycol.
Table 17. Glycol performance impact factors
Range Factor Glycol Concentration Percentages and Performance Impact
Propylene Glycol
Concentration
30% 40% 50%
Lowest Ambient Temperature 10 °F (-12 °C) -4 °F (-10 °C) -20 °F (-29 °C)
Recommended Minimum
Leaving Fluid Temperature
25 °F (-4 °C) 10 °F (-12 °C) -10 °F (-23 °C)
Leaving Temperature
Capacity
Reduction Factor
Pressure Drop
Factor
Capacity
Reduction Factor
Pressure Drop
Factor
Capacity
Reduction
Factor
Pressure Drop
Factor
70 °F (21 °C)
0.96 1.27 0.93 1.43 0.91 1.63
60 °F (15.6 °C)
0.95 1.31 0.92 1.47 0.90 1.68
55 °F (13 °C)
0.95 1.31 0.92 1.50 0.89 1.73
50 °F (10 °C)
0.94 1.33 0.91 1.51 0.88 1.75
Operating Procedures
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