Enertech ACD024B, Installation & Operation Manual, Page: 26 / 66

26
Enertech Global IOM, BS/BT Models
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. Please see Table
8 for guidelines.
Potential
Problem
Chemical(s) or Condition
Range for Copper
Heat Exchangers
Range for Cupro-Nickel
Heat Exchanger
Range Stainless Steel
Heat Exchanger
Scaling
Calcium & Magnesium
Carbonate
Less than 350 ppm Less than 350 ppm Less than 350 ppm
Corrosion
pH Range 7 - 9 5 - 9 7 - 9
Total Dissolved Solids Less than 1000 ppm Less than 1500 ppm Less than 1500 ppm
Ammonia, Ammonium
Hydroxide
Less than 0.5 ppm Less than 0.5 ppm Less than 0.5
Ammonium Chloride,
Ammonium Nitrate
Less than 0.5 ppm Less than 0.5 ppm Less than 0.5
Calcium/Sodium Chloride
See Note 4
Less than 125 ppm Less than 125 ppm Less than 125 ppm
Chlorine Less than 0.5 ppm Less than 0.5 ppm Less than 0.5
Hydrogen Sulfide None Allowed None Allowed None Allowed
Biological
Growth
Iron Bacteria None Allowed None Allowed None Allowed
Iron Oxide Less than 1 ppm Less than 1 ppm Less than 1 ppm
Erosion
Suspended Solids - Note 5 Less than 10 ppm Less than 10 ppm Less than 10 ppm
Water Velocity Less than 8 ft/s Less than 12 ft/s Less than 12ft/s
N
OTES
:
1. H
ARDNESS IN PPM IS EQUIVALENT TO HARDNESS IN MG
/
L
2. G
RAINS
/
GALLON
=
PPM DIVIDED BY
17.1
3. C
OPPER AND
C
UPRO
-
NICKEL HEAT EXCHANGERS ARE NOT RECOMMENDED FOR POOL APPLICATIONS FOR WATER
OUTSIDE THE RANGE OF THE TABLE
. S
ECONDARY HEAT EXCHANGERS ARE REQUIRED FOR APPLICATIONS NOT
MEETING THE REQUIREMENTS SHOWN ABOVE
.
4. S
ALTWATER APPLICATIONS
(
APPROX
... 25,000
PPM
)
REQUIRE SECONDARY HEAT EXCHANGERS DUE TO COPPER
PIPING BETWEEN THE HEAT EXCHANGER AND THE UNIT FITTINGS
. 5. F
ILTER FOR MAXIMUM OF
600
MICRON SIZE
.
5. Filter for maximum of 600 micron size.
Section 6: Unit Piping Installation