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7
Step 7 — Electrical Wiring
All field installed wiring, including the electrical ground,
MUST comply with the National Electrical Code (NEC) as
well as applicable local codes. In addition, all field wiring must
conform to the Class II temperature limitations described in the
NEC.
Refer to unit wiring diagram Fig. 4 for a schematic of the
field connections which must be made by the installing (or
electrical) contractor.
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 flexi-
ble conduit to minimize vibration and sound transmission to
the building.
SUPPLY VOLTAGE — Operating voltage to unit must be
within voltage range indicated on unit nameplate.
On 3-phase units, voltages under load between phases must
be balanced within 2%. Use the following formula to deter-
mine the percentage voltage imbalance:
% Voltage Imbalance
Example: Supply voltage is 460-3-60.
AB = 452 volts
BC = 464 volts
AC = 455 volts
Determine maximum deviation from average voltage:
(AB) 457 – 452 = 5 v
(BC) 464 – 457 = 7 v
(AC) 457 – 455 = 2 v
Maximum deviation is 7 v.
Determine percent voltage imbalance.
= 1.53%
This amount of phase imbalance is satisfactory as it is
below the maximum allowable 2%.
Operation on improper line voltage or excessive phase
imbalance constitutes abuse and may cause damage to electri-
cal components.
NOTE: If more than 2% voltage imbalance is present, contact
local electric utility.
208-VOLT OPERATION — All 208-230 volt units are factory
wired for 208 volts. The transformers may be switched to
230-volt operation (as illustrated on the wiring diagram) by
switching the red (208 volt) wire with the orange (230 volt)
wire at the L1 terminal.
BLOWER SELECTION — All water source heat pumps are
factory set with the appropriate motor and sheave combination
to achieve the desired airflow performance. Performance is
selected by matching the desired performance with the appro-
priate region in Tables 4-12. Per the table notes, regions desig-
nated by A, B, C and D represent motor drive options.
NOTE: Factory-installed sheaves are field adjustable. Refer to
Tables 4-12 for adjustment points.
Table 2 — 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.
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.
Use only copper conductors for field-installed electrical
wiring. Unit terminals are not designed to accept other
types of conductors.
= 100 x
max voltage deviation from average voltage
average voltage
Average Voltage =
452 + 464 + 455
3
=
1371
3
= 457
% Voltage Imbalance = 100 x
7
457
CONDITION ACCEPTABLE LEVEL
pH
7 to 9 range for copper. Cupro-nickel 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 Cupro-nickel heat exchanger when concentrations of calcium or sodium chloride are greater
than 125 ppm are present. (Seawater is approximately 25,000 ppm.)