10
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 that 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 treatment
firm, independent testing facility or local water authority for
specific recommendations to maintain water quality within the
published limits.
3.7.3 - Ground-loop applications
Temperatures between -4 to 43
°
C and a liquid flow rate of
0.040 to 0.054 l/s per kW of cooling capacity 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 (P/T) plugs to measure flow of
pressure drop.
3.8 - Electrical wiring
WARNING: To avoid possible injury or death due to electrical
shock, open the power supply disconnect switch and secure it
in an open position during installation.
CAUTION: Use only copper conductors for field-installed
electrical wiring. Unit terminals are not designed to accept
other types of conductors.
All field-installed wiring, including the electrical ground,
MUST comply with applicable local, national and regional
codes.
Refer to unit wiring diagrams Figs. 9-12 for a schematic of the
field connections, which must be made by the installing (or
electrical) contractor. Refer to electrical data for fuse sizes.
Consult the unit wiring diagram located on the inside of the
compressor access panel to ensure proper electrical hookup.
The installing (or electrical) contractor must make the field
connections when using field-supplied disconnect.
Operating voltage must be the same voltage and phase as shown
in electrical data shown in Table 3.
Make all final electrical connections with a length of flexible
conduit to minimise vibration and sound transmission to the
building.
Table 2 - Water quality guidelines
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 350 ppm.
Iron oxides
Less than 1 ppm.
Iron bacteria
No level allowable.
Corrosion*
Max. allowable
Coaxial
level
metal
Ammonia,
0.5 ppm
Cu
ammonium hydroxide
ammonium chloride,
0.5 ppm
Cu
ammonium nitrate
ammonium sulphate
0.5 ppm
Cu
chlorine/chlorides
0.5 ppm
CuNi
hydrogen sulphide**
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.)
*
If the concentration of these corrosives exceeds the maximum allowable level, then the potential for serious corrosion problems exists.
**
Sulphides in the water quickly oxidise when exposed to air, requiring that no agitation occur as the sample is taken. Unless tested immediately at the site, the sample
will require stabilisation with a few drops of one molar zinc acetate solution, allowing accurate sulphide determination up to 24 hours after sampling. A low pH and high
alkalinity 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 contains a pH of 7.0.
Note: Hardness in mg/l is equivalent to ppm.
