Enertech WS036, Installation & Operation Manual, Page: 11 / 40

Enertech Global, LLC 11
WS Rev. E Models
Installation and Operations Manual
Water Quality
The quality of the water used in geothermal systems is very
important. In closed loop systems the dilution water (water
mixed with antifreeze) must be of high quality to ensure
adequate corrosion protection. Water of poor quality
contains ions that make the fluid “hard” and corrosive.
Calcium and magnesium hardness ions build up as scale on
the walls of the system and reduce heat transfer. These ions
may also react with the corrosion inhibitors in glycol based
heat transfer fluids, causing them to precipitate out of
solution and rendering the inhibitors ineffective in protecting
against corrosion. In addition, high concentrations of
corrosive ions, such as chloride and sulfate, will eat through
any protective layer that the corrosion inhibitors form on the
walls of the system.
Ideally, de-ionized water should be used for dilution with
antifreeze solutions since de-ionizing removes both corrosive
and hardness ions. Distilled water and zeolite softened water
are also acceptable. Softened water, although free of
hardness ions, may actually have increased concentrations of
corrosive ions and, therefore, its quality must be monitored.
It is recommended that dilution water contain less than 100
PPM calcium carbonate or less than 25 PPM calcium plus
magnesium ions; and less than 25 PPM chloride or sulfate
ions.
In an open loop system the water quality is of no less
importance. Due to the inherent variation of the supply
water, it should be tested prior to making the decision to use
an open loop system. Scaling of the heat exchanger and
corrosion of the internal parts are two of the potential
problems. The Department of Natural Resources or your local
municipality can direct you to the proper testing agency. See
Water Quality Table for guidelines.
Water Quality Table
Potential Problem Chemical(s) or Condition Range for Copper Heat
Exchangers
Cupro-Nickel Heat
Exchanger Ranges
Stainless Steel Heat
Exchanger Ranges
Scaling
Calcium & Magnesium
Carbonate
Less than 350 ppm Less than 350 ppm Less than 0.1 ppm
Corrosion
pH Range 7 - 9 5 - 9 7 - 9
Total Dissolved Solids Less than 1000 ppm Less than 1500 ppm No rigid setpoint
Ammonia, Ammonium
Hydroxide
Less than 0.5 ppm Less than 0.5 ppm No Limit
Ammonium Chloride,
Ammonium Nitrate
Less than 0.5 ppm Less than 0.5 ppm Less than 2-20 ppm
Calcium/Sodium
Chloride
(Note 5)
Less than 125 ppm Less than 125 ppm None Allowed
Chlorine
(Note 1)
Less than 0.5 ppm Less than 0.5 ppm
Less than 1 ppm
(Note 1)
Hydrogen Sulfide None Allowed None Allowed Less than 0.05 ppm
Biological Growth
Iron Bacteria None Allowed None Allowed None Allowed
Iron Oxide Less than 1 ppm Less than 1 ppm Less than 0.2 ppm
Erosion
Suspended Solids
(Note 6)
Less than 10 ppm Less than 10 ppm
16-20 mesh strainer
recommended
Water Velocity Less than 8 ft/s Less than 12 ft/s
Less than 5.5 m/s in the
port
Notes:
1. Chlorine can not be used with 304 Stainless Steel.
2. Hardness in ppm is equivalent to hardness in mg/l.
3. Grains/gallon = ppm divided by 17.1.
4. Unit internal heat exchangers are not recommended for pool applications or water outside the range of the table
5. Secondary heat exchangers are required for pool or other applications not meeting the requirements shown above.
6. Saltwater applications (approx. 25,000 ppm) require secondary heat exchangers due to copper piping between the heat
exchanger
7. Filter for maximum of 600 micron size.
Section 5: Unit Piping Installation