Ground-Loop Applications - Carrier Aquazone 50PTH036 Installation, Start-Up And Service Instructions Manual

Water Supply and Quantity — Check water supply. Water
supply should be plentiful and of good quality. See Table 2 for
water quality guidelines.
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. This damage is not the
responsibility of the manufacturer.
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.
CONDITION
Scaling Potential — Primary Measurement
Above the given limits, scaling is likely to occur. Scaling indexes should be calculated using the limits below.
pH/Calcium
Hardness Method
Index Limits for Probable Scaling Situations (Operation outside these limits is not recommended.)
Scaling indexes should be calculated at 150 F for direct use and HWG applications, and at 90 F for indirect HX use. A monitoring plan should be imple-
mented.
Ryznar Stability Index
Langelier Saturation Index
Iron Fouling
2+
Iron Fe (Ferrous)
(Bacterial Iron Potential)
Iron Fouling
Corrosion Prevention††
pH
Hydrogen Sulfide (H S)
2
Ammonia Ion as Hydroxide,
Chloride, Nitrate and Sulfate
Compounds
Maximum Chloride Levels
Erosion and Clogging
Particulate Size and Erosion
Brackish
LEGEND
HWG — Hot Water Generator
HX — Heat Exchanger
N/A — Design Limits Not Applicable Considering Recirculating
Potable Water
NR — Application Not Recommended
SS — Stainless Steel
*Heat exchanger materials considered are copper, cupronickel, 304 SS
(stainless steel), 316 SS, titanium.
†Closed recirculating system is identified by a closed pressurized piping
system.
**Recirculating open wells should observe the open recirculating design
considerations.
Table 2 — Water Quality Guidelines
CLOSED
HX MATERIAL*
RECIRCULATING†
All N/A
All N/A
All N/A
All N/A
All N/A
6 - 8.5
All
Monitor/treat as needed.
All N/A
All N/A
Copper N/A
Cupronickel N/A
304 SS N/A
316 SS N/A
Titanium N/A
<10 ppm of particles and a
maximum velocity of 6 fps.
All
Filtered for maximum
800 micron size.
All N/A
GROUND-LOOP APPLICATIONS — Temperatures between
20 and 110 F and a cooling capacity of 2.25 to 3 gpm of flow
per ton is recommended. 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 plugs to measure flow of pres-
sure drop.
OPEN LOOP AND RECIRCULATING WELL**
pH < 7.5 and Ca Hardness, <100 ppm
If >7.5 minimize steel pipe use.
If <–0.5 minimize steel pipe use.
Based upon 150 F HWG and direct well, 85 F indirect well HX.
<0.2 ppm (Ferrous)
2+
If Fe (ferrous) >0.2 ppm with pH 6 - 8, O
<0.5 ppm of Oxygen
Above this level deposition will occur.
Minimize steel pipe below 7 and no open tanks with pH <8.
At H S>0.2 ppm, avoid use of copper and cupronickel piping or HXs.
2
Rotten egg smell appears at 0.5 ppm level.
Copper alloy (bronze or brass) cast components are okay to <0.5 ppm.
Maximum allowable at maximum water temperature.
50 F (10 C)
<20 ppm
<150 ppm
<400 ppm
<1000 ppm
>1000 ppm
<10 ppm (<1 ppm "sandfree" for reinjection) of particles and a maximum
velocity of 6 fps. Filtered for maximum 800 micron size. Any particulate that
is not removed can potentially clog components.
Use cupronickel heat exchanger when concentrations of calcium or sodium
chloride are greater than 125 ppm are present. (Seawater is approximately
25,000 ppm.)
††If the concentration of these corrosives exceeds the maximum allow-
able 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 can cause
system 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 registers a pH of 7.0.
To convert ppm to grains per gallon, divide by 17. Hardness in mg/l is
equivalent to ppm. considered to be basic. Neutral water contains a
pH of 7.0. To convert ppm to grains per gallon, divide by 17. Hardness
in mg/l is equivalent to ppm.
9
6.0 - 7.5
–0.5 to +0.5
<5 ppm check for iron bacteria.
2
6 - 8.5
<0.5 ppm
<0.5 ppm
75 F (24 C) 100 F (38 C)
NR NR
NR NR
<250 ppm <150 ppm
<550 ppm <375 ppm
>550 ppm >375 ppm