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17
Water Supply and Quantity
— Check water supply. Water
supply should be plentiful and of good quality. See Table 4 for
water quality guidelines.
In all applications, the quality of the water circulated
through the heat exchanger must fall within the ranges listed in
the Water Quality Guidelines table. Consult a local water treat-
ment firm, independent testing facility, or local water authority
for specific recommendations to maintain water quality within
the published limits.
GROUND-LOOP APPLICATIONS (Not Applicable to
50RHC,RVC Units) — Temperatures between 25 to 110 F
and a cooling capacity of 2.25 to 3 gpm of flow per ton is rec-
ommended. In addition to complying with any applicable
codes, consider the following for system piping:
• Limit piping materials to only polyethylene fusion in the
buried sections of the loop.
• Do not use galvanized or steel fittings at any time due to
corrosion.
• Avoid all plastic to metal threaded fittings due to the
potential to leak. Use a flange fitted substitute.
• Do not overtighten connections.
• Route piping to avoid service access areas to unit.
• Use pressure-temperature (P/T) plugs to measure flow of
pressure drop.
Table 4 — Water Quality Guidelines
*If the concentration of these corrosives exceeds the maximum allowable level, then the potential for serious corrosion
problems exists.
†Sulfides in the water quickly oxidize when exposed to air, requiring that no agitation occur as the sample is taken.
Unless tested immediately at the site, the sample will require stabilization with a few drops of one Molar zinc acetate
solution, allowing accurate sulfide determination up to 24 hours after sampling. A low pH and high alkalinity cause sys-
tem problems, even when both values are within ranges shown. The term pH refers to the acidity, basicity, or neutrality
of the water supply. Below 7.0, the water is considered to be acidic. Above 7.0, water is considered to be basic. Neutral
water contains a pH of 7.0.
NOTE: To convert ppm to grains per gallon, divide by 17. Hardness in mg/l is equivalent to ppm.
IMPORTANT: Failure to comply with the above required
water quality and quantity limitations and the closed-
system application design requirements may cause damage
to the tube-in-tube heat exchanger that is not the responsi-
bility of the manufacturer.
CONDITION ACCEPTABLE LEVEL
pH 7 to 9 range for copper. Cupronickel may be used in the 5 to 9 range.
Total Hardness Calcium and magnesium carbonate should not exceed 20 grains per gallon (350 ppm).
Iron Oxides Less than 1 ppm.
Iron Bacteria No level allowable.
Corrosion* Max Allowable Level Coaxial Metal
Ammonia, Ammonium Hydroxide 0.5 ppm Cu
Ammonium Chloride, Ammonium Nitrate 0.5 ppm Cu
Ammonium Sulfate 0.5 ppm Cu
Chlorine/Chlorides 0.5 ppm CuNi
Hydrogen Sulfide† None Allowable —
Brackish Use Cupronickel heat exchanger when concentrations of calcium or sodium chloride are greater
than 125 ppm are present. (Seawater is approximately 25,000 ppm.)
Pressure-
Temperature
Plugs
Boiler
Drains
Strainer – Field-Installed Accessory
(16 to 20 mesh recommended for
filter sediment)
Shut-Off
Valve
Water
Control
Valve
Flow
Regulator
Pressure
Tank
Water Out
Water In
From Pump
Fig. 18 — Typical Ground-Water Piping Installation