Comfort-Aire HTS Series Split System,Two Stage, 2-5 Tons - Manual (Page 14)

Water Quality Standards
14
Installation, Operation & Maintenance HTS SERIES SPLIT SYSTEM Heat Controller, LLC
Table 4: Water Quality Standards
Water Quality
Parameter
HX
Material
Closed
Recirculating
Open Loop and Recirculating Well
Scaling Potential - Primary Measurement
pH/Calcium Hardness
All
-
pH < 7.5 and Ca Hardness <100ppm
Method
Index Limits for Probable Scaling Situations - (Operation outside these limits is not recommended)
Ryznar
All
- 6.0 - 7.5
Stability Index If >7.5 minimize steel pipe use.
Langelier All
- -0.5 to +0.5
Saturation Index
If <-0.5 minimize steel pipe use. Based upon 66°C HWG and
Direct well, 29°C Indirect Well HX
Iron Fouling
Iron Fe 2+ (Ferrous)
All
-
<0.2 ppm (Ferrous)
(Bacterial Iron potential) If Fe 2+ (ferrous)>0.2 ppm with pH 6 - 8, O2<5 ppm check for iron bacteria.
Iron Fouling All
- <0.5 ppm of Oxygen
Above this level deposition will occur .
Corrosion Prevention
pH All
6 - 8.5
6 - 8.5
Monitor/treat as
needed
Minimize steel pipe below 7 and no open tanks with pH <8
Hydrogen Sulfide (H
2
S) All
- <0.5 ppm
At H
2
S>0.2 ppm, avoid use of copper and copper nickel piping or HX's.
Rotten egg smell appears at 0.5 ppm level.
Copper alloy (bronze or brass) cast components are OK to <0.5 ppm.
Ammonia ion as hydroxide, chloride,
nitrate and sulfate compounds All -
<0.5 ppm
Maximum
Maximum Allowable at maximum water temperature.
Chloride Levels
10$C 24$C 38 C
Copper
Cupronickel
- <20ppm NR NR
- <150 ppm NR NR
304 SS
-
<400 ppm <250 ppm <150 ppm
316 SS - <1000 ppm <550 ppm < 375 ppm
Titanium - >1000 ppm >550 ppm >375 ppm
Erosion and Clogging
Particulate Size and
Erosion
All
<10 ppm of particles
and a maximum
velocity of 1.8 m/s
Filtered for maximum
841 micron [0.84 mm,
20 mesh] size.
<10 ppm (<1 ppm "sandfree” for reinjection) of particles and a maximum
velocity of 1.8 m/s. Filtered for maximum 841 micron 0.84 mm,
20 mesh] size. Any particulate that is not removed can potentially
clog components.
Notes:
Rev.: 3/22/2012
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Above the given limits, scaling is likely to occur. Scaling indexes should be calculated using the limits below
Scaling indexes should be calculated at 66°C for direct use and HWG applications, and at 32°C for indirect HX use.
A monitoring plan should be implemented.
The Water Quality Table provides water quality requirements for coaxial heat exchangers. When water properties are outside of those requirements, an external
secondary heat exchanger must be used to isolate the heat pump heat exchanger from the unsuitable water. Failure to do so will void the warranty for the coaxial heat
exchanger.